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Sample records for laser nd-yag em

  1. Laser-diode pumped Nd:YAG lasers; Laser diode reiki Nd:YAG lasear

    Energy Technology Data Exchange (ETDEWEB)

    Yuasa, H.; Akiyama, Y.; Nakayama, M. [Toshiba Corp., Tokyo (Japan)

    2000-04-01

    Laser-diode pumped Nd:YAG lasers are expected to be applied to laser processing fields such as welding, cutting, drilling, and marking due to their potential for high efficiency and compactness. We are designing and developing laser-diode pumped Nd:YAG lasers using numerical analysis simulation techniques such as ray tracing and thermal analysis. We have succeeded in achieving a laser power of more than 3 kW with 20% efficiency, which is the best ever obtained. In addition, we have developed a laser-diode pumped green laser by second harmonic generation, for precision machining on silicon wafers. (author)

  2. Nd:YAG laser for holography

    International Nuclear Information System (INIS)

    Bykovsky, Yu.A.; Evtihiev, N.N.; Larkin, A.I.

    1982-01-01

    Different possibilities to use photonics, holography and optical processing for nuclear physics has been investigated in our works. The paper presents the results of the study of time and spatial coherence of Nd:YAG laser and application in holography. (orig./HSI)

  3. Nd: YAG laser in art works restoration

    International Nuclear Information System (INIS)

    Flores, T.; Ponce, L.; Arronte, M.; Moreno, B.; Fernandez, M.; Garcia, C.

    1998-01-01

    Laser cleaning in works of art has a number of advantages over traditional techniques of restoration. In this article, the technique used and the physical mechanisms that explain the process of ablation of pollutants are described. The results obtained in the cleaning of statues of marble and alabaster are exposed as well as oil-painting restoration. In this last specific case, the Nd: YAG laser is used with successful results. (Author) 6 refs

  4. Pulsed Nd-YAG laser in endodontics

    Science.gov (United States)

    Ragot-Roy, Brigitte; Severin, Claude; Maquin, Michel

    1994-12-01

    The purpose of this study was to establish an operative method in endodontics. The effect of a pulsed Nd:YAG laser on root canal dentin has been examined with a scanning electron microscope. Our first experimentation was to observe the impacts carried out perpendicularly to root canal surface with a 200 micrometers fiber optic in the presence of dye. Secondarily, the optical fiber was used as an endodontic instrument with black dye. The irradiation was performed after root canal preparation (15/100 file or 40/100 file) or directly into the canal. Adverse effects are observed. The results show that laser irradiation on root canal dentin surfaces induces a nonhomogeneous modified dentin layer, melted and resolidified dentin closed partially dentinal tubules. The removal of debris is not efficient enough. The laser treatment seems to be indicated only for endodontic and periapical spaces sterilization after conventional root canal preparation.

  5. In vitro study of hydroxy apatite and enamel powder fused in human enamel by Nd:YAG laser; Estudo in vitro da fusao de hidroxiapatita e esmalte em superficies de esmalte humano pelo laser de Nd:YAg

    Energy Technology Data Exchange (ETDEWEB)

    Ferrreira, Marcus Vinicius Lucas

    2000-07-01

    The aim of this study was to evaluate the effects of pulsed Nd:YAG (1064 nm) laser irradiation on hydroxyapatite and enamel powder fusion. This laser beam is not well absorbed by this two compounds for this reason they were mixed with vegetal coal to increase the absorption of the laser beam. Fifteen enamel flat surfaces and six occlusal enamel surfaces were prepared with three different substances: hydroxyapatite mixed with vegetal coal (3:1 in weigh); enamel powder mixed with vegetal coal (3:1 in weigh); vegetal coal. The occlusal surfaces were utilized to determine if the compounds could seal pits and fissures. Flat surfaces were utilized to determine fusion of hydroxyapatite and enamel powder. All samples were irradiated with Nd:YAG laser with the parameters: 80 mJ, 15 Hz, 1,2 W, 100 {mu}s pulse-width, 131,1 J/cm{sup 2}. Laser beam was delivered to the samples with a 300 {mu}m diameter fiber optic. Morphology of the irradiated surfaces were examined by scanning electron microscopy (SEM). The compounds with hydroxyapatite and enamel powder were fused to enamel surfaces. Only partial pits and fissures sealing could be observed. (author)

  6. The bactericidal effect of a Genius (R) Nd : YAG laser

    NARCIS (Netherlands)

    Kranendonk, A.A.; Reijden, W.A. van der; Winkelhoff, A.J. van; Weijden, G.A. van der

    PURPOSE: To evaluate the 'in vitro' bactericidal effect of the Nd:YAG laser (Genius, MØlsgaard Dental, Copenhagen, Denmark) on six periodontal pathogens. METHODS: Suspensions of six different periodontal pathogens (Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella

  7. [Nd-YAG laser photocoagulation of scrotal sebaceous cysts].

    Science.gov (United States)

    Franco de Castro, A; Truhán, D; Carretero González, P; Alcover García, J

    2002-02-01

    Scrotum's sebaceous cyst is an usual pathology, not life threatening, but susceptible of infection, producing abscess with their associated cosmetic and psychological disturbance. The classical management is the complete excision, under local anaesthesia, to prevent its recidive. Until today, the use of de Nd-YAG laser for the management of the scrotum's sebaceous cysts as not been reported. We report a case of a young man with several scrotum's sebaceous cysts, treated successfully with the use of a Nd-YAG laser.

  8. Hybrid Pulsed Nd:YAG Laser

    Science.gov (United States)

    Miller, Sawyer; Trujillo, Skyler; Fort Lewis College Laser Group Team

    This work concerns the novel design of an inexpensive pulsed Nd:YAG laser, consisting of a hybrid Kerr Mode Lock (KLM) and Q-switch pulse. The two pulse generation systems work independently, non simultaneously of each other, thus generating the ability for the user to easily switch between ultra-short pulse widths or large energy density pulses. Traditionally, SF57 glass has been used as the Kerr medium. In this work, novel Kerr mode-locking mediums are being investigated including: tellurite compound glass (TeO2), carbon disulfide (CS2), and chalcogenide glass. These materials have a nonlinear index of refraction orders of magnitude,(n2), larger than SF57 glass. The Q-switched pulse will utilize a Pockels cell. As the two pulse generation systems cannot be operated simultaneously, the Pockels cell and Kerr medium are attached to kinematic mounts, allowing for quick interchange between systems. Pulse widths and repetition rates will vary between the two systems. A goal of 100 picosecond pulse widths are desired for the mode-locked system. A goal of 10 nanosecond pulse widths are desired for the Q-switch system, with a desired repetition rate of 50 Hz. As designed, the laser will be useful in imaging applications.

  9. Development of an automation system for iodine-125 brachytherapy seed production by (Nd:YAG) laser welding; Automacao do processo de soldagem a laser (Nd:YAG) para confeccao das sementes de iodo-125 utilizadas em braquiterapia

    Energy Technology Data Exchange (ETDEWEB)

    Somessari, Samir Luiz

    2010-07-01

    The aim of this work is to develop an automation system for iodine-125 radioactive seed production by (Nd:YAG) laser welding, which has been used successfully in Low Dose Rate (LDR) brachytherapy treatment. This small seed consists of a welded titanium capsule, with 0.8mm in diameter and 4.5mm in length, containing iodine-125 adsorbed onto a silver rod. The iodine-125 seeds are implanted into the human prostate to irradiate the tumor for cancer treatment. Nowadays, the Radiation Technology Center, at IPEN-CNEN/SP imports and distributes 36,000 iodine-125 seeds per year, for the clinics and hospitals in the country. However, the Brazilian market potential is now over 8,000 iodine-125 seeds per month. The local production of these iodine-125 radioactive sources becomes a priority for the Institute, in order to reduce the price and the problems of prostate cancer management. It will permit to spread their use to a largest number of patients in Brazil. On the other hand, the industrial automation plays an important role for iodine-125 seeds in order to increase the productivity, with high quality and assurance, avoiding human factors, implementing and operating with Good Manufacturing Practices (GMP). The technology consists of appliance electronic and electro-mechanical parts and components to control machines and processes. The automation system technology for iodine-125 seed production developed in this work was mainly assembled employing Programmable Logic Controller (PLC), stepper motors, drivers, (Nd:YAG) laser welding machine, photoelectric sensors and supervisory. (author)

  10. Highly efficient solar-pumped Nd:YAG laser.

    Science.gov (United States)

    Liang, Dawei; Almeida, Joana

    2011-12-19

    The recent progress in solar-pumped laser with Fresnel lens and Cr:Nd:YAG ceramic medium has revitalized solar laser researches, revealing a promising future for renewable reduction of magnesium from magnesium oxide. Here we show a big advance in solar laser collection efficiency by utilizing an economical Fresnel lens and a most widely used Nd:YAG single-crystal rod. The incoming solar radiation from the sun is focused by a 0.9 m diameter Fresnel lens. A dielectric totally internally reflecting secondary concentrator is employed to couple the concentrated solar radiation from the focal zone to a 4 mm diameter Nd:YAG rod within a conical pumping cavity. 12.3 W cw laser power is produced, corresponding to 19.3 W/m(2) collection efficiency, which is 2.9 times larger than the previous results with Nd:YAG single-crystal medium. Record-high slope efficiency of 3.9% is also registered. Laser beam quality is considerably improved by pumping a 3 mm diameter Nd:YAG rod.

  11. Nd:YAG Laser Firmware Design under RTOS Operation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, B. G.; Kim, W. Y.; Park, G. R.; Moon, D. S.; Hong, J. H.; Kim, H. J.; Cho, J. S. [Pusan National University (Korea)

    2000-07-01

    A pulsed Nd:YAG laser is used widely for materials processing and medical instrument. It's very important to control the laser energy density in those fields using a pulsed Nd:YAG laser. A pulse repetition rate and a pulse width are regarded as the most dominant factors to control the energy density of laser beam. In this paper, the alternating charge and discharge system was designed to adjust a pulse repetition rate. This system is controlled by microprocessor and allows to replace an expensive condenser for high frequency to cheap one of low frequency. In addition, The microcontroller monitors the flow of cooling water, short circuit, and miss firing and so on. We designed Nd:YAG laser firmware with smart microcontroller, and want to explain general matters about the firmware from now. (author). 8 refs., 6 figs.

  12. Análises morfométrica e morfológica das alterações cutâneas após uso do laser Nd-YAG em tecidos palpebrais humanos Cutaneous changes morphometrical and histological analysis after the use of laser Nd-YAG in human eyelid tissue

    Directory of Open Access Journals (Sweden)

    Lúcia de Noronha

    2004-06-01

    Full Text Available O uso do laser neodymium-yttrium-aluminium-garnet (Nd-YAG como instrumento auxiliar para o rejuvenescimento propiciou um refinamento da técnica tradicional. Tal procedimento mostra resultados satisfatórios com relação ao aprimoramento técnico e à recuperação pós-operatória. OBJETIVO: Evidenciar as alterações histológicas e morfométricas encontradas na pálpebra de humanos após aplicação do laser Nd-YAG e comparar com a pele normal. MATERIAL E MÉTODO: Nove pacientes do sexo feminino foram submetidas à aplicação do laser Nd-YAG em região palpebral direita. A pálpebra esquerda correspondeu à área controle, livre de qualquer tipo de procedimento. Foram realizadas várias aplicações do laser Nd-YAG, sendo que, no último dia, foi realizada biópsia palpebral bilateralmente. Os critérios morfométricos avaliados foram: medida da espessura da epiderme, da área subepidérmica livre de lesão, da zona de degeneração do colágeno e da espessura total da derme. RESULTADOS: Nas áreas submetidas à aplicação do laser Nd-YAG, a espessura média da epiderme foi de 33,53 micrômetros (µm e a da pele normal foi de 29,61µm (p = 0,1099. A média da medida da área subepidérmica livre de lesão, no lado direito, foi de 40,93µm, e de 36,27µm (p = 0,1373 no esquerdo. A espessura da região de degeneração do colágeno na pálpebra que recebeu tratamento com laser teve média de 293,54µm, enquanto que na pálpebra normal ela foi de 292,22µm (p = 0,4835. No lado onde se aplicou o laser Nd-YAG, a espessura total da derme teve uma média de 681,48µm e, no lado livre de procedimento, 664,14µm (p = 0,3492. DISCUSSÃO E CONCLUSÕES: Apesar da diferença clínica observada após tratamento de lesões de envelhecimento em pálpebra de humanos com o uso do laser Nd-YAG, nota-se que não houve diferença histológica ou morfométrica após tal procedimento.The use of laser Neodymium-Yttrium-Aluminium-Garnet (Nd-YAG as an auxiliary

  13. Nd-YAG laser welding of bare and galvanised steels

    International Nuclear Information System (INIS)

    Kennedy, S.C.; Norris, I.M.

    1989-01-01

    Until recently, one of the problems that has held back the introduction of lasers into car body fabrication has been the difficulty of integrating the lasers with robots. Nd-YAG laser beams can be transmitted through fibre optics which, as well as being considerably easier to manipulate than a mirror system, can be mounted on more lightweight accurate robots. Although previously only available at low powers, recent developments in Nd-YAG laser technology mean that lasers of up to 1kW average power will soon be available, coupled to a fibre optic beam delivery system. The increasing usage of zinc coated steels in vehicle bodies has led to welding problems using conventional resistance welding as well as CO 2 laser welding. The use of Nd-YAG lasers may be able to overcome these problems. This paper outlines work carried out at The Welding Institute on a prototype Lumonics 800W pulsed Nd-YAG laser to investigate its welding characteristics on bare and zinc coated car body steels

  14. Pulsed Nd:YAG laser beam drilling: A review

    Science.gov (United States)

    Gautam, Girish Dutt; Pandey, Arun Kumar

    2018-03-01

    Laser beam drilling (LBD) is one of non contact type unconventional machining process that are employed in machining of stiff and high-strength materials, high strength temperature resistance materials such as; metal alloys, ceramics, composites and superalloys. Most of these materials are difficult-to-machine by using conventional machining methods. Also, the complex and precise holes may not be obtained by using the conventional machining processes which may be obtained by using unconventional machining processes. The laser beam drilling in one of the most important unconventional machining process that may be used for the machining of these materials with satisfactorily. In this paper, the attention is focused on the experimental and theoretical investigations on the pulsed Nd:YAG laser drilling of different categories of materials such as ferrous materials, non-ferrous materials, superalloys, composites and Ceramics. Moreover, the review has been emphasized by the use of pulsed Nd:YAG laser drilling of different materials in order to enhance productivity of this process without adverse effects on the drilled holes quality characteristics. Finally, the review is concluded with the possible scope in the area of pulsed Nd:YAG laser drilling. This review work may be very useful to the subsequent researchers in order to give an insight in the area of pulsed Nd:YAG laser drilling of different materials and research gaps available in this area.

  15. Tapered diode laser pumped 946 nm Nd:YAG laser

    DEFF Research Database (Denmark)

    Cheng, Haynes Pak Hay; Jensen, Ole Bjarlin; Petersen, Paul Michael

    2009-01-01

    We successfully implemented a 946 nm Nd:YAG laser based on a 808 nm tapered diode pump laser. The tapered diode is developed at the Ferdinand-Braun-Institute fur Hochstfrequenztechnik in Germany. Figure 2 shows the experimental setup and results of each pump source coupled into a 1.5 mm crystal...... laser, we show that tapered diode laser pumping potentially increase the power of 946 nm lasers by a factor of two and reduce the threshold by a factor of three....

  16. Cutting of nonmetallic materials using Nd:YAG laser beam

    Institute of Scientific and Technical Information of China (English)

    Bashir Ahmed Tahir; Rashid Ahmed; M. G. B. Ashiq; Afaq Ahmed; M. A. Saeed

    2012-01-01

    This study deals with Nd:YAG laser cutting nonmetallic materials,which is one of the most important and popular industrial applications of laser.The main theme is to evaluate the effects of Nd:YAG laser beam power besides work piece scanning speed.For approximate cutting depth,a theoretical study is conducted in terms of material property and cutting speed.Results show a nonlinear relation between the cutting depth and input energy.There is no significant effect of speed on cutting depth with the speed being larger than 30 mm/s.An extra energy is utilized in the deep cutting.It is inferred that as the laser power increases,cutting depth increases.The experimental outcomes are in good agreement with theoretical results.This analysis will provide a guideline for laser-based industry to select a suitable laser for cutting,scribing,trimming,engraving,and marking nonmetallic materials.

  17. Cutting of nonmetallic materials using Nd:YAG laser beam

    International Nuclear Information System (INIS)

    Tahir, Bashir Ahmed; Ashiq, M.G. B.; Saeed, M.A.; Ahmed, Rashid; Ahmed, Afaq

    2012-01-01

    This study deals with Nd:YAG laser cutting nonmetallic materials, which is one of the most important and popular industrial applications of laser. The main theme is to evaluate the effects of Nd:YAG laser beam power besides work piece scanning speed. For approximate cutting depth, a theoretical study is conducted in terms of material property and cutting speed. Results show a nonlinear relation between the cutting depth and input energy. There is no significant effect of speed on cutting depth with the speed being larger than 30 mm/s. An extra energy is utilized in the deep cutting. It is inferred that as the laser power increases, cutting depth increases. The experimental outcomes are in good agreement with theoretical results. This analysis will provide a guideline for laser-based industry to select a suitable laser for cutting, scribing, trimming, engraving, and marking nonmetallic materials. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  18. Análise micromorfológica de esmalte e dentina expostos ao laser de Nd: YAG em regime de picossegundos

    Directory of Open Access Journals (Sweden)

    Lizarelli Rosane de Fátima Zanirato

    2002-01-01

    Full Text Available A eficiência da ablação com laser através de um regime de picossegundos minimiza a destruição do material adjacente devido à formação de plasma e ataque. Isso previne a geração excessiva de ondas de choque e promove uma considerável diminuição nos efeitos mecânicos. Nesse estudo foi utilizado um laser de Nd:YAG em picossegundo "Q-switched" e "mode-locked" (Antares 76-s, Coherent, Palo Alto, CA, três molares humanos recém-extraídos e foram realizados 15 microcavidades em esmalte e 9 em dentina. Os parâmetros para irradiar o esmalte seguiram uma freqüência fixa de 100 Hz e potência média de 1,3 W; enquanto que para a dentina, a freqüência foi fixa em 15 Hz enquanto que a potência média variou em 800, 700 e 600 mW. O esmalte demonstrou ser mais capaz de dissipar as ondas de choque do que a dentina, uma vez que as trincas originadas nas microcavidades foram mais freqüentes em tecido dentinário, diferentemente do esmalte. Em conclusão, parece que para manter os aspectos de definição de bordas é importante escolher tempos de irradiação mais curtos, quando as potências médias forem mantidas mais altas, ou seja, energia total entregue mais baixa e bem localizada.

  19. Photo-switch of pulsed Nd:YAG laser

    International Nuclear Information System (INIS)

    Ketta, W.W.J.

    1989-01-01

    In this work passive Q-switching and its effect on the output laser beam from a pulsed Nd:YAG laser was studied. This was achieved using the photochemically stable (BDNI) dye after dissolving it in dichloroethane. The absorption spectra of the dye solution and how suitable to use with Nd:YAG laser was also dealt with. Cooling unit for the laser system, a detector to detect the output pulse, and an electronic counter to measure the pulse duration were constructed. In the free-running regime, the divergence angle was measured. The form of the output, its energy, and how it is affected by the pumping energy were also studied. In the Q-switching regime, the relation between output and pumping energies was studied and compared to the same relation under the free-running regime. 5 tabs.; 33 figs.; 57 refs

  20. Nd:YAG laser in caries prevention: a clinical study

    International Nuclear Information System (INIS)

    Boari, Heloisa Gomes Dimiranda

    2000-01-01

    The caries prevention by using laser irradiation has been investigated during the last 30 years. The Nd: YAG laser associated with acidulated phosphate fluoride has been shown as a very promising technique for enamel caries prevention. The aim of this work was to clinically evaluate the efficiency of Nd: YAG laser associated with acidulated phosphate fluoride in pit and fissure caries prevention of children and adolescents. In this work it was determined the dye that enhance the effect of Nd: YAG laser in enamel. It was selected 242 pre-molar and molar teeth from 33 children and adolescents, aged from 7 to 15 years old. The selected teeth were free from caries or decalcification marks (active white marks) to the clinical and radiographic exams. The teeth were divided into two groups: the first group was laser irradiated and their homologous remained as a control. The right side teeth were dye-assisted Nd:YAG laser irradiated. The dye solution was a moisture of dust coal and equal parts of water and alcohol. The irradiation conditions were 60 mJ/10 Hz, optical fiber in contact mode, with diameter of 300 μm, resulting in an energy density of 84,9 J/cm 2 . The oclusal surface of the teeth was completely irradiated, specially on the slopes and in the deepest part of the pits and fissures. This procedure was repeated three times. In the sequence it was applied the acidulated phosphate fluoride for 4 minutes. On the left side teeth - control group- only acidulated phosphate fluoride was applied for the same time. The final examination considered the presence of caries and active white marks after a period of one year. There were statistical significant differences (p < 0.01) between the lased + fluoride group and the non irradiated group. The present study concluded that the technique used in this work can be an alternative clinical method for caries prevention. (author)

  1. Bactericidal effect of Nd:YAG laser irradiation in endodontics

    Science.gov (United States)

    Aun, Carlos E.; Barberini, Alexandre F.; Camargo, Selma C. C.; Silva Kfouri, Luciana; Lorenzetti Simionato, Maria R.

    1999-05-01

    The success of endodontic therapy is based on the elimination of bacterial colonization from the endodontic system and periapical tissues. Recent studies have been showing the bactericidal effect of laser in root canal treatment. The propose of the study is to evaluate the effect of Nd:YAG laser irradiation in contaminated root canal treatment. The propose of the study is to evaluate the effect of Nd:YAG laser irradiation in contaminated root canals from upper central incisor. For the experiment 12 teeth were selected, respect at the apical third, sterilized, and 10 μm Streptococcus sanguis liquid culture were inoculated in the root canals. The laser test groups were irradiated with Nd:YAG laser at standard setting of 15Hz, 100mj and 1,5 W for 10, 20 and 30 seconds each in slow helicoidal movements from the apex to the top using a 300 micrometers fiber. After the procedure the specimens were placed in Tryptic Soy Agar, the number of colony forming units was evaluated. The experiment showed a significant reduction on viability of Streptococcus sanguis at the respective time of 20 and 30 seconds.

  2. Palliation of oesophagogastric neoplasms with Nd:YAG laser treatment

    Energy Technology Data Exchange (ETDEWEB)

    Schulze, S.; Fischerman, K. (Rigshospitalet, Copenhagen (Denmark))

    1990-01-01

    The palliative effect of endoscopic Nd:YAG laser treatment of malignant strictures of the oesophagus and cardia was prospectively evaluated in 30 patients. Most were primarily treated for dysphagia, and swallowing was improved in 21 and normalized in 14 of these patients. Two patients were successfully treated for bleeding. Six patients developed complications (including two perforations), and four of these were fatal. The median survival was four months. It is concluded that in a great number of patients with inoperable cancer of the oesophagus and cardia, laser treatment is better than other palliative procedures. 23 refs., 2 tabs.

  3. Thermal effects associated with the Nd/YAG dental laser.

    Science.gov (United States)

    von Fraunhofer, J A; Allen, D J

    1993-01-01

    The heat produced at the dentinal pulpal wall opposite the irradiation site was measured during etching of dental enamel with an Nd:YAG laser in preparation for direct bonding of orthodontic appliances. Forty extracted human teeth were randomly divided into four groups of 10 teeth. Within each group, the buccal surfaces of 5 teeth and the lingual surfaces of the other 5 teeth were laser treated for 12 sec. Irradiation was performed with a commercial Nd:YAG laser at the power settings of 80mJ, 1W, 2W and 3W. Prior to irradiation, an occlusal access preparation was made into the pulp in order to facilitate the placement of a thermocouple for measurement of temperature changes at the dentinal pulpal wall opposite the irradiation site. The thermocouple was held against the dentinal pulpal wall and the resulting temperature changes were recorded. Heating effects at the dentinal pulpal wall on both buccal and lingual surfaces showed an increase in heat as a function of the increase in power output from the laser unit (p damage to the pulp tissue immediately opposite the site of laser irradiation.

  4. Nd:YAG laser in art works restoration

    Directory of Open Access Journals (Sweden)

    Flores, T.

    1998-04-01

    Full Text Available Laser cleaning in works of art has a number of advantages over traditional techniques of restoration. In this article, the technique used and the physical mechanisms that explain the process of ablation of pollutants are described. The results obtained in the cleaning of statues of marble and alabaster are exposed as well as oil-painting restoration. In this last specific case, the Nd:YAG laser is used with successful results.

    La limpieza de obras de arte por láser presenta una serie de ventajas sobre técnicas tradicionales de restauración. En el presente trabajo se describen la técnica empleada y los mecanismos físicos que explican el proceso de ablación de contaminantes. Se reportan los resultados alcanzados en la limpieza de estatuas de mármol y alabastro, así como en la restauración de pintura al óleo. En este último caso, se emplea por primera vez el láser de Nd:YAG con resultados ventajosos.

  5. LASIK flap breakthrough in Nd:YAG laser treatment of epithelial ingrowth

    NARCIS (Netherlands)

    Lapid-Gortzak, Ruth; Hughes, John M.; Nieuwendaal, Carla P.; Mourits, Maarten P.; van der Meulen, Ivanka J. E.

    2015-01-01

    To present two cases with complications after Nd:YAG laser treatment of epithelial ingrowth. Case reports. Dense central recurrent epithelial ingrowth was treated with a Nd:YAG laser directed at the epithelial nests in the LASIK flap interface in one case. Misalignment of the aiming beam after

  6. Single, composite, and ceramic Nd:YAG 946-nm lasers

    Science.gov (United States)

    Lan, Rui-Jun; Yang, Guang; Zheng-Ping, Wang

    2015-06-01

    Single, composite crystal and ceramic continuous wave (CW) 946-nm Nd:YAG lasers are demonstrated, respectively. The ceramic laser behaves better than the crystal laser. With 5-mm long ceramic, a CW output power of 1.46 W is generated with an optical conversion efficiency of 13.9%, while the slope efficiency is 17.9%. The optimal ceramic length for a 946-nm laser is also calculated. Project supported by the National Natural Science Foundation of China (Grant No. 61405171), the Natural Science Foundation of Shandong Province, China (Grant No. ZR2012FQ014), and the Science and Technology Program of the Shandong Higher Education Institutions of China (Grant No. J13LJ05).

  7. Precision cutting and drilling with the Nd-YAG laser

    International Nuclear Information System (INIS)

    Lingenfelter, A.C.; Anglin, C.D.; Westrich, C.N.; Murchie, J.R.

    1986-01-01

    The Laser Processing Facility of the Materials Fabrication Division of Lawrence Livermore National Laboratory has two pulsed Nd-YAG lasers mounted on machine tool bases. Over the years the authors have had requirements for cutting a wide variety of materials, frequently to very tight dimensional tolerances. They have found that the laser process is particularly well suited for two application areas; (1) for thin cross sections of most all materials, and (2) for refractory metals and ceramics such as tungsten, tantalum, and molybdenum, silicon wafers, alumina, and graphite foil. Some of these materials are difficult if not impossible to cut and drill in any other manner. Examples of each of these types of applications are sighted. Data are presented to illustrate the effects and interactions of laser parameter variables such as aperturing, choice of lenses, focus, pulse length, and energy level. Examples of applications are shown

  8. Numerical simulation of a battlefield Nd:YAG laser

    Science.gov (United States)

    Henriksson, Markus; Sjoqvist, Lars; Uhrwing, Thomas

    2005-11-01

    A numeric model has been developed to identify the critical components and parameters in improving the output beam quality of a flashlamp pumped Q-switched Nd:YAG laser with a folded Porro-prism resonator and polarization output coupling. The heating of the laser material and accompanying thermo-optical effects are calculated using the finite element partial differential equations package FEMLAB allowing arbitrary geometries and time distributions. The laser gain and the cavity are modeled with the physical optics simulation code GLAD including effects such as gain profile, thermal lensing and stress-induced birefringence, the Pockels cell rise-time and component aberrations. The model is intended to optimize the pumping process of an OPO providing radiation to be used for ranging, imaging or optical countermeasures.

  9. Treatment of rosacea with long-pulsed Nd: YAG laser

    Directory of Open Access Journals (Sweden)

    Ekin Meşe Say

    2013-03-01

    Full Text Available Background and Design: Rosacea is a chronic inflammatory disorder of the face. There is no curative treatment for the disease. Facial flushing and vascular lesions due to rosacea may significantly affect a patient’s quality of life. Topical and oral antibiotics are not effective for treating rosacea. Currently, laser treatment of vascular lesions has been reported in the literature. We aimed to investigate the efficacy of long-pulse 1064-nm neodymium: YAG (Nd: YAG laser in the treatment of vascular lesions (erythema and telangiectasia in rosacea patients. Materials and Methods: Thirty-nine patients (29 women, 10 men with erythematotelangiectatic rosacea (ETR were recruited into the study. Severity of the disease (ETR-score: 0-3 was assessed for all patients. We used long-pulsed Nd: YAG laser for vascular lesions at 3-4 weeks intervals. The face was divided into seven anatomic regions for evaluation. Assessment was made by comparing pretreatment and posttreatment photographs by using ETR-scores. For evaluating patient satisfaction, a scale of 0 to 3 was used. Results: The patients were divided into three groups according to the ETR scores [ETR-1 (n=12, ETR-2 (n=9, ETR-3 (n=18]. Following an average of 3.95 (2-8 sessions laser treatments, the clinical improvement was statistically significant in all groups (p<0.05. The mean reduction of ETR-score was 91.70% in patients with ETR-1 and. the clinical improvement was to be decreased in severe forms of ETR. The most common sites for the lesions were the malar region, ala nasi and the nasal dorsum, respectively. The lesions on the ala nasi were more recalcitrant to the treatment than those on the other areas. Regarding to physician assessment of treatment’s success, 97% of the patients was associated with moderate and excellent improvement. According to physicians’ assessment, excellent improvement was noticed in 43.58% and, 61.5% of patients reported a high degree of satisfaction with this

  10. Improvement of the technique in treatment of internal hemorrhoids with Nd:YAG laser

    Science.gov (United States)

    Bao, Xiao-qing; Zhu, Jing; Shi, Hong-Min

    2005-07-01

    Objective: To observe and study the improvement of the technique in treatment of internal hemorrhoids with Nd:YAG laser and evaluate the effective rate. Methods: 60 patients of internal hemorrhoids were treated with Nd:YAG laser (10-15mw) irradiating on the mucosa of the lesions. Results: Among 60 patients, 57 patients were primarily cured with one treatment, 3 patients were primarily cured with two treatments. The effective rate was 95% with one treatment, and it reached to 100% with two treatments. Conclusions: the improvement of the technique in treatment of internal hemorrhoids with Nd:YAG laser is effective and easy to operate.

  11. Combination of CO2 and Q-switched Nd:YAG lasers is more effective than Q-switched Nd:YAG laser alone for eyebrow tattoo removal.

    Science.gov (United States)

    Radmanesh, Mohammad; Rafiei, Zohreh

    2015-04-01

    The eyebrow tattoo removal using Q-switched lasers is usually prolonged. Other modalities may be required to enhance the efficacy and shorten the treatment course. To compare the efficacy of Q-switched neodymium-doped yttrium aluminum garnet (Nd:YAG) laser alone versus combination of Q-switched Nd:YAG and Ultrapulse CO2 lasers for eyebrow tattoo removal after a single session. After local anesthesia, the right eyebrow of 20 patients was treated with Ultrapulse CO2 laser with the parameters of 4 J/cm(2) and 3.2 J/cm(2) for the first and the second passes. Both eyebrows were then treated with 1064-nm and 532-nm Q-switched Nd:YAG laser. The spot size and pulse duration were 3 mm and 5 nanoseconds for both wavelengths, and the fluence was 7 J/cm(2) for 1064 nm and 3 J/cm (2) for 532 nm. The side treated with combination of Q-switched Nd:YAG and CO2 lasers improved 75-100% in 6 of 20 patients versus only 1 of 20 in the side treated with Q-switched Nd:YAG alone. Similarly, the right side in 13 of 20 patients showed more than 50% improvement with combination therapy versus the left side (the monotherapy side), where only 6 of 20 cases showed more than 50% improvement. The Mann-Whitney test was 2.85 for the right side and 1.95 for the left side (P value = 0.007). Using Ultra pulse CO2 laser enhances the efficacy of Q-switched Nd:YAG laser in eyebrow tattoo removal.

  12. Effects of neodymium concentration on optical characteristics of polycrystalline Nd:YAG laser materials

    International Nuclear Information System (INIS)

    Ikesue, A.; Kamata, K.; Yoshida, K.

    1996-01-01

    A neodymium-doped yttrium-aluminum garnet (Y 3 Al 5 O 12 , YAG) (Nd:YAG) ceramic that contained 0.3--4.8 at.% neodymium additives and exhibited nearly the same optical properties as those of a single crystal was fabricated by a solid-state reaction method using high-purity powders. Although the integrated absorption intensity of the 2 H 9/2 + 4 F 5/2 bands simply increased as the neodymium concentration in the YAG ceramics decreased, the fluorescence intensity of the 2.4 at.% Nd:YAG ceramic was the strongest among Nd:YAG ceramics with various neodymium concentrations and a 0.9 at.% Nd:YAG single crystal. An oscillation experiment was performed on a continuous-wave (cw) laser with a diode-laser exciting system using those ceramics and the single crystal. The oscillation threshold and slope efficiency in that analysis were 309 mW and 28%, respectively, for the 1.1 at.% Nd:YAG ceramics and 356 mW and 40%, respectively, for the 2.4 at.% Nd:YAG ceramics. The lasing characteristics of the ceramics in the present work were superior to those of a 0.9 at.% Nd:YAG single crystal that was fabricated by the Czochralski (Cz) method

  13. Continuous-wave ceramic Nd:YAG laser at 1123 nm

    International Nuclear Information System (INIS)

    Zhang, S S; Wang, Q P; Zhang, X Y; Cong, Z H; Fan, S Z; Liu, Z J; Sun, W J

    2009-01-01

    Ceramic Nd:YAG (cNd:YAG) materials are employed to generate 1123-nm laser. A fiber-coupled continuous-wave (CW) 808-nm diode laser is used as the pumping source. With an incident diode power of 26.1 W, a CW output power of up to 10.8 W is obtained with a 10-mm-long ceramic Nd:YAG rod (1.0 at.%-Nd-doped). The conversion efficiency from diode power to 1123-nm laser power is 41.4%. The laser performance of another 10-mm-long cNd:YAG rod with a Nd-doping concentration of 0.6 at.% is studied as a comparison

  14. Q-switched pulse laser generation from double-cladding Nd:YAG ceramics waveguides.

    Science.gov (United States)

    Tan, Yang; Luan, Qingfang; Liu, Fengqin; Chen, Feng; Vázquez de Aldana, Javier Rodríguez

    2013-08-12

    This work reports on the Q-switched pulsed laser generation from double-cladding Nd:YAG ceramic waveguides. Double-cladding waveguides with different combination of diameters were inscribed into a sample of Nd:YAG ceramic. With an additional semiconductor saturable absorber, stable pulsed laser emission at the wavelength of 1064 nm was achieved with pulses of 21 ns temporal duration and ~14 μJ pulse energy at a repetition rate of 3.65 MHz.

  15. High-power Nd:YAG lasers using stable-unstable resonators

    CERN Document Server

    Mudge, D; Ottaway, D J; Veitch, P J; Munch, J P; Hamilton, M W

    2002-01-01

    The development of a power-scalable diode-laser-pumped continuous-wave Nd:YAG laser for advanced long-baseline interferometric detectors of gravitational waves is described. The laser employs a chain of injection-locked slave lasers to yield an efficient, frequency-stable, diffraction-limited laser beam.

  16. Nd:YAG Lasers Treating of Carious Lesion and Root Canal In Vitro

    Directory of Open Access Journals (Sweden)

    Danqing Xia

    2012-01-01

    Full Text Available Dental caries is a transmissible bacterial disease process, with cavities at the end, and caused by acids from bacterial metabolism. The essence of dental treatment is to clean and disinfect bacterial contamination from the tooth. In this work, we tried to demonstrate the cleaning and disinfecting effects of Nd:YAG laser irradiation on dental carious lesion and root canal in vitro. Acousto-optic Q-switched quasicontinuous and Cr3+:YAG crystal Q-switched pulse Nd:YAG lasers were employed to treat caries lesion and the root canal, respectively. Results showed that acousto-optic Q-switched quasicontinuous Nd:YAG laser irradiation and Cr3+:YAG crystal Q-switched pulse Nd:YAG laser irradiation could rapidly clean decayed material and bacterial contamination from dental carious lesion and the narrow tail end of root canal with minimally invasive in vitro, respectively. It was concluded that acousto-optic Q-switched quasicontinuous laser irradiation may be a rapid and effective alternative caries treatment, and Cr3+:YAG crystal Q-switched pulse Nd:YAG laser irradiation may be an effective method for canal cleaning and disinfecting during root canal therapy.

  17. Nd:YAG laser therapy for rectal and vaginal venous malformations.

    Science.gov (United States)

    Gurien, Lori A; Jackson, Richard J; Kiser, Michelle M; Richter, Gresham T

    2017-08-01

    Limited therapeutic options exist for rectal and vaginal venous malformations (VM). We describe our center's experience using Nd:YAG laser for targeted ablation of abnormal veins to treat mucosally involved pelvic VM. Records of patients undergoing non-contact Nd:YAG laser therapy of pelvic VM at a tertiary children's hospital were reviewed. Symptoms, operative findings and details, complications, and outcomes were evaluated. Nine patients (age 0-24) underwent Nd:YAG laser therapy of rectal and/or vaginal VM. Rectal bleeding was present in all patients and vaginal bleeding in all females (n = 5). 5/7 patients had extensive pelvic involvement on MRI. Typical settings were 30 (rectum) and 20-25 W (vagina), with 0.5-1.0 s pulse duration. Patients underwent the same-day discharge. Treatment intervals ranged from 14 to 180 (average = 56) weeks, with 6.1-year mean follow-up. Five patients experienced symptom relief with a single treatment. Serial treatments managed recurrent bleeding successfully in all patients, with complete resolution of vaginal lesions in 40% of cases. No complications occurred. Nd:YAG laser treatment of rectal and vaginal VM results in substantial improvement and symptom control, with low complication risk. Given the high morbidity of surgical resection, Nd:YAG laser treatment of pelvic VM should be considered as first line therapy.

  18. Localization of the pumping reflector for a Nd:YAG laser

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kwang Suk; Kim, Chul Joong [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1994-12-01

    For the first year plan of this program, the pumping reflectors, which are gold plated reflectors and ceramic diffuse reflectors, of the Nd:YAG laser have been localized. The laser output performances with these reflectors have been investigated. Developed reflectors can be applied successfully to our commercialized Nd:YAG laser which was worked in previous project. We designed the optical pumping system with GaAlAs diode laser bar to improve the pumping efficiency. Moreover, we investigated a simple pumping technique without changing the fleshlamp, which makes the Nd:YAG laser operate in a cw, a pulsed, and a mixed of the two mode. We expert many new applications of this diversification of output pulse shapes in industry and in medicine. 38 figs, 9 tabs, 18 refs. (Author).

  19. UNS S32750 super duplex steel welding using pulsed Nd:YAG laser; Soldagem do aco superduplex UNS S32750 com laser pulsado Nd:YAG

    Energy Technology Data Exchange (ETDEWEB)

    Francini, O.D.; Andrade, G.G.; Clemente, M.S.; Gallego, J.; Ventrella, V.A., E-mail: ventrella@dem.feis.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Ilha Solteira, SP (Brazil). Departamento de Engenharia Mecanica

    2016-07-01

    Laser is a flexible and powerful tool with many relevant applications in industry, mainly in the welding area. Lasers today provide the welding industry technical solutions to many problems. This work studied the weld metal obtained by pulsed laser welding of Nd: YAG super duplex stainless steel UNS S32750 employed in the oil and natural gas, analyzing the influence of high cooling rate, due to the laser process, the swing phase ferrite / austenite. Were performed weld beads in butt joint with different repetition rates. The different microstructures were obtained by optical microscopy and scanning electron microscopy. The results showed that the effect of varying the welding energy of Nd: YAG laser on the volume fractions of the phases ferrite/austenite in the weld metal was its ferritization and low austenite amount on the grain boundary. (author)

  20. Characterization of Stone Cleaning by Nd:YAG Lasers with Different Pulse Duration

    International Nuclear Information System (INIS)

    Bartoli, L.; Siano, S.; Salimbeni, R.; Pouli, P.; Fotakis, C.

    2006-01-01

    The present work is a comparative study on the laser cleaning of stonework using Nd:YAG lasers at different pulse durations. The ablation rate, the degree of cleaning, and the appearance of the treated surface were studied irradiating a simulated sample and a real stone artefact using three different Nd:YAG laser systems with pulse duration of 90 microseconds, 15 nanoseconds, and 150 picoseconds. To our knowledge, the picosecond laser is here used for the first time in stone conservation. Differences in efficiency and in cleaning result are shown and discussed.

  1. Efeito do laser Nd:YAG no selamento de fóssulas e fissuras: estudo in vivo = Nd:yag laser effect on pit and fissures sealing: an in vivo study

    Directory of Open Access Journals (Sweden)

    Firoozmand, Leily Macedo

    2007-01-01

    Full Text Available O objetivo desta pesquisa foi o de avaliar o comportamento clínico do laser Nd: YAG em comparação ao de um selante com carga, durante o período de 12 meses, observando; a pigmentação do sulco, incidência de cárie e fratura ou perda do selante. Foram selecionados 62 primeiros e segundos premolares hígidos de pacientes na faixa etária de 12 a 15 anos, de uma escola da rede pública de São José dos Campos. Nos 31 primeiros premolares foi aplicado o laser Nd: YAG, Pulse Máster 600 IQ em toda a extensão do sulco oclusal por 30 segundos utilizando 60 mJ, 10 HZ, 0,6W. Nos 31 segundos premolares foi realizado o selamento dos sulcos oclusais com o selante Fluorshield. Após 6 meses observou-se que dos casos selados com Fluorshield 19,35% apresentaram perda e/ou fratura do selante e em 16,66% os sulcos apresentaram cárie incipiente. Já nos casos em que foi aplicado o laser Nd: YAG 6,45% apresentaram início de lesão de cárie. Com 12 meses de avaliação tanto com selante Fluorshield como com o laser Nd: YAG observou-se o aparecimento de sulcos pigmentados em 12, 90% dos casos e uma incidência de 9,67% de lesões incipientes de cárie. Utilizando-se o selante Fluorshield houve queda do material em 25,80% e fratura em 3,22% dos casos. Concluímos que após 12 meses de avaliação o laser Nd: YAG e o selante Fluorshield apresentaram comportamento clínico semelhante, diante das mesmas condições bucais, sendo que a porcentagem de aparecimento de lesão inicial de cárie foi igual para os dois métodos de prevenção utilizados

  2. 885-nm laser diode array pumped ceramic Nd:YAG master oscillator power amplifier system

    Science.gov (United States)

    Yu, Anthony W.; Li, Steven X.; Stephen, Mark A.; Seas, Antonios; Troupaki, Elisavet; Vasilyev, Aleksey; Conley, Heather; Filemyr, Tim; Kirchner, Cynthia; Rosanova, Alberto

    2010-04-01

    The objective of this effort is to develop more reliable, higher efficiency diode pumped Nd:YAG laser systems for space applications by leveraging technology investments from the DoD and other commercial industries. Our goal is to design, build, test and demonstrate the effectiveness of combining 885 nm laser pump diodes and the use of ceramic Nd:YAG for future flight missions. The significant reduction in thermal loading on the gain medium by the use of 885 nm pump lasers will improve system efficiency.

  3. Diode-pumped continuous-wave eye-safe Nd:YAG laser at 1415 nm.

    Science.gov (United States)

    Lee, Hee Chul; Byeon, Sung Ug; Lukashev, Alexei

    2012-04-01

    We describe the output performance of the 1415 nm emission in Nd:YAG in a plane-concave cavity under traditional pumping into the 4F5/2 level (808 nm) and direct in-band pumping into the 4F3/2 level (885 nm). An end-pumped Nd:YAG laser yielded maximum cw output power of 6.3 W and 4.2 W at 885 nm and 808 nm laser diode (LD) pumping, respectively. To the best of our knowledge, this is the highest output power of a LD-pumped 1415 nm laser.

  4. Effects of a pulsed Nd:YAG laser on enamel and dentin

    Science.gov (United States)

    Myers, Terry D.

    1990-06-01

    Enamel and dentin samples were exposed extraorally to a pulsed neodymium yttriuma1uminumgarnet (Nd:YAG) laser. The lased samples were observed using both scanning electron microscopy and histological techniques to determine the effects of the laser. The present study has provided the following points: (1) Properly treated, enamel can be 1aser etched to a depth comparable to that achieved with phosphoric acid etching; and (2) both carious and noncarious dentin can be vaporized by the Nd:YAG laser. No cracking or chipping of any enamel or dentin sample was observed histologically or under the SEM.

  5. Laser amplification of optical images using a CW Nd:YAG amplifier

    International Nuclear Information System (INIS)

    Aman, H

    2013-01-01

    In this paper a scheme for the amplification of optical images is described, using a continuous wave (CW) diode-pumped Nd:YAG (yttrium aluminum garnet) laser module. A passively q-switched end-pumped Nd:YAG laser is used as a pump source, which carries the optical image distribution as an input which is transmitted towards the amplifier at a distance of about ten feet. For amplification, a three-side-pumped CW Nd:YAG laser module is utilized without the cavity mirrors. In this way, optical images are amplified by a factor of 3.2 and imaged at a distance of ten feet with a spatial resolution of 500 μm. (paper)

  6. High-power pulsed and CW diode-pumped mode-locked Nd:YAG lasers

    Science.gov (United States)

    Marshall, Larry R.; Hays, A. D.; Kaz, Alex; Kasinski, Jeff; Burnham, R. L.

    1991-01-01

    The operation of both pulsed and CW diode-pumped mode-locked Nd:YAG lasers are presented. The pulsed laser produced 1.0 mJ with pulsewidths of 90 psec at 20 Hz. The CW pumped laser produced 6 W output at 1.064 microns and 3 W output at 532 nm.

  7. Efficient delivery of 60 J pulse energy of long pulse Nd:YAG laser ...

    Indian Academy of Sciences (India)

    2014-02-09

    Feb 9, 2014 ... Most of today's industrial Nd:YAG lasers use fibre-optic beam delivery. ... optical fibre and successfully delivered up to 60 J of pulse energy with .... and electrical pump input to laser output conversion efficiency is about 5%. ... [3] W Koechner, Solid state laser engineering, 5th edn (Springer, Berlin, 1999).

  8. Effect of Nd:YAG laser on the solvent evaporation of adhesive systems.

    Science.gov (United States)

    Batista, Graziela Ribeiro; Barcellos, Daphne Câmara; Rocha Gomes Torres, Carlos; Damião, Álvaro José; de Oliveira, Hueder Paulo Moisés; de Paiva Gonçalves, Sérgio Eduardo

    2015-01-01

    This study evaluated the influence of Nd:YAG laser on the evaporation degree (ED) of the solvent components in total-etch and self-etch adhesives. The ED of Gluma Comfort Bond (Heraeus-Kulzer) one-step self-etch adhesive, and Adper Single Bond 2 (3M ESPE), and XP Bond (Dentsply) total-etch adhesives was determined by weight alterations using two techniques: Control--spontaneous evaporation of the solvent for 5 min; Experimental--Nd:YAG laser irradiation for 1 min, followed by spontaneous evaporation for 4 min. The weight loss due to evaporation of the volatile components was measured at baseline and after 10 s, 20 s, 30 s, 40 s, 50 s, 60 s, 70 s, 80 s, 90 s, 100 s, 110 s, 2 min, 3 min, 4 min, and 5 min. Evaporation of solvent components significantly increased with Nd:YAG laser irradiation for all adhesives investigated. Gluma Comfort Bond showed significantly higher evaporation of solvent components than Adper Single Bond 2 and XP Bond. All the adhesives lost weight quickly during the first min of Nd:YAG laser irradiation. The application of Nd:YAG laser on adhesives before light curing had a significant effect on the evaporation of the solvent components, and the ED of Gluma Comfort Bond one-step self-etch adhesive was significantly higher than with Adper Single Bond 2 and XP Bond total-etch adhesives. The use of the Nd:YAG laser on the uncured adhesive technique can promote a greater ED of solvents, optimizing the longevity of the adhesive restorations.

  9. Femtosecond laser inscribed cladding waveguides in Nd:YAG ceramics: fabrication, fluorescence imaging and laser performance.

    Science.gov (United States)

    Liu, Hongliang; Jia, Yuechen; Vázquez de Aldana, Javier Rodríguez; Jaque, Daniel; Chen, Feng

    2012-08-13

    We report on the fabrication of depressed cladding waveguide lasers in Nd:YAG (neodymium doped yttrium aluminum garnet, Nd:Y3Al5O12) ceramics microstructured by femtosecond laser pulses. Full control over the confined light spatial distribution is demonstrated by the fabrication of high contrast waveguides with hexagonal, circular and trapezoidal configurations. The confocal fluorescence measurements of the waveguides reveal that the original luminescence features of Nd3+ ions are well-preserved in the waveguide regions. Under optical pump at 808 nm, cladding waveguides showed continuous wave efficient laser oscillation. The maximum output power obtained at 1064.5 nm is ~181 mW with a slope efficiency as high as 44%, which suggests that the fabricated Nd:YAG ceramic waveguides are promising candidates for efficient integrated laser sources.

  10. Nd : YAG surgical laser effects in canine prostate tissue: temperature and damage distribution

    NARCIS (Netherlands)

    van Nimwegen, S. A.; L'Eplattenier, H. F.; Rem, A. I.; van der Lugt, J. J.; Kirpensteijn, J.

    2009-01-01

    An in vitro model was used to predict short-term, laser-induced, thermal damage in canine prostate tissue. Canine prostate tissue samples were equipped with thermocouple probes to measure tissue temperature at 3, 6, 9 and 12 mm depths. The tissue surface was irradiated with a Nd:YAG laser in contact

  11. 5.4W cladding-pumped Nd:YAG silica fiber laser

    OpenAIRE

    Yoo, S.; Webb, A.S.; Standish, R.J.; May-Smith, T.C.; Sahu, J.K.

    2012-01-01

    We report on the spectroscopy and laser characteristics of Nd-doped fiber, fabricated by rod-in-tube from Nd:YAG as a core material with silica cladding. A cladding-pumped CW laser operation at 1058nm with 52% slope-efficiency is demonstrated.

  12. Efficient delivery of 60 J pulse energy of long pulse Nd:YAG laser ...

    Indian Academy of Sciences (India)

    2014-02-09

    Feb 9, 2014 ... Most of today's industrial Nd:YAG lasers use fibre-optic beam delivery. In such lasers, fibre core diameter is an important consideration in deploying a beam delivery system. Using a smaller core diameter fibre allows higher irradiances at focus position, less degradation of beam quality, and a larger ...

  13. Removal effects of the Nd:YAG laser and Carisolv on carious dentin.

    Science.gov (United States)

    Yamada, Y; Hossain, M; Kawanaka, T; Kinoshita, J; Matsumoto, K

    2000-10-01

    The purpose of this study was to investigate the removal effect of the Nd:YAG laser irradiation and Carisolv on carious dentin. Many previous studies have reported several simple and alternative techniques, such as lasers and chemicals, for caries removal. Carisolv was applied on the surface of 20 extracted human anterior and molar teeth for 1 min and then the Nd:YAG laser was irradiated with a continuous water spray for another 1 min. The energy densities were varied from 2 to 6W with a repetition rate of 20 pps. As caries removal progressed, the cavity was carefully assessed by DIAGNOdent. Each lesion was photographed before and after treatment, and the treated cavity was observed microscopically using a stereoscope and with scanning electron microscope (SEM). Thermal change at the time of laser irradiation was measured by thermovision. Our results revealed that application of Carisolv followed by Nd:YAG laser irradiation at 4-6W pulse energy effectively removed dentin caries. The total procedure was usually repeated once or twice for complete caries removal. From the SEM study, it was found that the cavity surface treated with the laser revealed various patterns of microirregularity, often accompanied by microfissure propagation. There was also no smear layer. It was revealed that Nd:YAG laser and Carisolv could provide an alternative technique for caries removal instead of the conventional mechanical drilling and cutting.

  14. New long-wavelength Nd:YAG laser at 1.44 micron: effect on brain.

    Science.gov (United States)

    Martiniuk, R; Bauer, J A; McKean, J D; Tulip, J; Mielke, B W

    1989-02-01

    A wavelength-shifted Nd:YAG laser, tuned to coincide with the infrared absorption peak of water at 1.44 microns, was used to make lesions in normal rabbit brain. A total of 48 lesions were made with power up to 20 W, with energy up to 40 joules, and with two different spot sizes. These lesions were compared to lesions made with 1.06 microns radiation from an Nd:YAG laser under identical operating conditions. Measurements of blood-brain barrier damage and width, depth, and volume of tissue affected were obtained 30 minutes after placement of the lesions. It was found that 1.44-microns lesions produced photoevaporative tissue loss at the highest intensities used. The layer of coagulated tissue remaining after photovaporization had a mean thickness of 0.6 mm irrespective of the volume of tissue removed. There was no photovaporization in the 1.06-microns lesions. In addition, the amount of peripheral edema per unit volume of tissue coagulated was approximately half at the 1.44-microns wavelength. These findings suggest that the 1.44-microns Nd:YAG laser may be a useful surgical instrument since it combines the photoevaporative effect of the CO2 laser while maintaining the advantages of the conventional Nd:YAG laser (quartz fiber delivery and effective hemostasis).

  15. Influência da energia de soldagem em uniões de lâminas finas através de laser pulsado de Nd:YAG Effect of the heat input on pulsed Nd:YAG laser welding of thin foil

    Directory of Open Access Journals (Sweden)

    Vicente A. Ventrella

    2010-12-01

    Full Text Available A soldagem laser vem sendo utilizada como um importante processo de manufatura. Ela pode ser utilizada tanto no modo contínuo quanto no modo pulsado. No processo onde se utiliza laser pulsado é possível realizar soldas de costura em lâminas finas, através da sobreposição dos pulsos. Nesse caso a velocidade de soldagem é definida pela taxa de sobreposição, taxa de repetição e diâmetro do pulso. A soldagem de sobreposição de lâminas finas apresenta problemas típicos como distorção excessiva da junta soldada, falta de contato entre as lâminas a serem soldadas (presença de um gap de ar, perfuração da junta e presença de altos níveis de tensões residuais. O processo de laser pulsado é preferido em relação ao processo por laser contínuo, pois ele possibilita um melhor controle da energia de soldagem. O presente trabalho estudou a influência da energia do pulso, no caso processo de soldagem laser Nd:YAG, na soldagem de lâminas finas ( 100µm de aço inoxidável austenítico AISI 316L, utilizado no revestimento de sensores (que trabalham em ambiente corrosivo da indústria sucroalcooleira. Utilizou-se energia de pulso de 1,0 a 2,25 Joules, com incremento de 0,25 Joules e largura temporal de 4 ms. As soldas foram realizadas com proteção gasosa de argônio. Foram realizadas análises macrográficas das juntas soldadas, através de secções transversais das mesmas e, ensaios de microdureza Vickers e ensaios de tração. Os resultados obtidos mostraram que o controle da energia do pulso, em processo de soldagem por laser de lâminas finas é de fundamental importância para a geração de juntas soldadas com boas propriedades mecânicas e livres de descontinuidades. O limite de resistência da junta soldada aumentou no início e depois sofreu um pequeno decréscimo em função do aumento da energia do pulso. O processo mostrou-se muito sensível à presença de gap entre as lâminas.Laser beam welding has been used widely

  16. Bioceramic hydroxyapatite coating fabricated on TI-6Al-4V using Nd:YAG Laser

    CSIR Research Space (South Africa)

    Tlotleng, Monnamme

    2014-11-01

    Full Text Available Driven Innovation, 15th Annual International Conference, Stellenbosch, South Africa, 6-7 November 2014 Bioceramic hydroxyapatite coating fabricated on TI-6Al-4V using Nd:YAG Laser M. Tlotleng1, 4*, E. Akinlabi1, M. Shukla2, 3, S. Pityana4, T...

  17. Passively model-locked Nd: YAG laser with a component GaAs

    International Nuclear Information System (INIS)

    Zhang Zhuhong; Qian Liejia; Chen Shaohe; Fan Dianyuan; Mao Hongwei

    1992-01-01

    An all solid-state passively mode-locked Nd: YAG laser with a 400 μm, (100) oriented GaAs component is reported for the first time and model locked pulses with a duration of 16 ps, average energy of 10 μJ were obtained with a probability of 90%

  18. Nd:YAG laser in urogenital surgery of the dog and cat

    NARCIS (Netherlands)

    van Nimwegen, S.A.

    2008-01-01

    It was hypothesized that the fiber-guided Nd:YAG laser with its incisional and hemostatic action, could be useful for meticulous tissue dissection in a subcapsular partial prostatectomy in dogs, and in laparoscopic surgery of dogs and cats. Prior to clinical use, its action was investigated in

  19. Generation of ultra short pulses by auto injection in the Nd: YAG laser

    International Nuclear Information System (INIS)

    Faria, I.C. de.

    1986-01-01

    Yhe work presented here, was concerned to the construction of a coherent light source in the near infrared region with pulses of 10 -10 seconds. The auto-injection technique was employed for generating these short pulses with posterior extraction of the pulse applied to a Nd=YAG-pulsed laser. (author) [pt

  20. Combined pulsed dye laser and fiberoptic Nd-YAG laser for the treatment of hypertrophic port wine stain.

    Science.gov (United States)

    Radmanesh, Mohammed; Radmanesh, Ramin

    2017-10-01

    The hypertrophic Port Wine Stain (PWS) is only partially and superficially treated with the Pulsed dye laser (PDL) because of its limited depth of penetration. We used combined PDL and fiberoptic 1444-nm Nd-YAG laser to treat a case with hypertrophic PWS. After tumescent anesthesia, few holes were made by a 16-gauge needle on different sides of the lesion. The fiberoptic tip of 1444-nm Nd-YAG laser was inserted within the holes and was pushed forward while triggering. In a fan pattern and by a back and forth movement, the subcutaneous and deep dermal areas were coagulated. The skin and outer mucosal surfaces were then treated by PDL. The fiberoptic system used was Accusculpt 1444-nm Nd-YAG laser (Lutronic lasers, South Korea), and the PDL used was 585 nm Nlite system (Chromogenex UK). The parameters used for PDL were fluence = 9 Joules/cm 2 and the spot size was 5 mm. The parameters used for fiberoptic 1444-nm Nd-YAG laser were: Pulse rate = 30 Hz, pulse energy = 300 mJ, power = 6 W, and the total energy = 4000 J for the whole face and mucosa. Little sign of regression and moderate purpura were detected immediately after combined fiberoptic Nd-YAG and PDL therapy. The lesion gradually regressed within 4 months with satisfactory color and volume change. Combined fiberoptic Nd-YAG laser and PDL can be used for the treatment of deeper and superficial layers of hypertrophic PWS.

  1. Diode and Nd:YAG laser in a case of refractory acne keloidalis nuchae

    Directory of Open Access Journals (Sweden)

    Ravi Kumar Chittoria

    2015-03-01

    Full Text Available Acne keloidalis nuchae (AKN is a disease of unclear etiology that mainly affects males. Medical treatment of AKN is difficult, with refractory cases often requiring ablation by laser or surgical resection. We report herein, a 23-year-old male with refractory AKN treated successfully with combined laser ablation, using an 810-nm diode laser and a 1064-nm Nd:YAG laser.

  2. [Effects of Nd: YAG laser irradiation on the root surfaces and adhesion of Streptococcus mutans].

    Science.gov (United States)

    Yuanhong, Li; Zhongcheng, Li; Mengqi, Luo; Daonan, Shen; Shu, Zhang; Shu, Meng

    2016-12-01

    This study aimed to evaluate the effects of treatment with different powers of Nd: YAG laser irradiation on root surfaces and Streptococcus mutans (S. mutans) adhesion. Extracted teeth because of severe periodontal disease were divided into the following four groups: control group, laser group 1, laser group 2, and laser group 3. After scaling and root planning, laser group 1, laser group 2, and laser group 3 were separately treated with Nd: YAG laser irradiation (4/6/8 W, 60 s); however, the control group did not receive the treatment. Scanning electron microscopy (SEM) was used to determine the morphology. S. mutans were cultured with root slices from each group. Colony forming unit per mL (CFU·mL⁻¹) was used to count and compare the amounts of bacteria adhesion among groups. SEM was used to observe the difference of bacteria adhesion to root surfaces between control group (scaling) and laser group 2 (6 W, 60 s), thereby indicating the different bacteria adhesions because of different treatments. Morphology alterations indicated that root surfaces in control group contain obvious smear layer, debris, and biofilm; whereas the root surfaces in laser group contain more cracks with less smear layer and debris. The bacteria counting indicated that S. mutans adhesion to laser group was weaker than that of control group (P0.05) was observed. Morphology alterations also verified that S. mutans adhesion to laser group 2 (6 W, 60 s) was weaker than that of control group (scaling). This study demonstrated that Nd: YAG laser irradiation treatment after scaling can reduce smear layer, debris, and biofilm on the root surfaces as compared with conventional scaling. The laser treatment reduces the adhesion of S. mutans as well. However, Nd: YAG laser irradiation can cause cracks on the root surfaces. In this experiment, the optimum laser power of 6 W can thoroughly remove the smear layer and debris, as well as relatively improve the control of thermal damagee.

  3. Changes in nail keratin observed by Raman spectroscopy after Nd:YAG laser treatment.

    Science.gov (United States)

    Shin, Min Kyung; Kim, Tae In; Kim, Wan Sun; Park, Hun-Kuk; Kim, Kyung Sook

    2017-04-01

    Lasers and photodynamic therapy have been considered a convergence treatment for onychomycosis, which is a fungal infection on the nail bed and nail plate. Laser therapies have shown satisfactory results without significant complications for onychomycosis; however, the mechanism of clearing remains unknown. In this work, we investigated changes in the chemical structure of nail keratin induced by Nd:YAG laser using Raman spectroscopy. Toe nails with onychomycosis were treated with 1064 nm Nd:YAG laser. After laser treatment, the disulfide band (490-590 cm -1 ) of nail keratin was rarely observed or was reduced in intensity. The amide I band (1500-1700 cm -1 ) also showed changes induced by the laser. The α-helical (1652 cm -1 ) structures dominated the β-sheet (1673 cm -1 ) in nontreated nail, but the opposite phenomenon was observed after laser treatment. © 2016 Wiley Periodicals, Inc.

  4. Intraoperative localized urticarial reaction during Q-switched Nd:YAG laser tattoo removal.

    Science.gov (United States)

    Wilken, Reason; Ho, Derek; Petukhova, Tatyana; Jagdeo, Jared

    2015-03-01

    Q-switched lasers, such as the neodymium:yttrium-aluminum-garnet (Nd:YAG) laser, are the gold standard for tattoo removal. Allergy to tattoo pigment is well-documented, but adverse allergic reactions during or shortly after laser tattoo removal are rare with few reports in the medical literature. Here we describe an intraoperative, localized urticarial reaction that developed during treatment of a tattoo using a 1064-nm Nd:YAG laser. As laser tattoo removal becomes increasingly popular amongst our patients, it is important for dermatologists to be aware of urticarial allergic reactions as well as their management. We outline our recommendations for medical management of this condition and hope that these guidelines will facilitate patient care by dermatologists who encounter this immune skin reaction to laser tattoo removal

  5. Design of a high-power, high-brightness Nd:YAG solar laser.

    Science.gov (United States)

    Liang, Dawei; Almeida, Joana; Garcia, Dário

    2014-03-20

    A simple high-power, high-brightness Nd:YAG solar laser pumping approach is presented in this paper. The incoming solar radiation is both collected and concentrated by four Fresnel lenses and redirected toward a Nd:YAG laser head by four plane-folding mirrors. A fused-silica secondary concentrator is used to compress the highly concentrated solar radiation to a laser rod. Optimum pumping conditions and laser resonator parameters are found through ZEMAX and LASCAD numerical analysis. Solar laser power of 96 W is numerically calculated, corresponding to the collection efficiency of 24  W/m². A record-high solar laser beam brightness figure of merit of 9.6 W is numerically achieved.

  6. Development of surgical CW Nd:YAG laser with optical fiber delivery system

    International Nuclear Information System (INIS)

    Kim, Cheol Jung; Kim, Jeong Mook; Jung, Chin Mann; Kim, Kwang Suk; Kim, Min Suk; Cho, Jae Wan; Kim, Duk Hyun

    1992-06-01

    We developed a surgical CW Nd:YAG laser with optical fiber delivery system. Several commercial models have been investigated in design and performance. We improved its quality to the level of commercial Nd:YAG laser by an endurance test for each parts of laser system. The maximum power of our surgical laser was 150 W and the laser pulse width could be controlled to 99 sec continuously by 0.1 sec. Many optical parts were localized and lowered much in cost. Only few parts were imported and almost 90% in cost were localized. Also, to find out the maintenance problem of this surgical laser, it was applicated to the production line of our joint company. (Author)

  7. Instant recording of the duration of a single mode-locked Nd:YAG laser pulse

    International Nuclear Information System (INIS)

    Lompre, L.A.; Mainfray, G.; Thebault, J.

    1975-01-01

    An electro-optic streak camera incorporating a storage memory video system has been developed and used to instantly visualize and record the shape of a 1.06-μ-wavelength pulse generated by a mode-locked Nd:YAG laser. The duration of a single laser pulse (approximately 30 psec) has been directly measured with and without laser amplification. (U.S.)

  8. Test of remote control cutting equipment by Nd:YAG laser

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, Akio [Fuji Electric Corp. Research and Development Ltd., Yokosuka, Kanagawa (Japan); Hosoda, Hiroshi

    1997-11-01

    Technology of remote controlled cutting and reduction of generative secondary products have been required to the cutting system for decommissioning nuclear equipments. At a point of view that laser cutting technology by use of a Nd:YAG laser is effective, we have developed the laser cutting machine and carried out cutting tests for several stainless steel plates. This report is described the result of experiment by test equipment, about element technology of remote controlled cutting nuclear equipments. (author)

  9. Hot cracking characteristic of welding using Nd:YAG laser beam

    International Nuclear Information System (INIS)

    Ro, Kyoung Bo; Yoo, Young Tae; Oh, Yong Seak; Shin, Ho Jun; Kim, Ji Hwan

    2003-01-01

    The Nd:YAG laser process is known to have high speed and deep penetration capability to become one of the most advanced welding technologies. In spite of its good mechanical characteristics, SM45C carbon steel has a high carbon contents and suffers a limitation in the industrial application due to the poor welding properties. The major process parameters studied in the present laser welding experiment were position of focus, travel speed and laser power

  10. Test of remote control cutting equipment by Nd:YAG laser

    International Nuclear Information System (INIS)

    Shimizu, Akio; Hosoda, Hiroshi.

    1997-01-01

    Technology of remote controlled cutting and reduction of generative secondary products have been required to the cutting system for decommissioning nuclear equipments. At a point of view that laser cutting technology by use of a Nd:YAG laser is effective, we have developed the laser cutting machine and carried out cutting tests for several stainless steel plates. This report is described the result of experiment by test equipment, about element technology of remote controlled cutting nuclear equipments. (author)

  11. UNS S32750 super duplex steel welding using pulsed Nd:YAG laser

    International Nuclear Information System (INIS)

    Francini, O.D.; Andrade, G.G.; Clemente, M.S.; Gallego, J.; Ventrella, V.A.

    2016-01-01

    Laser is a flexible and powerful tool with many relevant applications in industry, mainly in the welding area. Lasers today provide the welding industry technical solutions to many problems. This work studied the weld metal obtained by pulsed laser welding of Nd: YAG super duplex stainless steel UNS S32750 employed in the oil and natural gas, analyzing the influence of high cooling rate, due to the laser process, the swing phase ferrite / austenite. Were performed weld beads in butt joint with different repetition rates. The different microstructures were obtained by optical microscopy and scanning electron microscopy. The results showed that the effect of varying the welding energy of Nd: YAG laser on the volume fractions of the phases ferrite/austenite in the weld metal was its ferritization and low austenite amount on the grain boundary. (author)

  12. Experimental analysis of Nd-YAG laser cutting of sheet materials - A review

    Science.gov (United States)

    Sharma, Amit; Yadava, Vinod

    2018-01-01

    Cutting of sheet material is considered as an important process due to its relevance among products of everyday life such as aircrafts, ships, cars, furniture etc. Among various sheet cutting processes (ASCPs), laser beam cutting is one of the most capable ASCP to create complex geometries with stringent design requirements in difficult-to-cut sheet materials. Based on the recent research work in the area of sheet cutting, it is found that the Nd-YAG laser is used for cutting of sheet material in general and reflective sheet material in particular. This paper reviews the experimental analysis of Nd-YAG laser cutting process, carried out to study the influence of laser cutting parameters on the process performance index. The significance of experimental modeling and different optimization approaches employed by various researchers has also been discussed in this study.

  13. Injection seeded, diode pumped regenerative ring Nd:YAG amplifier for spaceborne laser ranging technology development

    Science.gov (United States)

    Coyle, D. Barry; Kay, Richard B.; Degnan, John J.; Krebs, Danny J.; Seery, Bernard D.

    1992-01-01

    A small, all solid state, regenerative ring amplifier designed as a prototype for space application is discussed. Novel features include dual side pumping of the Nd:YAG crystal and a triangular ring cavity design which minimizes the number of optical components and losses. The amplifier is relatively small (3 ns round trip time) even though standard optical elements are employed. The ring regeneratively amplifies a 100 ps single pulse by approximately 10(exp 5) at a repetition rate of 10 to 100 Hz. The amplifier is designed to be injection seeded with a pulsed, 100 ps laser diode at 1.06 microns, but another Nd:YAG laser system supplying higher pulse energies was employed for laboratory experiment. This system is a prototype laser oscillator for the Geoscience Laser Ranging System (GLRS) platform. Results on measurements of beam quality, astigmatism, and gain are given.

  14. Depigmentation therapy with Q-switched Nd: YAG laser in universal vitiligo

    Directory of Open Access Journals (Sweden)

    Imran Majid

    2013-01-01

    Full Text Available Background: Any residual pigment left in patients of universal vitiligo is managed with topical treatments, cryotherapy, and lasers. Aim: The study aims to assess the efficacy and safety of Q-switched Nd: YAG laser in treating the residual pigmentation in patients with universal vitiligo. Materials and Methods: Fifteen patients of universal vitiligo with residual pigmentation on the face, hands, or feet, resistant to topical treatments, were treated with single or multiple sessions of Q-switched Nd: YAG laser treatment. Topical treatments were continued in between the laser sessions and the depigmentation achieved was monitored by clinical examination and repeat digital photographs. Response to the treatment was labelled as excellent if the residual pigment could be reduced by at least 90% while 50-90% resolution of pigmentation was labelled as a partial response. Adverse effects to the treatment offered were also monitored. Results: Thirteen of the 15 patients enrolled for the study showed an excellent response to the treatment offered. Two other patients showed a poor response with less than 50% resolution of pigmentation. The number of laser sessions needed at a particular site ranged from 1 to 3 and no patient was offered more than three sessions of laser treatment at any site. No significant adverse events were reported by any patient. Conclusions: Residual pigmentation in patients with universal vitiligo that does not respond to topical treatment options alone can be managed quite effectively with Q-switched Nd: YAG laser without any significant adverse effects.

  15. Inhibition of enamel demineralisation using "Nd-YAG and diode laser assisted fluoride therapy".

    Science.gov (United States)

    Chand, B R; Kulkarni, S; Mishra, P

    2016-02-01

    This in vitro study was to evaluate the irradiation efficacy of the Diode laser and the Nd-YAG laser either un-assisted or assisted by acidulated phosphate fluoride (APF) treatment on enamel's acid resistance. Seventy-two enamel samples, obtained from 12 extracted human molars, were randomly assigned to 6 groups as follows: (1) Control (C); (2) Exposed to APF gel (F); (3) Diode laser (DL); (4) Irradiated with Diode laser through APF gel (DL/F); (5) Nd-YAG laser (NL) and (6) Irradiated with Nd-YAG laser through APF gel (NL/F). The specimens were individually demineralised in an acidified hydroxyethylcellulose system, and the acid resistance was evaluated by determining the calcium ion dissolution using atomic absorption spectrometry. The average concentration of the calcium ion determined in groups 1 to 6 was 901, 757, 736, 592, 497 and 416 parts per million micrograms/gram, respectively. The results showed that demineralisation in the NL/F group was significantly less than the other groups and the control group was significantly greater than the other groups (P laser irradiation, used alone or in combination with APF, in decreasing the enamel demineralisation was greater than all the other groups.

  16. New application of a bipolar Nd:YAG handpiece in laser cardiac surgery

    Science.gov (United States)

    Mizutani, Tetsuo; Suzuki, Hitoshi; Katayama, Yoshihiko

    1997-05-01

    A bipolar Nd-YAG laser (1.064 micrometer) handpiece was experimentally examined for a venous dissection without scissors and sutures and clinically introduced for the vein graft harvesting in coronary artery bypass grafting (CABG). Experimental study: One hundred and thirty-five segments of the mongrel dog veins were employed. Nd-YAG laser was irradiated on the vein held by the bipolar Nd-YAG handpiece at the power of 5, 9, 13, and 17 watts, and success defined as a complete vein citing without bleeding at the laser-applied sites were gained in all except three; 97.8% of success rate. Laser exposure time for cutting the vein decreased in order to an increase of the applied laser power, and the veins of bigger diameter needed more longer exposure time in the group of the same laser power. An average exposure time was 4.4 seconds for the veins of 1 mm diameter at 13 watts. In histological examination, a vascular lumen at the cutting site was diminished and covered with a degenerated vascular wall, and bleeding was not seen in all specimen. Clinical study: In 18 cases of CABG the bipolar Nd-YAG handpiece was applied to cut the branches of the great saphenous vein without scissors and sutures. Forty-two grafts harvested by this handpiece were used for aortocoronary bypass grating. All were survived and the angiographic examination demonstrated a 90% of graft patency at an average period of 3.5 years after the operation. Laser-induced morphological change such as aneurysmal formation or graft stenosis was not recognized.

  17. 11-GHz waveguide Nd:YAG laser CW mode-locked with single-layer graphene.

    Science.gov (United States)

    Okhrimchuk, Andrey G; Obraztsov, Petr A

    2015-06-08

    We report stable, passive, continuous-wave (CW) mode-locking of a compact diode-pumped waveguide Nd:YAG laser with a single-layer graphene saturable absorber. The depressed cladding waveguide in the Nd:YAG crystal is fabricated with an ultrafast laser inscription method. The saturable absorber is formed by direct deposition of CVD single-layer graphene on the output coupler. The few millimeter-long cavity provides generation of 16-ps pulses with repetition rates in the GHz range (up to 11.3 GHz) and 12 mW average power. Stable CW mode-locking operation is achieved by controlling the group delay dispersion in the laser cavity with a Gires-Tournois interferometer.

  18. Endoscopic palliation of esophageal and cardial cancer: Nd:YAG laser and prosthesis

    Science.gov (United States)

    Norberto, Lorenzo; Ranzato, Riccardo; Marino, Saverio; Angriman, Imerio; Vella, Vincenzo; Donadi, Michele; D'Amico, D. F.

    1997-12-01

    From November 1, 1992 to January 31, 1997, 227 patients with inoperable esophageal and cardial carcinomas were treated with Nd:YAG laser therapy and prosthesis intubation. The retrograde technique was used in most cases. The tumor involved in 75 pts the Cardia, in 65 the middle thoracic esophagus, in 47 pts the lower thoracic esophagus, in 23 in the upper thoracic esophagus and in 17 in the cervical esophagus. The indications for palliative Nd:YAG laser and prosthesis intubation were a locally advanced or metastatic tumor in 146 pts (64.4%) and poor surgical risk in 81 pts (35.6%). The quality of palliation was evaluated according to the ability to swallow. The mean survival rate of the patients during the follow up was 22 weeks for the laser therapy and 16 weeks for the prosthesis intubation.

  19. Freeze frame analysis on high speed cinematography of Nd/YAG laser explosions in ocular tissues.

    Science.gov (United States)

    Vernon, S A; Cheng, H

    1986-01-01

    High speed colour cinematography at 400 frames per second was used to photograph both single and train burst Nd/YAG laser applications in ox eyes at threshold energy levels. Measurements of the extent and speed of particle scatter and tissue distortion from the acoustic transient were made from a sequential freeze frame analysis of the films. Particles were observed to travel over 8 mm from the site of Nd/YAG application 20 milliseconds after a single pulse at initial speeds in excess of 20 km/h. The use of train bursts of pulses was seen to increase the number of particles scattered and project the wavefront of particles further from the point of laser application. Images PMID:3754458

  20. Actively Q-switched laser with novel Nd:YAG/YAG polygonal active-mirror

    Science.gov (United States)

    Lang, Ye; Chen, Yanzhong; Ge, Wenqi; He, Jianguo; Zhang, Hongbo; Liao, Lifen; Xin, Jianguo; Zhang, Jian; Fan, Zhongwei

    2018-03-01

    In this work, we demonstrate an efficient actively Q-switched laser based on a novel crystal Nd:YAG/YAG polygonal active mirror. A passively cooled crystal Nd:YAG/YAG polygonal active mirror with an end pump scheme was used as the gain medium. For the overlap between the TEM00 laser mode and large gain profile, a cavity was carefully designed with a large fundamental mode volume. With a maximum absorbed power of 3.1 W, a 685 mW average output power with a pulse repetition of 5 kHz was attained, and the corresponding optical-optical and slope efficiency were 22.1% and 27.7%, respectively. The pulse width was 133.9 ns. The beam quality (M 2) was 1.561 in the horizontal direction and 1.261 in the vertical direction.

  1. Inner structure detection by optical tomography technology based on feedback of microchip Nd:YAG lasers.

    Science.gov (United States)

    Xu, Chunxin; Zhang, Shulian; Tan, Yidong; Zhao, Shijie

    2013-05-20

    We describe a new optical tomography technology based on feedback of microchip Nd:YAG lasers. In the case of feedback light frequency-shifted, light can be magnified by a fact of 10(6) in the Nd:YAG microchip lasers, which makes it possible to realize optical tomography with a greater depth than current optical tomography. The results of the measuring and imaging of kinds of samples are presented, which demonstrate the feasibility and potential of this approach in the inner structure detection. The system has a lateral resolution of ~1 μm, a vertical resolution of 15 μm and a longitudinal scanning range of over 10mm.

  2. Freeze frame analysis on high speed cinematography of Nd/YAG laser explosions in ocular tissues.

    Science.gov (United States)

    Vernon, S A; Cheng, H

    1986-05-01

    High speed colour cinematography at 400 frames per second was used to photograph both single and train burst Nd/YAG laser applications in ox eyes at threshold energy levels. Measurements of the extent and speed of particle scatter and tissue distortion from the acoustic transient were made from a sequential freeze frame analysis of the films. Particles were observed to travel over 8 mm from the site of Nd/YAG application 20 milliseconds after a single pulse at initial speeds in excess of 20 km/h. The use of train bursts of pulses was seen to increase the number of particles scattered and project the wavefront of particles further from the point of laser application.

  3. Long-term remission of folliculitis decalvans after treatment with the long-pulsed Nd:YAG laser.

    Science.gov (United States)

    Meesters, Arne A; Van der Veen, J P Wietze; Wolkerstorfer, Albert

    2014-04-01

    Folliculitis decalvans (FD) is a rare inflammatory scalp disorder presenting with tufted folliculitis, follicular papules and pustules, progressing to cicatricial alopecia. Current treatments mainly consist of antibiotic and immunomodulatory therapies and are often disappointing. FD has previously shown to respond to treatment with neodymium:yttrium aluminium garnet (Nd:YAG) laser in one case. We present a case of recalcitrant FD, successfully treated with a long-pulsed Nd:YAG laser.

  4. Flaw evaluation of Nd:YAG laser welding based plume shape by infrared thermal camera

    International Nuclear Information System (INIS)

    Kim, Jae Yeol; Yoo, Young Tae; Yang, Dong Jo; Song, Kyung Seol; Ro, Kyoung Bo

    2003-01-01

    In Nd:YAG laser welding evaluation methods of welding flaw are various. But, the method due to plume shape is difficult to classification od welding flaw. The Nd:YAG laser process is known to have high speed and deep penetration capability to become one of the most advanced welding technologies. At the present time, some methods are studied for measurement of plume shape by using high-speed camera and photo diode. This paper describes the machining characteristics of SM45C carbon steel welding by use of an Nd:YAG laser. In spite of its good mechanical characteristics, SM45C carbon steel has a high carbon contents and suffers a limitation in the industrial application due to the poor welding properties. In this study, plume shape was measured by infrared thermal camera that is non-contact/non-destructive thermal measurement equipment through change of laser generating power, speed, focus. Weld was performed on bead-on method. Measurement results are compared as two equipment. Here, two results are composed of measurement results of plume quantities due to plume shape by infrared thermal camera and inspection results of weld bead include weld flaws by ultrasonic inspector.

  5. Utilization of Nd-YAG (1064 nm) laser for female hair removal

    International Nuclear Information System (INIS)

    Ahmed, Ahlam Hassan

    2013-05-01

    The Cutera. Inc, cool Glide system laser is along pulsed Nd-YAG 1064 nm, of energy density 25 to 30 J/cm 2 and pulse duration 25 ms in all individual sessions.This study was held in Medical Arms Service Hospital. The period of study taken was three month. The study sample consisted of five patients base line photographs were taken before treatments and also after treatments. Photos show the satisfactory results of the laser treatment. In this study the hair removal treat went was conducted for female middle age group of 25-40 years. The Nd-YAG (1064 nm) laser was found to more effective in treatment of the hair removal, and complications can be minimized by using anesthesia and anti bio tics. The Nd-YAG laser therapy should be considered as a good and dependable alternative to other treatment radiation techniques. And effectiveness of treatment can be increased by using optimum power and duration.(Author)

  6. Treatment of recurrent pilonidal cysts with nd-YAG laser: report of our experience.

    Science.gov (United States)

    Dragoni, F; Moretti, S; Cannarozzo, G; Campolmi, P

    2018-02-01

    Surgical treatment remains the first-line therapy of pilonidal cyst but is associated with high levels of postoperative pain, adverse events and a recurrence rate of 30%. We report our experience with laser hair removal using the Nd-YAG laser for the treatment of pilonidal cyst. Ten patients affected by pilonidal cyst were examined and treated from October 2011 to November 2016. Treatments were carried out using the Nd-YAG laser (Deka M.E.L.A, Calenzano, Florence, Italy) at a wavelength of 1064 nm at 30-day interval. Nine patients were asymptomatic after the second treatment, while in one case the symptom disappeared after the fourth session. After 4-8 treatments, the pilonidal cyst had clinically disappeared and patients subjectively felt healed. In all cases, the soft-tissue ultrasounds performed before the first and after the last session showed the disappearance of the pilonidal cyst. In the follow-up, all the patients remained asymptomatic without any disease recurrence. Nd-YAG laser is an effective treatment for pilonidal cysts, providing excellent results with quick healing and no risk of serious adverse side-effects. It could be a very attractive alternative to open surgery, enabling patients to prevent the frequent and severe postoperative issues associated with surgery.

  7. A 526 W Diode-Pumped Nd:YAG Ceramic Slab Laser

    International Nuclear Information System (INIS)

    Chen Yan-Zhong; Bo Yong; Xu Jian; Xu Yi-Ting; Xu Jia-Lin; Guo Ya-Ding; Yang Feng-Tu; Peng Qin-Jun; Cui Da-Fu; Xu Zu-Yan; Liu Wen-Bin; Jiang Ben-Xue; Kou Hua-Min; Pan Yu-Bai; Jiang Dong-Liang

    2011-01-01

    A diode-side-pumped Nd:YAG ceramic slab laser with a high power output is presented. An average power of 526 W is achieved at 1064 nm with a repetition rate of 120 Hz and a pulse width of 180 μs from a 93mm × 52mm × 8 mm ceramic slab at a pump power of 1928 W, corresponding to an optical-to-optical efficiency of 27.3%. (fundamental areas of phenomenology(including applications))

  8. CdS thin films prepared by continuous wave Nd:YAG laser

    Science.gov (United States)

    Wang, H.; Tenpas, Eric W.; Vuong, Khanh D.; Williams, James A.; Schuesselbauer, E.; Bernstein, R.; Fagan, J. G.; Wang, Xing W.

    1995-08-01

    We report new results on continuous wave Nd:YAG laser deposition of cadmium sulfide thin films. Substrates were soda-lime silicate glass, silica glass, silicon, and copper coated formvar sheets. As deposited films were mixtures of cubic and hexagonal phases, with two different grain sizes. As revealed by SEM micrographs, films had smooth surface morphology. As revealed by TEM analysis, grain sizes were extremely small.

  9. Interpreting coherent anti-Stokes Raman spectra measured with multimode Nd:YAG pump lasers

    International Nuclear Information System (INIS)

    Farrow, R.L.; Rahn, L.A.

    1985-01-01

    We report comparisons of coherent anti-Stokes Raman spectroscopy (CARS) measurements using single-axial-and multiaxial-mode Nd:YAG lasers. Our results demonstrate the validity of a recently proposed convolution expression for unresolved CARS spectra. The results also support the use of a relative delay of several coherence lengths between pump-beam paths for reducing the effects of pump-field statistics on the CARS spectral profile

  10. Stabilization of the quasi-periodic motion of a Q-switched Nd:YAG laser

    International Nuclear Information System (INIS)

    Kim, Chil-Min; Rim, Sunghwan; Kye, Won-Ho; Kim, Jeong-Moog; Lee, Kang-Soo

    2004-01-01

    We have developed a stabilization method of quasi-periodicity based on a return map. The method is explained in the forced Van der Pol oscillator, and applied experimentally to a quasi-periodic output of a Q-switched Nd:YAG laser. Even though the attractors have no unstable periodic orbit, we were able to stabilize them to an arbitrarily chosen orbit by targeting the trajectory into it

  11. Single session of Nd:YAG laser intracanal irradiation neutralizes endotoxin in dental root dentin.

    Science.gov (United States)

    Archilla, José R F; Moreira, Maria S N A; Miyagi, Sueli P H; Bombana, Antônio C; Gutknecht, Norbert; Marques, Márcia M

    2012-11-01

    Endotoxins released in the dental root by Gram-negative microorganisms can be neutralized by calcium hydroxide, when this medication is applied inside the root canal for at least seven days. However, several clinical situations demand faster root canal decontamination. Thus, for faster endotoxin neutralization, endodontists are seeking additional treatments. The in vitro study tested whether or not intracanal Nd:YAG laser irradiation would be able to neutralize endotoxin within the human dental root canal in a single session. Twenty-four human teeth with one root were mounted between two chambers. After conventional endodontic treatment, root canals were contaminated with Escherichia coli endotoxin. Then they were irradiated or not (controls) in contact mode with an Nd:YAG laser (1.5 W, 15 Hz, 100 mJ and pulse fluency of 124  J/cm2). The endotoxin activity was measured using the limulus lysate technique and data were statistically compared (p≤0.05). The concentration of active endotoxin measured in the negative control group was significantly lower than that of the positive control group (p=0.04). The concentrations of endotoxin in both irradiated groups were significantly lower than that of the positive control group (p=0.027) and similar to that of negative control group (p=0.20). A single session of intracanal Nd:YAG laser irradiation is able to neutralize endotoxin in the dental root tissues.

  12. Single session of Nd:YAG laser intracanal irradiation neutralizes endotoxin in dental root dentin

    Science.gov (United States)

    Archilla, José R. F.; Moreira, Maria S. N. A.; Miyagi, Sueli P. H.; Bombana, Antônio C.; Gutknecht, Norbert; Marques, Márcia M.

    2012-11-01

    Endotoxins released in the dental root by Gram-negative microorganisms can be neutralized by calcium hydroxide, when this medication is applied inside the root canal for at least seven days. However, several clinical situations demand faster root canal decontamination. Thus, for faster endotoxin neutralization, endodontists are seeking additional treatments. The in vitro study tested whether or not intracanal Nd:YAG laser irradiation would be able to neutralize endotoxin within the human dental root canal in a single session. Twenty-four human teeth with one root were mounted between two chambers. After conventional endodontic treatment, root canals were contaminated with Escherichia coli endotoxin. Then they were irradiated or not (controls) in contact mode with an Nd:YAG laser (1.5 W, 15 Hz, 100 mJ and pulse fluency of 124 J/cm2). The endotoxin activity was measured using the limulus lysate technique and data were statistically compared (p≤0.05). The concentration of active endotoxin measured in the negative control group was significantly lower than that of the positive control group (p=0.04). The concentrations of endotoxin in both irradiated groups were significantly lower than that of the positive control group (p=0.027) and similar to that of negative control group (p=0.20). A single session of intracanal Nd:YAG laser irradiation is able to neutralize endotoxin in the dental root tissues.

  13. Nd:YAG laser for epithelial ingrowth after laser in situ keratomileusis.

    Science.gov (United States)

    Mohammed, Osama Ali; Mounir, Amr; Hassan, Amin Aboali; Alsmman, Alahmady Hamad; Mostafa, Engy Mohamed

    2018-05-04

    To evaluate the efficacy of neodymium:yttrium-aluminum-garnet (Nd:YAG) laser for treatment of epithelial ingrowth after laser in situ keratomileusis (LASIK). Fifty-eight patients with epithelial ingrowth presented to Sohag refractive center, Sohag, Egypt, between January 2015 and March 2017. Only 41 patients (18 females and 23 males, mean age: 33.4 years) involving 41 eyes were indicated for treatment by Nd:YAG laser as the rest of the eyes were only under observation. Patients with epithelial ingrowth were recognized at a mean of 6 months after primary LASIK procedure (range: 2-16 months). Four eyes had undergone previous LASIK enhancements. Four eyes had the epithelial ingrowth removed by flap lift and scrapping. The mean intensity of the spots used was 0.8 mJ with variable number of shots depending on the size and density of the epithelial ingrowth area. Twenty-eight eyes showed complete regression after one session, while the rest necessitated 2-3 sessions for complete resolution. Mean follow-up period was 8 months (range 5-12 months). Epithelial ingrowth was treated successfully in all 41 eyes. The uncorrected visual acuities were 20/20, and there was no evidence of recurrent epithelial ingrowth after 6 months with no complications reported. YAG laser is a simple, effective outpatient procedure for the management of epithelial ingrowth after LASIK.

  14. Single-Frequency Nd:YAG Ring Lasers with Corner Cube Prism

    Science.gov (United States)

    Wu, Ke-Ying; Yang, Su-Hui; Zhao, Chang-Ming; Wei, Guang-Hui

    2000-10-01

    We put forward another form of the non-planar ring lasers, in which the corner cube prism is the key element and the Nd:YAG crystal is used as a Porro prism to enclose the ring resonator. The phase shift due to the total internal reflections of the three differently orientated reflection planes of the corner cube prism, Faraday rotation in the Nd:YAG crystal placed in a magnetic field and the different output coupling in S and P polarization form an optical diode and enforce the single-frequency generating power. A round trip analysis of the polarization properties of the resonator is made by the evaluation of Jones matrix.

  15. High-efficient Nd:YAG microchip laser for optical surface scanning

    Science.gov (United States)

    Šulc, Jan; Jelínková, Helena; Nejezchleb, Karel; Škoda, Václav

    2017-12-01

    A CW operating, compact, high-power, high-efficient diode pumped 1064nm laser, based on Nd:YAG active medium, was developed for optical surface scanning and mapping applications. To enhance the output beam quality, laser stability, and compactness, a microchip configuration was used. In this arrangement the resonator mirrors were deposited directly on to the laser crystal faces. The Nd-doping concentration was 1 at.% Nd/Y. The Nd:YAG crystal was 5mm long. The laser resonator without pumping radiation recuperation was investigated {the output coupler was transparent for pumping radiation. For the generated laser radiation the output coupler reflectivity was 95%@1064 nm. The diameter of the samples was 5 mm. For the laser pumping two arrangements were investigated. Firstly, a fibre coupled laser diode operating at wavelength 808nm was used in CW mode. The 400 ¹m fiber was delivering up to 14W of pump power amplitude to the microchip laser. The maximum CW output power of 7.2W @ 1064nm in close to TEM00 beam was obtained for incident pumping power 13.7W @ 808 nm. The differential efficiency in respect to the incident pump power reached 56 %. Secondly, a single-emitter, 1W laser diode operating at 808nm was used for Nd:YAG microchip pumping. The laser pumping was directly coupled into the microchip laser using free-space lens optics. Slope efficiency up to 70% was obtained in stable, high-quality, 1064nm laser beam with CW power up to 350mW. The system was successfully used for scanning of super-Gaussian laser mirrors reflectivity profile.

  16. Femtosecond laser irradiation on Nd:YAG crystal: Surface ablation and high-spatial-frequency nanograting

    Science.gov (United States)

    Ren, Yingying; Zhang, Limu; Romero, Carolina; Vázquez de Aldana, Javier R.; Chen, Feng

    2018-05-01

    In this work, we systematically study the surface modifications of femtosecond (fs) laser irradiated Nd:YAG crystal in stationary focusing case (i.e., the beam focused on the target in the steady focusing geometry) or dynamic scanning case (i.e., focused fs-laser beam scanning over the target material). Micro-sized structures (e.g. micro-craters or lines) are experimentally produced in a large scale of parameters in terms of pulse energy as well as (effective) pulse number. Surface ablation of Nd:YAG surface under both processing cases are investigated, involving the morphological evolution, parameter dependence, the ablation threshold fluences and the incubation factors. Meanwhile, under specific irradiation conditions, periodic surface structures with high-spatial-frequency (Investigations on the evolution of nanograting formation and fluence dependence of period are performed. The experimental results obtained under different cases and the comparison between them reveal that incubation effect plays an important role not only in the ablation of Nd:YAG surface but also in the processes of nanograting formation.

  17. Effects of Q-switched and long-pulsed 1064 nm Nd:YAG laser on enlarged facial pores.

    Science.gov (United States)

    Lee, Chang Nam; Kim, You Jeong; Lee, Hyun Seung; Kim, Hei Sung

    2009-12-01

    'Enlarged facial pore' is a subjective term, which is not clearly defined but often complained by many. A diverse range of treatments are used though evidence of efficacy remains largely anecdotal. We report a series of nine patients who underwent a split face trial with Q-switched 1064 nm Nd:YAG and long-pulsed 1064 nm Nd:YAG laser to treat enlarged facial pores.

  18. Biostimulative effects of Nd:YAG Q-switch dye on normal human fibroblast cultures: study of a new chemosensitizing agent for the Nd:YAG laser

    International Nuclear Information System (INIS)

    Castro, D.J.; Saxton, R.E.; Fetterman, H.R.; Castro, D.J.; Ward, P.H.

    1987-01-01

    Kodak Q-switch II is a new chemical with an absorption maxima at 1051 nm, designed to be used as an Nd:YAG dye laser. The potential for this dye as a new chemosensitizing agent in the treatment of connective tissue diseases and wound healing with low energy Nd:YAG laser was examined. Two normal fibroblast cell lines were tested for sensitivity to various levels of this dye in vitro. These cells were exposed to Q-switch II dye at concentrations of 0.01, 0.1, 1, 10, 50, and 100 micrograms/ml for 1 and 24 hours. Cell viability was assessed by the trypan blue exclusion test. Cell duplication and DNA synthesis were measured by the incorporation of [ 3 H]-thymidine at 6 and 24 hours postexposure to Q-switch II dye. At concentrations up to 10 micrograms/ml, both cell lines tested showed no changes in cell viability. However, at concentrations equal or higher than 50 micrograms/ml, more than 40% of the fibroblasts incorporated trypan blue after 24 hours of exposure to this dye, indicating significant cell destruction. The results indicate that Q-switch II dye is nontoxic to normal human fibroblast cultures and showed significant biostimulative effects on cell duplication at concentrations equal to or lower than 10 micrograms/ml. Further studies will be required to determine the usefulness of Q-switch II dye as a new photochemosensitizing agent for potential biostimulation of wound healing and/or treatment of connective tissue diseases with the Nd:YAG laser (near infrared, 1060 nm) at nonthermal levels of energies

  19. Pore formation during C.W.Nd: YAG laser welding of aluminum alloys for automotive applications

    International Nuclear Information System (INIS)

    Pastor, M.; Zhao, H.; DebRoy, T.

    2000-01-01

    Pore formation is an important concern in laser welding of automotive aluminum alloys. This paper investigates the influence of the laser beam defocusing on pore formation during continuous wave Nd:YAG laser welding of aluminum automotive alloys 5182 and 5754. It was found that the instability of the keyhole during welding was a dominant cause of pore formation while hydrogen rejection played an insignificant role. The defocusing of the laser beam greatly affected the stability of the keyhole. Finally, the mechanism of the collapse of the keyhole and pore formation is proposed. (Author) 45 refs

  20. The measurement of capillary waves on a weldpool formed by a Nd:YAG laser

    International Nuclear Information System (INIS)

    Deam, R.T.; Brandt, M.; Harris, J.

    2002-01-01

    Experiments were performed using an on-line pyrometer to measure the capillary waves on a weldpool formed by a Nd: YAG laser. The surface temperature measurements taken from the weldpool revealed strong temporal fluctuations. Fourier transform of the pyrometer data revealed distinct peaks, consistent with calculated resonant frequencies for capillary surface waves on the weldpool formed by the laser. The possibility of using on-line measurement of surface temperature fluctuations to control weldpool depth in laser welds is discussed. The work forms part of an on-going programme to develop closed loop control for laser processing at Swinburne University

  1. Advantages of fulguration of posterior urethral valves by Nd: YAG laser

    Directory of Open Access Journals (Sweden)

    D K Gupta

    2000-01-01

    Full Text Available Posterior Urethral Valves (PUV are one of the com-monest urolgical problems seen in children and the electro-coagulation, which is the most widely preferred modality to ablate the valves, may not be feasible in small-for-date and low-birth-weight neonates as the suitable size resec-toscope/cystoscope may not available. With the availa-bility of Nd: YAG laser at our institute recently, we started performing the laser fulguration instead of electrocoagu-lation of the valves. We reviewed our experience with the emerging role of the Nd: YAG laser in the fulguration of PUV, comparing the results with a historical control group who underwent the classical electrocoagulation of the PUV. The boys (n=50 diagnosed to have PUV by VCUG were confirmed by Wolf 8.5 size cystoscope, underwent Nd: YAG laser fulguration of the valves with a bare fiber, as a day-care procedure without postoperative catheteri-zation. Historical controls (n=50 who had undergone classical electrocoagulation using 9.5 size Wolf resectos-cope served as the controls. The mean age was 1.3 y and 2.6 y in laser and electrocoagulation group respectively. The mean hospital stay of the electrocoagulation group was 3.8 d. Three patients after electrocoagulation devel-oped hematuria and 4 required refulguration whereas in the laser group 5 required refulguration and none devel-oped hematuria. In conclusion, endoscopic laser fulgura-tion of PUV is technically feasible even in neonates and small children. Laser offers excellent results that are com-parable to the time-honored electrocoagulation procedure. This has the additional advantage forfulgurating the PUV in smaller caliber urethra as this can be performed with the smaller available cystoscope that has a side channel, admitting the laser fiber.

  2. Nd-YAG laser treatment in a patient with complicated pilonidal cysts

    DEFF Research Database (Denmark)

    Lindholt, Christine S; Lindholt, Jes S.; Lindholt, Jan

    2009-01-01

    A 38-year-old woman with a recurrent suppurative pilonidal cyst was successfully treated causally with an Nd-YAG (neodymium-doped yttrium aluminium garnet) laser, and with no recurrence at 3-month follow-up. A similar success was observed for another 15 consecutively treated patients, including...... suppurative cases. The effect could be attributable to the ability of the YAG laser to operate at a wavelength of 1064 nm and to penetrate the skin to levels deeper than that of most other lasers before the energy is absorbed in melanin and oxyhaemoglobin. Consequently, the contents of the cyst can be reached...

  3. Development of a 100 W, single frequency, CW Nd:YAG Laser

    International Nuclear Information System (INIS)

    Veitch, P.J.; Mudge, D.; Munch, J.; Hamilton, M.W.; Ostermeyer, M.; Hosken, D.; Brooks, A.

    2002-01-01

    Full text: High power, diode-laser-pumped, continuous wave (cw) solid-state lasers with excellent beam quality, efficiency and reliability are required for demanding applications, including gravitational wave interferometry, where current additional requirements include single frequency, low noise and Nd:YAG. Our approach is a chain of injection locked laser oscillators, theoretically capable of achieving the lowest noise possible. We use a single-frequency (100 mW) master laser to injection lock a medium-power (10 W) laser that in turn injection locks a 100 W laser. Injection locking requires an optimized, single mode, power slave laser at each stage. We shall describe the nearly completed 10 W brass-board laser, which will also be deployed at the ACIGA Test Facility at Gingin. We shall also describe our 100 W laser using a scalable diode pumping scheme, an active control of thermal lensing and a stable-unstable resonator. Initial tests showed mode control to be limited by thermal focusing and thermally induced birefringence in the Nd:YAG medium at 70 W output. Recent efforts have identified the source of the thermal lens and significantly reduced its magnitude, leading to a modified design. We shall present our latest results from the experiments to demonstrate single mode, single frequency laser at 100 W

  4. Effect of Nd: YAG laser irradiation on surface properties and bond strength of zirconia ceramics.

    Science.gov (United States)

    Liu, Li; Liu, Suogang; Song, Xiaomeng; Zhu, Qingping; Zhang, Wei

    2015-02-01

    This study investigated the effect of neodymium-doped yttrium aluminum garnet (Nd: YAG) laser irradiation on surface properties and bond strength of zirconia ceramics. Specimens of zirconia ceramic pieces were divided into 11 groups according to surface treatments as follows: one control group (no treatment), one air abrasion group, and nine laser groups (Nd: YAG irradiation). The laser groups were divided by applying with different output power (1, 2, or 3 W) and irradiation time (30, 60, or 90 s). Following surface treatments, the morphological characteristics of ceramic pieces was observed, and the surface roughness was measured. All specimens were bonded to resin cement. After, stored in water for 24 h and additionally aged by thermocycling, the shear bond strength was measured. Dunnett's t test and one-way ANOVA were performed as the statistical analyses for the surface roughness and the shear bond strength, respectively, with α = .05. Rougher surface of the ceramics could be obtained by laser irradiation with higher output power (2 and 3 W). However, cracks and defects were also found on material surface. The shear bond strength of laser groups was not obviously increased, and it was significantly lower than that of air abrasion group. No significant differences of the shear bond strength were found among laser groups treated with different output power or irradiation time. Nd: YAG laser irradiation cannot improve the surface properties of zirconia ceramics and cannot increase the bond strength of the ceramics. Enhancing irradiation power and extending irradiation time cannot induce higher bond strength of the ceramics and may cause material defect.

  5. Clinical and bacteriological study of the effect of Nd:YAG laser in gingivitis therapy

    Science.gov (United States)

    Colojoara, Carmen; Mavrantoni, Androniki; Miron, Mariana I.

    2000-06-01

    The relationship between dental plaque and gingivitis was verified. Nonspecific gingivitis is an inflammatory process, frequently caused by enzymes and toxins liberate by bacteria form dental plaque. Loose plaque has come under a great deal of investigation because of its role in attachment loss. The current methods used in the treatment of non specific gingivitis encompass the use of antibiotics and conventional surgical techniques. Treating gingivitis with laser energy may further reduce the gingival inflammation and decrease the wound healing time. The lack of correlation between the quantity of dental plaque and the intensity of gingivitis determined us to study the effect of Nd:YAG pulsed laser in reduction of gingival inflammation and wound healing. The aim of this work is to evaluate clinically the anti- inflammatory and wound healing effect of pulsed Nd:YAG laser and to compare the appearance and the levels of the bacteria in the supergingival and subgingival plaque in adolescents with tooth crowding after Nd:YAG laser. The experimental procedure consisted of a clinical and bacteriological study which was undertaken in 20 patients presenting moderate gingivitis. A group of 10 patients was the subject of a bacteriological study and the other group of 10 was used for clinical and histological examination. For each group the clinical criteria of evaluation were: the gingival index, papillary bleeding index, spontaneous aches. Each patient was tested before and after laser exposure or conventional therapy for bacteriological analyses. The results prove that early gingivitis exposure to laser registers a decrease of bacterial colony number and absence of loss of attachment as compared to the application of the conventional treatment. Clinical study has shown that the combination of scaling and root planning with laser therapy is enough to provide improvement in clinical indices and reduction in the number of bacterial colonies.

  6. Efficient room temperature cw Yb:glass laser pumped by a 946nm Nd:YAG laser

    OpenAIRE

    Koch, R.; Clarkson, W.A.; Hanna, D.C.; Jiang, S.; Myers, M.J.; Rhonehouse, D.; Hamlin, S.J.; Griebner, U.; Schönnagel, H.

    1997-01-01

    By pumping with a cw diode-pumped Nd:YAG laser operating at 946nm laser operation of a new Yb-doped phosphate glass with 440mW cw output power and a slope efficiency of 48% with respect to the absorbed pump power was achieved at room temperature

  7. High Efficient LGp0 End Pumped Nd:YAG Laser

    CSIR Research Space (South Africa)

    Ngcobo, S

    2012-07-01

    Full Text Available the slope efficiency of the laser due to the increased in the fundamental mode volume of the laser. The beam shaping is achieved by using an annular binary Diffractive Optical Element whose geometry is in connection with the location of the Laguerre...

  8. Applications of Nd:YAG laser micromanufacturing in high temperature gas reactor research

    International Nuclear Information System (INIS)

    Rooyen, I.J. van; Smal, C.A.; Steyn, J.

    2012-01-01

    Highlights: ► Two innovative applications of Nd:YAG laser micromachining techniques demonstrated. ► Firstly an alumina jig to contain multiple 500 μm diameter ZrO 2 spheres. ► Secondly the manufacture of a sealing system using laser micromachining. ► ZrO 2 micro plugs isolate the openings of micro-machined cavities to produce a gas-tight seal. ► Manufacturing processes for both the tapered seating cavity and the plug are demonstrated. - Abstract: Two innovative applications of Nd:YAG laser micromachining techniques are demonstrated in this publication. Research projects to determine the fission product transport mechanisms in TRISO coated particles necessitate heat treatment studies as well as the manufacturing of a unique sealed system for experimentation at very high temperatures. This article describes firstly the design and creation of an alumina jig designed to contain 500 μm diameter ZrO 2 spheres intended for annealing experiments at temperatures up to 1600 °C. Functional requirements of this jig are the precision positioning of spheres for laser ablation, welding and post weld heat treatment in order to ensure process repeatability and accurate indexing of individual spheres. The design challenges and the performance of the holding device are reported. Secondly the manufacture of a sealing system using laser micromachining is reported. ZrO 2 micro plugs isolate the openings of micro-machined cavities to produce a gas-tight seal fit for application in a high temperature environment. The technique is described along with a discussion of the problems experienced during the sealing process. Typical problems experienced were seating dimensions and the relative small size (∼200 μm) of these plugs that posed handling challenges. Manufacturing processes for both the tapered seating cavity and the plug are demonstrated. In conclusion, this article demonstrates the application of Nd-YAG micromachining in an innovative way to solve practical research

  9. Endoscopic Nd-YAG laser treatment and adjuvant therapy for metastatic lesions of airway

    Energy Technology Data Exchange (ETDEWEB)

    Okitsu, Hiroshi; Oho, Kenkichi; Naitoh, Jun; Tajika, Eishiro; Amemiya, Ryuta; Hayata, Yoshihiro [Tokyo Medical Coll. (Japan)

    1989-06-01

    Endoscopic Nd-YAG laser treatment and adjuvant therapy were performed in 44 cases with metastatic lesions of airway. The best results were obtained in 31 cases (93.9%) out of 33 cases complaining of ventilatory disturbance in which endoscopic Nd-YAG laser treatment was indicated as an emergency procedure. In most of these cases with metastatic lesions of airway consisted of respiratory tract invasion from mediastinal lymph nodes in cases of esophageal cancer or lung cancer. In these cases, after laser treatment for ventilatory disturbance, the patients condition improved to the extent that adjuvant therapy could be performed. Adjuvant therapy was performed in 38 cases, there were 7 cases treated surgically resection of the metastatic lesions of airway in 3 cases, tracheal tube stent operation in 4 cases 0, 28 radiotherapy in 28 cases Linac irradiation in 24 cases, /sup 60/Co intraluminal irradiation of the trachea in 4 cases 0, and 32 cases were treated with chemotherapy. Tracheal tube stent operation was useful for maintenance of the tracheal lumen following laser treatment, and /sup 60/Co intraluminal irradiation was effective for the residual intratracheal tumor. The 1-year survival rate of 44 cases with metastatic lesions of airway was 42% and the 2-year survival rate was 22%, so this result suggested endoscopic Nd-YAG laser treatment and adjuvant therapy for metastatic lesions of airway was useful to prolong survival time. However the main value of this modality is for the rapid relief of severe ventilatory disturbance due to obstructive airway lesions. (author).

  10. Development of frequency tunable Ti:sapphire laser and dye laser pumped by a pulsed Nd:YAG laser

    International Nuclear Information System (INIS)

    Yi, Jong Hoon; Horn, Roland; Wendt, K.

    2001-01-01

    We investigated lasing characteristics of two kinds of tunable laser, liquid dye laser and solid Ti:sapphire crystal laser, pumped by high pulse repetition rate Nd:YAG laser. Dye laser showed drastically reduced pulsewidth compared with that of pump laser and it also contained large amount of amplified spontaneous emission. Ti:sapphire laser showed also reduced pulsewidth. But, the laser conversion pump laser and Ti:sapphire laser pulse, we used a Brewster-cut Pockel's cell for Q-switching. The laser was frequency doubled by a type I BBO crystal outside of the cavity.

  11. Bond strength of an adhesive system irradiated with Nd:YAG laser in dentin treated with Er:YAG laser

    International Nuclear Information System (INIS)

    Malta, D A M P; De Andrade, M F; Costa, M M; Lizarelli, R F Z; Pelino, J E P

    2008-01-01

    The purpose of this in vitro study was to verify through micro tensile bond test the bond strength of an adhesive system irradiated with Nd:YAG laser in dentine previously treated with Er:YAG laser. Twenty caries free extracted human third molars were used. The teeth were divided in four experimental groups (n = 5): (G1) control group; (G2) irradiation of the adhesive system with the Nd:YAG laser; (G3) dentin treatment with Er:YAG laser; (G4) dentin treatment with Er:YAG laser followed by the irradiation of the adhesive system with Nd:YAG laser. The Er:YAG laser fluency parameter for the dentin treatment was of 60 J/cm 2 . The adhesive system was irradiated with the Nd:YAG laser with fluency of 100 J/cm 2 . Dental restorations were performed with Adper Single Bond 2/Z250. One tooth from each group was prepared for the evaluation of the adhesive interface under SEM and bond failure tests were also performed and evaluated. The statistical analysis showed statistical significant difference between the groups G1 and G3, G1 and G4, G2 and G3, and G2 and G4; and similarity between the groups G1 and G2, and G3 and G4. The adhesive failures were predominant in all the experimental groups. The SEM analysis showed an adhesive interface with features confirming the results of the mechanical tests. The Nd:YAG laser on the adhesive system did not influence the bond strength in dentin treated or not with the Er:YAG laser

  12. Polycarbonate surface cell's adhesion examination after Nd:YAG laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Ramazani, S.A. Ahmad, E-mail: Ramazani@sharif.ir [Polymer Group, Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Mousavi, Seyyed Abbas, E-mail: Musavi@che.sharif.ir [Department of Chemistry, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Seyedjafari, Ehsan [Department of Biotechnology, University College of Science, University of Tehran (Iran, Islamic Republic of); Poursalehi, Reza [Department of Physics, University of Shahed, Tehran (Iran, Islamic Republic of); Sareh, Shohreh [Research Center of Iranian Blood Transfusion Organization, Tehran (Iran, Islamic Republic of); Silakhori, Kaveh [Laser Research Center, Atomic Energy Organization, Tehran (Iran, Islamic Republic of); Poorfatollah, Ali Akbar [Research Center of Iranian Blood Transfusion Organization, Tehran (Iran, Islamic Republic of); Shamkhali, Amir Nasser [Department of Chemistry, Sharif University of Technology, Tehran (Iran, Islamic Republic of)

    2009-05-05

    Nd:YAG laser treatment was used in order to increase surface cell adhesion aspects of polycarbonate (PC) films prepared via melt process. The treatment was carried out under different wavelengths and beam diameters. ATR-FTIR and UV spectra obtained from different samples before and after laser treatment in air showed that laser irradiation has induced some chemical and physical changes in surface properties. The irradiated films were also characterized using scanning electron microscopy (SEM) and contact angle measurements. Effect of pulse numbers on the surface properties was also investigated. Cell culture test was used to evaluate cell adhesion property on the PC films before and after treatment. The results obtained from this test showed that after laser treatment, the cells were attached and proliferated extensively on the Nd:YAG laser treated films in comparison with the unmodified PC. Moreover, it was revealed that a decrease in the laser beam diameter and an increase in the irradiated pulse numbers increased surface wettability and caused a better cell attachment on the polymer surface. The obtained results also showed that a decrease in the laser beam diameter and an increase in the irradiated pulse numbers increased surface wettability and caused a better cell attachment on the polymer surface.

  13. Performance study of highly efficient 520 W average power long pulse ceramic Nd:YAG rod laser

    Science.gov (United States)

    Choubey, Ambar; Vishwakarma, S. C.; Ali, Sabir; Jain, R. K.; Upadhyaya, B. N.; Oak, S. M.

    2013-10-01

    We report the performance study of a 2% atomic doped ceramic Nd:YAG rod for long pulse laser operation in the millisecond regime with pulse duration in the range of 0.5-20 ms. A maximum average output power of 520 W with 180 J maximum pulse energy has been achieved with a slope efficiency of 5.4% using a dual rod configuration, which is the highest for typical lamp pumped ceramic Nd:YAG lasers. The laser output characteristics of the ceramic Nd:YAG rod were revealed to be nearly equivalent or superior to those of high-quality single crystal Nd:YAG rod. The laser pump chamber and resonator were designed and optimized to achieve a high efficiency and good beam quality with a beam parameter product of 16 mm mrad (M2˜47). The laser output beam was efficiently coupled through a 400 μm core diameter optical fiber with 90% overall transmission efficiency. This ceramic Nd:YAG laser will be useful for various material processing applications in industry.

  14. Effects of various parameters of the 1064 nm Nd:YAG laser for the treatment of enlarged facial pores.

    Science.gov (United States)

    Roh, Mi Ryung; Chung, Hye Jin; Chung, Kee Yang

    2009-01-01

    A variety of treatment modalities have been used to reduce the size of enlarged facial pores without obvious success. To assess and compare the effects of various parameters of a 1064 nm Nd:YAG laser in the treatment of enlarged facial pores. This was a prospective intra-individual left-right comparative study. A total of 40 individuals with enlarged facial pores were recruited for this study. Ten individuals were respectively treated on one half of the face with a quasi long-pulsed 1064 nm Nd:YAG laser (method 1), a Q-switched 1064 nm Nd:YAG laser (method 2), both quasi long-pulsed and Q-switched 1064 nm Nd:YAG lasers without carbon-suspended lotion (method 3), and both quasi long-pulsed and Q-switched 1064 nm Nd:YAG lasers with carbon-suspended lotion (method 4). The other half of the face was left untreated as a control. Five laser sessions were performed with a 3-week interval. The pore sizes were measured using an image analysis program and the sebum level was measured with a Sebumeter before and after the treatments. The pore size and sebum level decreased in all four methods on the treated side compared to the control (p pore size and sebum level.

  15. Laser welding by dental Nd:YAG device

    Science.gov (United States)

    Fornaini, Carlo; Bertrand, Caroline; Merigo, Elisabetta; Bonanini, Mauro; Rocca, Jean-Paul; Nammour, Samir

    2009-06-01

    Welding laser was introduced in jewellery during years 70 and, just after, was successfully used also by dental technicians. Welding laser gives a great number of advantages, versus traditional welding and, for this reason, this procedure had a great diffusion in the technician laboratories and stimulated the companies to put in the market more and more evolutes appliances. Some aspects, such great dimensions, high costs and delivery system today still characterize these machines by fixed lenses, which have strictly limited its use only to technician laboratories. The aim of this study is to demonstrate the possibility, by using a fibber-delivered laser normally utilized in the dental office, to make, by dentist himself in his office, welding on different metals and to evaluate advantages and possibilities of this new technique.

  16. Nd:YAG Laser-aided ceramic brackets debonding: Effects on shear bond strength and enamel surface

    Science.gov (United States)

    Han, Xianglong; Liu, Xiaolin; Bai, Ding; Meng, Yao; Huang, Lan

    2008-11-01

    In order to evaluate the efficiency of Nd:YAG laser-aided ceramic brackets debonding technique, both ceramic brackets and metallic brackets were bonded with orthodontic adhesive to 30 freshly extracted premolars. The specimens were divided into three groups, 10 in each, according to the brackets employed and the debonding techniques used: (1) metallic brackets with shear debonding force, (2) ceramic brackets with shear debonding force, and (3) ceramic brackets with Nd:YAG laser irradiation. The result showed that laser irradiation could diminish shear bond strength (SBS) significantly and produce the most desired ARI scores. Moreover, scanning electron microscopy investigation displayed that laser-aided technique induced little enamel scratch or loss. It was concluded that Nd:YAG laser could facilitate the debonding of ceramic brackets and diminish the amount of remnant adhesive without damaging enamel structure.

  17. Nd:YAG Laser-aided ceramic brackets debonding: Effects on shear bond strength and enamel surface

    International Nuclear Information System (INIS)

    Han Xianglong; Liu Xiaolin; Bai Ding; Meng Yao; Huang Lan

    2008-01-01

    In order to evaluate the efficiency of Nd:YAG laser-aided ceramic brackets debonding technique, both ceramic brackets and metallic brackets were bonded with orthodontic adhesive to 30 freshly extracted premolars. The specimens were divided into three groups, 10 in each, according to the brackets employed and the debonding techniques used: (1) metallic brackets with shear debonding force, (2) ceramic brackets with shear debonding force, and (3) ceramic brackets with Nd:YAG laser irradiation. The result showed that laser irradiation could diminish shear bond strength (SBS) significantly and produce the most desired ARI scores. Moreover, scanning electron microscopy investigation displayed that laser-aided technique induced little enamel scratch or loss. It was concluded that Nd:YAG laser could facilitate the debonding of ceramic brackets and diminish the amount of remnant adhesive without damaging enamel structure

  18. Effects of Nd:YAG and CO2 lasers on cerebral microvasculature. Study in normal rabbit brain.

    Science.gov (United States)

    Kuroiwa, T; Tsuyumu, M; Takei, H; Inaba, Y

    1986-01-01

    The effect of Nd:YAG and CO2 laser beams on cerebral microvasculature was examined in experimental animals. Soft x-ray microangiography and histological examination of the brain after Nd:YAG laser exposure revealed broad avascular or oligovascular zones in the irradiated and the surrounding edematous tissue, in which the surviving vessels were narrowed and tapered without significant leakage of blood. After CO2 laser exposure, a wedge-shaped tissue defect surrounded by layers of charring, coagulation, and edema was observed. The main finding in the surrounding coagulation and edematous layers was dilatation of the vessels. Hemorrhage was sometimes observed, mainly in the edematous layer. These findings seem to explain the effective hemostatic capability of the Nd:YAG laser and the occasional hemorrhage following CO2 laser exposure, especially at high energy output.

  19. Nd:YAG Laser-aided ceramic brackets debonding: Effects on shear bond strength and enamel surface

    Energy Technology Data Exchange (ETDEWEB)

    Han Xianglong [State Key Laboratory of Oral Diseases, Sichuan University, Chengdu 610041 (China); Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041 (China); Liu Xiaolin [Department of Orthodontics, Stomatology Hospital, Dalian University, Dalian 116021 (China); Bai Ding [State Key Laboratory of Oral Diseases, Sichuan University, Chengdu 610041 (China); Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041 (China)], E-mail: baiding88@hotmail.com; Meng Yao; Huang Lan [Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041 (China)

    2008-11-15

    In order to evaluate the efficiency of Nd:YAG laser-aided ceramic brackets debonding technique, both ceramic brackets and metallic brackets were bonded with orthodontic adhesive to 30 freshly extracted premolars. The specimens were divided into three groups, 10 in each, according to the brackets employed and the debonding techniques used: (1) metallic brackets with shear debonding force, (2) ceramic brackets with shear debonding force, and (3) ceramic brackets with Nd:YAG laser irradiation. The result showed that laser irradiation could diminish shear bond strength (SBS) significantly and produce the most desired ARI scores. Moreover, scanning electron microscopy investigation displayed that laser-aided technique induced little enamel scratch or loss. It was concluded that Nd:YAG laser could facilitate the debonding of ceramic brackets and diminish the amount of remnant adhesive without damaging enamel structure.

  20. Nd:YAG laser associated with metal salts solutions in the treatment of dentinal hypersensitivity

    International Nuclear Information System (INIS)

    Glauche, Carlos Eugenio Correia

    2001-01-01

    The objective of this study was to observe the ultrastructural changes caused by the radiation of Nd:YAG laser on the tooth tissue and determine qualitatively the presence of Sn ++ , Sr ++ and F - , inside the dentin, being it irradiated or not. Ten molar teeth recently extracted were cut into 2 mm discs. The samples were soaked in a EDTA solution at 17% for 2 minutes and divided into five groups. Group I: the samples were irradiated with Nd:YAG laser (1,5 W, 100 mJ, 15 Hz, 150 μs and 125 J/cm 2 ) and after that, a treatment with an SnF 2 aqueous solution at 10% for 30 minutes. Group II: the samples got laser irradiation with the same parameters and then a treatment with an SrCl 2 solution at 10% as a toothpaste (Sensodyne TM ) for 30 minutes. Group III: the samples just got a treatment with a SnF 2 aqueous solution at 10% for 30 minutes. Group IV: the samples just got a treatment with a SrCl 2 toothpaste (Sensodyne TM ) for 30 minutes. Group V: samples that just got laser irradiation in the parameters above mentioned. Then, all samples were prepared for scanning electronic microscopy (SEM) and the samples of groups I, II, III and IV for energy dispersive X-ray microanalysis (EDX). The ultrastructure aspect of the dentin showed the surface totally altered by the irradiation. Pits and whitish globules were found amidst an heterogenous and rough structure, due to the melting and resolidification of the dental structure. Craters were also observed. Carbonization areas were absent. Ions Sn ++ were found at a depth of 250 μm in the samples of group I (Nd:YAG + SnF 2 ), whereas in the samples of group III, Sn ++ were not found deeper than 100 μm. Sr ++ could be detected at least at 500 μm in the inner dentin in the samples of group II (Nd:YAG + SrCl 2 ). However, Sn ++ were not found at 50 μm in group IV samples. Ions F - were just found in the irradiated samples of group I. According to the study results we observed that through ultrastructural changes, caused by

  1. Hypopigmentation Induced by Frequent Low-Fluence, Large-Spot-Size QS Nd:YAG Laser Treatments.

    Science.gov (United States)

    Wong, Yisheng; Lee, Siong See Joyce; Goh, Chee Leok

    2015-12-01

    The Q-switched 1064-nm neodymium-doped yttrium aluminum garnet (QS 1064-nm Nd:YAG) laser is increasingly used for nonablative skin rejuvenation or "laser toning" for melasma. Multiple and frequent low-fluence, large-spot-size treatments are used to achieve laser toning, and these treatments are associated with the development of macular hypopigmentation as a complication. We present a case series of three patients who developed guttate hypomelanotic macules on the face after receiving laser toning treatment with QS 1064-nm Nd:YAG.

  2. Use of contact Nd:YAG sapphire-laser system for performing partial hepatectomy and splenectomy in dogs

    Science.gov (United States)

    Yu, Chibing; Jing, Shujuan; Cai, Huimin; Shao, Lanxing; Zou, Hegui

    1993-03-01

    An Nd:YAG Sapphire laser blade was used for performing hepatectomy and splenectomy in dogs. The results suggest that a laser blade provides a new way to reduce intraoperative bleeding and to minimize tissue damage. In recent years, there have been some reports on performing surgical procedures using a contact Nd:YAG Sapphire laser system. The current animal study was conducted in order to explore the capability of incision and excision of the laser tip, the damage to the tissue, and the recovery course.

  3. Single-mode, All-Solid-State Nd:YAG Laser Pumped UV Converter

    Science.gov (United States)

    Prasad, Narasimha S.; Armstrong, Darrell, J.; Edwards, William C.; Singh, Upendra N.

    2008-01-01

    In this paper, the status of a high-energy, all solid-state Nd:YAG laser pumped nonlinear optics based UV converter development is discussed. The high-energy UV transmitter technology is being developed for ozone sensing applications from space based platforms using differential lidar technique. The goal is to generate greater than 200 mJ/pulse with 10-50 Hz PRF at wavelengths of 308 nm and 320 nm. A diode-pumped, all-solid-state and single longitudinal mode Nd:YAG laser designed to provide conductively cooled operation at 1064 nm has been built and tested. Currently, this pump laser provides an output pulse energy of >1 J/pulse at 50 Hz PRF and a pulsewidth of 22 ns with an electrical-to-optical system efficiency of greater than 7% and a M(sup 2) value of UV converter arrangement basically consists of an IR Optical Parametric Oscillator (OPO) and a Sum Frequency Generator (SFG) setups that are pumped by 532 nm wavelength obtained via Second Harmonic Generation (SHG). In this paper, the operation of an inter cavity SFG with CW laser seeding scheme generating 320 nm wavelength is presented. Efforts are underway to improve conversion efficiency of this mJ class UV converter by modifying the spatial beam profile of the pump laser.

  4. A 1J LD pumped Nd:YAG pulsed laser system

    Science.gov (United States)

    Yi, Xue-bin; Wang, Bin; Yang, Feng; Li, Jing; Liu, Ya-Ping; Li, Hui-Jun; Wang, Yu; Chen, Ren

    2017-11-01

    A 1J LD pumped Nd;YAG pulsed laser was designed. The laser uses an oscillation and two-staged amplification structure, and applies diode bar integrated array as side-pump. The TEC temperature control device combing liquid cooling system is organized to control the temperature of the laser system. This study also analyzed the theoretical threshold of working material, the effect of thermal lens and the basic principle of laser amplification. The results showed that the laser system can achieve 1J, 25Hz pulse laser output, and the laser pulse can be output at two width: 6-7ns and 10ns, respectively, and the original beam angle is 1.2mrad. The laser system is characterized by small size, light weight, as well as good stability, which make it being applied in varied fields such as photovoltaic radar platform and etc

  5. Design of a high-power Nd:YAG Q-switched laser cavity

    Science.gov (United States)

    Singh, Ikbal; Kumar, Avinash; Nijhawan, O. P.

    1995-06-01

    An electro-optically Q-switched Nd:YAG laser resonator that uses two end prisms placed orthogonally perpendicular to each other has been designed. This configuration improves the stability of the resonator and does not alter the characteristics of the electro-optical Q switch. The outcoupling ratio of the cavity is optimized by a change in the azimuthal angle of a phase-matched Porro prism placed at one end of the cavity. The prism placed at the other end of the cavity is designed so that it introduces a phase change of Pi , regardless of its orientation and index of refraction, resulting in a more efficient and stable cavity.

  6. Comparison of pulsed Nd : YAG laser welding qualitative features with plasma plume thermal characteristics

    International Nuclear Information System (INIS)

    Sabbaghzadeh, J; Dadras, S; Torkamany, M J

    2007-01-01

    A spectroscopic approach was used to study the effects of different operating parameters on st14 sheet metal welding with a 400 W maximum average power pulsed Nd : YAG laser. The parameters included pulse duration and peak power and type and flow rate of the assist gas and welding speed. Weld quality, including penetration depth and melt width, has been compared with the FeI electron temperature obtained from spectroscopic observations of a plasma plume. A correlation between the standard deviation of the electron temperature and the quality of welding has also been found

  7. A study on the clinical characteristics of treating nevus of Ota by Q-switched Nd:YAG laser.

    Science.gov (United States)

    Yan, Liu; Di, Li; Weihua, Wang; Feng, Liu; Ruilian, Li; Jun, Zhou; Hui, Su; Zhaoxia, Ying; Weihui, Zeng

    2018-01-01

    The purpose of this study was to retrospectively analyze the clinical characteristics of treating nevus of Ota by Q-switched Nd:YAG laser in Laser Cosmetology Center of Department of Dermatology, the Second Hospital, Xi'an Jiaotong University. The data of 1168 patients of nevus of Ota were analyzed retrospectively, which included the correlation among lesion color, treatment sessions, sex, age, lesion types, and effect. The Q-switched (QS) Nd:YAG laser system had a higher number of treatment sessions which were positively associated with a better response to treatment. Other variables, including gender, age, the categorization of the lesion according to Tanino's classification, and the color of the lesion, were not associated with the response to treatment. The treatment of nevus of Ota with QS Nd:YAG laser is safe and effective, with rare complications.

  8. High-frequency ultrasound evaluation of cellulite treated with the 1064 nm Nd:YAG laser.

    Science.gov (United States)

    Bousquet-Rouaud, Regine; Bazan, Marie; Chaintreuil, Jean; Echague, Agustina Vila

    2009-03-01

    To investigate non-invasive laser treatment for cellulite using the 1064 nm Nd:YAG laser and to correlate clinical results with high-frequency skin ultrasound images. Twelve individuals of normal weight were treated on either the left or right posterior side of the thigh with the following parameters: fluence 30 J/cm, 18 mm spot size and dynamic cooling device pulse duration of 30 ms. Three treatments were performed at intervals of 3-4 weeks, and followed-up 1 and 3 months after the last session. Photographs and ultrasound imaging were assessed before each session. The 1064 nm Nd:YAG laser resulted in a tightening of the skin and an improvement in cellulite. No side effects were reported. High-resolution ultrasound imaging showed a significant improvement in dermis density and a reduction of dermis thickness. The method is described in detail in Appendix 1. Infra-red lasers may constitute a safe and effective treatment for cellulite and high-frequency ultrasound imaging provides a quantitative and objective measurement of the treatment efficacy.

  9. Efficient continuous-wave 1112 nm Nd:YAG laser operation under direct diode pumping at 885 nm

    International Nuclear Information System (INIS)

    Gao, J; Dai, X J; Zhang, L; Wu, X D

    2013-01-01

    We report compact diode-end-pumped continuous-wave laser operation at 1112 nm under 885 nm diode-direct pumping for the first time. On the basis of the R 2 →Y 6 transition in a conventional Nd:YAG (yttrium aluminum garnet) single crystal, the maximum output power of 12.5 W is achieved, with an optical to optical efficiency of 46.6% and a slope efficiency of 52.9%. To the best of our knowledge, this represents the highest output at 1112 nm generated by a diode-end-pumped Nd:YAG laser. Furthermore, it is the highest optical to optical efficiency ever reported for 1112 nm Nd:YAG lasers. The short term power stability is ∼0.32% at 12.0 W output. (letter)

  10. Nd:YAG laser hyaloidotomy for valsalva pre-macular haemorrhage.

    LENUS (Irish Health Repository)

    Kirwan, R P

    2012-02-01

    AIM: To report a case of successful drainage of a large pre-macular haemorrhage using laser photo-disruption of the posterior hyaloid membrane. MATERIALS AND METHODS: A case report. RESULTS: A 47-year-old man presented acutely to our emergency department complaining of a 24-h history of sudden onset, painless and persistent loss of vision in his left eye. Immediately before noticing this loss of vision, he had been vomiting violently from excessive alcohol intake. The left visual acuity was counting fingers. Dilated fundoscopy of the left eye revealed a large pre-macular haemorrhage which was 14 disc diametres in size. Clotting investigations were normal. A diagnosis of valsalva retinopathy was made and the patient elected to receive a prompt neodymium-doped yttrium aluminium garnet (Nd:YAG) laser posterior hyaloidotomy as an outpatient. At 1 week follow-up, the haemorrhage had drained completely into the vitreous space revealing a healthy macula and the visual acuity had improved to 6\\/12 unaided. At 6-month follow-up the left visual acuity stabilised at 6\\/9 unaided. CONCLUSION: Nd:YAG laser posterior hyaloidotomy is a useful outpatient procedure for successful clearance of large pre-macular haemorrhages that offers patients rapid recovery of visual acuity and the avoidance of more invasive intraocular surgery.

  11. Solar-Pumped TEM₀₀ Mode Nd:YAG laser.

    Science.gov (United States)

    Liang, Dawei; Almeida, Joana

    2013-10-21

    Here we show a significant advance in solar-pumped laser beam brightness by utilizing a 1.0 m diameter Fresnel lens and a 3 mm diameter Nd:YAG single-crystal rod. The incoming solar radiation is firstly focused by the Fresnel lens on a solar tracker. A large aspheric lens and a 2D-CPC concentrator are then combined to further compress the concentrated solar radiation along the thin laser rod within a V-shaped pumping cavity. 2.3 W cw TEM₀₀ (M² ≤ 1.1) solar laser power is finally produced, attaining 1.9 W laser beam brightness figure of merit, which is 6.6 times higher than the previous record. For multimode operation, 8.1 W cw laser power is produced, corresponding to 143% enhancement in collection efficiency.

  12. Compact, passively Q-switched Nd:YAG laser for the MESSENGER mission to Mercury.

    Science.gov (United States)

    Krebs, Danny J; Novo-Gradac, Anne-Marie; Li, Steven X; Lindauer, Steven J; Afzal, Robert S; Yu, Anthony W

    2005-03-20

    A compact, passively Q-switched Nd:YAG laser has been developed for the Mercury Laser Altimeter, an instrument on the Mercury Surface, Space Environment, Geochemistry, and Ranging mission to the planet Mercury. The laser achieves 5.4% efficiency with a near-diffraction-limited beam. It passed all space-flight environmental tests at subsystem, instrument, and satellite integration testing and successfully completes a postlaunch aliveness check en route to Mercury. The laser design draws on a heritage of previous laser altimetry missions, specifically the Ice Cloud and Elevation Satellite and the Mars Global Surveyor, but incorporates thermal management features unique to the requirements of an orbit of the planet Mercury.

  13. Efficacy of long pulse Nd:YAG laser versus fractional Er:YAG laser in the treatment of hand wrinkles.

    Science.gov (United States)

    Robati, Reza M; Asadi, Elmira; Shafiee, Anoosh; Namazi, Nastaran; Talebi, Atefeh

    2018-04-01

    There are different modalities for hand rejuvenation. Fractional Er:YAG laser and long pulse Nd:YAG laser were introduced for treating hand wrinkles. We plan to compare fractional Er:YAG laser and long pulse Nd:YAG laser in a randomized controlled double-blind design with multiple sessions and larger sample size in comparison with previous studies. Thirty-three participants with hand wrinkles entered this study. They were randomly allocated to undergo three monthly laser treatments on each hand, one with a fractional Er:YAG laser and the other with a long pulse Nd:YAG laser. The evaluations included assessment of clinical improvement determined by two independent dermatologists not enrolled in the treatment along with measuring skin biomechanical property of hands using a sensitive biometrologic device with the assessment of cutaneous resonance running time (CRRT). Moreover, potential side effects and patients' satisfaction have been documented at baseline, 1 month after each treatment, and 3 months after the final treatment session. Clinical evaluation revealed both modalities significantly reduce hand wrinkles (p value lasers. Mean CRRT values also decreased significantly after the laser treatment compared to those of the baseline in both laser groups. There was no serious persistent side effect after both laser treatments. Both fractional Er:YAG and long pulse Nd:YAG lasers show substantial clinical improvement of hand skin wrinkles with no serious side effects. However, combination treatment by these lasers along with the other modalities such as fat transfer could lead to better outcomes in hand rejuvenation. IRCT2016032020468N4.

  14. Optical spectroscopy in channel waveguides made in Nd:YAG crystals by femtosecond laser writing

    International Nuclear Information System (INIS)

    Torchia, G.A.; Mendez, C.; Roso, L.; Tocho, J.O.

    2008-01-01

    In this work, we present an optical characterization of channel waveguides fabricated by means of femtosecond laser writing on Nd:YAG substrates. These guiding structures show a refractive index increment of about 1x10 -3 which allows TE propagation. By pumping with a CW solid-state laser at 532 nm reaching the 2 G 9/2 and 4 G 7/2 manifolds of Nd 3+ ions, we have explored the emission band corresponding to 4 F 3/2 → 4 I 9/2 optical transitions (peaked at 890 nm). From data, we have found that emission showed similar characteristics for waveguide and bulk. On the other hand, the lifetime corresponding to the 4 F 3/2 metaestable level was determined to be 240 μs for bulk and waveguide. Summarizing, we have made suitable channel waveguides in Nd:YAG crystals, by fs interaction, with similar spectroscopic properties to those of the bulk, a fact that boosters the photonics application of these devices. For the first time to our knowledge, a direct index increment waveguide made by interaction with ultra-short intense pulses in YAG crystals has been performed. This fabrication procedure can be an efficient tool to make several optical circuits in active materials by means of the one-step, fast and low-cost processing

  15. Comparison of the ablation ability of nucleus pulposus after 1,064 nm Nd:YAG laser and 980 nm diode laser radiation.

    Science.gov (United States)

    Yin, Jian; Han, Zhengfeng; Guo, Baofeng; Guo, Han; Zhang, Tongtong; Zeng, Yanjun; Ren, Longxi

    2015-07-01

    To compare the ablation ability of nucleus pulposus after 1,064 nm Nd:YAG laser and 980 nm diode laser radiation. Goat spine specimen (GSS) was radiated using Nd:YAG laser and 980 nm diode laser and then divided into five groups based on the final energy--200, 400, 600, 800 and 1,000 J groups. The ablation quality of nucleus pulposus after radiation was recorded. The ablation quality of GSS was greater at higher radiation energies in both lasers. When compared at the same energy level, the ablation quality of GSS was greater in 980 nm diode laser than in 1,064 nm Nd:YAG laser. Statistical significance was observed in 200 and 400 J groups (P diode laser showed better ablation ability than 1,064 nm Nd:YAG laser.

  16. High power Nd:YAG laser welding in manufacturing of vacuum vessel of fusion reactor

    Energy Technology Data Exchange (ETDEWEB)

    Jokinen, Tommi E-mail: tommi.jokinen@vtt.fi; Kujanpaeae, Veli E-mail: veli.kujanpaa@lut.fi

    2003-09-01

    Laser welding has shown many advantages over traditional welding methods in numerous applications. The advantages are mainly based on very precise and powerful heat source of laser light, which change the phenomena of welding process when compared with traditional welding methods. According to the phenomena of the laser welding, penetration is deeper and thus welding speed is higher. Because of the precise power source and high-welding speed, the heat input to the workpiece is small and distortions are reduced. Also, the shape of laser weld is less critical for distortions than traditional welds. For welding thick sections, the usability of lasers is not so practical than with thin sheets, because with power levels of present Nd:YAG lasers depth of penetration is limited up to about 10 mm by single-pass welding. One way to overcome this limitation is to use multi-pass laser welding, in which narrow gap and filler wire is applied. By this process, thick sections can be welded with smaller heat input and then smaller distortions and the process seems to be very effective comparing 'traditional' welding methods, not only according to the narrower gap. Another way to increase penetration and fill the groove is by using the so-called hybrid process, in which laser and GMAW (gas metal arc welding) are combined. In this paper, 20-mm thick austenitic stainless steel was welded using narrow gap configuration with a multi-pass technique. Two welding procedures were used: Nd:YAG laser welding with filler wire and with addition of GMAW, the hybrid process. In the welding experiments, it was noticed that both processes are feasible for welding thicker sections with good quality and with minimal distortions. Thus, these processes should be considered when the evaluation of the welding process is done for joining vacuum vessel sectors of ITER.

  17. Spectral investigation of highly ionized bismuth plasmas produced by subnanosecond Nd:YAG laser pulses

    Science.gov (United States)

    Wu, Tao; Higashiguchi, Takeshi; Li, Bowen; Arai, Goki; Hara, Hiroyuki; Kondo, Yoshiki; Miyazaki, Takanori; Dinh, Thanh-Hung; Dunne, Padraig; O'Reilly, Fergal; Sokell, Emma; O'Sullivan, Gerry

    2016-02-01

    The unresolved transition arrays (UTAs) emitted from laser produced bismuth (Bi) plasma sources show potential for single-shot live cell imaging. We have measured extreme ultraviolet spectra from bismuth laser produced plasmas in the 1-7 nm region using a λ = 1064 nm Nd:YAG laser with a pulse duration of 150 ps. Comparison of spectra obtained under different laser power densities with calculations using the Hartree-Fock with configuration interaction Cowan suite of codes and the UTA formalism, as well as consideration of previous predictions of isoelectronic trends, are employed to identify lines and a number of new features in spectra from Bi XXIII to Bi XLVII. The results show that Δn = 0, n = 4-4 emission from highly charged ions merges to form intense UTAs in the 4 nm region and Δn = 1, n = 4-5 resonance transitions UTAs dominate the 1-3 nm region of the Bi spectrum.

  18. Micro-Welding of Copper Plate by Frequency Doubled Diode Pumped Pulsed Nd:YAG Laser

    Science.gov (United States)

    Nakashiba, Shin-Ichi; Okamoto, Yasuhiro; Sakagawa, Tomokazu; Takai, Sunao; Okada, Akira

    A pulsed laser of 532 nm wavelength with ms range pulse duration was newly developed by second harmonic generation of diode pumped pulsed Nd:YAG laser. High electro-optical conversion efficiency more than 13% could be achieved, and 1.5 kW peak power green laser pulse was put in optical fiber of 100 μm in diameter. In micro- welding of 1.0 mm thickness copper plate, a keyhole welding was successfully performed by 1.0 kW peak power at spot diameter less than 200 μm. The frequency doubled pulsed laser improved the processing efficiency of copper welding, and narrow and deep weld bead was stably obtained.

  19. Precise alignment of a longitudinal Pockels Cell for Q-switch operation Nd:YAG laser

    International Nuclear Information System (INIS)

    Nisperuza, D.; Botero, G.; Bastidas, A.

    2009-01-01

    The failure to accurately center optical components may, especially in the case of high gain of the Nd:YAG lasers, produce strong parasitic off-axis laser action capable of causing severe component damage typically to the Pockels cell. We report a precise longitudinal alignment of the Pockels cell by modulating the laser polarization using an experimental setup of circular dichroism. This procedure is based on the use of an analyzer at 0 o or 45 o of the Pockels cell axes, and it allows us to adjust the Q-switching delay for best pulse shape, maximum output energy and to reduce the lack of symmetry of the spot laser considerably. (Author)

  20. Spectral investigation of highly ionized bismuth plasmas produced by subnanosecond Nd:YAG laser pulses

    International Nuclear Information System (INIS)

    Wu, Tao; Higashiguchi, Takeshi; Arai, Goki; Hara, Hiroyuki; Kondo, Yoshiki; Miyazaki, Takanori; Dinh, Thanh-Hung; Li, Bowen; Dunne, Padraig; O’Reilly, Fergal; Sokell, Emma; O’Sullivan, Gerry

    2016-01-01

    The unresolved transition arrays (UTAs) emitted from laser produced bismuth (Bi) plasma sources show potential for single-shot live cell imaging. We have measured extreme ultraviolet spectra from bismuth laser produced plasmas in the 1–7 nm region using a λ = 1064 nm Nd:YAG laser with a pulse duration of 150 ps. Comparison of spectra obtained under different laser power densities with calculations using the Hartree–Fock with configuration interaction Cowan suite of codes and the UTA formalism, as well as consideration of previous predictions of isoelectronic trends, are employed to identify lines and a number of new features in spectra from Bi XXIII to Bi XLVII. The results show that Δn = 0, n = 4–4 emission from highly charged ions merges to form intense UTAs in the 4 nm region and Δn = 1, n = 4–5 resonance transitions UTAs dominate the 1–3 nm region of the Bi spectrum. (paper)

  1. Time-dependent preparation of gelatin-stabilized silver nanoparticles by pulsed Nd:YAG laser

    Science.gov (United States)

    Darroudi, Majid; Ahmad, M. B.; Zamiri, Reza; Abdullah, A. H.; Ibrahim, N. A.; Sadrolhosseini, A. R.

    2011-03-01

    Colloidal silver nanoparticles (Ag-NPs) were successfully prepared using a nanosecond pulsed Nd:YAG laser, λ = 1064 nm, with laser fluence of approximately about 360 mJ/pulse, in an aqueous gelatin solution. In this work, gelatin was used as a stabilizer, and the size and optical absorption properties of samples were studied as a function of the laser ablation times. The results from the UV-vis spectroscopy demonstrated that the mean diameter of Ag-NPs decrease as the laser ablation time increases. The Ag-NPs have mean diameters ranging from approximately 10 nm to 16 nm. Compared with other preparation methods, this work is clean, rapid, and simple to use.

  2. Histologic evaluation of laser lipolysis: pulsed 1064-nm Nd:YAG laser versus cw 980-nm diode laser.

    Science.gov (United States)

    Mordon, Serge; Eymard-Maurin, Anne Françoise; Wassmer, Benjamin; Ringot, Jean

    2007-01-01

    The use of the laser as an auxiliary tool has refined the traditional technique for lipoplasty. During laser lipolysis, the interaction between the laser and the fat produced direct cellular destruction before the suction, reduced bleeding, and promoted skin tightening. This study sought to perform a comparative histologic evaluation of laser lipolysis with the pulsed 1064-nm Nd:YAG laser versus a continuous 980-nm diode laser. A pulsed 1064-nm Nd:YAG (Smart-Lipo; Deka, Italy) and a CW 980-nm diode laser (Pharaon, Osyris, France) were evaluated at different energy settings for lipolysis on the thighs of a fresh cadaver. The lasers were coupled to a 600-microm optical fiber inserted in a 1-mm diameter cannula. Biopsy specimens were taken on irradiated and non-irradiated areas. Hematoxylin-erythrosin-safran staining and immunostaining (anti-PS100 polyclonal antibody) were performed to identify fat tissue damage. In the absence of laser exposures (control specimens), cavities created by cannulation were seen; adipocytes were round in appearance and not deflated. At low energy settings, tumescent adipocytes were observed. At higher energy settings, cytoplasmic retraction, disruption of membranes, and heat-coagulated collagen fibers were noted; coagulated blood cells were also present. For the highest energy settings, carbonization of fat tissue involving fibers and membranes was clearly seen. For equivalent energy settings, 1064-nm and 980-nm wavelengths gave similar histologic results. Laser lipolysis is a relatively new technique that is still under development. Our histologic findings suggest several positive benefits of the laser, including skin retraction and a reduction in intraoperative bleeding. The interaction of the laser with the tissue is similar at 980 nm and 1064 nm with the same energy settings. Because higher volumes of fat are removed with higher total energy, a high-power 980-nm diode laser could offer an interesting alternative to the 1064-nm Nd:YAG

  3. Mathematical simulation of the thermal diffusion in dentine irradiated with Nd:YAG laser using finite difference method

    Science.gov (United States)

    Moriyama, Eduardo H.; Zangaro, Renato A.; Lobo, Paulo D. d. C.; Villaverde, Antonio G. J. B.; Watanabe-Sei, Ii; Pacheco, Marcos T. T.; Otsuka, Daniel K.

    2002-06-01

    Thermal damage in dental pulp during Nd:YAG laser irradiation have been studied by several researchers; but due to dentin inhomogeneous structure, laser interaction with dentin in the hypersensitivity treatment are not fully understood. In this work, heat distribution profile on human dentine samples irradiated with Nd:YAG laser was simulated at surface and subjacent layers. Calculations were carried out using the Crank-Nicolson's finite difference method. Sixteen dentin samples with 1,5 mm of thickness were evenly distributed into four groups and irradiated with Nd:YAG laser pulses, according to the following scheme: (I) 1 pulse of 900 mJ, (II) 2 pulses of 450 mJ, (III) 3 pulses of 300 mJ, (IV) 6 pulses of 150 mJ; corresponding to a total laser energy of 900 mJ. The pulse interval was 300ms, the pulse duration of 900 ms and irradiated surface area of 0,005 mm2. Laser induced morphological changes in dentin were observed for all the irradiated samples. The heat distribution throughout the dentin layer, from the external dentin surface to the pulpal chamber wall, was calculated for each case, in order to obtain further information about the pulsed Nd:YAG laser-oral hard tissue interaction. The simulation showed significant differences in the final temperature at the pulpal chamber, depending on the exposition time and the energy contained in the laser pulse.

  4. Argon green-Nd: YAG dual laser posterior hyaloidotomy: An innovative approach toward treatment of premacular hemorrhage

    Directory of Open Access Journals (Sweden)

    Ashish Sharma

    2013-01-01

    Full Text Available Background: Neodymium: YAG (Nd: YAG laser and argon laser has been used to treat premacular hemorrhage either alone or rarely in combination. Materials and Methods: We describe a new technique of treating premacular hemorrhage by performing hyaloidotomy using a combination of argon green-Nd: YAG laser. We utilized subthreshold energy levels of Nd: YAG laser of 2.0 mJ as compared to the normal recommendation of 3.6-50 mJ. Results and Conclusions: This technique is easy, effective, and safe to manage premacular hemorrhage. The principle behind this combined laser treatment was to make the internal limiting membrane (ILM taut by initial exposure to argon green laser, which allowed us to employ the subthreshold energy levels of Nd: YAG laser. We would like to assess the role of this combined treatment modality in comparison to other modalities, including solitary laser therapy in the management of premacular hemorrhage by performing a prospective, randomized long-term study.

  5. Microchannel fabrication on cyclic olefin polymer substrates via 1064 nm Nd:YAG laser ablation

    Energy Technology Data Exchange (ETDEWEB)

    McCann, Ronán [Advanced Processing Technology Research Centre, Dublin City University, Glasnevin, Dublin 9 (Ireland); School of Mechanical and Manufacturing Engineering, Dublin City University, Dublin 9 (Ireland); Irish Separation Science Cluster, National Centre for Sensor Research, Dublin City University, Dublin 9 (Ireland); National Centre for Plasma Science and Technology, Dublin City University, Dublin 9 (Ireland); Bagga, Komal; Groarke, Robert [Advanced Processing Technology Research Centre, Dublin City University, Glasnevin, Dublin 9 (Ireland); School of Mechanical and Manufacturing Engineering, Dublin City University, Dublin 9 (Ireland); Irish Separation Science Cluster, National Centre for Sensor Research, Dublin City University, Dublin 9 (Ireland); Stalcup, Apryll [Irish Separation Science Cluster, National Centre for Sensor Research, Dublin City University, Dublin 9 (Ireland); School of Chemical Sciences, Dublin City University, Dublin 9 (Ireland); Vázquez, Mercedes, E-mail: mercedes.vazquez@dcu.ie [Advanced Processing Technology Research Centre, Dublin City University, Glasnevin, Dublin 9 (Ireland); Irish Separation Science Cluster, National Centre for Sensor Research, Dublin City University, Dublin 9 (Ireland); School of Chemical Sciences, Dublin City University, Dublin 9 (Ireland); Brabazon, Dermot [Advanced Processing Technology Research Centre, Dublin City University, Glasnevin, Dublin 9 (Ireland); School of Mechanical and Manufacturing Engineering, Dublin City University, Dublin 9 (Ireland); Irish Separation Science Cluster, National Centre for Sensor Research, Dublin City University, Dublin 9 (Ireland); National Centre for Plasma Science and Technology, Dublin City University, Dublin 9 (Ireland)

    2016-11-30

    Highlights: • Rapid single-step microchannel fabrication on optically transparent cyclic olefin polymer using IR Nd:YAG laser. • Ability to tailor channel depth between 12–47 μm demonstrated for single laser pass. • Use of multiple laser passes showed capability for finer depth control. • Potential applications in lab-on-chip and microfluidic devices. - Abstract: This paper presents a method for fabrication of microchannels on cyclic olefin polymer films that have application in the field of microfluidics and chemical sensing. Continuous microchannels were fabricated on 188-μm-thick cyclic olefin polymer substrates using a picosecond pulsed 1064 nm Nd:YAG laser. The effect of laser fluence on the microchannel morphology and dimensions was analysed via scanning electron microscopy and optical profilometry. Single laser passes were found to produce v-shaped microchannels with depths ranging from 12 μm to 47 μm and widths from 44 μm to 154 μm. The ablation rate during processing was lower than predicted theoretically. Multiple laser passes were applied to examine the ability for finer control over microchannel morphology with channel depths ranging from 22 μm to 77 μm and channel widths from 59 μm to 155 μm. For up to five repeat passes, acceptable reproducibility was found in the produced microchannel morphology. Infrared spectroscopy revealed oxidation and dehydrogenation of the polymer surface following laser ablation. These results were compared to other work conducted on cyclic olefin polymers.

  6. Microchannel fabrication on cyclic olefin polymer substrates via 1064 nm Nd:YAG laser ablation

    International Nuclear Information System (INIS)

    McCann, Ronán; Bagga, Komal; Groarke, Robert; Stalcup, Apryll; Vázquez, Mercedes; Brabazon, Dermot

    2016-01-01

    Highlights: • Rapid single-step microchannel fabrication on optically transparent cyclic olefin polymer using IR Nd:YAG laser. • Ability to tailor channel depth between 12–47 μm demonstrated for single laser pass. • Use of multiple laser passes showed capability for finer depth control. • Potential applications in lab-on-chip and microfluidic devices. - Abstract: This paper presents a method for fabrication of microchannels on cyclic olefin polymer films that have application in the field of microfluidics and chemical sensing. Continuous microchannels were fabricated on 188-μm-thick cyclic olefin polymer substrates using a picosecond pulsed 1064 nm Nd:YAG laser. The effect of laser fluence on the microchannel morphology and dimensions was analysed via scanning electron microscopy and optical profilometry. Single laser passes were found to produce v-shaped microchannels with depths ranging from 12 μm to 47 μm and widths from 44 μm to 154 μm. The ablation rate during processing was lower than predicted theoretically. Multiple laser passes were applied to examine the ability for finer control over microchannel morphology with channel depths ranging from 22 μm to 77 μm and channel widths from 59 μm to 155 μm. For up to five repeat passes, acceptable reproducibility was found in the produced microchannel morphology. Infrared spectroscopy revealed oxidation and dehydrogenation of the polymer surface following laser ablation. These results were compared to other work conducted on cyclic olefin polymers.

  7. Diode-pumped laser amplifiers: application to 0.946 {mu}m Nd:YAG

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, Norman P [NASA Langley Research Center, Hampton, VA 23681 (United States); Axenson, Theresa J [Science and Technology Corporation, 10 Basil Sawyer Drive, Hampton, VA 23666 (United States); Jr, Donald J Reichle [NASA Langley Research Center, Hampton, VA 23681 (United States); Walsh, Brian M [NASA Langley Research Center, Hampton, VA 23681 (United States)

    2003-03-14

    A diode-pumped laser amplifier model is derived from first principles and applied to a Nd:YAG amplifier operating on the {sup 4}F{sub 3/2} to {sup 4}I{sub 9/2} transition at 0.946 {mu}m. The effects of amplified spontaneous emission are included in the model and the addition of this effect is shown to produce better agreement with the data. The amplifier model includes effects of the transverse and longitudinal variation of the pump beam, transverse and longitudinal variation of the probe beam, and multiple passes of the probe beam. Experimental results obtained with a quasi four-level Nd:YAG amplifier operating at 0.946 {mu}m are used to validate the model. The amplifier was evaluated as a function of the pump energy, the probe energy, the probe beam radius, the pulse repetition frequency and the temperature. For all of the experimental conditions, the experimental results and the model agree.

  8. Characterization of caries progression on dentin after irradiation with Nd:YAG laser by FTIR spectroscopy and fluorescence imaging

    Science.gov (United States)

    Ana, P. A.; Brito, A. M. M.; Zezell, D. M.; Lins, E. C. C. C.

    2015-06-01

    Considering the use of high intensity lasers for preventing dental caries, this blind in vitro study evaluated the compositional and fluorescence effects promoted by Nd:YAG laser (λ=1064 nm) when applied for prevention of progression of dentin caries, in association or not with topical application of acidulated phosphate fluoride (APF). Sixty bovine root dentin slabs were prepared and demineralized by 32h in order to create early caries lesions. After, the slabs were distributed into six experimental groups: G1- untreated and not submitted to a pH-cycling model; G2- untreated and submitted to a pH-cycling model; G3- acidulated phosphate fluoride application (APF); G4- Nd:YAG irradiation (84.9 J/cm2, 60 mJ/pulse); G5- treated with Nd:YAG+APF; G6- treated with APF+Nd:YAG. After treatments, the samples of groups G2 to G6 were submitted to a 4-day pH-cycling model in order to simulate the progression of early caries lesions. All samples were characterized by the micro-attenuated total reflection technique of Fourier transformed infrared spectroscopy (μATR-FTIR), using a diamond crystal, and by a fluorescence imaging system (FIS), in which it was used an illuminating system at λ= 405±30 nm. Demineralization promoted reduction in carbonate and phosphate contents, exposing the organic matter; as well, it was observed a significant reduction of fluorescence intensity. Nd:YAG laser promoted additional chemical changes, and increased the fluorescence intensity even with the development of caries lesions. It was concluded that the compositional changes promoted by Nd:YAG, when associated to APF, are responsible for the reduction of demineralization progression observed on root dentin.

  9. Development of high average power industrial Nd:YAG laser with peak power of 10 kW class

    International Nuclear Information System (INIS)

    Kim, Cheol Jung; Kim, Jeong Mook; Jung, Chin Mann; Kim, Soo Sung; Kim, Kwang Suk; Kim, Min Suk; Cho, Jae Wan; Kim, Duk Hyun

    1992-03-01

    We developed and commercialized an industrial pulsed Nd:YAG laser with peak power of 10 kW class for fine cutting and drilling applications. Several commercial models have been investigated in design and performance. We improved its quality to the level of commercial Nd:YAG laser by an endurance test for each parts of laser system. The maximum peak power and average power of our laser were 10 kW and 250 W, respectively. Moreover, the laser pulse width could be controlled from 0.5 msec to 20 msec continuously. Many optical parts were localized and lowered much in cost. Only few parts were imported and almost 90% in cost were localized. Also, to accellerate the commercialization by the joint company, the training and transfer of technology were pursued in the joint participation in design and assembly by company researchers from the early stage. Three Nd:YAG lasers have been assembled and will be tested in industrial manufacturing process to prove the capability of developed Nd:YAG laser with potential users. (Author)

  10. Nd:YAG laser combined with gold nanorods for potential application in port-wine stains: an in vivo study

    Science.gov (United States)

    Xing, Linzhuang; Chen, Bin; Li, Dong; Wu, Wenjuan; Wang, Guoxiang

    2017-11-01

    Neodymium:yttrium aluminum garnet (Nd:YAG) lasers exhibit considerable potential for treating deeply buried port-wine stains. However, the application of Nd:YAG laser is limited by its weak absorption to blood. This in vivo study tested the efficacy and safety of utilizing thiol-terminated methoxypolyethylene glycol-modified gold nanorods (PEG-GNRs) to enhance the absorption of Nd:YAG laser to blood. Mouse mesentery and dorsal skinfold chamber (DSC) model were prepared to analyze the thermal responses of a single venule without anatomic structures, as well as blood vessels in the complex structure of the skin, to laser light. After the injection of 0.44 mg of PEG-GNRs, the required threshold density of laser energy for blood coagulation and complete vasoconstriction decreased from 24 to 18 J/cm2 in the mesentery model and from 36 to 31 J/cm2 in the DSC model. The laser pulse required for blood coagulation and complete vasoconstriction decreased by 67.75% and 62.25% on average in the mesentery model and by 67.55% and 54.45% on average in the DSC model. Histological and histochemical results confirmed that PEG-GNRs are nontoxic in the entire mouse life span. Therefore, combining PEG-GNRs with Nd:YAG laser may be effective and safe for inducing an obvious thermal response of blood vessels under low energy density and minimal pulse conditions.

  11. Heating of multi-layered samples by a Nd: YAG pulsed laser

    Directory of Open Access Journals (Sweden)

    Diniz Neto, O. O.

    1998-04-01

    Full Text Available In the work we examine the heating of multi-layered samples by a powerful Nd - YAG pulsed láser. The samples are made of two and three layers, conductor-isolator (Al-Al2O3, conductor-conductor (Al-Ag; Al-Au and conductor-conductor-conductor (Al-Au-Ag; Ag-Au-Al. The transient behaviour of the temperature distribution throughout the sample is computed. We carry out three dimensional model calculations for the heating process in which we consider not only the temperature dependence of the sample thermal and optical parameters but also the space and time characteristics of the laser beam as the heating source. We showed the influence of the substrate in the thermal profile, in space and time, and máximum temperature on the multi-layered samples.

    Em nosso trabalho examinamos o aquecimento de amostras compostas de duas e três camadas, condutor- isolante e condutor-condutor, com um pulso potente de láser. O comportamento transiente da distribuição de temperatura através da amostra foi calculado. Em nosso modelo de calculo para o processo de aquecimento levamos em conta a dependência com a temperatura dos parâmetros térmicos (difusividade, capacidade e condutividade térmica, óticos (refletividade e coeficiente de absorção, bem como a dependência das condições de contorno com o tempo e consequentemente com a temperatura. Aplicamos nossa metodología para calcular o aquecimento amostras compostas: Al-Au, Al-Ag, Al-Al2O3, Al-Au-Ag e Ag-Au-Al. Concluimos que o substrato influencia as temperaturas máximas nas superfície exposta ao láser e a forma com que a frente de calor se propaga nas amostras termicamente finas.

  12. Diode-pumped cw Nd:YAG three-level laser at 869 nm.

    Science.gov (United States)

    Lü, Yanfei; Xia, Jing; Cheng, Weibo; Chen, Jifeng; Ning, Guobin; Liang, Zuoliang

    2010-11-01

    We report for the first time (to our knowledge) a diode-pumped Nd:YAG laser emitting at 869 nm based on the (4)F(3/2)-(4)I(9/2) transition, generally used for a 946 nm emission. Power of 453 mW at 869 nm has been achieved in cw operation with a fiber-coupled laser diode emitting 35.4 W at 809 nm. Intracavity second-harmonic generation in the cw mode has also been demonstrated with power of 118 mW at 435 nm by using a BiB(3)O(6) nonlinear crystal. In our experiment, we used a LiNbO(3) crystal lens to complement the thermal lens of the laser rod, and we obtained good beam quality and high output power stability.

  13. Diode-side-pumped 131 W, 1319 nm single-wavelength cw Nd:YAG laser.

    Science.gov (United States)

    Haiyong, Zhu; Ge, Zhang; Chenghui, Huang; Yong, Wei; Lingxiong, Huang; Jing, Chen; Weidong, Chen; Zhenqiang, Chen

    2007-01-20

    A diode-side-pumped high-power 1319 nm single-wavelength Nd:YAG continuous wave (cw) laser is described. Through reasonable coating design of the cavity mirrors, the 1064 nm strongest line as well as the 1338 nm one have been successfully suppressed. The laser output powers corresponding to four groups of different output couplers operating at 1319 nm single wavelength have been compared. The output coupler with the transmission T=5.3% has the highest output power, and a 131 W cw output power was achieved at the pumping power of 555 W. The optical-optical conversion efficiency is 23.6%, and the slope efficiency is 46%. The output power is higher than the total output power of the dual-wavelength laser operating at 1319 nm and 1338 nm in the experiment.

  14. Beam splash effects on ATLAS silicon microstrip detectors evaluated using 1-w Nd YAG laser

    CERN Document Server

    Hara, K; Kohriki, T; Kuwano, T; Moorhead, G F; Terada, S; Unno, Y

    2005-01-01

    On an incident of accelerator beam loss, the tracking detector located close to the beam line is subjected to receive intensive radiation in a short period. We used a 1-W focused Nd: YAG laser and simulated the effects on the ATLAS microstrip detector. The laser corresponds to intensity of up to 1 multiplied by 109mips/pulse with a pulse width of about 10 ns. We observed breaks on Al strips on extreme conditions, depending on the laser intensity and bias voltage applied to the silicon sensor. The break can be interpreted as the oxide breakdown due to a large voltage locally created across the oxide by the intensive signal charges. The robustness of the Semiconductor Tracker (SCT) module including readout ASICs is also evaluated.

  15. Design and Construction of a pulsed Nd:YAG laser for LIBS applications

    Science.gov (United States)

    Garcia-Villarreal, A.; Sobral, H.

    2015-01-01

    A multi-pulse Nd:YAG laser was designed and built, that can be used as an excitation source for Laser Induced Breakdown Spectroscopy (LIBS) experiments. A trigger and a power supply for the flash lamp has been successfully developed. A cooling system that uses a distilled water flow for the active medium was implemented. The laser has an output energy of 306 ± 7 mJ for 1 Hz repetition rate and its temporal profile is multi-pulse with 1 ps of average separation between them. To validate the system, the output was used as an ablation source of an aluminum target and the emission was investigated by spectroscopy analysis.

  16. High stable electro-optical cavity-dumped Nd:YAG laser

    International Nuclear Information System (INIS)

    Ma, Y F; Yu, X; Zhang, J W; Li, H

    2012-01-01

    In this paper, an electro-optical cavity-dumped 10 Hz Nd:Y 3 Al 5 O 12 (Nd:YAG) laser was demonstrated. We designed an optimized high stable concavo-convex cavity according to the thermal-insensitive theory that the cavity could be deep stable and be insensitive to the change of thermal lens of laser crystal when g 1 *g 2 = 1/2. The output pulse width was constant at 6.0±0.1 ns. The maximum output energy was 40 mJ. The laser had outstanding stability of output characteristics. The fluctuations of average output energy and divergence angle within 8 cycles were 1.24% and 0.06 mrad, respectively

  17. Nd:YAG laser in endodontics: filling-material edge bordering on a root channel laser cavity

    Science.gov (United States)

    Belikov, Andrei V.; Sinelnik, Yuri A.; Moroz, Boris T.; Pavlovskaya, Irina V.

    1997-12-01

    For the very first time it is represented a study of filling material edge bordering upon root channel cavity modified with a laser. As a filling material it is used a glass ionomer cement. It is demonstrated that Nd:YAG laser radiation effects on increase of grade of edge bordering on the average of 20 - 30% at temperature rise of no more than 2 - 3 degrees in periodontium area in a period of operation.

  18. Nd:Yag laser iridotomy in Shaffer-Etienne grade 1 and 2:angle widening in our case studies

    Directory of Open Access Journals (Sweden)

    Sandra Cinzia Carlesimo

    2015-08-01

    Full Text Available AIM:To obtain widening of a potentially occludable angle, in according to Kanski’s indications, through preventive Nd:Yag laser iridotomy. The observational study was performed by using gonioscopy for the selection and follow-up of 1165 treated eyes and exploiting Shaffer-Etienne gonioscopic classification as a quality/quantity test of the angle recession.METHODS:Between September 2000 and July 2012, 586 patients were selected at the Outpatients’ Ophthalmological Clinic of the Policlinico Umberto I of Rome in order to undergo Nd:Yag laser iridotomy. A Goldmann type contact lens, Q-switched mode, 2-3 defocus, and 7-9 mJ intensity with 2-3 impulse discharges were used for surgery.RESULTS:From as early as the first week, a whole 360° angle widening were evident in the patients, thus showing the success of Nd:Yag laser iridotomy in solving relative pupil block. The angle remained narrow by 270° in 14 eyes only, despite repetitions of further treatment with laser iridotomy in a different part of the iris, twice in 10 eyes and three times in 4 eyes.CONCLUSION:Nd:Yag laser iridotomy revealed itself as being a safe and effective treatment in widening those critical Shaffer-Etienne grade 1 and 2 potentially occludable angles.

  19. Q-Switched Nd:YAG Laser Removal of Facial Amateur Tattoos in Patients With Fitzpatrick Type VI: Case Series.

    Science.gov (United States)

    Haik, Josef; Kornhaber, Rachel; Harats, Moti; Israeli, Hadar; Orenstein, Arie

    2016-11-01

    Q-switched neodymium:YAG (Nd:YAG) lasers are reported to be gold standard for laser tattoo removal. In particular, the Q-switched Nd:YAG laser at 1064 nm is widely recognized for the removal of blue/black amateur tattoos. However, treatment modalities in Fitzpatrick Type VI skin carry a greater risk of complications including alterations in pigmentation compared to fairer skin (Fitzpatrick Type I-IV skin). Therefore, the aim of this case series was to describe with the use of the Q-Switched Nd:YAG laser, the removal of carbon-based amateur tattoos on patients with Fitzpatrick Type VI skin as an effective and safe method. Twenty- five patients with Fitzpatrick type VI skin, from Ethiopian origins, with facial tribal tattoos, were treated with the Q- Switched Nd:YAG laser at 1064 nm. Digital images were taken upon every treatment and the clearance rates of the tattoo was evalu- ated by imaging software. We observed an average tattoo clearance rate of 95% among the 45 facial tattoos in 25 patients presented in the case series with minimal pigmentary and textual changes evident. These positive aesthetic results have a signi cant psychosocial impact on the lives of those with Fitzpatrick Type VI skin, in particular the Ethiopian Jewish population. J Drugs Dermatol. 2016;15(11):1448-1452..

  20. Detection and Investigation of Carbon Ions Induced by Nd:YAG laser using SSNTDs

    International Nuclear Information System (INIS)

    Qindeel, Rabia; Ali, Jalil Bin; Chaudhary, K. T.; Hussain, M. S.

    2011-01-01

    A Q-Switched Nd:YAG laser pulse of pulsed width of 9∼14 ns, wavelength of 1064 nm, repetition rate of 0.5 Hz, power of 1.1 MW and energy of 10 mJ has been used to ablate the 4N pure graphite target through IR lens. Solid state nuclear track detector (SSNTD) CR-39 has been used to calculate the energy of carbon ions produced as a result of laser ablation and the whole experiment has been performed under pressure ∼10 -3 Torr in stainless steel vacuum chamber. The minimum and maximum energy of carbon ions observed are 0.2 KeV to 250 KeV respectively.

  1. Heating of multi-layered samples by a Nd: YAG pulsed laser

    International Nuclear Information System (INIS)

    Diniz Neto, O.O.

    1998-01-01

    In the work we examine the heating of multi-layered samples by a powerful Nd-YAG pulsed laser. The samples are made of two and three layers, conductor-isolator (Al-Al 2 O 3 ). conductor-conductor (Al-Ag: Al-Au) an conductor-conductor-conductor (Al-Au-Ag:Ag-Au-Al). The transient behaviour of the temperature distribution throughout the samples is computed. We carry out three dimensional model calculations for the heating process in which we consider not only the temperature dependence of the sample thermal and optical parameters but also the space and time characteristics of the laser beams as the heating source. We showed the influence of the substrate in the thermal profile, in space and time, and maximum temperature on the multi-layered samples. (Author) 11 refs

  2. Diode-pumped dual-frequency microchip Nd : YAG laser with tunable frequency difference

    Energy Technology Data Exchange (ETDEWEB)

    Ren Cheng; Zhang Shulian, E-mail: ren-c06@mails.tsinghua.edu.c [State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instruments and Mechanology, Tsinghua University, Beijing 100084 (China)

    2009-08-07

    The diode-pumped dual-frequency microchip Nd : YAG laser with tunable frequency difference is presented. The gain medium used is a microchip 2 mm in thickness for miniaturized and integrated design. Two quarter-wave plates are placed into the laser cavity and the intra-cavity birefringence produces two orthogonally linearly polarized modes. The rotation of one of the two quarter-wave plates introduces a controlled and variable cavity birefringence which causes a variable frequency difference between the two orthogonally polarized modes. The frequency difference can be tuned through the whole cavity free spectral range. The obtained frequency difference ranges from 14 MHz to 1.5 GHz. The variation of the beat frequency over a period of 10 min is less than 10 kHz. The lock-in between modes is not found. Experimental results are presented, which match well with the theoretical analysis based on Jones matrices.

  3. Treatment of pigmented keratosis pilaris in Asian patients with a novel Q-switched Nd:YAG laser.

    Science.gov (United States)

    Kim, Sangeun

    2011-06-01

    Treatment for most cases of keratosis pilaris requires simple reassurance and general skin care recommendations. Many Asian patients find lesions due to pigmented keratosis pilaris to be cosmetically unappealing. Treatment of post-inflammatory hyperpigmentation using a 1064-nm Q-switched Nd:YAG laser with low fluence is reported. To investigate the efficacy of a novel Q-switched Nd:YAG laser for the treatment of pigmented keratosis pilaris in Asian patients. Ten patients with pigmented keratosis pilaris underwent five weekly treatments using a Q-switched Nd:YAG laser (RevLite(®); HOYA ConBio(®), Freemont, CA, USA) at 1064 nm with a 6-mm spot size and a fluence of 5.9 J/cm(2). Photographic documentation was obtained at baseline and 2 months after the final treatment. Clinical improvement was achieved in all 10 patients with minimal adverse effects. For the treatment of keratosis pilaris, the use of a Q-switched Nd:YAG laser can be helpful for improving cosmetic appearance as it can improve pigmentation.

  4. Hollow fiber optics with improved durability for high-peak-power pulses of Q-switched Nd:YAG lasers.

    Science.gov (United States)

    Matsuura, Yuji; Tsuchiuchi, Akio; Noguchi, Hiroshi; Miyagi, Mitsunobu

    2007-03-10

    To improve the damage threshold of hollow optical waveguides for transmitting Q-switched Nd:YAG laser pulses, we optimize the metallization processes for the inner coating of fibers. For silver-coated hollow fiber as the base, second, and third Nd:YAG lasers, drying silver films at a moderate temperature and with inert gas flow is found to be effective. By using this drying process, the resistance to high-peak-power optical pulse radiation is drastically improved for fibers fabricated with and without the sensitizing process. The maximum peak power transmitted in the fiber is greater than 20 MW. To improve the energy threshold of aluminum-coated hollow fibers for the fourth and fifth harmonics of Nd:YAG lasers, a thin silver film is added between the aluminum film and the glass substrate to increase adhesion of the aluminum coating. By using this primer layer, the power threshold improves to 3 MW for the fourth harmonics of a Q-switched Nd:YAG laser light.

  5. Comparison of two Nd:YAG laser posterior capsulotomy: cruciate pattern vs circular pattern with vitreous strand cutting.

    Science.gov (United States)

    Kim, Jin-Soo; Choi, Jung Yeol; Kwon, Ji-Won; Wee, Won Ryang; Han, Young Keun

    2018-01-01

    To investigate the effects and safety of neodymium: yttrium-aluminium-garnet (Nd:YAG) laser posterior capsulotomy with vitreous strand cutting. A total of 40 eyes of 37 patients with symptomatic posterior capsular opacity (PCO) were included in this prospective randomized study and were randomly subjected to either cruciate pattern or round pattern Nd:YAG posterior capsulotomy with vitreous strand cutting (modified round pattern). The best corrected visual acuity (BCVA), intraocular pressure (IOP), refractive error, endothelial cell count (ECC), anterior segment parameters, including anterior chamber depth (ACD) and anterior chamber angle (ACA) were measured before and 1mo after the laser posterior capsulotomy. In both groups, the BCVA improved significantly ( P <0.001 for the modified round pattern group, P =0.001 for the cruciate pattern group); the IOP and ECC did not significantly change. The ACD significantly decreased ( P <0.001 for both) and the ACA significantly increased ( P =0.001 for the modified round pattern group and P =0.034 for the cruciate group). The extent of changes in these parameters was not significantly different between the groups. Modified round pattern Nd:YAG laser posterior capsulotomy is an effective and safe method for the treatment of PCO. This method significantly changes the ACD and ACA, but the change in refraction is not significant. Modified round pattern Nd:YAG laser posterior capsulotomy can be considered a good alternative procedure in patients with symptomatic PCO.

  6. Comparison of two Nd:YAG laser posterior capsulotomy: cruciate pattern vs circular pattern with vitreous strand cutting

    Directory of Open Access Journals (Sweden)

    Jin-Soo Kim

    2018-02-01

    Full Text Available AIM: To investigate the effects and safety of neodymium: yttrium-aluminium-garnet (Nd:YAG laser posterior capsulotomy with vitreous strand cutting METHODS: A total of 40 eyes of 37 patients with symptomatic posterior capsular opacity (PCO were included in this prospective randomized study and were randomly subjected to either cruciate pattern or round pattern Nd:YAG posterior capsulotomy with vitreous strand cutting (modified round pattern. The best corrected visual acuity (BCVA, intraocular pressure (IOP, refractive error, endothelial cell count (ECC, anterior segment parameters, including anterior chamber depth (ACD and anterior chamber angle (ACA were measured before and 1mo after the laser posterior capsulotomy. RESULTS: In both groups, the BCVA improved significantly (P<0.001 for the modified round pattern group, P=0.001 for the cruciate pattern group; the IOP and ECC did not significantly change. The ACD significantly decreased (P<0.001 for both and the ACA significantly increased (P=0.001 for the modified round pattern group and P=0.034 for the cruciate group. The extent of changes in these parameters was not significantly different between the groups. CONCLUSION: Modified round pattern Nd:YAG laser posterior capsulotomy is an effective and safe method for the treatment of PCO. This method significantly changes the ACD and ACA, but the change in refraction is not significant. Modified round pattern Nd:YAG laser posterior capsulotomy can be considered a good alternative procedure in patients with symptomatic PCO.

  7. Holographic cinematography of time-varying reflecting and time-varying phase objects using a Nd:YAG laser

    Science.gov (United States)

    Decker, A. J.

    1982-01-01

    The use of a Nd:YAG laser to record holographic motion pictures of time-varying reflecting objects and time-varying phase objects is discussed. Sample frames from both types of holographic motion pictures are presented. The holographic system discussed is intended for three-dimensional flow visualization of the time-varying flows that occur in jet-engine components.

  8. Chemical and physical analysis on hard tissues after irradiation with short pulse Nd:YAG laser

    International Nuclear Information System (INIS)

    Pereira, Andrea Antunes

    2003-01-01

    This work reports on a study that was designed to investigate chemical, physical and morphological alterations in the dental enamel surface. The influence of application of laser in enamel surface by microscopic technical, X-ray fluorescence for chemical analysis, physical property as well as hardness and thermal analysis with Nd:YAG laser is also pointed out. A prototype of Nd:YAG (Q-switched) laser developed at the Center of Lasers and Applications - Institute of Energetic and Nuclear Research, aiming applications in the Medical Sciences that typical wavelength of 1.064 nm was used. The modifications in human dental enamel chemical composition for major and trace elements are here outlined. The accuracy of procedures was performed by analysis of natural hydroxyapatite as standard reference material. The identification and quantification of the chemical elements presented in the dental tissue samples were performed trough EDS, XRF and INAA. We determined the rate Calcium/Phosphorus (Ca/P) for different techniques. We performed an analysis in different regions of the surface and for different areas allowing a description of the chemical change in the total area of the specimen and the assessment of the compositional homogeneity of the each specimen. A comparison between XRF and INAA is presented. Based on morphological analysis of the irradiated surfaces with short pulse Nd:YAG laser we determined the area surrounded by the irradiation for the parameters for this thesis, and this technique allowed us to visualize the regions of fusion and re-solidification. The energy densities ranged from 10 J/cm 2 to 40 J/cm 2 , with pulse width of 6, 10 e 200 ns, and repetition rates of 5 and 7 Hz. In this thesis, FTIR-spectroscopy is used to analyze powder of mineralized tissue as well as enamel, dentine, root and cementum for human and bovine teeth after irradiation with short-pulse Nd:YAG laser. Characteristic spectra were obtained for the proteins components and mineral

  9. Experimental investigation on cleaning of corroded ancient coins using a Nd:YAG laser

    Science.gov (United States)

    Zhu, Huazhong; Lu, Jian; Ni, Xiaowu; Shen, Zhonghua

    2017-05-01

    The objective of the work reported is to study experimentally on the removal of corrosion layer from the ancient coins using laser beam as the conservation tool. With the use of Q-switched Nd:YAG laser radiation at 1064 nm, dry laser cleaning, steam laser cleaning and chemical-assisted laser cleaning were used to find out a more suitable and efficient laser treatment for corrosion removal. Cleaning tests were performed on ancient Chinese coins. Experimental results shows that the dry laser cleaning was not successful at removing all types of corrosion crust. It was possible to remove the outer thicker layer of the corrosion products (typically known as patina), but failed on the thinner layer of cuprite. The steam laser cleaning could decrease the initial removal threshold and improve the removal efficiency especially for the oxidation with powdery structure. As for chemical-assisted laser treatment, the cleaning results demonstrate that the combination of laser and chemical reagent could provide a considerable improvement in corrosion removal compared with the conventional laser treatments. Most of the corrosion contaminant was stripped, even the cuprite layer. Moreover, no secondary pollution was formed on the cleaned surface. X-ray fluorescence was applied to determine the variation of composition of surface layer and bulk metal before and after the coins cleaned. It shows that all of the three laser treatments were efficient to reduce the chlorine concentration on the surface of the coins more than 75%.

  10. Ultrasound imaging of Nd:YAG laser-induced tissue coagulation in porcine livers.

    Science.gov (United States)

    Ritzel, U; Wietzke-Braun, P; Brinck, U; Leonhardt, U; Ramadori, G

    2001-12-01

    Absorption of laser light energy induces denaturation of proteins and thermocoagulation of irradiated tissue. Recently, MRI-guided laser coagulation in combination with MR thermometry was reported as a treatment of liver tumours. In the present study ultrasonographic imaging was evaluated for its suitability in laser induced tissue thermocoagulation. Fresh porcine livers were used for ex vivo examinations. Placement of the laser catheter and tissue coagulation during laser light emission were online monitored by ultrasonography. Nd:YAG laser-induced tissue damage was evaluated by macroscopical and microscopical examinations of histological sections. During laser light emission a marked hyperdense signal enhancement was observed by ultrasonography which strongly correlated with the extent of macroscopic tissue damage. The size of laser-induced coagulation zone depended on both the power setting and total energy delivered. Carbonization of the tissue surrounding the laser tip is a limiting factor because of laser light absorption. However our data indicate that using appropriate laser energy and exposure time prevent carbonization although carbonization can not be visualized by ultrasonography. It is concluded from the present ex vivo studies that laser coagulation can be effectively performed under ultrasonographic guidance.

  11. The influence of the Nd:YAG laser bleaching on physical and mechanical properties of the dental enamel.

    Science.gov (United States)

    Marcondes, Maurem; Paranhos, Maria Paula Gandolfi; Spohr, Ana Maria; Mota, Eduardo Gonçalves; da Silva, Isaac Newton Lima; Souto, André Arigony; Burnett, Luiz Henrique

    2009-07-01

    The Nd:YAG laser can be used in Dentistry to remove soft tissue, disinfect canals in endodontic procedures and prevent caries. However, there is no protocol for Nd:YAG laser application in dental bleaching. The aims of this in vitro study were: (a) to observe the tooth shade alteration when hydrogen peroxide whitening procedures are associated with dyes with different wavelengths and irradiated with Nd:YAG laser or halogen light; (b) to measure the Vickers (VHN) enamel microhardness before and after the whitening procedure; (c) to evaluate the tensile bond strength of two types of adhesive systems applied on bleached enamel; (d) to observe the failure pattern after bond strength testing; (e) to evaluate the pulpal temperature during the bleaching procedures with halogen light or laser; (f) to measure the kinetic reaction of hydrogen peroxide. Extracted sound human molar crowns were sectioned in the mesiodistal direction to obtain 150 fragments that were divided into five groups for each adhesive system: WL (H(2)O(2) + thickener and Nd:YAG), WH (H(2)O(2) + thickener and halogen light), QL (H(2)O(2) + carbopol + Q-switch and Nd:YAG), QH (H(2)O(2) + carbopol + Q-switch and halogen light), and C (Control, without whitening agent). Shade assessment was made with a shade guide and the microhardness tests were performed before and after the bleaching procedures. Immediately afterwards, the groups were restored with the adhesive systems Adper Single Bond 2 or Solobond M plus composite resin, and the tensile bond strength test was performed. The temperature was measured by thermocouples placed on the enamel surface and intrapulpal chamber. The kinetics of hydrogen peroxide was observed by ultraviolet analysis. The shade changed seven levels for Nd:YAG laser groups and eight levels for halogen light. According to the student's t-test, there was no statistical difference between the VHN before and after the whitening protocols (p > 0.05). The tensile bond strength showed no

  12. Efectividad del Nd- Yag láser en la capsulotomía posterior Effectiveness of Nd-Yag laser in posterior capsulotomy

    Directory of Open Access Journals (Sweden)

    Alina Pedroso Llanes

    2004-06-01

    Full Text Available Este trabajo se propuso determinar la efectividad del neodimio YAG láser (Nd-YAG láser en la realización de capsulotomía posterior a 150 pacientes (ojos operados de catarata senil o presenil en el centro de Microcirugía Ocular en Serie del Hospital Oftalmológico Docente "Ramón Pando Ferrer" en el período comprendido de febreroa diciembre de 1999. En este grupo se analizaron como variables la edad, sexo, raza, implante o no de lente intraocular, tipo de opacidad de cápsula posterior, agudeza visual con corrección pre y postratamiento, complicaciones encontradas, comportamiento de la presión intraocular, así como la energía empleada para realizar dicho proceder. Estos datos se analizaron a través de tablas de contingencias Chi cuadrado. Como resultado de esta investigación se encontró que el láser es altamente efectivo para el mejoramiento de la agudeza visual en los pacientes afectados de catarata secundaria (74,7 %. Se observó además aumento transitorio de la presión intraocular en las dos primeras horas posteriores al láser (60,7 %, y no se encontró ninguna complicación que afectara la visión de los ojos estudiadosThe aim of this paper was to determine the effectiveness of neodymium YAG laser (Nd-YAG laser on performing the posterior capsulotomy in 150 patients (eyes operated on of senile or presenile cataract at the Center of Serial Ocular Microsurgery (CSOM of "Ramón Pando Ferrer" Ophthalmological Teaching Hospital from February to December 1999. Age, sex, race, implantation or not of the intraocular lens (IOL, type of opacity of the posterior capsule, visual acuity with pre- and posttreatment correction (Avcc, complications found, behavior of the intraocular pressure (IOP, as well as the energy used to carry out such procedure, were analyzed. The Chi square contingency tables were used to this end. As a result of this research, it was found that the laser is highly effective for improving visual acuity in patients

  13. Ação do laser de Nd:YAG intracanal sobre endotoxinas na dentina radicular

    OpenAIRE

    Jose Ricardo de Freitas Archilla

    2007-01-01

    As endotoxinas são responsáveis por importantes reações sistêmicas e locais, podendo comprometer o sucesso do tratamento endodôntico. O hidróxido de cálcio, mesmo com limitações, mostra-se como opção única efetiva entre as soluções irrigadoras e as medicações intracanal na redução das endotoxinas nos túbulos dentinários. O experimento realizado avaliou a eficiência do laser de Nd:YAG frente à uma endotoxina inoculada no canal radicular pela utilização de duas cinemáticas de irradiação. Após u...

  14. Growth of large microcones in steel under multipulsed Nd:YAG laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Dolgaev, S.I. [University of Barcelona, Department of Applied Physics and Optics, Barcelona (Spain); A.M. Prokhorov General Physics Institute, Wave Research Centre, Moscow (Russian Federation); Fernandez-Pradas, J.M.; Morenza, J.L.; Serra, P. [University of Barcelona, Department of Applied Physics and Optics, Barcelona (Spain); Shafeev, G.A. [A.M. Prokhorov General Physics Institute, Wave Research Centre, Moscow (Russian Federation)

    2006-06-15

    We report the growth of conical microstructure arrays on a stainless steel substrate under multi-pulsed Nd:YAG laser irradiation (wavelength of 1.064 {mu}m, pulse duration of 300 ns, repetition rate of 5 kHz) at atmospheric air pressure. The average period of microcones is 70 {mu}m, and they protrude 50-60 {mu}m above the substrate. At an air pressure of 1 Pa, the well-defined conical shape is lost and the resulting microstructure shows a smaller period and height. At 10{sup -3} Pa, only small protrusions separated by about 5 {mu}m are observed. The different mechanisms involved in the growth of conical microstructures are discussed. (orig.)

  15. High Power 1443.5 nm Laser with Nd:YAG Single Crystal Fiber

    Directory of Open Access Journals (Sweden)

    Han Rao

    2017-07-01

    Full Text Available A high-power eye-safe 1443.5 nm laser was demonstrated with an Nd:YAG single crystal fiber (SCF as the gain medium. For continuous wave (CW operation, a maximum output power of 13.3 W was obtained under an absorbed pump power of 95.0 W, corresponding to an optical-to-optical conversion efficiency of 14.0%. For acousto-optically (AO Q-switched regime, an output power of 1.95 W was obtained at a pulse repetition frequency (PRF of 10 kHz. The pulse duration was 69.5 ns. The pulse energy and peak power were calculated to be 195 µJ and 2.81 kW, respectively.

  16. Iron plasma generation using a Nd:YAG laser pulse of several hundred picoseconds

    Energy Technology Data Exchange (ETDEWEB)

    Tamura, Jun, E-mail: jtamura@post.j-parc.jp [J-PARC Center, Japan Atomic Energy Agency, Ibaraki 319-1195 (Japan); Kumaki, Masafumi [Research Institute for Science and Engineering, Waseda University, Tokyo 169-8555 (Japan); Kondo, Kotaro [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Tokyo 152-8550 (Japan); Kanesue, Takeshi; Okamura, Masahiro [Collider-Accelerator Department, Brookhaven National Laboratory, Upton, New York 11973 (United States)

    2016-02-15

    We investigated the high intensity plasma generated by using a Nd:YAG laser to apply a laser-produced plasma to the direct plasma injection scheme. The capability of the source to generate high charge state ions strongly depends on the power density of the laser irradiation. Therefore, we focused on using a higher power laser with several hundred picoseconds of pulse width. The iron target was irradiated with the pulsed laser, and the ion current of the laser-produced iron plasma was measured using a Faraday cup and the charge state distribution was investigated using an electrostatic ion analyzer. We found that higher charge state iron ions (up to Fe{sup 21+}) were obtained using a laser pulse of several hundred picoseconds in comparison to those obtained using a laser pulse of several nanoseconds (up to Fe{sup 19+}). We also found that when the laser irradiation area was relatively large, the laser power was absorbed mainly by the contamination on the target surface.

  17. Suppression of parasitic oscillations in a core-doped ceramic Nd:YAG laser by Sm:YAG cladding.

    Science.gov (United States)

    Huss, Rafael; Wilhelm, Ralf; Kolleck, Christian; Neumann, Jörg; Kracht, Dietmar

    2010-06-07

    The onset of parasitic oscillations limits the extraction efficiency and therefore energy scaling of Q-switched lasers. A solid-state laser was end pumped with a fiber-coupled diode laser and operated in q-cw as well as in passively Q-switched operation. For Q-switched operation, we demonstrate the suppression of parasitic oscillations in a core-doped ceramic Nd:YAG laser by Sm:YAG cladding.

  18. Management of intermittent angle closure glaucoma with Nd: yag laser iridotomy as a primary procedure

    International Nuclear Information System (INIS)

    Ahmed, M.

    2006-01-01

    To assess the efficacy and complications of Nd: YAG laser iridotomy in patients with intermittent (sub-acute) angle closure glaucoma. Twenty-five eyes of twenty-three patients with periodic (intermittent) angle closure, selected in outpatient department, were kept on pilocarpine until YAG laser iridotomy was performed. After YAG laser iridotomy oral acetazolamide and topical dexamethasone was used to control post laser rise of IOP and inflammation respectively. Patency of iridotomy was confirmed and intra-ocular pressure was measured one hour after the procedure. Immediate complication, if any, was noted. Follow-up was done for six months. Prophylactic laser iridotomy was done in fellow eye with occludable angle. Levene's test for equality of variance and t-test for equality of means were used for statistical analysis. This study revealed a significant difference in IOP before and after YAG laser iridotomy (p = .002). Complete follow-up of 6 months was possible in 25 eyes of 23 subjects. After YAG Laser iridotomy, 21 (84%) eyes showed negative provocative test, intraocular pressure below 19mm Hg without medication and anterior chamber angle no more occludable and were labeled successful. Iridotomy remained patent in 96% of eyes. Iridotomy failed to reduce IOP in 4 (16%) eyes. The complications were minimal and transient. (author)

  19. Efficient 10 kW diode-pumped Nd:YAG rod laser

    Science.gov (United States)

    Akiyama, Yasuhiro; Takada, Hiroyuki; Sasaki, Mitsuo; Yuasa, Hiroshi; Nishida, Naoto

    2003-03-01

    As a tool for high speed and high precision material processing such as cutting and welding, we developed a rod-type all-solid-state laser with an average power of more than 10 kW, an electrical-optical efficiency of more than 20%, and a laser head volume of less than 0.05 m3. We developed a highly efficient diode pumped module, and successfully obtained electrical-optical efficiencies of 22% in CW operation and 26% in QCW operation at multi-kW output powers. We also succeeded to reduce the laser head volume, and obtained the output power of 12 kW with an efficiency of 23%, and laser head volume of 0.045 m3. We transferred the technology to SHIBAURA mechatronics corp., who started to provide the LD pumped Nd:YAG laser system with output power up to 4.5 kW. We are now continuing development for further high power laser equipment.

  20. Study on surface properties of gilt-bronze artifacts, after Nd:YAG laser cleaning

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyeyoun [Division of Restoration Technology, National Research Institute of Cultural Heritage, Daejeon (Korea, Republic of); Cho, Namchul, E-mail: nam1611@hanmail.net [Department of Cultural Heritage Conservation Science, Kongju National University, Gongju, 314-701 (Korea, Republic of); Lee, Jongmyoung [Laser Engineering Group, IMT Co. Ltd, Gyeonggi (Korea, Republic of)

    2013-11-01

    As numerous pores are formed at plating gilt-bronze artifacts, the metal underlying the gold is corroded and corrosion products are formed on layer of gold. Through this study, the surfaces of gilt-bronze are being investigated before and after the laser irradiation to remove corrosion products of copper by using Nd:YAG laser. For gilt-bronze specimens, laser and chemical cleaning were performed, and thereafter, surface analysis with SEM-EDS, AFM, and XPS were used to determine the surface characteristics. Experimental results show that chemical cleaning removes corrosion products of copper through dissolution but it was not removed uniformly and separated the metal substrate and the gold layer. Nevertheless, through laser cleaning, some of the corrosions were removed with some damaged areas due to certain conditions and brown residues remained. Brown residues were copper corrosion products mixed with soil left within the gilt layer. It was due to surface morphology of uneven and rough gilt layer. Hence, they did not react effectively to laser beams, and thus, remained as residues. The surface properties of gilt-bronze should be thoroughly investigated with various surface analyses to succeed in laser cleaning without damages or residues.

  1. Highly-efficient, frequency-tripled Nd:YAG laser for spaceborne LIDARs

    Science.gov (United States)

    Treichel, R.; Hoffmann, H.-D.; Luttmann, J.; Morasch, V.; Nicklaus, K.; Wührer, C.

    2017-11-01

    For a spaceborne lidar a highly reliable, long living and efficient laser source is absolutely essential. Within the frame of the development of a laser source for the backscatter lidar ATLID, which will be flown on EarthCare mission, we setup and tested a predevelopment model of an injection-seeded, diode pumped, frequency tripled, pulsed high power Nd:YAG MOPA laser operating nominally at 100 Hz pulse repetition frequency. We also tested the burst operation mode. The excellent measured performance parameter will be introduced. The oscillator rod is longitudinally pumped from both sides. The oscillator has been operated with three cavity control methods: "Cavity Dither", "Pound-Drever-Hall" and "Adaptive Ramp & Fire". Especially the latter method is very suitable to operate the laser in harsh vibrating environment such in airplanes. The amplifier bases on the InnoSlab design concept. The constant keeping of a moderate fluence in the InnoSlab crystal permits excellent possibilities to scale the pulse energy to several 100 mJ. An innovative pump unit and optics makes the laser performance insensitive to inhomogeneous diode degradation and allows switching of additional redundant diodes. Further key features have been implemented in a FM design concept. The operational lifetime is extended by the implementation of internal redundancies for the most critical parts. The reliability is increased due to the higher margin onto the laser induced damage threshold by a pressurized housing. Additionally air-to-vacuum effects becomes obsolete. A high efficient heat removal concept has been implemented.

  2. Multi-Fresnel lenses pumping approach for improving high-power Nd:YAG solar laser beam quality.

    Science.gov (United States)

    Liang, Dawei; Almeida, Joana

    2013-07-20

    To significantly improve the present-day high-power solar laser beam quality, a three-stage multi-Fresnel lenses approach is proposed for side-pumping either a Nd:YAG single-crystal or a core-doped Sm(3+)Nd:YAG ceramic rod. Optimum pumping and laser beam parameters are found through ZEMAX and LASCAD numerical analysis. The proposed scheme offers a uniform absorption profile along the rod. 167 W laser power can be achieved, corresponding to 29.3 W/m(2) collection efficiency. High brightness figure of merit of 8.34 W is expected for the core-doped rod within a convex-concave resonator, which is 1300 times higher than that of the most-recent high-power solar laser.

  3. Optical and electronic properties of HWCVD and PECVD silicon films irradiated using excimer and Nd:Yag lasers

    International Nuclear Information System (INIS)

    Shaikh, M.Z.; O'Neill, K.A.; Anthony, S.; Persheyev, S.K.; Rose, M.J.

    2006-01-01

    Thin silicon film samples were deposited using HWCVD and PECVD techniques to study the influence of laser annealing on their optical and electronic properties. Samples were annealed in air using a XeCl excimer and Nd:Yag lasers. Excimer laser annealing (ELA) at 50 to 222 mJ/cm 2 increased conductivity in PECVD films by 2 to 3 orders of magnitude and in HWCVD films by 1 to 2 orders of magnitude. ELA was also seen to decrease the optical gap in PECVD films by 0.5 eV and HWCVD films by 0.15 eV. Silicon-oxygen bond content was higher in as-deposited HWCVD films than PECVD films. Hydrogen content (at.%) in PECVD films was higher than HWCVD for higher H dilution ratios. A Nd:Yag laser 3-beam interference pattern was used to produce a periodic array of crystals in both PECVD and HWCVD films

  4. Clinical application of the Nd-YAG and Ho-YAG lasers in otolaryngology: head and neck surgery

    Science.gov (United States)

    Kukwa, Andrzej; Tulibacki, Marek P.; Dudziec, Katarzyna; Wojtowicz, Piotr

    1997-10-01

    The authors present their clinical experience regarding the possibilities of application of Nd:YAG and Ho:YAG lasers for the treatment of disorders in the area of the upper respiratory tract sinuses and ears. This technique makes it possible to perform a number of procedures in local anesthesia which considerably improves the economic effectiveness of the treatment. In case of the Nd:YAG laser they have also utilized the effect of deep coagulation of the soft tissues, whereas the Ho:YAG laser energy was applied for the surgery of bone tissue. The surgeries performed using laser beam enabled very good effect of treatment. They are competitive compared wit the methods used by traditional surgery.

  5. Passive Q switching of a solar-pumped Nd:YAG laser.

    Science.gov (United States)

    Lando, M; Shimony, Y; Noter, Y; Benmair, R M; Yogev, A

    2000-04-20

    Passive Q switching is a preferable choice for switching the Q factor of a solar-pumped laser because it requires neither a driver nor an electrical power supply. The superior thermal characteristics and durability of Cr(4+):YAG single crystals as passive Q switches for lamp and diode-pumped high-power lasers has been demonstrated. Here we report on an average power of 37 W and a switching efficiency of 80% obtained by use of a solar-pumped Nd:YAG laser Q switched by a Cr(4+):YAG saturable absorber. Concentration of the pumping solar energy on the laser crystal was obtained with a three-stage concentrator, composed of 12 heliostats, a three-dimensional compound parabolic concentrator (CPC) and a two-dimensional CPC. The water-cooled passive Q switch also served as the laser rear mirror. Repetition rates of as much as 50 kHz, at pulse durations between 190 and 310 ns (FWHM) were achieved. From the experimental results, the saturated single-pass power absorption of the Cr(4+):YAG device was estimated as 3 ? 1%.

  6. Effects of process variables on characteristics of Nd:YAG laser welds of Inconel 600

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chang Hee [Hanyang University, Seoul (Korea)

    1998-04-01

    This report described a basic study of the pulse shaping effects on weld dimension and weld discontinuities in the continuous seam welds of STS 310S using Nd:YAG laser. Further, laser weldability tests for STS 310S and Inconel 600 was carried out. Pulse shapes used in this experiment were general type, which has been applied generally in laser material processing, ramped-up type (3 steps) and ramped-down type (3 steps). The pulse energy was constant regardless of types of pulse shape. The penetration of laser welds became deeper as the pulse width was longer and the peak power was increased. The pulse of ramped-up type was most effective for deep penetration compared with others. With regard to the laser weldability and reduction of weld discontinuities such as porosity and hot cracking, the general type pulse was the worst and the ramped-down type pulse was the best among 3 types of pulse shape studied in this investigation. (author). 36 refs., 25 figs., 5 tabs.

  7. Compact corner-pumped Nd:YAG/YAG composite slab 1319 nm/1338 nm laser

    International Nuclear Information System (INIS)

    Liu, H; Gong, M; Wushouer, X; Gao, S

    2010-01-01

    A corner-pumped type is a new pumping type in the diode-pumped solid-state lasers, which has the advantages of high pump efficiency and favorable pump uniformity. A corner-pumped Nd:YAG/YAG composite slab continuous-wave 1319 nm/1338 nm dual-wavelength laser is first demonstrated in this paper. When the cavity length is 25 mm, the maximal output power is up to 7.62 W with a slope efficiency of 16.6% and an optical-to-optical conversion efficiency of 17%. The corresponding spectral line widths of 1319 nm laser and 1338 nm laser are 0.11 and 0.1 nm, respectively. The short-term instability of the output power is better than 1% when the pumping power is 39.5 W. The experimental results show that a corner-pumped type is a kind of feasible schedules in the design of diode-pumped solid-state 1.3 μm lasers with low or medium output powers

  8. Study of CW Nd-Yag laser welding of Zn-coated steel sheets

    International Nuclear Information System (INIS)

    Fabbro, Remy; Coste, Frederic; Goebels, Dominique; Kielwasser, Mathieu

    2006-01-01

    The welding of Zn-coated steel thin sheets is a great challenge for the automotive industry. Previous studies have defined the main physical processes involved. For non-controlled conditions, the zinc vapour expelled from the interface of the two sheets violently expands inside the keyhole and expels the melt pool. When using CO 2 lasers, we have previously shown that an elongated laser spot produces an elongated keyhole, which is efficient for suppressing this effect. We have adopted a similar approach for CW Nd : Yag laser welding and we observe that an elongated spot is not necessary for achieving good weld seams. Several diagnostics were used in order to understand these interesting results. High-speed video camera visualizations of the top and the bottom of the keyhole during the process show the dynamics of the keyhole hydrodynamic behaviour. It appears that the role of the reflected beam on the front keyhole wall for generating a characteristic rear wall deformation is crucial for an efficient stabilization of the process. Our dynamic keyhole modelling, which includes ray tracing, totally confirms this interpretation and explains the results for very different experimental conditions (effect of welding speed, laser intensity, variable sheet thickness, laser beam intensity distribution) that will be presented

  9. Stress corrosion cracking behavior of Nd:YAG laser-treated aluminum alloy 7075

    International Nuclear Information System (INIS)

    Yue, T.M.; Yan, L.J.; Chan, C.P.

    2006-01-01

    Nd-YAG laser surface treatment was conducted on 7075-T651 aluminum alloy with the aim of improving the stress corrosion cracking resistance of the alloy. Laser surface treatment was performed under two different gas environments, air and nitrogen. After the laser treatment, coarse constituent particles were removed and fine cellular/dendritic structures had formed. In addition, for the N 2 -treated specimen, an AlN phase was detected. The results of the stress corrosion test showed that after 30 days of immersion, the untreated specimen had been severely attacked by corrosion, with intergranular cracks having formed along the planar grain boundaries of the specimen. For the air-treated specimen, some relatively long stress corrosion cracks and a small number of relatively large corrosion pits were found. The cracks mainly followed the interdendritic boundaries; the fusion boundary was found to be acting as an arrestor to corrosion attacks. In contrast, only few short stress corrosion cracks appeared in the N 2 -treated specimen, indicating an improvement in corrosion initiation resistance. The superior corrosion resistance was attributed to the formation of the AlN phase in the surface of the laser-melted layer, which is an electrical insulator. The electrochemical impedance measurements taken during the stress corrosion test showed that the film resistance of the laser-treated specimens was always higher than that of the untreated specimen, with the N 2 -treated specimen showing the highest resistance

  10. Pulsed Nd-YAG laser welding of Prototype Fast Breeder Reactor fuel elements

    International Nuclear Information System (INIS)

    Suresh Varma, P.V.; Gupta, Amit; Amit, K.; Bhatt, R.B.; Afzal, Mohd.; Panakkal, J.P.; Kamath, H.S.

    2009-02-01

    End plug welding of Prototype Fast Breeder Reactor (PFBR) fuel elements involves welding of fully Austenitic Stainless Steel (ASS) of grade D9 clad tube with 316M end plug. Pulsed Gas Tungsten Arc Welding (GTAW) is being used for the production of PFBR fuel elements at Advanced Fuel Fabrication Facility (AFFF). GTAW is an established process for end plug welding and hence adopted by many countries. GTAW has got certain limitations like heat input, arc gap sensitivity and certain sporadic defects like tungsten inclusion. Experiments have been carried out at AFFF to use Laser Beam Welding (LBW) technique as LBW offers a number of advantages over the former process. This report mainly deals with the optimization of laser parameters for welding of PFBR fuel elements. To facilitate pulsed Nd-YAG laser spot welding, parameters like peak power, pulse duration, pulse energy, frequency and defocusing of laser beam on to the work piece have been optimized. On the basis of penetration requirement laser welding parameters have been optimized. (author)

  11. Nd:YAG laser in caries prevention: a clinical study; Avaliacao clinica da eficiencia do laser de Nd:YAG associado ao fluor fosfato acidulado na prevencao de caries de sulcos e fissuras de criancas e adolescentes

    Energy Technology Data Exchange (ETDEWEB)

    Boari, Heloisa Gomes Dimiranda

    2000-07-01

    The caries prevention by using laser irradiation has been investigated during the last 30 years. The Nd: YAG laser associated with acidulated phosphate fluoride has been shown as a very promising technique for enamel caries prevention. The aim of this work was to clinically evaluate the efficiency of Nd: YAG laser associated with acidulated phosphate fluoride in pit and fissure caries prevention of children and adolescents. In this work it was determined the dye that enhance the effect of Nd: YAG laser in enamel. It was selected 242 pre-molar and molar teeth from 33 children and adolescents, aged from 7 to 15 years old. The selected teeth were free from caries or decalcification marks (active white marks) to the clinical and radiographic exams. The teeth were divided into two groups: the first group was laser irradiated and their homologous remained as a control. The right side teeth were dye-assisted Nd:YAG laser irradiated. The dye solution was a moisture of dust coal and equal parts of water and alcohol. The irradiation conditions were 60 mJ/10 Hz, optical fiber in contact mode, with diameter of 300 {mu}m, resulting in an energy density of 84,9 J/cm{sup 2}. The oclusal surface of the teeth was completely irradiated, specially on the slopes and in the deepest part of the pits and fissures. This procedure was repeated three times. In the sequence it was applied the acidulated phosphate fluoride for 4 minutes. On the left side teeth - control group- only acidulated phosphate fluoride was applied for the same time. The final examination considered the presence of caries and active white marks after a period of one year. There were statistical significant differences (p < 0.01) between the lased + fluoride group and the non irradiated group. The present study concluded that the technique used in this work can be an alternative clinical method for caries prevention. (author)

  12. Comparison of levobunolol and brimonidine in prophylaxis of intraocular pressure (iop|) rise following nd: yag laser capsulotomy

    International Nuclear Information System (INIS)

    Habib, M.; Akram, A

    2015-01-01

    To compare the efficacy of topical 0.5% Levobunolol and 0.2% Brimonidine in preventing intraocular pressure rise after Nd: YAG laser posterior capsulotomy. Study Design: Randomized controlled trial (RCT). Setting and Duration of Study: Ophthalmology Department Combined Military Hospital Multan, from September 2010 to March 2011. Patients and Methods: A total of 82 patients fulfilling the inclusion criteria were selected from out-patient department and randomly divided into two equal groups. Topical 0.5% levobunolol was instilled in group A while 0.2% brimonidine was instilled in group B one hour before and immediately after doing Nd:YAG laser capsulotomy. The intraocular pressure (IOP) was measured using Goldmann applanation tonometer 1, 3 and 24 hours later. Data was analyzed using SPSS version 15.0. Results: There was no statistically significant difference in mean IOP between 0.5% Levobunolol group (Group A) and 0.2% Brimonidine group (Group B) at 1 hour, 3 hours and 24 hours after Nd:YAG laser capsulotomy. The mean intraocular pressure (IOP) one hour after Nd:YAG laser and topical treatment in group A was 16.10 ± 1.60 mmHg while in group B was 15.65 ± 3.01 mmHg (P=0.401). Mean IOP after three hours in group A was 15.80 ± 1.35 mm Hg and in group B was 15.05 ± 2.15 mmHg (p=0.062). Mean IOP after 24 hours in group A was 15.13 ± 2.05 mmHg while in group B was 14.32 ± 1.62 mmHg (p=0.058). Conclusion: Both 0.5% Levobunolol and 0.2% Brimonidine are equally effective in controlling the IOP spike after Nd: YAG laser capsulotomy. Either of these medicines can be used as a prophylaxis to prevent rise in IOP after Nd:YAG laser capsulotomy. (author)

  13. Pulsed 1064 nm Nd-YAG Laser Deposition of Titanium on Silicon in a Nitrogen Environment

    Directory of Open Access Journals (Sweden)

    Wilson Garcia

    1999-12-01

    Full Text Available Pulsed laser deposition (PLD technique was demonstrated for the deposition of titanium nitride (TiN thin films on Si (100 substrates. A 1064 nm pulsed Nd-YAG laser is focused on a titanium (99.5% target in a nitrogen environment to generate the atomic flux needed for the film deposition. Spectroscopic analysis of the plasma emission indicates the presence of atomic titanium and nitrogen, which are the precursors of TiN. Images of the films grown at different laser pulse energies show an increase in the number and size of deposited droplets and clusters with increasing laser pulse energy. A decrease in cluster and droplet size is also observed, with an increase in substrate temperature. EDS data show an increase in the titanium peak relative to the silicon as the ambient nitrogen pressure is decreased. An increase in deposition time was found to result in large clusters and irregularly shaped structures on the substrate. Post-deposition annealing of the samples enhanced the crystallinity of the film.

  14. Nd:YAG (2 omega) pumped dye laser using self-filtering unstable resonator

    CERN Document Server

    Rahimian, K; Hariri, H

    2002-01-01

    A self-filtering unstable resonator with a magnification of M=-3 in a Nd:YAG (2 omega) dye laser has been studied. The dye solution is Rhodamine 6 G in alcohol with the concentration of 5*10 sub - 3 Mol/lit. The spatial intensity distribution of the resonator has been compared has been compared with that of a plane-parallel resonator of equal length. The output energy in both configurations are comparable (20 mu J ,and 26 mu J ,respectively). A significant difference between these two resonators is the laser beam divergence, where beam divergences of 0.77 mrad for the self-filtering unstable resonator and 1.6 mrad for the plane-parallel resonator have been measured. The brightness corresponding to these two resonators are 1.5* 10 sub 1 1 and 2.2* 10 sub 1 0W.cm sub - 2.Sr sub - 1, and the pulse widths are 7 and 17 ns, respectively. These figures show clearly that laser resonator based on the self-filtering unstable resonator design an increase the laser brightness a factor of 10, with a beam divergence of a f...

  15. Distributed Nd-YAG laser welding and process control in inert glove boxes

    International Nuclear Information System (INIS)

    Milewski, J.O.; Lewis, G.K.; Barbe, M.R.; Cremers, D.A.

    1993-01-01

    We have fabricated and assembled a fiber optic delivered ND-YAG laser welding work station that consists of three glove boxes served by a single 1kw laser. Processing considerations related to the welding of special nuclear materials, toxic materials and complex part geometry are addressed within each work cell. We are proceeding with a development effort to integrate the equipment capabilities with remote sensing, process monitoring and control systems. These systems will provide real time data acquisition during welding, monitoring and verification of weld parameters, and CAD/CAM to CNC generated positioning paths. Computerized information storage, retrieval and network methods are used for weld process documentation and data analysis. A virtual control panel is being configured to integrate the monitoring and control operation of individual subsystems, such as laser and motion control into a single graphical interface. Development work on sensors to monitor laser beam characteristics and weld depth in real time with potential for adaptive control is in progress. System capabilities and results of these development efforts are presented

  16. SBS pulse compression applied to a commercial Q-switch Nd-YAG laser

    International Nuclear Information System (INIS)

    Aliaga-Rossel, R.; Bayley, J.; Mamin, A.; Nizienko, Y.

    1997-01-01

    In optical diagnosis of dense Z-pinches, sub-nanosecond laser pulses are required in order to freeze the movement of the plasma during the probing. Commercial lasers can provide such type of pulses but they are either very expensive, or they have a very low energy per pulse. A technique that uses Stimulated Brillouin Scattering (SBS) to compress a 8 ns pulse of a commercial Q-switched Nd-YAG laser is reported here. To carry out this passive compression technique, a frequency doubled laser pulse of 10 ns was focused into a single SBS gas cell, 2 m long, filled with a mixture of argon and sulphurhexafluoride (SF 6 ) at a total pressure of 40 bar. A shorter and high intensity pulse was reflected from the cell (created by SBS) and it travelled back along its original path until it was separated from its original direction by using a dichroic polariser. The pumping volume of the SBS cell, the convergence of the incident beam and the pressure of the gas cell, were optimised to maximise both temporal compression and the output energy. Pulses of 10 ns were compressed to less than 400 ps with a conversion efficiency of 80%. This SBS pulse compression system has been used to make most of the optical measurements of a dense fibre pinch plasma produced in the MAGPIE generator

  17. Diode pumped 1kHz high power Nd:YAG laser with excellent beam quality

    NARCIS (Netherlands)

    Godfried, Herman; Godfried, H.P; Offerhaus, Herman L.

    1997-01-01

    The design and operation of a one kilohertz diode pumped all solid-state Nd:YAG master oscillator power amplifier system with a phase conjugate mirror is presented. The setup allows high power scaling without reduction in beam quality.

  18. Nd:YAG laser combined with gold nanorods for potential application in port-wine stains: an in vivo study.

    Science.gov (United States)

    Xing, Linzhuang; Chen, Bin; Li, Dong; Wu, Wenjuan; Wang, Guoxiang

    2017-11-01

    Neodymium:yttrium aluminum garnet (Nd:YAG) lasers exhibit considerable potential for treating deeply buried port-wine stains. However, the application of Nd:YAG laser is limited by its weak absorption to blood. This in vivo study tested the efficacy and safety of utilizing thiol-terminated methoxypolyethylene glycol-modified gold nanorods (PEG-GNRs) to enhance the absorption of Nd:YAG laser to blood. Mouse mesentery and dorsal skinfold chamber (DSC) model were prepared to analyze the thermal responses of a single venule without anatomic structures, as well as blood vessels in the complex structure of the skin, to laser light. After the injection of 0.44 mg of PEG-GNRs, the required threshold density of laser energy for blood coagulation and complete vasoconstriction decreased from 24 to 18  J/cm2 in the mesentery model and from 36 to 31  J/cm2 in the DSC model. The laser pulse required for blood coagulation and complete vasoconstriction decreased by 67.75% and 62.25% on average in the mesentery model and by 67.55% and 54.45% on average in the DSC model. Histological and histochemical results confirmed that PEG-GNRs are nontoxic in the entire mouse life span. Therefore, combining PEG-GNRs with Nd:YAG laser may be effective and safe for inducing an obvious thermal response of blood vessels under low energy density and minimal pulse conditions. (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

  19. Highly efficient end-side-pumped Nd:YAG solar laser by a heliostat-parabolic mirror system.

    Science.gov (United States)

    Almeida, J; Liang, D; Vistas, C R; Guillot, E

    2015-03-10

    We report a large improvement in the collection and slope efficiency of an Nd:YAG solar laser pumped by a heliostat-parabolic mirror system. A conical fused silica lens was used to further concentrate the solar radiation from the focal zone of a 2 m diameter primary concentrator to a Nd:YAG single-crystal rod within a conical pump cavity, which enabled multipass pumping to the active medium. A 56 W cw laser power was measured, corresponding to 21.1  W/m2 record-high solar laser collection efficiency with the heliostat-parabolic mirror system. 4.9% slope efficiency was calculated, corresponding to 175% enhancement over our previous result.

  20. Are lasers superior to lights in the photoepilation of Fitzpatrick V and VI skin types? - A comparison between Nd:YAG laser and intense pulsed light.

    Science.gov (United States)

    Bs, Bibilash; Chittoria, Ravi Kumar; Thappa, Devinder Mohan; Mohapatra, Devi Prasad; Mt, Friji; S, Dineshkumar; Pandey, Sandhya

    2017-10-01

    There are no large volume comparative studies available to compare the efficacy of lasers over lights for hair removal in Fitzpatrick V and VI skin types. This study is designed to compare the efficacy of Nd:YAG laser versus IPL in the darker skin types. Thirty-nine patients included in Group-1 were treated with Nd:YAG and 31 in Group-2 with IPL. Both groups received 5 sessions of treatment. The hair counts were assessed using digital photography and manual counting method before and after treatment and the results were analysed. Patient satisfaction scores and pain scores were recorded in each session and compared. Mean hair reduction in the IPL group was 25.70 and Nd:YAG group was 24.12 (95% CI). In the Nd:YAG group, 59% of subjects had burning sensation while the figure was 32.3% in IPL group. Burning was less in IPL group (p < 0.023). There were no statistically significant differences noticed regarding hyperpigmentation in both the groups (p < 0.115). Both Nd:YAG and IPL are equally effective for epilation of the darker skin types. Nd:YAG is associated with mild burning sensation in a significant number of patients. Patient satisfaction scores were comparable in both the groups.

  1. Efficient second harmonics generation of a laser-diode-pumped Nd:YAG laser and its applications. Laser diode reiki Nd:YAG laser no kokoritsu daini kochoha hassei to sono oyo

    Energy Technology Data Exchange (ETDEWEB)

    Kubota, S.; Oka, M. (Sony Corp., Tokyo (Japan))

    1991-08-10

    Stabilization of the second harmonics in a laser-diode-pumped Nd:YAG laser and its application are described. The laser is a quantum noise limiting laser, in which a mode competing noise is generated from an interaction between the laser medium Nd:YAG and the type II nonlinear optical crystal KTiOPO{sub 4} when generating a second harmonics in the resonator. However, the quantum noise limiting second harmonics was obtained by means of inserting (1/4) wave length plate in the resonator to release the bond between two intersecting inherent polarization modes. This stabilized green laser is of a single lateral mode is nearly free of aberration. Therefore, an optical disc prototype having three times as much of the currently used density was made using an objective lens having high number of openings to collect lights, which was verified capable of regeneration at a high signal to noise ratio. In addition, higher output is possible by means of parallelizing the excitation, and high output is realized from edge excitation at a fiber bundle. 18 refs., 3 figs.

  2. Q-switch Nd:YAG laser welding of AISI 304 stainless steel foils

    Energy Technology Data Exchange (ETDEWEB)

    P' ng, Danny [Laboratory for Lasers, MEMS and Nanotechnology, Department of Mechanical Engineering, Iowa State University, Ames, IA 50011-2161 (United States); Molian, Pal [Laboratory for Lasers, MEMS and Nanotechnology, Department of Mechanical Engineering, Iowa State University, Ames, IA 50011-2161 (United States)], E-mail: molian@iastate.edu

    2008-07-15

    Conventional fusion welding of stainless steel foils (<100 {mu}m thickness) used in computer disk, precision machinery and medical device applications suffer from excessive distortion, formation of discontinuities (pore, void and hot crack), uncontrolled melting (melt-drop through) and poor aesthetics. In this work, a 15 ns pulsed, 400 mJ Nd:YAG laser beam was utilized to overcome these barriers in seam welding of 60 {mu}m thin foil of AISI 304 stainless steel. Transmission electron microscopy was used to characterize the microstructures while hardness and tensile-shear tests were used to evaluate the strengths. Surface roughness was measured using a DekTak profilometer while porosity content was estimated using the light microscope. Results were compared against the data obtained from resistance seam welding. Laser welding, compared to resistance seam welding, required nearly three times less heat input and produced welds having 50% narrower seam, 15% less porosity, 25% stronger and improved surface aesthetics. In addition, there was no evidence of {delta}-ferrite in laser welds, supporting the absence of hot cracking unlike resistance welding.

  3. Bioceramic coating of hydroxyapatite on titanium substrate with Nd-YAG laser

    International Nuclear Information System (INIS)

    Cheng, Gary J.; Pirzada, Daniel; Cai, M.; Mohanty, Pravansu; Bandyopadhyay, Amit

    2005-01-01

    The ability to bond to bone tissue is a unique property of bioactive ceramics. Hydroxyapatite (HAp) is one of the potential bioceramics candidates due to its superior bio-compatibility. Significant effort has been devoted to coat HAp ceramics on metallic substrates. Most of these processes, such as ion-beam sputter coating, thermal spraying, and flame spraying, are high temperature line of sight processes, which suffer from undesirable phase formation and weak metal/HAP bonding strength. This paper presents a unique process to coat HAp powders on titanium substrates at low temperature and enhance the coating/substrate interface by laser surface engineering. Nd-YAG laser transmits HAp powders and the laser power is absorbed by titanium substrate to produce a thin layer of molten region. During coating process, HAp powders are kept at low temperature before they are entrapped in metallic layer. Scanning electron microscope (SEM) was used to investigate the microstructure of coating; the chemical composition of the coating is determined by energy dispersive spectrometry (EDS). Mechanical properties of the interface between coating and Ti substrate were investigated by nanoindentation

  4. Mechanical behaviour of Nd:YAG laser welded superelastic NiTi

    International Nuclear Information System (INIS)

    Vieira, L. Alberty; Fernandes, F.M. Braz; Miranda, R.M.; Silva, R.J.C.; Quintino, L.; Cuesta, A.; Ocana, J.L.

    2011-01-01

    Highlights: → The main innovations claimed are: understand rolling direction effect on mechanical cycling of laser welded NiTi. → Functionality confirmed by stabilization of hysteretic response up to 8% strain. → Welds tensile cycled exhibited superior functional mechanical behaviour. → For applied stresses of 50 MPa below UTS the joints showed superelastic behaviour. - Abstract: Joining techniques for shape memory alloys (SMA) has become of great interest, as their functional properties, namely shape memory effect (SME) and superelasticity (SE), present unique solutions for state-of-the-art applications, although limited results concerning mechanical properties are reported. This paper reports experimental work performed with Nd:YAG continuous wave laser welding of superelastic cold-rolled plates of NiTi 1 mm thick. The mechanical behaviour was evaluated by means of tensile tests performed both to failure and to cycling. The superelastic behaviour of the welded joints was observed for applied stresses close to about 50 MPa below the ultimate tensile strength of the welds. The functionality was confirmed by analyzing the stabilization of the mechanical hysteretic response to strain levels up to 8%. For tensile cycling involving strain levels larger than 6%, welded specimens were found to exhibit superior functional mechanical behaviour presenting larger recoverable strain levels. The fracture surfaces were observed by scanning electron microscopy (SEM) and the effect of the rolling direction on mechanical properties was evaluated and discussed, reinforcing the importance of joint design when laser welding these alloys.

  5. Nd:YAG laser incision of the vesical neck in obstructive BPH

    Science.gov (United States)

    Gilbert, Peter T. O.

    2003-06-01

    From February, 1995 through June, 2002, 68 patients underwent laser incision of the prostate at our clinic. By means of a 23 F cytoscope and a 600 micrometer lateral firing quartz fiber the vesical neck was incised at the 5 and 7 o'clock position at 60 W power. Total energy averaged 13648 J. Operative time did not exceed 15 minutes. General anesthesia was employed in all but one patient. 38 patients remained catheter-free whereas 30 patients were catheterized for two hours. Except for three cases, all patients were discharged on the same day, usually after the first micturition. Anti-inflammatory treatment was administered for two weeks, Cotrimoxazole for 5 days. No serious complications were encountered. Minor side effects included urinary retention (1 pat.), urinary infection (3 pat.) and retrograde ejaculation (1 pat.). Considering a mean follow-up of 21 months, the average Qmax improved enormously (25.4 ml/s versus 10.9 ml/s), as did residual urine volume (35 ml versus 95 ml) and IPSS (7.1 versus 20.5). Three patients required TUR-P 2-3 years after laser surgery and one patient underwent radical retropubic prostatectomy for prostate cancer 2 years later. In conclusion, Nd:YAG laser incision of the prostate is a simple, safe, reliable and cost-effective outpatient procedure.

  6. Nd:YAG 1.44 laser ablation of human cartilage

    Science.gov (United States)

    Cummings, Robert S.; Prodoehl, John A.; Rhodes, Anthony L.; Black, Johnathan D.; Sherk, Henry H.

    1993-07-01

    This study determined the effectiveness of a Neodymium:YAG 1.44 micrometers wavelength laser on human cartilage. This wavelength is strongly absorbed by water. Cadaveric meniscal fibrocartilage and articular hyaline cartilage were harvested and placed in normal saline during the study. A 600 micrometers quartz fiber was applied perpendicularly to the tissues with a force of 0.098 N. Quantitative measurements were then made of the ablation rate as a function of fluence. The laser energy was delivered at a constant repetition rate of 5 Hz., 650 microsecond(s) pulsewidth, and energy levels ranging from 0.5 joules to 2.0 joules. Following the ablation of the tissue, the specimens were fixed in formalin for histologic evaluation. The results of the study indicate that the ablation rate is 0.03 mm/mj/mm2 for hyaline cartilage and fibrocartilage. Fibrocartilage was cut at approximately the same rate as hyaline cartilage. There was a threshold fluence projected to be 987 mj/mm2 for hyaline cartilage and fibrocartilage. Our results indicate that the pulsed Nd:YAG laser operating at 1.44 micrometers has a threshold fluence above which it will ablate human cartilage, and that its ablation rate is directly proportional to fluence over the range of parameters tested. Fibrocartilage and hyaline cartilage demonstrated similar threshold fluence and ablation rates which is related to the high water content of these tissues.

  7. Effects of Nd:YAG laser pulse frequency on the surface treatment of Ti 6Al 4V alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gursel, Ali [International University of Sarajevo (Bosnia and Herzegovina). Dept. of Mechanical Engineering

    2016-07-01

    The desirable properties of titanium and titanium alloys, including excellent corrosion resistance, high strength to weight ratio and high operating temperature, have led to their successful application in various fields such as the medical and aerospace industries. Among the reliable treatment techniques, laser welding can provide significant advantages for the titanium alloys because of its precision, rapid processing capability and ability to control the welding parameters and their effects. The morphology and the quality of pulsed seam welds are directly or synergistically influenced by the Nd:YAG laser parameters of pulse shape, energy, duration, travel speed, peak power and frequency of repetition. In this study, a 1.5 mm thick Ti-6Al-4V alloy sheet surface was treated by SigmaLaser {sup registered} 300 Nd:YAG pulsed laser. The influence of the pulse frequency on seam morphology and surface effects was then investigated. The seam and surface quality were characterized in terms of weld morphology and microhardness. The results showed that, for Nd:YAG laser seams used for surface treatment, pulse repetition was more effective on the cooling rate than had been expected.

  8. A high-power diode-laser-pumped CW Nd:YAG laser using a stable-unstable resonator

    International Nuclear Information System (INIS)

    Mudge, M.; Ostermeyer, P.; Veitch, J.; Munch, J.; Hamilton, M.W.

    2000-01-01

    Full text: The design and operation of a power-scalable diode-laser-pumped CW Nd:YAG zigzag slab laser that uses a stable-unstable resonator with a graded reflectivity mirror as an output coupler is described. We demonstrate control of the thermal lens strength in the unstable plane and weak thermal lensing in the stable plane that is independent of pump power, vital for efficient scalability. This enabled CW operation of the stable-unstable resonator with excellent near- and far-field beam quality

  9. Comparison of Q-switched Nd:YAG laser alone versus its combination with ultrapulse CO2 laser for the treatment of black tattoo.

    Science.gov (United States)

    Vanarase, Mithila; Gautam, Ram Krishan; Arora, Pooja; Bajaj, Sonali; Meena, Neha; Khurana, Ananta

    2017-10-01

    Q-switched lasers are conventionally used for the treatment of black tattoo. However, they require multiple sittings, and the response may be slow due to competing epidermal pigment in dark skin. To compare the efficacy of Q-switched Nd:YAG laser alone with its combination with ultrapulse CO 2 for the removal of black tattoo. Sixty patients with black tattoo were randomized into two groups viz., group A and group B. Group A was treated with QS Nd:YAG laser (1064 nm) alone, and group B received combination of ablative ultrapulse CO 2 followed by fixed-dose QS Nd:YAG laser (1064 nm), at 6-week interval for a maximum of 6 sittings. After each sitting, 3 independent physicians noted percentage of improvement that was evaluated using visual analogue scale (VAS) and grading system for tattoo ink lightening (TIL). Combination laser (group B) showed statistically significant improvement in mean VAS score in the last 2 noted visits as compared to 1st session (p tattoos, combination of ultrapulse CO 2 laser and QS Nd:YAG laser is superior to QS Nd:YAG laser alone.

  10. Optimized fiber delivery system for Q-switched, Nd:YAG lasers

    International Nuclear Information System (INIS)

    Setchell, R.E.

    1997-01-01

    Interest in the transmission of high intensities through optical fibers is being motivated by an increasing number of applications. Using different laser types and fiber materials, various studies are encountering transmission limitations due to laser-induced damage processes. For a number of years we have been investigating these limiting processes during the transmission of Q-switched, multimode, Nd:YAG laser pulses through step-index, multimode, fused-silica fiber. We have found that fiber transmission is often limited by a plasma-forming breakdown occurring at the fiber entrance face. This breakdown can result in subtle surface modifications that leave the entrance face more resistant to further breakdown or damage events. Catastrophic fiber damage can also occur as a result of a variety of mechanisms, with damage appearing at fiber entrance and exit faces, within the initial entry segment of the fiber path, and at other internal sites due to fiber fixturing and routing effects. System attributes that will affect breakdown and damage thresholds include laser characteristics, the design and alignment of laser-to-fiber injection optics, and fiber end-face preparation. In the present work we have combined insights gained in past studies in order to establish what thresholds can be achieved if all system attributes can be optimized to some degree. Our multimode laser utilized past modifications that produced a relatively smooth, quasi-Gaussian profile. The laser-to-fiber injection system achieved a relatively low value for the ratio of peak-to-average fluences at the fiber entrance face, incorporated a mode scrambler to generate a broad mode power distribution within the initial segment of the fiber path, and had improved fixturing to insure that the fiber axis was collinear with the incident laser beam. Test fibers were from a particular production lot for which initial-strength characteristics were established and a high-stress proof test was performed

  11. Histological and ultrastructural effect of an Nd:YAG pulsed laser beam on dental hard tissue and pulp

    Science.gov (United States)

    Vignato, Costantino; Vignato, Giuseppe; Nardelli, Antonella; Baldan, Arianna; Mason, Pier N.

    1994-09-01

    The purpose of this study was to determine histological and ultrastructural modifications produced by an Nd:YAG pulsed laser beam after an in vivo exposure of human molars. Using a Nd:YAG pulsed laser beam delivered by a 600 micrometers optical fiber and concurrent air and water cooling spray, 14 human third molars with artificial first class cavities were exposed at different power levels (6, 7, and 8 W). All the teeth were extracted at different time periods between 10 and 25 days and prepared for histological examination. The results of the histological examination showed no evidence of degeneration or necrosis of the pulpar tissue. Analysis of the dentinal surfaces after exposure demonstrated that the dentinal tubules are completely closed due to the melted dentin. In conclusion a Nd:YAG pulsed laser beam with an air and water cooling spray is safe for treatments of class I decay and no necrosis or degeneration of the pulp was found for laser powers of 6, 7, and 8 W.

  12. Microprocessor-controlled Nd:YAG laser for hyperthermia induction in the RIF-1 tumor.

    Science.gov (United States)

    Waldow, S M; Russell, G E; Wallner, P E

    1992-01-01

    Near-infrared radiation from a Nd:YAG laser at 1,064 nm was used interstitially or superficially to induce hyperthermia in RIF-1 tumors in C3H male mice. A single 600-microns quartz fiber with a 0.5-cm cylindrical diffusor or a weakly diverging microlens at its distal end was used to deliver laser energy to tumors in the hind leg (mean volume = 100 mm3). Two thermocouples were inserted into each tumor. One thermocouple controlled a microprocessor-driven hyperthermia program (maximum output of 3.5 Watts) to maintain the desired temperature. Tumors were exposed to various temperature-time combinations (42-45 degrees C/30 min). Our initial results indicated that excellent temperature control to within 0.2 degrees C of the desired temperature at the feedback thermocouple was achievable during both superficial and interstitial heat treatments. Temperatures at the second thermocouple, however, were found to be lower by as much as 2.3 degrees C (using the cylindrical diffusor) or higher by up to 4.6 degrees C (using the microlens) when compared to the feedback thermocouple temperature. Several correlations were seen between total dose, tumor growth delay, percent skin necrosis, and temperature at the second thermocouple after several superficial and interstitial treatments. Statistically significant improvements in tumor growth delay (at 42 and 45 degrees C) and increased percent skin necrosis at all temperatures were observed after superficial versus interstitial treatment.

  13. Process optimization in Nd:YAG laser microdrilling of alumina–aluminium interpenetrating phase composite

    Directory of Open Access Journals (Sweden)

    Ranjib Biswas

    2015-07-01

    Full Text Available In laser beam micromachining process, the quality of the drilled hole is of great importance. The quality of the microdrilled hole mainly depends on appropriate selection of process parameters. Predefined diameter of hole with minimum taper is of today's demand. The composite used for microdrilling operation is alumina–aluminium (Al2O3–Al interpenetrating phase composite (IPC, which is widely used in aircraft and space stations. Until date, no experimental study has been done to obtain microdrilled hole of desired diameter. In the present paper three hole qualities such as hole diameter at entry, at exit and hole taper have been optimized individually as well as simultaneously using a central composite design (CCD based on response surface methodology (RSM during pulsed Nd:YAG laser microdrilling operation on alumina–aluminium IPC sheet of 1.14 mm thickness. The analysis of variance (ANOVA test has also been done to identify the process parameters that contributed the most to get desired hole quality.

  14. Long-pulsed Nd:YAG laser in the treatment of facial hypertrichosis during topical minoxidil therapy.

    Science.gov (United States)

    Benmously Mlika, Rym; Ben Hamida, Myriam; Hammami, Houda; Dorbani Ben Thabet, Imen; Rouatbi, Mondher; Mokhtar, Inçaf

    2013-08-01

    Hypertrichosis is a well-recognized adverse effect of therapy with either oral or topical minoxidil. We report a case of fronto-temporal hypertrichosis occurring in an 8-year-old girl treated for patchy alopecia areata of the frontal area of the scalp with 2% minoxidil solution. After failure of 5-months minoxidil-discontinuation, hair removal with Nd:YAG laser (1064 nm line) (Smartepil II, Deka) was tested leading to complete resolution within 2 sessions.

  15. An expanded study of long-pulsed 1064 nm Nd:YAG laser treatment of basal cell carcinoma.

    Science.gov (United States)

    Ortiz, Arisa E; Anderson, R Rox; DiGiorgio, Catherine; Jiang, Shang I Brian; Shafiq, Faiza; Avram, Mathew M

    2018-02-13

    Basal cell carcinoma (BCC) is an indolent form of skin cancer that is rarely life threatening, but can cause significant cosmetic and functional morbidity. Surgical treatments often result in disfiguring scars, while topical therapies frequently result in recurrence. The need for a more effective nonsurgical alternative has led to the investigation of laser treatment of BCC. We have previously conducted a pilot study which showed 100% histologic clearance at high fluences. Treatments were well tolerated with no significant adverse events. The objective of this larger study was to confirm preliminary results that the 1064 nm Nd:YAG laser is a safe and effective method for treating non-facial BCC. This is an IRB-approved, prospective, multi-center study evaluating the safety and efficacy of the 1064 nm Nd:YAG laser for the treatment of BCC on the trunk and extremities. Thirty-three subjects seeking treatment for biopsy-proven BCC that did not meet the criteria for Mohs surgery were recruited. Subjects on current anticoagulation therapy, or with a history of immunosuppression were excluded. Subjects received one treatment with the 1064 nm Nd:YAG laser as follows: 5-6 mm spot, fluence of 125-140 J/cm 2 and a pulse duration of 7-10 ms. Standard excision with 5 mm clinical margins was performed at 30 days after laser treatment to evaluate clinical and histologic clearance of BCC. Standardized photographs and adverse assessments were taken at the baseline visit, immediately after laser treatment and on the day of excision. Thirty-one subjects completed the study. BCC tumors had a 90% (28 of 31 BCC tumors) histologic clearance rate after one treatment with the long-pulsed 1064 nm Nd:YAG laser. Treatments were generally well tolerated without any anesthesia. Immediate side effects included edema and erythema. At 1-month follow-up, some patients had residual crusting. No significant adverse events occurred. The 1064 nm long-pulsed Nd:YAG laser is an

  16. Efficient quasi-three-level Nd:YAG laser at 946 nm pumped by a tunable external cavity tapered diode laser

    DEFF Research Database (Denmark)

    Cheng, Haynes Pak Hay; Jensen, Ole Bjarlin; Tidemand-Lichtenberg, Peter

    2010-01-01

    Using a tunable external cavity tapered diode laser (ECDL) pumped quasi-three-level Nd:YAG laser, a fivefold reduction in threshold and twofold increase in slope efficiency is demonstrated when compared to a traditional broad area diode laser pump source. A TEM00 power of 800 mW with 65% slope...... efficiency is obtained, the highest reported TEM00 power from any 946 nm Nd:YAG laser pumped by a single emitter diode laser pump source. A quantum efficiency of 0.85 has been estimated from experimental data using a simple quasi-three-level model. The reported value is in good agreement with published...

  17. Role of Q-switched ND:YAG laser in nevus of Ota: A study of 25 cases

    Directory of Open Access Journals (Sweden)

    Shivangi Sharma

    2011-01-01

    Full Text Available Background: Nevus of Ota is common condition in Indian patients. The condition is more common in females, with a male-female ratio of 1:4.8. Aim : To evaluate long-term efficacy safety and stability of Q-switched ND:YAG laser in treatment of Nevus of Ota. Design: 6 month follow-up of patients of Nevus of Ota, treated with Q-switched ND:YAG laser Materials and Methods : Twenty-five patients of Nevus of Ota were treated with Q-switched ND:YAG laser for a period of 1 year and 9 months; patient had fitzpatricks skin type 4 and 5; detailed history, clinical examination, ophthalmoscopy, and otoscopy was done in all cases; clinical photographs were taken before and after the completion of treatments. Six-month follow-up was done after the last session. Response to treatment was graded based on physician′s global assessment. Result : More than 70% improvement was seen in 15 patients (60%. Eight patients (32% had moderate and two patients (8% showed mild improvement.

  18. A comparative clinical and mycological study of Nd-YAG laser versus topical terbinafine in the treatment of onychomycosis.

    Science.gov (United States)

    El-Tatawy, Rania A; Abd El-Naby, Naeim M; El-Hawary, Esraa E; Talaat, Raghda A Z

    2015-10-01

    Topical treatment of onychomycoses is time consuming, cost-intensive and subject to relatively high failure rates. Light-based devices may be effective treatment modalities. Aim of this work: To compare the clinical and mycological efficacy of Nd-YAG laser versus topical terbinafine in the treatment of onychomycosis. This study included 40 patients with onychomycosis randomized to receive four sessions of Nd-YAG laser (group A) or topical terbinafine twice daily for six months (group B). Follow-up was performed monthly. Mycological examination was done at third and sixth months following the start of treatment. After six months, all patients in group A showed marked improvement, while in group B only 50% of patients showed mild to moderate improvement. In addition, by the end of six months, 80% of the patients in group A showed mycological clearance, while all patients in group B still had positive cultures. Long pulse Nd-YAG laser therapy of onychomycosis is a safe and efficient method for treating onychomycosis. It is especially beneficial in elderly, compromised and hepatopathic patients for whom other alternative treatments could present some risks.

  19. Tritium Decontamination of TFTR D-T Graphite Tiles Employing Ultra Violet Light and a Nd:YAG Laser

    International Nuclear Information System (INIS)

    Gentile, C.A.; Skinner, C.H.; Young, K.M.; Ciebiera, L.

    1999-01-01

    The use of an ultra violet (UV) light source (wavelength = 172 nm) and a Nd:YAG Laser for the decontamination of the Tokamak Fusion Test Reactor (TFTR) deuterium-tritium (D-T) tiles will be investigated at the Princeton Plasma Physics Laboratory (PPPL). The development of this form of tritium decontamination may be useful for future D-T burning fusion devices which employ carbon plasma-facing components on the first wall. Carbon tiles retain hydrogen isotopes, and the in-situ tritium decontamination of carbon can be extremely important in maintaining resident in-vessel tritium inventory to a minimum. A test chamber has been designed and fabricated at PPPL. The chamber has the ability to be maintained under vacuum, be baked to 200 *C, and provides sample ports for gas analyses. Tiles from TFTR that have been exposed to D-T plasmas will be placed within the chamber and exposed to either an UV light source or the ND:YAG Laser. The experiment will determine the effectiveness of these two techniques for the removal of tritium. In addition, exposure rates and scan times for the UV light source and/or Nd:YAG Laser will be determined for tritium removal optimization from D-T tiles

  20. FT-Raman spectroscopic analysis of Nd:YAG and Er,Cr:YSGG laser irradiated enamel for preventive purposes

    Science.gov (United States)

    Ana, P. A.; Kauffmann, C. M. F.; Bachmann, L.; Soares, L. E. S.; Martin, A. A.; Gomes, A. S. L.; Zezell, D. M.

    2014-03-01

    This study evaluated the effect of combining laser irradiation with fluoride on an enamel microstructure and demineralization by FT-Raman spectroscopy (FTRS). Eighty human enamel slabs were divided into eight groups: (G1) untreated; (G2) acidulated phosphate fluoride application (APF—1.23% F- for 4 min) (G3) Nd:YAG irradiation (84.9 J cm-2, 60 mJ/pulse) (G4) Nd:YAG + APF; (G5) APF + Nd:YAG; (G6) Er,Cr:YSGG irradiation (2.8 J cm-2, 12.5 mJ/pulse) (G7) Er,Cr:YSGG + APF; and (G8) APF + Er,Cr:YSGG. After treatment, the samples were submitted to a ten-day pH-cycling model. Chemical changes were determined on the slabs before and after treatment, and also after pH-cycling, by FTRS in the range 400-4000 cm-1. The inorganic bands at 440, 590, 870, 960, 1100 cm-1, and the organic bands at 1270, 1450, 1670, 2945 cm-1 were considered. Demineralization promoted reduction in organic contents; Nd:YAG laser irradiation promoted loss of carbonate and organic content, while Er,Cr:YSGG did not produce significant changes in the relative band intensities of organic and inorganic contents of the enamel. In lased samples, no effects caused by pH-cycling on enamel were observed. In conclusion, laser treatment and its association with fluoride can somehow interfere with the demineralization dynamics, reducing its effects over the enamel.

  1. FT-Raman spectroscopic analysis of Nd:YAG and Er,Cr:YSGG laser irradiated enamel for preventive purposes

    International Nuclear Information System (INIS)

    Ana, P A; Kauffmann, C M F; Gomes, A S L; Bachmann, L; Soares, L E S; Martin, A A; Zezell, D M

    2014-01-01

    This study evaluated the effect of combining laser irradiation with fluoride on an enamel microstructure and demineralization by FT-Raman spectroscopy (FTRS). Eighty human enamel slabs were divided into eight groups: (G1) untreated; (G2) acidulated phosphate fluoride application (APF—1.23% F − for 4 min); (G3) Nd:YAG irradiation (84.9 J cm −2 , 60 mJ/pulse); (G4) Nd:YAG + APF; (G5) APF + Nd:YAG; (G6) Er,Cr:YSGG irradiation (2.8 J cm −2 , 12.5 mJ/pulse); (G7) Er,Cr:YSGG + APF; and (G8) APF + Er,Cr:YSGG. After treatment, the samples were submitted to a ten-day pH-cycling model. Chemical changes were determined on the slabs before and after treatment, and also after pH-cycling, by FTRS in the range 400−4000 cm −1 . The inorganic bands at 440, 590, 870, 960, 1100 cm −1 , and the organic bands at 1270, 1450, 1670, 2945 cm −1 were considered. Demineralization promoted reduction in organic contents; Nd:YAG laser irradiation promoted loss of carbonate and organic content, while Er,Cr:YSGG did not produce significant changes in the relative band intensities of organic and inorganic contents of the enamel. In lased samples, no effects caused by pH-cycling on enamel were observed. In conclusion, laser treatment and its association with fluoride can somehow interfere with the demineralization dynamics, reducing its effects over the enamel. (paper)

  2. Evaluation of primary tooth enamel surface morphology and microhardness after Nd:YAG laser irradiation and APF gel treatment--an in vitro study.

    Science.gov (United States)

    Banda, Naveen Reddy; Vanaja Reddy, G; Shashikiran, N D

    2011-01-01

    Laser irradiation and fluoride has been used as a preventive tool to combat dental caries in permanent teeth, but little has been done for primary teeth which are more prone to caries. The purpose of this study was to evaluate microhardness alterations in the primary tooth enamel after Nd-YAG laser irradiation alone and combined with topical fluoride treatment either before or after Nd-YAG laser irradiation. Ten primary molars were sectioned and assigned randomly to: control group, Nd-YAG laser irradiation, Nd-YAG lasing before APF and APF followed by Nd-YAG lasing. The groups were evaluated for microhardness. Surface morphological changes were observed using SEM. Statistical comparisons were performed. The control group's SEM showed a relatively smooth enamel surface and lasing group had fine cracks and porosities. In the lasing + fluoride group a homogenous confluent surface was seen. In the fluoride + lasing group an irregular contour with marked crack propagation was noted. There was a significant increase in the microhardness of the treatment groups. Nd-YAG laser irradiation and combined APF treatment of the primary tooth enamel gave morphologically hardened enamel surface which can be a protective barrier against a cariogenic attack.

  3. Nd:YAG Laser-Based Dual-Line Detection Rayleigh Scattering and Current Efforts on UV, Filtered Rayleigh Scattering

    Science.gov (United States)

    Otugen, M. Volkan; Popovic, Svetozar

    1996-01-01

    Ongoing research in Rayleigh scattering diagnostics for variable density low speed flow applications and for supersonic flow measurements are described. During the past several years, the focus has been on the development and use of a Nd:YAG-based Rayleigh scattering system with improved signal-to-noise characteristics and with applicability to complex, confined flows. This activity serves other research projects in the Aerodynamics Laboratory which require the non-contact, accurate, time-frozen measurement of gas density, pressure, and temperature (each separately), in a fairly wide dynamic range of each parameter. Recently, with the acquisition of a new seed-injected Nd:YAG laser, effort also has been directed to the development of a high-speed velocity probe based on a spectrally resolved Rayleigh scattering technique.

  4. Wavefront improvement in an end-pumped high-power Nd:YAG zigzag slab laser.

    Science.gov (United States)

    Shin, Jae Sung; Cha, Yong-Ho; Lim, Gwon; Kim, Yonghee; Kwon, Seong-Ouk; Cha, Byung Heon; Lee, Hyeon Cheor; Kim, Sangin; Koh, Kwang Uoong; Kim, Hyun Tae

    2017-08-07

    Techniques for wavefront improvement in an end-pumped Nd:YAG zigzag slab laser amplifier were proposed and demonstrated experimentally. First, a study on the contact materials was conducted to improve the heat transfer between the slab and cooling blocks and to increase the cooling uniformity. Among many attempts, only the use of silicon oil showed an improvement in the wavefront. Thus, the appropriate silicone oil was applied to the amplifier as a contact material. In addition, the wavefront compensation method using a glass rod array was also applied to the amplifier. A very low wavefront distortion was obtained through the use of a silicone-oil contact and glass rod array. The variance of the optical path difference for the entire beam height was 3.87 μm at a pump power of 10.6 kW, and that for the 80% section was 1.69 μm. The output power from the oscillator was 3.88 kW, which means the maximum output extracted from the amplifier at a pump power of 10.6 kW.

  5. A silicon avalanche photodiode detector circuit for Nd:YAG laser scattering

    International Nuclear Information System (INIS)

    Hsieh, C.L.; Haskovec, J.; Carlstrom, T.N.; DeBoo, J.C.; Greenfield, C.M.; Snider, R.T.; Trost, P.

    1990-06-01

    A silicon avalanche photodiode with an internal gain of about 50 to 100 is used in a temperature controlled environment to measure the Nd:YAG laser Thomson scattered spectrum in the wavelength range from 700 to 1150 nm. A charge sensitive preamplifier has been developed for minimizing the noise contribution from the detector electronics. Signal levels as low as 20 photoelectrons (S/N = 1) can be detected. Measurements show that both the signal and the variance of the signal vary linearly with the input light level over the range of interest, indicating Poisson statistics. The signal is processed using a 100 ns delay line and a differential amplifier which subtracts the low frequency background light component. The background signal is amplified with a computer controlled variable gain amplifier and is used for an estimate of the measurement error, calibration, and Z eff measurements of the plasma. The signal processing has been analyzed using a theoretical model to aid the system design and establish the procedure for data error analysis. 4 refs., 5 figs

  6. 120 watt continuous wave solar-pumped laser with a liquid light-guide lens and an Nd:YAG rod.

    Science.gov (United States)

    Dinh, T H; Ohkubo, T; Yabe, T; Kuboyama, H

    2012-07-01

    We propose a simple and efficient pumping approach for a high-power solar-pumped laser by using a liquid light-guide lens (LLGL) and a hybrid pumping cavity. A 2×2 m Fresnel lens is used as a primary concentrator to collect natural sunlight; 120 W cw laser power and a 4.3% total slope efficiency are achieved with a 6-mm diameter Nd:YAG rod within a 14-mm diameter LLGL. The corresponded collection efficiency is 30.0 W/m(2), which is 1.5 times larger than the previous record. This result is unexpectedly better than that of Cr:Nd:YAG ceramics. It is because the scattering coefficient of Cr:Nd:YAG ceramics is 0.004cm(1), which is 2 times larger than that of the Nd:YAG crystal, although both have similar saturation gains.

  7. Compact, Passively Q-Switched Nd:YAG Laser for the MESSENGER Mission to the Planet Mercury

    Science.gov (United States)

    Krebs, Danny J.; Novo-Gradac, Anne-Marie; Li, Steven X.; Lindauer, Steven J.; Afzal, Robert S.; Yu, Antony

    2004-01-01

    A compact, passively Q-switched Nd:YAG laser has been developed for the Mercury Laser Altimeter (MLA) instrument which is an instrument on the MESSENGER mission to the planet Mercury. The laser achieves 5.4 percent efficiency with a near diffraction limited beam. It has passed all space flight environmental tests at system, instrument, and satellite integration. The laser design draws on a heritage of previous laser altimetry missions, specifically ISESAT and Mars Global Surveyor; but incorporates thermal management features unique to the requirements of an orbit of the planet Mercury.

  8. Femtosecond-laser inscribed double-cladding waveguides in Nd:YAG crystal: a promising prototype for integrated lasers.

    Science.gov (United States)

    Liu, Hongliang; Chen, Feng; Vázquez de Aldana, Javier R; Jaque, D

    2013-09-01

    We report on the design and implementation of a prototype of optical waveguides fabricated in Nd:YAG crystals by using femtosecond-laser irradiation. In this prototype, two concentric tubular structures with nearly circular cross sections of different diameters have been inscribed in the Nd:YAG crystals, generating double-cladding waveguides. Under 808 nm optical pumping, waveguide lasers have been realized in the double-cladding structures. Compared with single-cladding waveguides, the concentric tubular structures, benefiting from the large pump area of the outermost cladding, possess both superior laser performance and nearly single-mode beam profile in the inner cladding. Double-cladding waveguides of the same size were fabricated and coated by a thin optical film, and a maximum output power of 384 mW and a slope efficiency of 46.1% were obtained. Since the large diameters of the outer claddings are comparable with those of the optical fibers, this prototype paves a way to construct an integrated single-mode laser system with a direct fiber-waveguide configuration.

  9. The sealing of second mandibular temporary molar pits and fissure with the laser of Nd: YAG, phosphoric acid and the glass ionomer cement

    International Nuclear Information System (INIS)

    Toda, Maria Aparecida

    2003-01-01

    The main of our study was to check the sealing of second mandibular temporary molar pits and fissure, in vitro, with the laser of Nd: YAG, phosphoric acid at 37% and the glass ionomer cement (CIV, Fuji IX GC).The proposal was to check the structural morphologic changes in the laser irradiation upon the enamel surface to watch the pits and fissure sealing with the glass ionomer cement use after the laser irradiation and to verify the efficiency of the 'double conditioning' (phosphoric acid + Nd: YAG). At the same time we watch the evolution of the temperature in the pulp chamber's inside. Our desire was to achieve a therapeutic alternative technic to prevent the dental caries. The Nd: YAG laser parameters were the same: 79 mJ of energy per pulse; frequency of 5 Hz; mean power of 0,4 W; optical fiber on contact of 320 μm diameter; fluency of 99,52 J/ cm 2 , assuming that the only differential was the time of the laser application on the enamel surface. The samples were prepared with this way: Laser Nd: YAG (53 second) + acid + CIV (Fuji IX); Laser Nd: YAG (53 s); Laser Nd: YAG (20 s + 20 s) + acid + CIV; Laser Nd: YAG (20 s + 20 s); Acid + CIV; Control. Through the scanning electron microscopy (MEV) we noticed fusion and resolidification regions due to the laser irradiation and a better adaptation of the glass ionomer cement when we did the 'double conditioning'. Concerning the temperature increase we can conclude that the echeloned period was the best recommended because the temperature was found in a pattern that would not cause any damage to the dental pulp. For future studies we suggest a longer relaxing time between the laser irradiation, a comparative study of this method with other lasers, the use of other sealing materials and the study with the permanent teeth. (author)

  10. Evaluation of Long Pulsed-ND: Yag Laser in The Treatment of Onychomycosis

    International Nuclear Information System (INIS)

    Ahmad, E.M.A.

    2013-01-01

    topical or systemic treatment (Donald et al., 2002). The choice of therapy is influenced by the presentation and severity of the disease, other medications that the patient is taking, physician and patient preference, and cost (Gupta et al., 2003). A novel non-invasive approach for treatment of onychomycosis is the application of laser energy to the nail plate targeting the fungal cells themselves. By using a laser with a specific wavelength of laser light energy, the fungus could be directly targeted in the nail and heated to the point it is killed, but without burning the surrounding tissue and with leaving the skin and nail intact (Kozarev and Vizintin, 2010). The Nd-Yag (neodymium-doped yttrium aluminium garnet; Nd: Y 3 Al 5 O 12 ) laser is such a device with a wavelength 1064 nm that will pass through the nail plate and into the nail bed resulting in superheating of the fungal material. Exposure of fungi to high temperatures inhibits their growth as well as causing cell damage and death (Hashimoto and Blumenthal, 1978). Several other types of lasers are introduced for the treatment of onychomycosis including diode laser (Landsman et al., 2010) femtosecond infrared titanium sapphire laser (Manevitch et al., 2010). A novel 0.65-millisecond pulsed Nd:YAG is also introduced for the treatment of onychomycosis (Mozena and Haverstock, 2010).

  11. Evaluation in vitro of effects of Er:YAG and Nd:YAG lasers irradiation on root canal wall, by stereoscopy, scanning electron micrography and thermographic camera

    International Nuclear Information System (INIS)

    Goya, Claudia

    2001-01-01

    This study was carried out to evaluate in vitro the effects of Nd:YAG laser and Er:YAG laser irradiation in the root canal wall by SEM, evaluating the apical leakage and the temperature changes during the laser irradiation. Seventy four extracted human teeth were used, they were instrumented and divided into seven groups of 10 teeth each. The teeth were evaluated through stereoscopy, by SEM, and with the thermographic camera. The Nd:YAG laser irradiation parameters were 100 mJ/p, 15 Hz, and Er:YAG laser were 160 mJ/p and 10 Hz, the irradiation was 4 times at 2 mm/sec speed, with 20 sec interval. The apical leakage was not observed in the teeth irradiated by Nd:YAG laser alone or in association with Er:YAG laser. However in the teeth irradiated only by the Er:YAG laser we observed a little leakage. By SEM observation the Nd:YAG laser irradiation showed melting and recrystallization in the dentin surface closing dentinal tubules, and in the samples irradiated by Er:Y AG laser a clean surface, opened dentinal tubules, and the combination by two lasers, showed melting covering some dentinal tubules The thermographic study found the temperature increase was not more than 6 deg C. This study showed the safety parameters applications of Er:YAG laser in association with Nd:YAG laser in root canal treatment, in order to not cause thermal damages to the periodontal tissues. (author)

  12. Study on growth techniques and macro defects of large-size Nd:YAG laser crystal

    Science.gov (United States)

    Quan, Jiliang; Yang, Xin; Yang, Mingming; Ma, Decai; Huang, Jinqiang; Zhu, Yunzhong; Wang, Biao

    2018-02-01

    Large-size neodymium-doped yttrium aluminum garnet (Nd:YAG) single crystals were grown by the Czochralski method. The extinction ratio and wavefront distortion of the crystal were tested to determine the optical homogeneity. Moreover, under different growth conditions, the macro defects of inclusion, striations, and cracking in the as-grown Nd:YAG crystals were analyzed. Specifically, the inclusion defects were characterized using scanning electron microscopy and energy dispersive spectroscopy. The stresses of growth striations and cracking were studied via a parallel plane polariscope. These results demonstrate that improper growth parameters and temperature fields can enhance defects significantly. Thus, by adjusting the growth parameters and optimizing the thermal environment, high-optical-quality Nd:YAG crystals with a diameter of 80 mm and a total length of 400 mm have been obtained successfully.

  13. Combined 1.06- and 1.32-um Nd:YAG laser in the treatment of rectosigmoideal tumors

    Science.gov (United States)

    Horak, Ladislav; Fanta, J.; Marek, Jan

    1993-07-01

    Since January 1988 we have been using the combined Nd:YAG laser Medicalas. The laser operates on the wavelength of 1.06 micrometers with maximum output power of 100 W, and a wavelength of 1.32 micrometers with maximum output power of 30 W. Introduction of the laser into clinical practice was preceded by experimental operation, where we verified the interaction of laser emittance on both wavelengths with the tissues of colon, stomach, esophagus, and open surgery of the abdominal and thoracic cavities.

  14. New application of the long-pulsed Nd-YAG laser as an ablative resurfacing tool for skin rejuvenation: a 7-year study.

    Science.gov (United States)

    Alshami, Mohammad Ali

    2013-09-01

    Carbon dioxide (CO2 ) and erbium-yttrium aluminum garnet (Er-YAG) lasers are the gold standards in ablative skin resurfacing. Neodymium-doped yttrium aluminum garnet (Nd-YAG) laser is considered a nonablative skin resurfacing laser whose usage is limited due to its high cost. To assess the efficacy and safety of Nd-YAG as an ablative resurfacing laser and to compare the results with those previously published for CO2 and Erbium-YAG lasers. A total of 296 patients (251 female and 45 male) with Fitzpatrick skin types III-IV and dermatological conditions amenable to ablative skin resurfacing participated in this study. Nd-YAG laser parameters assessed were wavelength (1064 nm), pulse duration (5 ms), fluence (10 J/cm(2) ), and spot size (8-10 mm). Efficacy of Nd-YAG laser was assessed by comparing pre- and posttreatment photographs. An improvement of 30-80% was observed in treated patients. The degree of improvement correlated positively with the number of laser sessions. The most common side effect was hyperpigmentation. Other side effects were less common and mild in intensity compared with published results for gold standard ablative lasers. Not only was the Nd-YAG laser found to be as effective as Er-YAG and CO2 lasers, but treated patients also had shorter recovery and treatment times, and at lower cost. © 2013 Wiley Periodicals, Inc.

  15. Cutting performances with new industrial continuous wave ND:YAG high power lasers

    International Nuclear Information System (INIS)

    Chagnot, C.; Dinechin, G. de; Canneau, G.

    2010-01-01

    Dismantling is a great challenge for nuclear companies which are facing with the cleaning of former nuclear sites. Among the available cutting processes is the multi-kilowatts laser whose power is transmitted through optical fibers. Unlike other cutting processes such as the plasma arc cutting process or the oxy-cutting process, the laser process can be easily implemented by robotic equipments. The mechanised robotic arm carries a laser cutting head to perform, with remote-controlled equipments, the cutting operation. The present study deals with the performances which can be reached with high power continuous wave ND:YAG lasers. The cutting tests were carried out up to 8 kW. The laser power was delivered through a specific power supply chain: a 0.4 mm fiber was transporting the power from the laser to a first interface (coupler) then a second 0.6 mm fiber was bringing the laser power to the cutting head. This solution allowed a power delivery chain whose length could be as high as 100 + 20/50 m. Another advantage of this kind of power supply is that the first fiber can be set in a non-contaminated environment whereas the second fiber lies in the contaminated area. The cutting head used for these tests was a specific tool developed for this laser dismantling work: it is a laser cutting head cooled by pressurized air. This tool was developed with the requirement to be able to sustain a laser power of 14 kW. The pressurized air used to cool the head is also used as cutting gas. The cutting capability was about 10 mm by kW. At the power of 8 kW, austenitic steel plates of thickness 100 mm were cut. These performances were reached with the cut started on the plate's edge. If the cut started in the middle of the plate, the cutting performances were not so high: 8 kW became the power to drill and to cut plates of thickness 40 mm.

  16. End-pumped Nd:YAG Q-switched laser with high energy and narrow pulse for glass carving

    Science.gov (United States)

    Ling, Ming; Jin, Guang-yong; Tan, Xue-chun; Wu, Zhi-chao; Liang, Zhu

    2009-05-01

    In order to raise the accuracy of glass carving and improve deep cutting, a novel diode end-pumed solid-state laser is researched. Selecting proper volume of laser crytal, one continue wave laser diode which longitudinally pumped Nd:YAG crystal is performed and an applied optics coupling system is designed with self focusing.Computing with ray trace software and MATLAB software, the best parameter is obtained, so pumping beam is coupled efficiently to Nd:YAG.Used a Cr4+:YAG crystal with the singnal transmission of 82% and a line plane-concave cavity, nanosecond narrow pulse is gotten. After two thermal-electrical coolers kept the laser to work at constant temperature instead of water cooling, the volume of laser is markedly reduced. The method of thermal-electrical cooling could increase the system efficiency,achieve the effect of low mode output.Experimental results indicate that the maximum laser output energy in 1064 nm is 118mJ,pulse width is 5 ns, conversion efficiency from light to light is 15.7% under the condition of the incident power of 5 W and the diameter of the output laser spot is less than 1 mm. This end-pumped Nd:YAG Q-switched laser with the light output of high quality and long life, which has 0.01 mm accuracy after lens focusing can satisfy the glass carving with higher precision, rapid speed as well as easy control. It can be used in carving all kinds of glass and replace current CO2 laser.

  17. Effect of Irradiation Parameters on Morphology of Polishing DF2 (AISI-O1 Surface by Nd:YAG Laser

    Directory of Open Access Journals (Sweden)

    Wei Guo

    2007-01-01

    Full Text Available Pulse Nd:YAG laser was used to polish DF2 cold work steel. Influence of irradiation parameters on the 3D surface morphology was studied by 3D profilometer, scanning electron microscopy (SEM, and atomic force microscope (AFM. Results among the tests showed when DF2 specimens were irradiated with parameters of (i laser input energy P=1 J, (ii pulse feedrate=300 mm/min, (iii pulse duration (PD =3 milliseconds, and (iv pulse frequency f=20∼25 Hz, laser polishing of DF2 cold work steel seemed to be successful.

  18. Split-face comparison of long-pulse-duration neodymium-doped yttrium aluminum garnet (Nd:YAG) 1,064-nm laser alone and combination long-pulse and Q-switched Nd:YAG 1,064-nm laser with carbon photoenhancer lotion for the treatment of enlarged pores in Asian women.

    Science.gov (United States)

    Wattanakrai, Penpun; Rojhirunsakool, Salinee; Pootongkam, Suwimon

    2010-11-01

    Long-pulse and Q-switched neodymium-doped yttrium aluminum garnet (Nd:YAG) 1,064-nm laser used for facial rejuvenation can improve pore size. Topical carbon has been used to enhance efficacy. To compare the efficacy and safety of a 1,064-nm long-pulse Nd:YAG laser alone with that of a combination Q-switched Nd:YAG laser with topical carbon lotion followed by long-pulse Nd:YAG to improve enlarged pores. Twenty Thai women randomly received five treatments with a long-pulse Nd:YAG laser on one facial half (LP side) and long-pulse Nd:YAG after carbon-assisted Q-switched Nd:YAG laser on the contralateral side (carbon QS+LP side) at 2-week intervals. Participants were evaluated using digital photography, complexion analysis, and a chromometer. There was significant decrease in pore counts of 35.5% and 33% from baseline on the carbon QS+LP and LP sides, respectively. Physician-evaluated pore size improvement was 67% on the carbon QS+LP sides and 60% on the LP sides. Chromometer measurement showed an increase in skin lightness index. There was no significant difference between the two treatments, although there were more adverse effects on the carbon QS+LP side. Long-pulse Nd:YAG 1,064-nm laser improves the appearance of facial pores and skin color. Adding carbon-assisted Q-switched Nd:YAG did not enhance the results but produced more side effects. © 2010 by the American Society for Dermatologic Surgery, Inc.

  19. Development of blue lasers, from second harmonic generation using a Nd:YAG laser emitting at 946 nm

    International Nuclear Information System (INIS)

    Nogueira, Gustavo Bernardes

    2010-01-01

    Blue lasers have attracted much attention for applications such as blue-ray, displays and as pumped source for the Ti:sapphire laser. A Nd:YAG crystal with diffusion bonded end-caps was used together with a pump wavelength of 802,3 nm, detuned from the absorption peak at 808 nm in order to minimize the thermal lens effect by providing for a better temperature distribution inside the crystal. Using different input mirror radii, the best relation between pump waist and laser was achieved in a linear cavity and resulted in 6.75W cw (continuous wave) laser power at 946 nm and slope efficiency of 48%. In a second step, a second harmonic generation crystal for blue emission at 473 nm was inserted into different types of resonators, and the blue output power at 473 nm was measured as a function of absorbed pump power. (author)

  20. Studi Analisis Serbuk dengan Teknik Krim Silikon Menggunakan Plasma Tekanan Tinggi yang Diinduksi oleh Laser Nd: YAG

    Directory of Open Access Journals (Sweden)

    Syahrun Nur Madjid

    2012-12-01

    Full Text Available Laser-Induced Breakdown Spectroscopy (LIBS is a technique that used for quantitative elemental analysis of various samples in different forms. In this technique, a laser light is focused on the surface of sample yielding a plasma just above the sample surface that used for analytical source. Nowadays, rapid powder analysis in tiny amount (mg has been carried out using plasma induced by high power laser of  Nd:YAG (Neodymium-doped Yttrium Aluminium Garnet at atmospheric pressure. However, powder analysis using high power laser is still difficult to be carried out  due to blow of powder when irradiated laser beam focused on a powder sample. In general, the powder must be transformed into pellet form prior to analysis. Pellet sample requires a lot of powder and it takes time for preparation. In this study, we developed a technique of powder sample with its size about  30 µm (± 5 mg that mixed with silicon grease (± 5 mg that act as a binder. The mixed sample then thinly painted on the metal plate as sub-target. The study showed that by employing sillicon grease technique, a semiquantitative analysis of several elements contain in coal, rock, and  water  can be conducted. Meanwhile heavy metal in soils is still not able to detect. This results showed that sillicon grease technique using  Nd:YAG laser can be applied for rapid semi-quantitative analysis of powder samples available only in tiny amounts. Keywords: high pressured plasma, Nd:YAG laser, powder analysis, silicon grease technique

  1. Micro machining workstation for a diode pumped Nd:YAG high brightness laser system

    NARCIS (Netherlands)

    Kleijhorst, R.A.; Offerhaus, Herman L.; Bant, P.

    1998-01-01

    A Nd:YAG micro-machining workstation that allows cutting on a scale of a few microns has been developed and operated. The system incorporates a telescope viewing system that allows control during the work and a software interface to translate AutoCad files. Some examples of the performance are

  2. A novel dual-wavelength, Nd:YAG, picosecond-domain laser safely and effectively removes multicolor tattoos.

    Science.gov (United States)

    Bernstein, Eric F; Schomacker, Kevin T; Basilavecchio, Lisa D; Plugis, Jessica M; Bhawalkar, Jayant D

    2015-07-14

    Although nanosecond-domain lasers have been the mainstay of laser tattoo removal for decades, recent disruptive innovations in laser design have introduced a new class of commercial Q-switched lasers that generate picosecond-domain pulses. A picosecond-domain, Nd:YAG laser with a KTP frequency-doubling crystal was used to treat 31 decorative tattoos in 21 subjects. Safety and effectiveness were determined by blinded evaluation of digital images in this prospective clinical study. The average clearance overall as evaluated by blinded observers evaluating randomized digital photographs was 79 ± 0.9% (mean ± sem) after an average of 6.5 treatments. Of the 31 tattoos completing treatment, 6 had evidence of mild hyper- or hypo-pigmentation by evaluation of photographs. The 350 picosecond, 532 nm, and 450 picosecond 1,064 nm Nd:YAG laser is safe and effective for removing decorative tattoos. Lasers Surg. Med. © 2015 The Authors. Lasers in Surgery and Medicine Published by Wiley Periodicals, Inc. © 2015 The Authors. Lasers in Surgery and Medicine Published by Wiley Periodicals, Inc.

  3. Randomized controlled trial comparing Nd:YAG laser photocoagulation and bipolar electrocautery in the management of epistaxis.

    Science.gov (United States)

    Zhang, Jing; Cao, Luhong; Wei, Chunsheng

    2017-09-01

    The objective of this study is to evaluate the efficacy and degree of comfort of Nd:YAG laser photocoagulation compared to bipolar electrocautery in the management of epistaxis. Seventy-two consecutive patients with a history of epistaxis were randomly assigned to receive treatment in an outpatient setting consisting of either bipolar electrocautery (group 1) or Nd:YAG laser photocoagulation (group 2). The study was conducted in university-affiliated teaching hospital. Seventy-two consecutive patients who suffered from anterior epistaxis and presented to the Otolaryngology Department at the Eye, Ear, Nose and Throat Hospital, Fudan University, between June 2015 and August 2015. The following outcome measures were assessed: bleeding intensity, bleeding frequency 4 and 16 weeks after treatment (0 = no bleeding, 1 = reduced bleeding, 2 = the same, and 3 = worse), participant perception of discomfort during treatment (grade 0-10, where 10 is the worst pain), and therapy duration and complications. At 16 weeks, 91% of the laser patients versus 91% of the bipolar electrocautery patients had no reported bleeding. The outcome scores at 4 and 16 weeks after treatment showed no significant difference between the two groups (P = 0.5 and P = 0.98, respectively; P > 0.05). The median pain levels experienced during the office laser and bipolar electrocautery procedures were 3.0 and 4.0, respectively, and the median durations of the laser and electrocautery therapies were 3.0 and 4.0, respectively. Neither groups had complications. It can be concluded that Nd:YAG laser photocoagulation and bipolar electrocautery are both effective in the treatment of epistaxis. These two therapies are recommended. As a whole, these two therapies, performed in an office setting, are timely, efficacious, and well tolerated in the treatment of epistaxis.

  4. Face and labial rejuvenation with the new Nd-Yag 1064 picoseconds laser

    Science.gov (United States)

    Teixeira, Heitor; Teixeira, Carolina

    2018-04-01

    Lips are the component of the oral cavity which synthesizes more functions and emotions. The nonverbal communication is established by the body, every movement gesture, posture and facial expression which shows a willingness to communicate directly or subtly, consciously or unconsciously. The smile is one of the expressions that attract us the most, for its simplicity and mainly for its puzzle. In Lips aging implies a loss of mucous membranes' density; lips' dehydrate and resect themselves, reducing its' thickness which causes an appearance of aging of the all face. The demands of public opinion of being young and stay young are becoming more and more pressing, therefore it is necessary to meet this demand. The responsibility of achieving this task is up to the doctor, the anti-aging medicine and the actual existing physical means, which are available to correct and prevent this disease. Having the possibility of using the new picoseconds Nd-Yag Laser in Lips' rejuvenation we must use them together and in accordance between them and the guideline we presented what we believe to be the guideline which allows us to obtain good results in a new and simple effective treatment that can be proved by the major aspect of the lip and by evidence and monitoring that we went through for about ten month. Obtained results of labial cracks' disappearance inside of the red mucosa increase in lips' volume and contour and disappearance of oral wrinkles creates an aesthetic appearance witch is remarkable. This is a non invasive method with minimal complications with low morbidity and in our opinion superior results when compared to other traditional methods considered soft tissue augmentation including peelings, botox injections, injectable fillers such as hyaluronic acid injections temporary and permanent injectable bio-implants, bio- catalysts and even surgery of the upper lip.

  5. Effect of laser-assisted bleaching with Nd:YAG and diode lasers on shear bond strength of orthodontic brackets.

    Science.gov (United States)

    Mirhashemi, Amirhossein; Emadian Razavi, Elham Sadat; Behboodi, Sara; Chiniforush, Nasim

    2015-12-01

    The aim of the present study was to assess the effect of laser-assisted bleaching with neodymium:yttrium-aluminum-garnet (Nd:YAG) and diode lasers on shear bond strength (SBS) of orthodontic brackets. One hundred and four extracted human premolars were randomly divided into four groups: group 1: No bleaching applied (control group); group 2: Teeth bleached with 40 % hydrogen peroxide; group 3: Teeth treated with 30 % hydrogen peroxide activated with Nd:YAG laser (1064 nm, 2.5 W, 25 Hz, pulse duration of 100 μs, 6 mm distance); and group 4: Teeth treated with 30 % hydrogen peroxide activated with diode laser (810 nm, 1 W, CW, 6 mm distance). Equal numbers of teeth in groups 2, 3, and 4 were bonded at start, 1 h, 24 h, and 1 week after bleaching. A universal testing machine measured the SBS of the samples 24 h after bonding. After bracket debonding, the amount of residual adhesive on the enamel surface was observed under a stereomicroscope to determine the adhesive remnant index (ARI) scores. The SBS in the unbleached group was significantly higher than that in the bleached groups bonded immediately and 1 h after laser-assisted bleaching (P laser-assisted bleaching, the SBS was found to be significantly lower than that in the control group. Significant differences in the ARI scores existed among groups as well. The SBS of brackets seems to increase quickly within an hour after laser-assisted bleaching and 24 h after conventional bleaching. Thus, this protocol can be recommended if it is necessary to bond the brackets on the same day of bleaching.

  6. Study of welding characteristics of inconel 600 alloy using a continuous wave Nd:YAG laser beam

    International Nuclear Information System (INIS)

    Song, Seong Wook; Yoo, Young Tae; Shin, Ho Jun

    2004-01-01

    Laser beam welding is increasingly being used in welding of structural steels. The laser welding process is one of the most advanced manufacturing technologies owing to its high speed and deep penetration. The thermal cycles associated with laser welding are generally much faster than those involved in conventional arc welding processes, leading to a rather small weld zone. Experiments are performed for Inconel 600 plates changing several process parameter such as laser power, welding speed, shielding gas flow rate, presence of surface pollution, with fixed or variable gap and misalignment between plate and plate, etc. The follow conclusions can be drawn that laser power and welding speed have a pronounced effect on size and shape of the fusion zone. Increase in welding speed resulted in an increase in weld depth/ aspect ratio and hence a decrease in the fusion zone size. The penetration depth increased with the increase in laser power. Welding characteristics of austienite Inconel 600 using a continuous wave Nd:YAG laser are experimentally investigated. This paper describes the weld ability of inconel 600 for machine structural use by Nd:YAG laser

  7. A novel dual‐wavelength, Nd:YAG, picosecond‐domain laser safely and effectively removes multicolor tattoos

    Science.gov (United States)

    Schomacker, Kevin T.; Basilavecchio, Lisa D.; Plugis, Jessica M.; Bhawalkar, Jayant D.

    2015-01-01

    Background and Objectives Although nanosecond‐domain lasers have been the mainstay of laser tattoo removal for decades, recent disruptive innovations in laser design have introduced a new class of commercial Q‐switched lasers that generate picosecond‐domain pulses. Study A picosecond‐domain, Nd:YAG laser with a KTP frequency‐doubling crystal was used to treat 31 decorative tattoos in 21 subjects. Safety and effectiveness were determined by blinded evaluation of digital images in this prospective clinical study. Results The average clearance overall as evaluated by blinded observers evaluating randomized digital photographs was 79 ± 0.9% (mean ± sem) after an average of 6.5 treatments. Of the 31 tattoos completing treatment, 6 had evidence of mild hyper‐ or hypo‐pigmentation by evaluation of photographs. Conclusion The 350 picosecond, 532 nm, and 450 picosecond 1,064 nm Nd:YAG laser is safe and effective for removing decorative tattoos. Lasers Surg. Med. 47:542–548, 2015. © 2015 The Authors. Lasers in Surgery and Medicine Published by Wiley Periodicals, Inc. PMID:26175187

  8. Single-treatment skin tightening by radiofrequency and long-pulsed, 1064-nm Nd: YAG laser compared.

    Science.gov (United States)

    Key, Douglas J

    2007-02-01

    To compare single-treatment facial skin tightening achieved with the current radiofrequency (RF) protocol with single-treatment tightening achieved with the long-pulsed, 1064-nm Nd:YAG laser. A total of 12 patients were treated with RF energy on one side of the face and laser energy on the other. Results were evaluated on a numerical scale (0-12 with 12 = greatest enhancement) from pre- and posttreatment photographs by a blinded panel. Upper face improvement (posttreatment score minus pretreatment score) was essentially the same on both sides (30.2 and 31.3% improvement for laser and RF, respectively, P=0.89). Lower face improvement was greater in the laser-treated side (35.7 and 23.8% improvement for laser and RF, respectively), but the difference was not significant (P=0.074). Overall face improvement was significantly greater on the laser-treated side (47.5 and 29.8% improvement for laser and RF, respectively, P=0.028). A single high-fluence treatment with the long-pulse 1064-nm Nd:YAG laser may improve skin laxity more than a single treatment with the RF device. Further controlled split-face or very large non-self controlled studies are needed to conclusively determine the relative efficacies of the two technologies. (c) 2007 Wiley-Liss, Inc.

  9. Nd:YAG laser associated with metal salts solutions in the treatment of dentinal hypersensitivity; O laser de Nd:YAG associado a solucoes de sais metalicos no tratamento da hipersensibilidade dentinaria

    Energy Technology Data Exchange (ETDEWEB)

    Glauche, Carlos Eugenio Correia

    2001-07-01

    The objective of this study was to observe the ultrastructural changes caused by the radiation of Nd:YAG laser on the tooth tissue and determine qualitatively the presence of Sn{sup ++}, Sr{sup ++} and F{sup -}, inside the dentin, being it irradiated or not. Ten molar teeth recently extracted were cut into 2 mm discs. The samples were soaked in a EDTA solution at 17% for 2 minutes and divided into five groups. Group I: the samples were irradiated with Nd:YAG laser (1,5 W, 100 mJ, 15 Hz, 150 {mu}s and 125 J/cm{sup 2}) and after that, a treatment with an SnF{sub 2} aqueous solution at 10% for 30 minutes. Group II: the samples got laser irradiation with the same parameters and then a treatment with an SrCl{sub 2} solution at 10% as a toothpaste (Sensodyne{sup TM}) for 30 minutes. Group III: the samples just got a treatment with a SnF{sub 2} aqueous solution at 10% for 30 minutes. Group IV: the samples just got a treatment with a SrCl{sub 2} toothpaste (Sensodyne{sup TM}) for 30 minutes. Group V: samples that just got laser irradiation in the parameters above mentioned. Then, all samples were prepared for scanning electronic microscopy (SEM) and the samples of groups I, II, III and IV for energy dispersive X-ray microanalysis (EDX). The ultrastructure aspect of the dentin showed the surface totally altered by the irradiation. Pits and whitish globules were found amidst an heterogenous and rough structure, due to the melting and resolidification of the dental structure. Craters were also observed. Carbonization areas were absent. Ions Sn{sup ++} were found at a depth of 250 {mu}m in the samples of group I (Nd:YAG + SnF{sub 2}), whereas in the samples of group III, Sn{sup ++} were not found deeper than 100 {mu}m. Sr{sup ++} could be detected at least at 500 {mu}m in the inner dentin in the samples of group II (Nd:YAG + SrCl{sub 2}). However, Sn{sup ++} were not found at 50 {mu}m in group IV samples. Ions F{sup -} were just found in the irradiated samples of group I

  10. 80-W cw TEM{sub 00} IR beam generation by use of a laser-diode-side-pumped Nd:YAG rod laser

    Energy Technology Data Exchange (ETDEWEB)

    Konno, Susumu; Fujikawa, Shuichi; Yasui, Koji [Mitsubishi Electric Corp. Amagasaki, Hyogo (Japan). Advanced Technology R and D Center

    1998-03-01

    We have demonstrated high-efficient and high-power operation of a diode-side-pumped Nd:YAG rod laser. The laser has a simple and scalable configuration consisting of a diffusive pumping reflector and an advanced cavity configuration for polarization-dependent bifocusing compensation. (author)

  11. Experimental investigation for determination of thermal effects in a Nd: YAG laser crystal by use of interferometry technique

    International Nuclear Information System (INIS)

    Safary, E.; Movahedinejad, H.; Razzaghi, H.; Haj Esmaeilbeigi, F.; Tohidi, T.; Shiri, M.

    2007-01-01

    Thermal effects have an important role in high power solid state laser designing. Known of this effect and their roles on intensity and quality of output beam needs so many experiments. In this paper, we focused on influence of temperature distribution on thermal lensing in the Nd:YAG laser by use of interferometry technique. Then we used from a plariscop set up for describing of intensity reduce and distortion of the wave shape when it use from the Polaroid into the resonator at side pump.

  12. Q-switching and mode-locking in a diode-pumped frequency-doubled Nd : YAG laser

    International Nuclear Information System (INIS)

    Donin, Valerii I; Yakovin, Dmitrii V; Gribanov, A V

    2012-01-01

    A new method for obtaining Q-switching simultaneously with mode-locking using one travelling-wave acousto-optic modulator in a frequency-doubled Nd : YAG laser cavity is described. Further shortening of output laser pulses (from 40 to 3.25 ps) is achieved by forming a Kerr lens in the frequency-doubling crystal. At an average power of ∼ 2 W and a Q-switching rate of 2 kHz, the peak power of the stably operating reached ∼ 50 MW.

  13. Distortion of optical feedback signals in microchip Nd:YAG lasers subjected to external multi-beam interference feedback

    International Nuclear Information System (INIS)

    Yi-Dong, Tan; Shu-Lian, Zhang; Zhou, Ren; Cheng, Ren; Yi-Nan, Zhang

    2010-01-01

    This paper proposes a theoretical analysis for the characteristics of an external cavity Nd:YAG laser with feedback of multiple-beam interference, which is induced by the multi-reentrance of the light from the external Fabry–Perot cavity. The theoretical model considers the multiple beam interference of the external Fabry–Perot cavity. It is found that the optical feedback signals are distorted to pulse waveforms instead of the sinusoidal ones in conventional feedback. The experimental results are in good agreement with the theoretical analysis. The obtained theoretical and experimental results can advance the development of a laser feedback interferometer

  14. The effects of a pulsed Nd:YAG laser on subgingival bacterial flora and on cementum: an in vivo study.

    Science.gov (United States)

    Ben Hatit, Y; Blum, R; Severin, C; Maquin, M; Jabro, M H

    1996-06-01

    The purpose of this study was to compare the effects of scaling and Nd:YAG laser treatments with that of scaling alone on cementum and levels of Actinobacillus actinomycetemcomitans, Bacteroides forsythus, Porphyromonas gingivalis, and Treponema denticola. Study samples consisted of 14 patients, age 30 to 75 years, 8 females and 6 males, with a total of 150 periodontally involved sites with probing depth > or = 5 mm. Group A consisted of 100 pockets that were subdivided into 4 equal groups that were treated with conventional scaling and pulsed Nd:YAG laser using an optic fiber of 300 microns and 4 different power levels as follows: Group 1: P = 0.8 W, f = 10 Hz, E = 100 mJ/pulse; Group 2: P = 1.0 W, f = 1.0 Hz, E = 100 mJ/pulse; Group 3: P = 1.2 W, f = 12 Hz, E = 100 mJ/purse; and Group 4: P = 1.5 W, f = 15 Hz, E = 100 mJ/pulse. The time of each treatment was 60 sec per pocket in all 4 groups. Group B consisted of 50 pockets that were treated by conventional scaling alone and served as a control group. Microbiological samples from group A were collected before scaling; after scaling = before laser, just after laser, 2 weeks later, 6 weeks later, and 10 weeks later. Microbiological samples from group B were collected before scaling, after scaling, 6 weeks later, and 10 weeks later. Microbiological analysis of all samples was done by the Institute Für Angewandte Immunologie (IAI) method. The effects of laser on root surfaces were assessed by SEM examination and the sample consisted of 13 teeth from 5 different patients. Four sets of 3 teeth each were treated with Nd:YAG laser using 0.8, 1.0, 1.2, and 1.5 W, respectively. One tooth was just scaled and not treated with laser to serve as a control. Microbiological analysis of Group A samples indicated posttreatment reduction in levels of all 4 bacterial types tested compared to pretreatment levels and Group B controls. SEM examination of the specimens treated with Nd:YAG laser at different levels exhibited different

  15. Evaluation of Nd:YAG laser on partial oxygen saturation of pulpal blood in anterior hypersensitive teeth.

    Science.gov (United States)

    Birang, Reza; Kaviani, Naser; Mohammadpour, Mehdi; Abed, Ahmad Moghareh; Gutknecht, Norbert; Mir, Maziar

    2008-07-01

    Dentine hypersensitivity has of long been known to be a common clinical problem in dental practices. Lasers have recently come to play a prominent role in the treatment of this disorder. They might, however, cause dental pulp damage. This study was conducted to evaluate the effect of Nd:yttrium-aluminum-garnet (YAG) laser on partial oxygen saturation of pulpal blood in sensitive anterior teeth. In this clinical trial, 65 hypersensitive teeth were selected and randomly allocated to two groups. The study group involved Nd:YAG laser treatment, while no treatment was employed for the control group. Using a pulse oximetry system, evaluations were preformed of the partial oxygen saturation in the pulpal blood before, immediately after, 1 week after, and 1 month after the treatment. The results were analyzed using the SPSS software and repeated-measures analysis of variance and paired-samples t tests. The mean partial oxygen saturation of the blood was found to be 85.4% in the study group, which was not significantly different from that of the control group. No significant differences were observed in the control group between the means obtained from pretreatment and post-treatment intervals (P > 0.05). The Post-treatment partial oxygen saturation mean rose to 89.3% (P = 0.001) and remained constant throughout the following week after it. However, no significant differences were found between the pretreatment partial oxygen saturation mean and the same measurement 1 month after treatment (P = 0.702). Nd:YAG laser therapy for dentine desensitization of anterior teeth caused no persistent changes in the partial oxygen saturation of pulpal blood. It may, therefore, be concluded that the diffusion of heat induced by the Nd:YAG laser into the pulp within the limit of the desensitization parameters cause no irreversible damages in the dental pulp.

  16. Long-pulsed Nd: YAG laser and intense pulse light-755 nm for idiopathic facial hirsutism: A comparative study

    Directory of Open Access Journals (Sweden)

    Arpit Shrimal

    2017-01-01

    Full Text Available Background: Hirsutism means excessive terminal hair growth in a female in male pattern distribution. Perception of hirsutism is subjective. Permanent laser hair reduction is a slow process taking many sessions and tracking of improvement parameters is tedious. Hence, a lot of confusion still exists regarding the type of laser most beneficial for treatment. Aim: The aim of this study was to compare the effectiveness and safety profile of long-pulsed Nd: YAG laser (1064 nm and intense pulse light (IPL-755 nm in management of idiopathic facial hirsutism. Settings and Design: Open-labelled, randomly allocated experimental study. Subjects and Methods: The study included 33 cases of idiopathic facial hirsutism. Patients were randomly divided into Group A, treated with long-pulsed Nd: YAG laser and Group B, treated with IPL-755 for a total of six sessions at 1 month interval. Statistical Analysis: Chi-square test was used in Medcalc® version 9.0 and the test of significance was taken to be P75% reduction in hair after six sessions in Group A was seen in fourteen (93.33% out of fifteen patients, whereas in Group B, it was seen only in three (16.66% out of eighteen patients. In Group A, erythema was seen in 26.67%, perifollicular edema and hyperpigmentation in 13.33% each. In Group B, erythema was seen in 50% patients, perifollicular edema in 16.67% and hyperpigmentation in 38.89% patients. Conclusions: Long-pulsed Nd: YAG Laser (1064 nm is better than IPL-755 nm in terms of safety and effectiveness in the management of idiopathic facial hirsutism.

  17. Investigation on Nd:YAG laser weldability of zircaloy-4 end cap closure for nuclear fuel elements

    International Nuclear Information System (INIS)

    Kim, Soo Sung; Lee, Chul Yung; Yang, Myung Seung

    2001-01-01

    Various welding processes are now available for end cap closure of nuclear fuel element such as TIG(Tungsten Inert Gas) welding, magnetic resistance welding and laser welding. Even though the resistance and TIG welding processes are widely used for manufacturing commercial fuel elements, they can not be recommended for the remote seal welding of a fuel element at a hot cell facility due to the complexity of electrode alignment, difficulty in the replacement of parts in the remote manner and a large heat input for a thin sheath. Therefore, the Nd:YAG laser system using optical fiber transmission was selected for Zircaloy-4 end cap welding inside hot cell. The laser welding apparatus was developed using a pulsed Nd:YAG laser of 500 watt average power with optical fiber transmission. The weldability of laser welding was satisfactory with respect to the microstructures and mechanical properties comparing with TIG and resistance welding. The optimum operation processes of laser welding and the optical fiber transmission system for hot cell operation in a remote manner have been developed. The effects of irradiation on the properties of the laser apparatus were also being studied

  18. Sclerosis and the Nd:YAG, Q-switched laser with multiple frequency for treatment of telangiectases, reticular veins, and residual pigmentation.

    Science.gov (United States)

    Cisneros, J L; Del Rio, R; Palou, J

    1998-10-01

    The combination of low concentrations of sclerosing solution and the Nd:YAG, Q-switched laser with multiple (quadruple) frequency provides good results in the treatment of telangiectases and reticular varicose veins of the lower extremities, as well as pigmentation that may appear during sclerotherapy. This paper is based on a series of patients with telangiectases and reticular veins who were treated with sclerotherapy and the Nd:YAG, Q-switched laser with quadruple frequency. Patients with telangiectases and reticular veins received two or three treatment sessions with polydocanol and the Nd:YAG, Q-switched laser with quadruple frequency. Then, they were assessed a clinical score corresponding to the level of improvement achieved. Residual hematic pigmentation lesions were also eliminated with the laser. Excellent improvement was evident in 90% of the patients with minimal residual lesions. The combined technique of sclerosing solution and the Nd:YAG laser with multiple frequency is a valid alternative for the elimination of telangiectases and reticular veins of the lower limbs. This technique has several advantages, such as the use of low concentrations of sclerosing solution, high patient acceptance levels due to minimal disturbances, and the fact that local anesthesia is unnecessary. Good results are obtained without complications and minimal residual pigmentation. These mild pigmentation can be treated with the Nd:YAG laser.

  19. On the use of a chirped Bragg grating as a cavity mirror of a picosecond Nd : YAG laser

    Energy Technology Data Exchange (ETDEWEB)

    Zubko, A E; Shashkov, E V; Smirnov, A V; Vorob' ev, N S [A M Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation); Smirnov, V I [OptiGrate Corp., 562 South Econ Circle, Oviedo, Florida 32765-4311 (United States)

    2016-02-28

    The first experimental evidence is presented that the use of a chirped volume Bragg grating (CVBG) as a cavity mirror of a Q-switched picosecond Nd : YAG laser with self-mode-locking leads to significant changes in the temporal parameters of the laser output. Measurements have been performed at two positions of the CVBG: with the grating placed so that shorter wavelengths reflected from its front part lead longer wavelengths or with the grating rotated through 180°, so that longer wavelengths are reflected first. In the former case, the duration of individual pulses in a train increased from ∼35 to ∼300 ps, whereas the pulse train shape and duration remained the same as in the case of a conventional laser with a mirror cavity. In the latter case, the full width at half maximum of pulse trains increased from ∼70 ns (Nd : YAG laser with a mirror cavity) to ∼1 ms, and the duration of individual pulses increased from 35 ps to ∼1.2 ns, respectively, which is more typical of free-running laser operation. (laser crystals and braggg ratings)

  20. FT-Raman spectroscopic characterization of enamel surfaces irradiated with Nd:YAG and Er:YAG lasers

    Directory of Open Access Journals (Sweden)

    Sima Shahabi

    2016-12-01

    Full Text Available Background. Despite recent advances in dental caries prevention, caries is common and remains a serious health problem. Laser irradiation is one of the most common methods in preventive measures in recent years. Raman spectroscopy technique is utilized to study the microcrystalline structure of dental enamel. In this study, FT-Raman spectroscopy was used to evaluate chemical changes in enamel structure irradiated with Nd:YAG and Er:YAG lasers. Methods. We used 15 freshly-extracted, non-carious, human molars that were treated as follows: No treatment was carried out in group A (control group; Group B was irradiated with Er:YAG laser for 10 seconds under air and water spray; and Group C was irradiated with Nd:YAG laser for 10 seconds under air and water spray. After treatment, the samples were analyzed by FT-Raman spectroscopy. Results. The carbonate content evaluation with regard to the integrated area under the curve (1065/960 cm–1 exhibited a significant reduction in its ratio in groups B and C. The organic content (2935/960 cm-1 area exhibited a significant decrease after laser irradiation in group B and C. Conclusion. The results showed that the mineral and organic matrices of enamel structure were affected by laser irradiation; therefore, it might be a suitable method for caries prevention.

  1. Long-term changes in subfoveal choroidal thickness and central macula thickness after Nd:YAG laser capsulotomy.

    Science.gov (United States)

    Yilmaz, Tolga; Yilmaz, Ahu

    2017-08-01

    To evaluate changes in central macula thickness (CMT), subfoveal choroid thickness (SCT), and intraocular pressure (IOP) before and after neodymium:yttrium-aluminum-garnet (Nd:YAG) laser capsulotomy. 42 eyes of 42 patients who underwent Nd:YAG laser capsulotomy were included in this prospective study. CMT, SCT, and IOP were evaluated preoperatively and at postoperative week 1 and postoperative months 1, 3, 6, and 12. CMT was 238.1 ± 27.6 μm (mean ± SD) preoperatively, then 239.7 ± 29.8, 241.3 ± 28.7, 242.7 ± 27.2, 238.8 ± 23.7, and 238.3 ± 21.7 μm at postoperative week 1 and months 1, 3, 6, and 12, respectively. SCT was 263.3 ± 21.6 μm preoperatively, and 265.5 ± 24.8, 266.2 ± 25.7, 267.1 ± 26.3, 269.1 ± 24.2, and 269.9 ± 21.4 μm at postoperative week 1 and months 1, 3, 6, and 12, respectively. There were no significant differences between preoperative and postoperative results for CMT, SCT, or IOP (all p > 0.05). Although there were slight changes in choroid thickness in the long term, treatment of posterior capsule opacification with a low-energy Nd:YAG laser is a safe procedure that increases visual acuity without creating a significant increase in IOP, CMT, and SCT.

  2. Effectiveness and harmful effects of removal sulphated black crust from granite using Nd:YAG nanosecond pulsed laser

    Energy Technology Data Exchange (ETDEWEB)

    Pozo, S. [Dpto. Ingeniería de los Recursos Naturales y Medio Ambiente, ETSI Minas, University of Vigo, 36310 (Spain); Barreiro, P. [Dpto. Física Aplicada, E.T.S.I. Industriales, University of Vigo, 36310 (Spain); Rivas, T. [Dpto. Ingeniería de los Recursos Naturales y Medio Ambiente, ETSI Minas, University of Vigo, 36310 (Spain); González, P. [Dpto. Física Aplicada, E.T.S.I. Industriales, University of Vigo, 36310 (Spain); Fiorucci, M.P. [Centro de Investigacións Tecnolóxicas (CIT), University of A Coruña, 15403, Ferrol (Spain)

    2014-05-01

    Sulphated black crust is a common form of deterioration affecting stone used in monuments, usually occurs in contaminated atmospheres or urban environments. Its origin and cleaning have been studied extensively, for decades, in the case of carbonate rocks. Recent studies show that this form of alteration also affects granites. Scientific research on laser removal effectiveness of gypsum-rich black crust on granites needs to be scientifically addressed considering the inexistent references. This paper assesses the removal by laser of sulphate-rich black crusts on granite using the different harmonics of a Nd:YAG nanosecond pulsed laser (266 nm, 355 nm, 532 nm and 1064 nm). Effectiveness was evaluated using Scanning Electron Microscopy with Energy Dispersive X-ray Spectrometry (SEM–EDS), X-Ray Diffraction (XRD) and Attenuated Total Reflection-Fourier Infrared Transform Spectroscopy (ATR-FTIR). We also evaluated the effect of the radiation on granite-forming minerals and on the colour of the stone using Scanning Electron Microscopy and spectrophotometry colour measurements respectively. SEM–EDS, XRD and ATR-FTIR analyses show that the higher the wavelength, the more efficient the cleaning, so samples cleaned using 1064 nm pulsed laser recovered its original colour. Nevertheless, the Nd:YAG laser did not completely eliminate the crust, and gypsum crystals remaining on the rock surface are observed, even at the most effective wavelength.

  3. A 40 W cw Nd:YAG solar laser pumped through a heliostat: a parabolic mirror system

    International Nuclear Information System (INIS)

    Almeida, J; Liang, D; Guillot, E; Abdel-Hadi, Y

    2013-01-01

    Solar-pumped solid-state lasers are promising for renewable extreme-temperature material processing. Here, we report a significant improvement in solar laser collection efficiency by pumping the most widely used Nd:YAG single-crystal rod through a heliostat–parabolic mirror system. A conical-shaped fused silica light guide with 3D-CPC output end is used to both transmit and compress the concentrated solar radiation from the focal zone of a 2 m diameter parabolic mirror to a 5 mm diameter Nd:YAG rod within a conical pump cavity, which enables multi-pass pumping through the laser rod. 40 W cw laser power is measured, corresponding to 13.9 W m −2 record-high collection efficiency for the solar laser pumped through a heliostat–parabolic mirror system. 2.9% slope efficiency is fitted, corresponding to 132% enhancement over that of our previous pumping scheme. A 209% reduction in threshold pump power is also registered. (paper)

  4. 1.5  kW efficient CW Nd:YAG planar waveguide MOPA laser.

    Science.gov (United States)

    Wang, Juntao; Wu, Zhenhai; Su, Hua; Zhou, Tangjian; Lei, Jun; Lv, Wenqiang; He, Jing; Xu, Liu; Chen, Yuejian; Wang, Dan; Tong, Lixin; Hu, Hao; Gao, Qingsong; Tang, Chun

    2017-08-15

    In this Letter, we report a 1064 nm continuous wave Nd:YAG planar waveguide laser with an output power of 1544 W based on the structure of the master oscillator power amplification. A fiber laser is used as the master oscillator, and diode laser arrays are used as the pump source of the waveguide laser amplifier. The dimension of the waveguide is 1  mm (T)×10  mm (W)×60  mm (L), and the dual end oblique pumping is adopted with different angles. After a single-pass amplification, the power is scaled from 323 to 1544 W with the pump power of 2480 W, leading to an optical-to-optical efficiency of 49%. At the maximum output, the beam quality M 2 are measured to be 2.8 and 7.0 in the guided direction and the unguided direction, respectively. To the best of our knowledge, this is the highest output power of a Nd:YAG planar waveguide laser to date.

  5. Clinical study on the removal of gingival melanin pigmentation: comparison between Nd:YAG laser ablation and mechanical abrasion

    International Nuclear Information System (INIS)

    Lopes, Luis Mario de Melo

    2002-01-01

    Melanin pigmentation occurs as a result of excessive deposition of melanin, produced by the melanocytes present in the basal layer of the epithelium. This study compares clinical parameters such as inflammation and/or hemorrhage, healing process and re-pigmentation, caused by the Nd:YAG laser ablation and the mechanical abrasion of the melanin, by means of photographic images, taken during the first 30 days after the treatment. The patients comfort was monitored during the first ten days after the treatment using the method of the Visual Analog Scale to measure the pain. Six patients with gingival melanin pigmentation were selected. The left upper gingival quadrant was treated with the Nd:YAG laser using 125 mJ per pulse and 20 Hz, the right upper gingival quadrant received mechanical abrasion and the lower quadrants served for control. Both techniques did not result in inflammation and/or hemorrhage. The healing process was slower with the laser. Using mechanical abrasion, ali patients showed remaining pigmentation or re-pigmentation of varying intensity after a period of 30 days. With the laser 50 % of the patients did not show any re-pigmentation after this period. The pain analysis showed that the pain sensed 24 hours after the treatment with the laser is higher than using mechanical abrasion. (author)

  6. Effectiveness and harmful effects of removal sulphated black crust from granite using Nd:YAG nanosecond pulsed laser

    International Nuclear Information System (INIS)

    Pozo, S.; Barreiro, P.; Rivas, T.; González, P.; Fiorucci, M.P.

    2014-01-01

    Sulphated black crust is a common form of deterioration affecting stone used in monuments, usually occurs in contaminated atmospheres or urban environments. Its origin and cleaning have been studied extensively, for decades, in the case of carbonate rocks. Recent studies show that this form of alteration also affects granites. Scientific research on laser removal effectiveness of gypsum-rich black crust on granites needs to be scientifically addressed considering the inexistent references. This paper assesses the removal by laser of sulphate-rich black crusts on granite using the different harmonics of a Nd:YAG nanosecond pulsed laser (266 nm, 355 nm, 532 nm and 1064 nm). Effectiveness was evaluated using Scanning Electron Microscopy with Energy Dispersive X-ray Spectrometry (SEM–EDS), X-Ray Diffraction (XRD) and Attenuated Total Reflection-Fourier Infrared Transform Spectroscopy (ATR-FTIR). We also evaluated the effect of the radiation on granite-forming minerals and on the colour of the stone using Scanning Electron Microscopy and spectrophotometry colour measurements respectively. SEM–EDS, XRD and ATR-FTIR analyses show that the higher the wavelength, the more efficient the cleaning, so samples cleaned using 1064 nm pulsed laser recovered its original colour. Nevertheless, the Nd:YAG laser did not completely eliminate the crust, and gypsum crystals remaining on the rock surface are observed, even at the most effective wavelength.

  7. In vitro study of hydroxy apatite and enamel powder fused in human enamel by Nd:YAG laser

    International Nuclear Information System (INIS)

    Ferrreira, Marcus Vinicius Lucas

    2000-01-01

    The aim of this study was to evaluate the effects of pulsed Nd:YAG (1064 nm) laser irradiation on hydroxyapatite and enamel powder fusion. This laser beam is not well absorbed by this two compounds for this reason they were mixed with vegetal coal to increase the absorption of the laser beam. Fifteen enamel flat surfaces and six occlusal enamel surfaces were prepared with three different substances: hydroxyapatite mixed with vegetal coal (3:1 in weigh); enamel powder mixed with vegetal coal (3:1 in weigh); vegetal coal. The occlusal surfaces were utilized to determine if the compounds could seal pits and fissures. Flat surfaces were utilized to determine fusion of hydroxyapatite and enamel powder. All samples were irradiated with Nd:YAG laser with the parameters: 80 mJ, 15 Hz, 1,2 W, 100 μs pulse-width, 131,1 J/cm 2 . Laser beam was delivered to the samples with a 300 μm diameter fiber optic. Morphology of the irradiated surfaces were examined by scanning electron microscopy (SEM). The compounds with hydroxyapatite and enamel powder were fused to enamel surfaces. Only partial pits and fissures sealing could be observed. (author)

  8. Nd:YAG laser welding of aerospace grade ZE41A magnesium alloy: Modeling and experimental investigations

    International Nuclear Information System (INIS)

    Al-Kazzaz, H.; Medraj, M.; Cao, X.; Jahazi, M.

    2008-01-01

    Keyhole formation as well as the geometry of weld profiles during Nd:YAG laser welding of ZE41A-T5 were studied through combining various models and concepts. The results indicated that weld width and fusion area decrease with increasing welding speed. In the case of partially penetrated welding, penetration depth decreases with increasing welding speed. Also, the model predicted that excessive decrease in laser power or increase in defocusing distance decreases surface power density, thereby changing the welding mode from fully penetrated keyhole, to partially penetrated keyhole, and then to the conduction mode. The predicted conditions for keyhole stability and welding modes as well as the weld profiles for various processing conditions were validated by some selected welding experiments. These experiments included studying the effects of welding speed, laser power, joint gap and laser defocusing on the weld geometry of 2- and 6-mm butt joints or bead-on-plates of ZE41A-T5 sand castings using a continuous wave 4 kW Nd:YAG laser system and 1.6-mm EZ33A-T5 filler wire. Good agreements were found between the model predictions and experimental results indicating the validity of the assumptions made for the development of the model

  9. Pulsed Nd:YAG laser welding of Cu54Ni6Zr22Ti18 bulk metallic glass

    International Nuclear Information System (INIS)

    Kim, Jong Hyun; Lee, Changhee; Lee, D.M.; Sun, J.H.; Shin, S.Y.; Bae, J.C.

    2007-01-01

    Pulsed Nd:YAG laser was used to weld Cu 54 Ni 6 Zr 22 Ti 18 (numbers indicate at.%) metallic glass with glass forming ability of 6 mm. Through a single pulse irradiation on the glassy plate, the pulse condition for welding without crystallization was investigated. Under the selected pulse condition, the Cu 54 Ni 6 Zr 22 Ti 18 plate was periodically welded with different welding speeds. For the welding speed of 60 mm/min, no crystallization was observed in both weldment and heat-affected zone. For the 20 mm/min, the crystallized areas with a band shape were observed along the welding direction

  10. Drilling and cutting of thin metal plates in water with radiation of a repetitively pulsed Nd : YAG laser

    Energy Technology Data Exchange (ETDEWEB)

    Glova, A F; Lysikov, A Yu [State Research Center of Russian Federation ' Troitsk Institute for Innovation and Fusion Research' , Troitsk, Moscow Region (Russian Federation)

    2011-10-31

    The conditions of drilling and cutting of 0.15-mm-thick titanium and stainless steel plates in water with the radiation of a repetitively pulsed Nd : YAG laser having the mean power up to 30 W are studied experimentally in the absence of water and gas jets. Dependences of the maximal cutting speed in water on the radiation power are obtained, the cutting efficiency is determined, and the comparison with the conditions of drilling and cutting of plates in air is carried out.

  11. Film analysis employing subtarget effect using 355 nm Nd-YAG laser-induced plasma at low pressure

    Energy Technology Data Exchange (ETDEWEB)

    Hedwig, Rinda [Department of Computer Engineering, Faculty of Computer Studies, Bina Nusantara University, 9 K.H. Syahdan, Jakarta Barat 11480 (Indonesia); Budi, Wahyu Setia [Department of Physics, Faculty of Mathematics and Natural Sciences, Diponegoro University, Tembalang Campus, Semarang, Central Java (Indonesia); Abdulmadjid, Syahrun Nur [Department of Physics, Faculty of Mathematics and Natural Sciences, Syiah Kuala University, Darussalam, Banda Aceh, Nanggroe Aceh Darussalam (Indonesia); Pardede, Marincan [Research Center of Maju Makmur Mandiri Foundation, 40 Srengseng Raya, Kembangan, Jakarta Barat 11630 (Indonesia); Suliyanti, Maria Margaretha [Research Center of Maju Makmur Mandiri Foundation, 40 Srengseng Raya, Kembangan, Jakarta Barat 11630 (Indonesia); Lie, Tjung Jie [Research Center of Maju Makmur Mandiri Foundation, 40 Srengseng Raya, Kembangan, Jakarta Barat 11630 (Indonesia); Kurniawan, Davy Putra [Research Center of Maju Makmur Mandiri Foundation, 40 Srengseng Raya, Kembangan, Jakarta Barat 11630 (Indonesia); Kurniawan, Koo Hendrik [Research Center of Maju Makmur Mandiri Foundation, 40 Srengseng Raya, Kembangan, Jakarta Barat 11630 (Indonesia)]. E-mail: kurnia18@cbn.net.id; Kagawa, Kiichiro [Department of Physics, Faculty of Education and Regional Studies, 9-1 bunkyo 3-chome, Fukui 910-8507 (Japan); Tjia, May On [Department of Physics, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, 10 Ganesha, Bandung 40132 (Indonesia)

    2006-12-15

    The applicability of spectrochemical analysis for liquid and powder samples of minute amount in the form of thin film was investigated using ultraviolet Nd-YAG laser (355 nm) and low-pressure ambient air. A variety of organic samples such as commercial black ink usually used for stamp pad, ginseng extract, human blood, liquid milk and ginseng powder was prepared as film deposited on the surface of an appropriate hard substrate such as copper plate or glass slide. It was demonstrated that in all cases studied, good quality spectra were obtained with very low background and free from undesirable contamination by the substrate elements, featuring ppm or even sub-ppm sensitivity and worthy of application for quantitative analysis of organic samples. The proper preparation of the films was found to be crucial in achieving the high quality spectra. It was further shown that much inferior results were obtained when the atmospheric-pressure (101 kPa) operating condition of laser-induced breakdown spectroscopy or the fundamental wavelength of the Nd-YAG laser was employed due to the excessive or improper laser ablation process.

  12. Film analysis employing subtarget effect using 355 nm Nd-YAG laser-induced plasma at low pressure

    International Nuclear Information System (INIS)

    Hedwig, Rinda; Budi, Wahyu Setia; Abdulmadjid, Syahrun Nur; Pardede, Marincan; Suliyanti, Maria Margaretha; Lie, Tjung Jie; Kurniawan, Davy Putra; Kurniawan, Koo Hendrik; Kagawa, Kiichiro; Tjia, May On

    2006-01-01

    The applicability of spectrochemical analysis for liquid and powder samples of minute amount in the form of thin film was investigated using ultraviolet Nd-YAG laser (355 nm) and low-pressure ambient air. A variety of organic samples such as commercial black ink usually used for stamp pad, ginseng extract, human blood, liquid milk and ginseng powder was prepared as film deposited on the surface of an appropriate hard substrate such as copper plate or glass slide. It was demonstrated that in all cases studied, good quality spectra were obtained with very low background and free from undesirable contamination by the substrate elements, featuring ppm or even sub-ppm sensitivity and worthy of application for quantitative analysis of organic samples. The proper preparation of the films was found to be crucial in achieving the high quality spectra. It was further shown that much inferior results were obtained when the atmospheric-pressure (101 kPa) operating condition of laser-induced breakdown spectroscopy or the fundamental wavelength of the Nd-YAG laser was employed due to the excessive or improper laser ablation process

  13. COMPARATIVE STUDY OF THE SHEAR BOND STRENGTH OF COMPOSITE RESIN TO DENTAL ENAMEL CONDITIONED WITH PHOSPHORIC ACID OR Nd: YAG LASER

    Directory of Open Access Journals (Sweden)

    EDUARDO Carlos de Paula

    1997-01-01

    Full Text Available This study has been focused on a comparison between the shear bond strength of a composite resin attached to dental enamel surface, after a 35% phosphoric acid etching and after a Nd:YAG laser irradiation with 165.8 J/cm2 of energy density per pulse. After etching and attaching resin to these surfaces, the specimens were thermocycled and then underwent the shearing bond strength tests at a speed of 5 mm/min. The results achieved, after statistical analysis with Student's t-test, showed that the adhesion was significantly greater in the 35% phosphoric acid treated group than in the group treated with the Nd:YAG laser, thus demonstrating the need for developing new studies to reach the ideal parameters for an effective enamel surface conditioning as well as specific adhesives and composite resins when Nd:YAG laser is used

  14. Effect of mitomycin combined with Nd-YAG laser on cell proliferation and invasion as well as MEK/ERK signaling pathway in obstructive lacrimal duct model

    Directory of Open Access Journals (Sweden)

    Yu Yan

    2017-11-01

    Full Text Available Objective: To study the effect of mitomycin (MMC combined with Nd-YAG laser on cell proliferation and invasion as well as MEK/ERK signaling pathway in obstructive lacrimal duct model. Methods: New Zealand rabbits were selected as experimental animals and divided into model group, laser group and MMC + laser group; obstructive lacrimal duct model was established, then laser group were given Nd-YAG laser intervention, and MMC + laser group were given Nd-YAG laser combined with mitomycin intervention. 2 months after intervention, the expression of proliferation molecules, invasion molecules and MEK-ERK signaling molecules in lacrimal duct tissue were measured. Results: TGF-β, CTGF, PCNA, Ki-67, Col-I, Col-III, MEK, ERK1/2, MMP2 and MMP9 protein levels in lacrimal duct tissue of laser group were significantly higher than those of model group while TSG-6, Cthrc1 and TIMP1 protein levels were significantly lower than those of model group; TGF-β, CTGF, PCNA, Ki- 67, Col-I, Col-III, MEK, ERK1/2, MMP2 and MMP9 protein levels in lacrimal duct tissue of MMC + laser group were significantly lower than those of laser group while TSG-6, Cthrc1 and TIMP1 protein levels were significantly higher than those of laser group. Conclusion: Mitomycin can inhibit cell proliferation and invasion as well as MEK/ERK signaling pathway activation in obstructive lacrimal duct model after Nd-YAG laser treatment.

  15. Endoscopic treatment by snare electrocoagulation prior to Nd:YAG laser photocoagulation in 85 voluminous colorectal villous adenomas.

    Science.gov (United States)

    Aubert, A; Meduri, B; Fritsch, J; Aime, F; Baglin, A; Barbagelata, M

    1991-05-01

    The association of endoscopic resection with Nd:YAG laser photocoagulation was used to treat benign colorectal villous adenomas. Eight-five patients were included: 49 with surgical contraindications, 35 for whom surgical resection appeared to be too hazardous, and 1 who refused surgery. Forty-five tumors had an axial extension between 1 and 3 cm, and 40 tumors had an axial extension of at least 4 cm. Diathermic snare resection was performed to remove large tumoral fragments prior to laser photocoagulation of the residual flat lesions. Treatments were repeated every 15 days until total tumor destruction was achieved. A carcinoma was detected in biopsy specimens obtained during endoscopic treatment of five patients. Two patients were lost to follow-up. Treatment results could be analyzed in 78 patients. Successful treatment was achieved in 67 patients. Tumor destruction was complete in 77 percent of patients who had lesions of at least 4 cm diameter and in 93 percent of patients with smaller lesions. The axial extension of the tumor was the main factor affecting the results of treatment. No major complications occurred. During the average 103-week follow-up period, 21 percent of the patients with total tumor destruction had a recurrence. The risk of recurrence was correlated with the number of initial treatment sessions and previous surgery treatment. It would appear that the treatment with endoscopic resection prior to Nd:YAG laser photocoagulation is a safe and effective method in the destruction of colorectal villous adenomas.

  16. Laser-Assisted Liposuction Using the Novel 1,444-nm Nd:YAG Laser for the Treatment of Gynecomastia: A Pilot Study.

    Science.gov (United States)

    Yoo, Kwang Ho; Bae, Jung Min; Won, Chae Young; Chung, Yu Seok; Goo, Boncheol; Rho, Yong Kwan; Kim, Gyong Moon; Lee, Jongwon; Ahn, Byeong Heon; Kim, Beom Joon

    2015-01-01

    Laser-assisted liposuction (LAL) is currently widely used to reduce localized fat. A novel Nd:YAG laser that uses a wavelength of 1,444 nm, which is better absorbed by fat, has recently been introduced. In this study, we investigated the efficacy of 1,444-nm Nd:YAG LAL for the treatment of gynecomastia. Thirteen Korean male patients (20-28 years, mean age 23 years) diagnosed with gynecomastia were enrolled in this study. All patients were treated by LAL with 1,444-nm Nd:YAG laser (100 µs pulse width, 40 Hz frequency, 300 mJ pulse energy and 12 W power with continuous emission) after tumescent anesthetic infiltration and were then evaluated. Outcome was assessed using the following 4 methods: (1) clinical assessment with photographs obtained before and 12 weeks after LAL treatment, (2) comparison of pre- and postoperative patient chest circumferences, (3) computed tomography (CT) scans to evaluate changes in breast thickness and (4) a patient satisfaction survey at the end of the study. After 12 weeks, most patients (84.5%) showed an improvement greater than 50%. Mean chest circumference was significantly reduced from 109.6 ± 8.2 to 101.2 ± 4.4 cm 12 weeks after LAL (p Gynecomastia can be safely treated with 1,444-nm Nd:YAG LAL to reduce fatty tissue and total breast volume. © 2015 S. Karger AG, Basel.

  17. The sealing of second mandibular temporary molar pits and fissure with the laser of Nd: YAG, phosphoric acid and the glass ionomer cement; Selamento de fossulas e fissura de segundo molar deciduo inferior com laser de Nd: YAG, acido fosforico e cimento de ionomero de vidro

    Energy Technology Data Exchange (ETDEWEB)

    Toda, Maria Aparecida

    2003-07-01

    The main of our study was to check the sealing of second mandibular temporary molar pits and fissure, in vitro, with the laser of Nd: YAG, phosphoric acid at 37% and the glass ionomer cement (CIV, Fuji IX GC).The proposal was to check the structural morphologic changes in the laser irradiation upon the enamel surface to watch the pits and fissure sealing with the glass ionomer cement use after the laser irradiation and to verify the efficiency of the 'double conditioning' (phosphoric acid + Nd: YAG). At the same time we watch the evolution of the temperature in the pulp chamber's inside. Our desire was to achieve a therapeutic alternative technic to prevent the dental caries. The Nd: YAG laser parameters were the same: 79 mJ of energy per pulse; frequency of 5 Hz; mean power of 0,4 W; optical fiber on contact of 320 {mu}m diameter; fluency of 99,52 J/ cm{sup 2}, assuming that the only differential was the time of the laser application on the enamel surface. The samples were prepared with this way: Laser Nd: YAG (53 second) + acid + CIV (Fuji IX); Laser Nd: YAG (53 s); Laser Nd: YAG (20 s + 20 s) + acid + CIV; Laser Nd: YAG (20 s + 20 s); Acid + CIV; Control. Through the scanning electron microscopy (MEV) we noticed fusion and resolidification regions due to the laser irradiation and a better adaptation of the glass ionomer cement when we did the 'double conditioning'. Concerning the temperature increase we can conclude that the echeloned period was the best recommended because the temperature was found in a pattern that would not cause any damage to the dental pulp. For future studies we suggest a longer relaxing time between the laser irradiation, a comparative study of this method with other lasers, the use of other sealing materials and the study with the permanent teeth. (author)

  18. The sealing of second mandibular temporary molar pits and fissure with the laser of Nd: YAG, phosphoric acid and the glass ionomer cement; Selamento de fossulas e fissura de segundo molar deciduo inferior com laser de Nd: YAG, acido fosforico e cimento de ionomero de vidro

    Energy Technology Data Exchange (ETDEWEB)

    Toda, Maria Aparecida

    2003-07-01

    The main of our study was to check the sealing of second mandibular temporary molar pits and fissure, in vitro, with the laser of Nd: YAG, phosphoric acid at 37% and the glass ionomer cement (CIV, Fuji IX GC).The proposal was to check the structural morphologic changes in the laser irradiation upon the enamel surface to watch the pits and fissure sealing with the glass ionomer cement use after the laser irradiation and to verify the efficiency of the 'double conditioning' (phosphoric acid + Nd: YAG). At the same time we watch the evolution of the temperature in the pulp chamber's inside. Our desire was to achieve a therapeutic alternative technic to prevent the dental caries. The Nd: YAG laser parameters were the same: 79 mJ of energy per pulse; frequency of 5 Hz; mean power of 0,4 W; optical fiber on contact of 320 {mu}m diameter; fluency of 99,52 J/ cm{sup 2}, assuming that the only differential was the time of the laser application on the enamel surface. The samples were prepared with this way: Laser Nd: YAG (53 second) + acid + CIV (Fuji IX); Laser Nd: YAG (53 s); Laser Nd: YAG (20 s + 20 s) + acid + CIV; Laser Nd: YAG (20 s + 20 s); Acid + CIV; Control. Through the scanning electron microscopy (MEV) we noticed fusion and resolidification regions due to the laser irradiation and a better adaptation of the glass ionomer cement when we did the 'double conditioning'. Concerning the temperature increase we can conclude that the echeloned period was the best recommended because the temperature was found in a pattern that would not cause any damage to the dental pulp. For future studies we suggest a longer relaxing time between the laser irradiation, a comparative study of this method with other lasers, the use of other sealing materials and the study with the permanent teeth. (author)

  19. Evaluation in vitro of effects of Er:YAG and Nd:YAG lasers irradiation on root canal wall, by stereoscopy, scanning electron micrography and thermographic camera; Avaliacao in vitro dos efeitos da irradiacao laser de Er:YAG e Nd:YAG na parede dentinaria do canal radicular, sob observacao do estereoscopio, da micrografia eletronica e da camera termografica

    Energy Technology Data Exchange (ETDEWEB)

    Goya, Claudia

    2001-07-01

    This study was carried out to evaluate in vitro the effects of Nd:YAG laser and Er:YAG laser irradiation in the root canal wall by SEM, evaluating the apical leakage and the temperature changes during the laser irradiation. Seventy four extracted human teeth were used, they were instrumented and divided into seven groups of 10 teeth each. The teeth were evaluated through stereoscopy, by SEM, and with the thermographic camera. The Nd:YAG laser irradiation parameters were 100 mJ/p, 15 Hz, and Er:YAG laser were 160 mJ/p and 10 Hz, the irradiation was 4 times at 2 mm/sec speed, with 20 sec interval. The apical leakage was not observed in the teeth irradiated by Nd:YAG laser alone or in association with Er:YAG laser. However in the teeth irradiated only by the Er:YAG laser we observed a little leakage. By SEM observation the Nd:YAG laser irradiation showed melting and recrystallization in the dentin surface closing dentinal tubules, and in the samples irradiated by Er:Y AG laser a clean surface, opened dentinal tubules, and the combination by two lasers, showed melting covering some dentinal tubules The thermographic study found the temperature increase was not more than 6 deg C. This study showed the safety parameters applications of Er:YAG laser in association with Nd:YAG laser in root canal treatment, in order to not cause thermal damages to the periodontal tissues. (author)

  20. Comparison of pulsed dye laser versus combined pulsed dye laser and Nd:YAG laser in the treatment of inflammatory acne vulgaris.

    Science.gov (United States)

    Salah El Din, Manal Mohamed; Samy, Nevien Ahmed; Salem, Amira Eid

    2017-06-01

    Both pulsed dye laser and combined 585/1064-nm (sequential dual-wavelength PDL and Nd:YAG) laser improves inflammatory skin disorders including acne vulgaris. To compare the efficacy of 585-nm pulsed dye laser versus sequential dual-wavelength PDL and Nd:YAG in treatment of acne vulgaris. Thirty patients with acne vulgaris were treated by PDL alone on half of the face while contra lateral half was treated by combined 585/1064 nm laser. The study showed that inflammatory acne lesions count was significantly reduced by 82.5% (p 0.0001) on PDL sides and by 83.5% (p 0.00001) on combined 585/1064-nm side after 8 weeks, while reduction of non-inflammatory acne lesions was observed at 8 weeks by 58.4% and 71.5% respectively. However, difference between the two modalities was not statistically significant. PDL and combined PDL/Nd:YAG laser treatment were found to be an effective, safe and well-tolerated treatment option for inflammatory and non-inflammatory acne vulgaris.

  1. Two-photon excitation laser scanning microscopy of rabbit nasal septal cartilage following Nd:YAG-laser-mediated stress relaxation

    Science.gov (United States)

    Kim, Charlton C.; Wallace, Vincent P.; Coleno, Mariah L.; Dao, Xavier; Tromberg, Bruce J.; Wong, Brian J.

    2000-04-01

    Laser irradiation of hyaline cartilage result in stable shape changes due to temperature dependent stress relaxation. In this study, we determined the structural changes in chondrocytes within rabbit nasal septal cartilage tissue over a 12-day period using a two-photon laser scanning microscope (TPM) following Nd:YAG laser irradiation. During laser irradiation surface temperature, stress relaxation, and diffuse reflectance, were measured dynamically. Each specimen received one or two sequential laser exposures. The cartilage reached a peak surface temperature of about 61 degrees C during irradiation. Cartilage denatured in 50 percent EtOH was used as a positive control. TPM was performed to detect the fluorescence emission from the chondrocytes. Images of chondrocytes were obtained at depths up to 150 microns, immediately following laser exposure, and also following 12 days in culture. Few differences in the pattern or intensity of fluorescence was observed between controls and irradiated specimens imaged immediately following exposure, regardless of the number of laser pulses. However, following twelve days in tissue culture, the irradiated specimens increase, whereas the native tissue diminishes, in intensity and distribution of fluorescence in the cytoplasm. In contrast, the positive control shows only extracellular matrices and empty lacuna, feature consistent with cell membrane lysis.

  2. Systematic review of the adjunctive use of diode and Nd:YAG lasers for nonsurgical periodontal instrumentation.

    Science.gov (United States)

    Roncati, Marisa; Gariffo, Annalisa

    2014-04-01

    The aims of this study were (1) to conduct a literature search and systematically evaluate the additional therapeutic effects of pulsed Nd:YAG or diode laser use in patients with periodontitis, (2) to assess evidence supporting the additional benefit of laser-mediated periodontal treatment in conjunction with scaling and root planning (SRP) (not as monotherapy), and (3) to interpret the evidence presented in retrieved publications. Opinions about the additional use of diode lasers in the nonsurgical treatment of plaque-induced periodontal lesions are conflicting. The April 2011 American Academy of Periodontology's "Statement on the Efficacy of Lasers in the Non-Surgical Treatment of Inflammatory Periodontal Disease" asserted that the use of a laser as monotherapy or in addition to nonsurgical periodontal instrumentation conveyed no advantage. After initial screening, 23/77 potentially relevant articles and abstracts identified through electronic and manual searches of the MEDLINE(®)/PubMed database and the Cochrane Central Register of Controlled Trials (1990-2012) were included in this review. A meta-analysis could be performed. The results indicate that Nd:YAG or diode laser, used in an adjunctive capacity to SRP, may provide some additional benefit, in 6 month studies, compared with mechanical debridement. The results show the adjunctive benefits that diode laser treatment can provide when it is used as an adjunct to nonsurgical periodontal treatment in adults with chronic periodontitis. Further long-term, well-designed, parallel randomized clinical trials are needed to assess the effectiveness of the adjunctive use of the diode laser, as well as the appropriate dosimetry and laser settings.

  3. Shear bond strength of metal brackets to feldspathic porcelain treated by Nd:YAG laser and hydrofluoric acid.

    Science.gov (United States)

    Hosseini, Mohammad Hashem; Sobouti, Farhad; Etemadi, Ardavan; Chiniforush, Nasim; Shariati, Mahsa

    2015-02-01

    Adult orthodontic treatment requires bonding orthodontic attachment to dental restorations. Ceramics are commonly used as esthetic restorative materials for the crowns and bridges. The present study evaluated the shear bond strength of metal orthodontic brackets to the feldspathic porcelain surfaces following conditioning by different powers of neodymium-doped yttrium aluminum garnet (Nd:YAG) laser and hydrofluoric acid as a conventional method. Seventy-two glazed porcelain samples were prepared and randomly attributed to six equal groups of 12. In the conventional hydrofluoric (HF) group, the specimens were etched by 9.6% hydrofluoric acid for 4 min. In laser groups, samples were conditioned by 0.75-, 1-, 1.25-, 1.5-, and 2-W Nd:YAG laser for 10 s. Metal brackets were bonded to porcelain samples and after being stored in distilled water for 24 h, they were subjected to thermocycling for 500 cycles. The debonding was carried out by a Zwick testing machine. The data were statistically analyzed by ANOVA and Tamhane multiple comparisons tests. The mean ± SD of the shear bond strength in the laser group 0.75, 1, 1.25, 1.5, and 2 W and HF group was 2.2 ± 0.9, 4.2 ± 1.1, 4.9 ± 2.4, 7 ± 1.7, 9.6 ± 2.7, and 9.4 ± 2.5, respectively. Together with the increased power of laser, the mean shear bond strength was increased continuously and no significant differences were found between the HF group and the laser groups with power of 1.5 or 2 W. Also, there was no significant difference between all test groups in ARI scores. There was no significant difference between bond strength of laser groups with power of 1.5 and 2 W and HF-etched group. So, Nd:YAG laser with appropriate parameters can be used as an alternative method for porcelain etching.

  4. Efficient diode-end-pumped actively Q-switched Nd:YAG/SrWO4/KTP yellow laser.

    Science.gov (United States)

    Cong, Zhenhua; Zhang, Xingyu; Wang, Qingpu; Liu, Zhaojun; Li, Shutao; Chen, Xiaohan; Zhang, Xiaolei; Fan, Shuzhen; Zhang, Huaijin; Tao, Xutang

    2009-09-01

    An efficient intracavity frequency-doubled Raman laser was obtained by using an SrWO(4) Raman medium, an Nd:YAG ceramic gain medium, and a KTP frequency-doubling medium. Three laser cavities, including a two-mirror cavity, a three-mirror coupled cavity, and a folded cavity, were investigated. With the coupled cavity, a 2.93 W, 590 nm laser was obtained at an incident pump power of 16.2 W and a pulse repetition frequency of 20 kHz; the corresponding conversion efficiency was 18.1%. The highest conversion efficiency of 19.2% was obtained at an incident pump power of 14.1 W and a pulse repetition frequency of 15 kHz. The obtained maximum output power and conversion efficiency were much higher than the results previously obtained with intracavity frequency-doubled solid-state Raman lasers.

  5. Nanosecond-pulsed Q-switched Nd:YAG laser at 1064 nm with a gold nanotriangle saturable absorber

    Science.gov (United States)

    Chen, Xiaohan; Li, Ping; Dun, Yangyang; Song, Teng; Ma, Baomin

    2018-06-01

    Gold nanotriangles (GNTs) were successfully employed as a saturable absorber (SA) to achieve passively Q-switched lasers for the first time. The performance of the Q-switched Nd:YAG laser at 1064 nm has been systematically investigated. The corresponding shortest pulsewidth, the threshold pump power and the maximum Q-switched average output power were 275.5 ns, 1.37 W, and 171 mW, respectively. To our knowledge, this is the shortest pulsewidth and the lowest threshold in a passively Q-switched laser at approximately 1.1 µm based on a gold nanoparticle SA (GNPs-SA). Our experimental results proved that the GNTs-SA can be used as a promising saturable absorber for nanosecond-pulsed lasers.

  6. All passive synchronized Q-switching of a quasi-three-level and a four-level Nd:YAG laser

    DEFF Research Database (Denmark)

    Cheng, Haynes Pak Hay; Tidemand-Lichtenberg, Peter; Jensen, Ole Bjarlin

    2010-01-01

    Using an all passive approach, synchronized Q-switching of two Nd:YAG lasers, at 946 nm and 1064 nm, is reported. Two laser crystals are used to avoid gain competition, and stable operation is reported for the first time. The pulse trains are synchronized over a wide range of pump powers...

  7. A comparative study of via drilling and scribing on PEN and PET substrates for flexible electronic applications using excimer and Nd:YAG laser sources

    NARCIS (Netherlands)

    Mandamparambil, R.; Fledderus, H.; Brand, J. van den; Saalmink, M.; Kusters, R.; Podprocky, T.; Steenberge, G. van; Baets, J. de; Dietzel, A.H.

    2009-01-01

    A study on via drilling and channel scribing on PEN and PET substrates for flexible electronic application is discussed in this paper. For the experiments, both KIF excimer laser (248 nm) and frequency tripled Nd:YAG (355 nm) laser are used. Different measurement techniques like optical microscopy,

  8. A comparative study of pulsed dye laser versus long pulsed Nd:YAG laser treatment in recalcitrant viral warts.

    Science.gov (United States)

    Shin, Yo Sup; Cho, Eun Byul; Park, Eun Joo; Kim, Kwang Ho; Kim, Kwang Joong

    2017-08-01

    Viral warts are common infectious skin disease induced by human papillomavirus (HPV). But the treatment of recalcitrant warts is still challenging. In this study, we compared the effectiveness of pulsed dye laser (PDL) and long pulsed Nd:YAG (LPNY) laser in the treatment of recalcitrant viral warts. We retrospectively analyzed the medical records of patients with recalcitrant warts treated with laser therapy between January 2013 and February 2016. Seventy-two patients with recalcitrant warts were evaluated. Thirty-nine patients were treated with pulsed dye laser and thirty-three patients were treated with LPNY laser. The following parameters were used: PDL (spot size, 7 mm; pulse duration, 1.5 ms; and fluence, 10-14 J/cm 2 ) and LPNY (spot size, 5 mm; pulse duration, 20 ms; and fluence, 240-300 J/cm 2 ). Complete clearance of two patients (5.1%) in PDL group, and three patients (9.1%) in LPNY group were observed without significant side effects. The patients who achieved at least 50% improvement from baseline were 20 (51.3%) in PDL and 22 (66.7%) in LPNY, respectively. This research is meaningful because we compared the effectiveness of the PDL and LPNY in the recalcitrant warts. Both PDL and LPNY laser could be used as a safe and alternative treatment for recalcitrant warts.

  9. Flexural strength of pure Ti, Ni-Cr and Co-Cr alloys submitted to Nd:YAG laser or TIG welding.

    Science.gov (United States)

    Rocha, Rick; Pinheiro, Antônio Luiz Barbosa; Villaverde, Antonio Balbin

    2006-01-01

    Welding of metals and alloys is important to Dentistry for fabrication of dental prostheses. Several methods of soldering metals and alloys are currently used. The purpose of this study was to assess, using the flexural strength testing, the efficacy of two processes Nd:YAG laser and TIG (tungsten inert gas) for welding of pure Ti, Co-Cr and Ni-Cr alloys. Sixty cylindrical specimens were prepared (20 of each material), bisected and welded using different techniques. Four groups were formed (n=15). I: Nd:YAG laser welding; II- Nd:YAG laser welding using a filling material; III- TIG welding and IV (control): no welding (intact specimens). The specimens were tested in flexural strength and the results were analyzed statistically by one-way ANOVA. There was significant differences (pTIG and laser welding and also between laser alone and laser plus filling material. In conclusion, TIG welding yielded higher flexural strength means than Nd:YAG laser welding for the tested Ti, Co-Cr and Ni-Cr alloys.

  10. Variation on Molecular Structure, Crystallinity, and Optical Properties of Dentin Due to Nd:YAG Laser and Fluoride Aimed at Tooth Erosion Prevention

    Science.gov (United States)

    Freitas, Anderson Z.; Bachmann, Luciano; Benetti, Carolina; Ana, Patricia A.

    2018-01-01

    This in vitro study evaluated the compositional, crystalline, and morphological effects promoted by Nd:YAG laser on root dentin, and verified the effects of laser and topical acidulated phosphate fluoride application (APF-gel) on dentin erosion. 180 bovine dentin slabs were randomized into 4 groups (n = 45): G1–untreated, G2–APF-gel (1.23% F−, 4 min), G3–Nd:YAG (1064 nm, 84.9 J/cm2, 10 Hz), and G4–APF-gel application followed by Nd:YAG laser irradiation. The compositional, crystalline, and morphological effects promoted by treatments were investigated on five samples of each experimental group. The other samples were submitted to a 5-day, 10-day, or 15-day erosive and abrasive demineralization and remineralization cycling in order to create erosion lesions. The area and depth of lesions, as well as the optical attenuation coefficient, were assessed, and all data were statistically analysed (p laser promoted the reduction of carbonate, the formation of tetracalcium phosphate, as well as the melting and recrystallization of the dentin surface. Laser significantly decreased the area and depth of erosion lesions and altered the optical attenuation coefficient when compared to untreated and APF-gel groups, but the association of APF-gel and laser did not promote an additional effect. Nd:YAG laser irradiation can be a promissory treatment to prevent dentin erosion and the abrasion process. PMID:29389868

  11. High-energy azimuthally polarized laser beam generation from an actively Q-switched Nd:YAG laser with c-cut YVO4 crystal

    Science.gov (United States)

    Guo, Jing; Zhang, Baofu; Jiao, Zhongxing; He, Guangyuan; Wang, Biao

    2018-05-01

    A high-energy, azimuthally polarized (AP) and actively Q-switched Nd:YAG laser is demonstrated. The thermal bipolar lensing effect in the Nd:YAG laser rod is used as a polarization discriminator, and a c-cut YVO4 crystal is inserted into the laser cavity to increase the mode-selecting ability of the cavity for AP mode. The laser generated AP pulses with maximum pulse energy as high as 4.2 mJ. To the best of our knowledge, this is the highest pulse energy obtained from an actively Q-switched AP laser. The pulse energy remained higher than 1 mJ over a wide range of repetition rates from 5 kHz to 25 kHz.

  12. Penetration of 35% hydrogen peroxide into the pulp chamber in bovine teeth after LED or Nd:YAG laser activation.

    Science.gov (United States)

    Camargo, Samira Esteves Afonso; Cardoso, Paula Elaine; Valera, Marcia Carneiro; de Araújo, Maria Amélia Máximo; Kojima, Alberto Noriyuki

    2009-01-01

    This aim of the present study was to evaluate the pulp chamber penetration of 35% hydrogen peroxide activated by LED (light-emitting diode) or Nd:YAG laser in bovine teeth, after an in-office bleaching technique. Forty-eight bovine lateral incisors were divided into four groups, acetate buffer was placed into the pulp chamber and bleaching agent was applied as follows: for group A (n = 12), activation was performed by LED; for group B (n = 12), activation was performed by Nd:YAG laser (60 mJ, 20 Hz); group C (n = 12) received no light or laser activation; and the control group (n = 12) received no bleaching gel application or light or laser activation. The acetate buffer solution was transferred to a glass tube and Leuco Crystal Violet and horseradish peroxidase were added, producing a blue solution. The optical density of this solution was determined spectrophotometrically and converted into microgram equivalents of hydrogen peroxide. The results were analysed using ANOVA and Tukey's test (5%). It was verified that the effect of activation was significant, as groups activated by LED or laser presented greater hydrogen peroxide penetration into the pulp chamber (0.499 +/- 0.622 microg) compared with groups that were not (0.198 +/- 0.218 microg). There was no statistically significant difference in the penetration of hydrogen peroxide into the pulp chamber between the two types of activation (LED or laser). The results suggest that activation by laser or LED caused an increase in hydrogen peroxide penetration into the pulp chamber.

  13. Welding shape memory alloys with NdYAG lasers Soldadura de ligas de memória de forma com laser Nd-YAG

    Directory of Open Access Journals (Sweden)

    Luisa Quintino

    2012-09-01

    Full Text Available The demand of emerging joining techniques for shape memory alloys (SMA has become of great importance, as their functional properties namely shape memory effect (SME and superelasticity (SE present unique solutions for state-of-the-art applications. Welding of SMAs is a challenge due to the risk of reduced mechanical performance after laser processing. The wider application of these alloys in various sectors as aerospace, medical or electronic industry is hindered by the limitations in its processing. The need to weld SMAs to other materials is pressing for applications in the above referred sectors. In dissimilar joints the need to understand materials behavior is even more challenging since base materials have different physical properties leading to different heat flow, convection processes and residual stress distribution. The chemical composition across the weld pool varies and intermetallic compounds are formed. Research detailing the effects of laser processing on NiTi is essential to overcome many of these challenges. The objectives of the current study are to analyze the effects of laser welding in the weld shape of both similar and dissimilar joints of NiTi to stainless steel and titanium alloys.A procura de técnicas de ligação para ligas de memória de forma tem-se revetido de importância crescente, devido ao desenvolvimento de aplicações deste material com particulares propriedades de memória de forma e superelasticidade. A soldadura de ligas de memória de forma é um desafio devido ao risco de emporbrecimento das propriedades mecânicas depois do processamento laser. A aplicação alargarda destas ligas em vários sectores como o aeroespacial, medico ou electrónico é prejudicado pelas limitações de processamento. A necessidade de soldar ligas de memória de forma a outros materiais é premente para estes sectores. Em juntas dissimilares, o entendimento do comportamento dos materaias é um desafio ainda maior uma vez que

  14. Structure of picosecond pulses of a Q-switched and mode-locked diode-pumped Nd:YAG laser

    Energy Technology Data Exchange (ETDEWEB)

    Donin, V I; Yakovin, D V; Gribanov, A V [Institute of Automation and Electrometry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk (Russian Federation)

    2015-12-31

    The pulse duration of a diode-pumped Nd:YAG laser, in which Q-switching with mode-locking (QML regime) is achieved using a spherical mirror and a travelling-wave acousto-optic modulator, is directly measured with a streak camera. It is found that the picosecond pulses can have a non-single-pulse structure, which is explained by excitation of several competing transverse modes in the Q-switching regime with a pulse repetition rate of 1 kHz. In the case of cw mode-locking (without Q-switching), a new (auto-QML) regime is observed, in which the pulse train repetition rate is determined by the frequency of the relaxation oscillations of the laser field while the train contains single picosecond pulses. (control of laser radiation parameters)

  15. Shock waves and cavitation bubbles in water and isooctane generated by Nd:YAG laser: experimental and theoretical results

    Science.gov (United States)

    Muller, Milos; Garen, Walter; Koch, Sandra; Marsik, Frantisek; Neu, Walter; Saburov, Eduado

    2004-04-01

    Temporal evolution of laser generated cavitation bubbles and shock waves were studied. Q-switched Nd-Yag laser pulses at 1064 nm are focused into the liquid. An Imager 3 CCD camera with multi exposure mode allows recording of 10 images with minimal exposure delay of 100 ns and minimal exposure time of 100 ns. Illumination is provided by xenon flash lamp for single exposure (shock wave recording) and by halogen lamp for multi exposure mode (bubble recording). Distilled water and a retrograde fluid, isooctane, have been under investigation to identify the differences in the cavitation process and shock wave propagation. The calculation of the shock wave velocities in water and isooctane are based on image recording at constant exposure time of 100 ns and using laser differential interferometry. Strong differences of bubble oscillation were observed in water and isooctane. Gilmore's model is used for numerical simulation of bubble dynamics.

  16. Phase conjugation of speckle-inhomogeneous radiation in a holographic Nd:YAG laser with a short thermal hologram

    International Nuclear Information System (INIS)

    Yarovoi, V V; Kirsanov, A V

    2002-01-01

    A model of the so-called short hologram, which does not exhibit in-depth diffraction deformation of the fine speckle pattern of the recording fields, is studied. The investigation is performed by the example of a thermal hologram recorded by two speckle waves, which is the output mirror of a ring laser produced as a result of this recording. It is shown that the ability of this short hologram to select a wave conjugated to a speckle signal in the mode of the holographic laser depends both on the degree of mutual mixing of the speckles of recording beams in the hologram volume and on the effects of its saturation by the beams. The maximum accuracy of phase conjugation of speckle radiation in the holographic Nd:YAG laser achieved upon the best selection of the conjugate wave by the short thermal hologram was 93%. (nonlinear optical phenomena)

  17. Pulsed-diode-pumped, all-solid-state, electro-optically controlled picosecond Nd:YAG lasers

    International Nuclear Information System (INIS)

    Gorbunkov, Mikhail V; Shabalin, Yu V; Konyashkin, A V; Kostryukov, P V; Olenin, A N; Tunkin, V G; Morozov, V B; Rusov, V A; Telegin, L S; Yakovlev, D V

    2005-01-01

    The results of the development of repetitively pulsed, diode-pumped, electro-optically controlled picosecond Nd:YAG lasers of two designs are presented. The first design uses the active-passive mode locking with electro-optical lasing control and semiconductor saturable absorber mirrors (SESAM). This design allows the generation of 15-50-ps pulses with an energy up to 0.5 mJ and a maximum pulse repetition rate of 100 Hz. The laser of the second design generates 30-ps pulses due to combination of positive and negative electro-optical feedback and the control of the electro-optical modulator by the photocurrent of high-speed semiconductor structures. (active media. lasers)

  18. Nd:YAG laser double wavelength ablation of pollution encrustation on marble and bonding glues on duplicated painting canvas

    Science.gov (United States)

    Batishche, Sergei; Englezis, Apostolis; Gorovets, Tatiana; Kouzmouk, Andrei; Pilipenka, Uladzimir; Pouli, Paraskevi; Tatur, Hennady; Totou, Garyfallia; Ukhau, Viktar

    2005-07-01

    In the present study, a newly developed one-beam IR-UV laser cleaning system is presented. This system may be used for different applications in diverse fields, such as outdoors stonework conservation and canvas paintings restoration. The simultaneous use of the fundamental radiation of a Q-switched Nd:YAG laser at 1064 nm and its third harmonic at 355 nm was found appropriate to clean pollution crusts, while ensuring that no discoloration ("yellowing") would occur. The optimum ratio of UV to IR wavelengths in the final cleaning beam was investigated. In parallel, the same system was tested in diverse applications, such as the removal of bonding glues from duplicated canvases. The optimum laser parameters were investigated both on technical samples as well as on original paintings.

  19. Enhancement of light absorption by blood to Nd:YAG laser using PEG-modified gold nanorods.

    Science.gov (United States)

    Xing, Linzhuang; Li, Dong; Chen, Bin; Dai, Yuze; Wu, Wenjuan; Wang, Guoxiang

    2016-10-01

    On the basis of the principle of selective photothermolysis, laser therapy has been the most effective treatment strategy for Port-wine stains (PWSs) caused by the expansion of dermal capillaries. Neodymium:Yttrium Aluminum Garnet (Nd:YAG) laser at 1064 nm wavelength has great potential for deeply buried PWS, although its application is limited because of its weak absorption by blood. The purpose of this study is to investigate the effect of PEG-modified gold nanorods (NRs) on the blood absorption enhancement for Nd:YAG laser. PEG-modified gold nanorods (NRs) were synthesized via the seeded growth method. Then, the effect of PEG-modified gold NRs on blood light absorbance was investigated through adding different concentration of PEG-modified gold NRs to 1 ml of blood at room temperature. Finally, the optical properties of whole mice blood with or without PEG-modified gold NRs under slow heating were investigated. The average length and width of PEG-modified gold NRs are 79.5 ± 10.5 and 13.5 ± 0.9 nm, respectively, with the aspect ratio of 5.89, and a strong absorption peak exists at ∼1050 nm in the near-infrared range. A linear correlation between the blood absorbance at 1064 nm and the amount of PEG-modified gold NRs was obtained. The absorbance at 1064 nm increased 17.6, 33.0, 48.3, and 65.4 times when 0.4, 0.8, 1.2, and 1.6 mg of PEG-modified gold NRs was added to 1 ml of blood at room temperature, respectively. After adding 0.8 mg of PEG-modified gold NRs to 1 ml of blood, blood absorbance at 1064 nm at different temperatures increased by an average of 24.0 times. After intravenously injecting PEG-modified gold NRs (0.87 mg/ml) into Sprague-Dawley mice, the blood absorbance at 1064 nm increased from 0.014 to 0.5. Our findings suggest that PEG-modified gold NRs injection is an efficient way to enhance light absorption by blood to Nd:YAG laser. Lasers Surg. Med. 48:790-803, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley

  20. VIDRIADO CON LÁSER DE Nd: YAG SOBRE AZULEJOS RECUBIERTOS DE BARNICES DE COBALTO CON FRITA BORÁCICA Y SIN FRITA VIDRADO COM Laser De Nd: YAG SOBRE AZULEJOS RECOBERTOS DE VERNIZES DE COBALTO COM FRITA BORÁCICA E SEM FRITA Nd: YAG LASER ENAMELING ON GLAZED TILES COATED WITH COBALT VARNISHES WITH AND WITHOUT BORAX FRIT

    Directory of Open Access Journals (Sweden)

    Maryory Astrid Gómez

    2010-07-01

    ças durante o processo sem requerer longas paradas, e a geração de resíduos é mínima ou quase nula. Neste estudo se apresentam os resultados obtidos no vidrado com laser Nd:YAG (l=1064 nm, sobre as superfícies esmaltadas de azulejos, as quais foram previamente recobertas com pigmento preto de cobalto e um verniz constituído com este mesmo pigmento e frita borácica. Com o laser operando em modo contínuo (CW, marcaram-se uma série de linhas, cujo largo e profundidade evidenciaram uma dependência direta com a variação da potência e velocidade de deslocamento do feixe laser sobre a superfície do azulejo. Finalmente, estas linhas vidradas foram analisadas por microscopia óptica, espectroscopia de dispersão de energia (EDS e difração de raios X.Ceramic and architectonic materials industries employ different marking techniques with two classical applications, identification and decoration of manufactured objects. Laser techniques using for these proposes are been implemented in growing way, due to theirs advantages with regard to the conventional baking such as: heat is concentrated only on the radiated zone which involves a smaller energy consumption without affecting significantly the rest of the piece; graphic patterns with of highly spatial resolution are obtained; it permits to introduce changes during the process no requiring long stops and low or almost none generation of residues. In this study the results obtained from Nd:YAG (l=1064 nm laser glazing on the enameled surfaces of glazed tiles, which were previously covered with cobalt black pigment and an enamel constituted with this same pigment and borax frit, are presented. With the laser operating in continuous wave (CW, a series of lines were marked, whose width and depth showed a direct dependence with the variation in the power and scan speed of the laser beam on the glazed tile surface. Finally, these glazed lines were characterized by optical microscopy, energy dispersion spectroscopy (EDS, and X

  1. Growth of superconducting MgB2 films by pulsed-laser deposition using a Nd-YAG laser

    International Nuclear Information System (INIS)

    Badica, P; Togano, K; Awaji, S; Watanabe, K

    2006-01-01

    Thin films of MgB 2 on r-cut Al 2 O 3 substrates have been grown by pulsed-laser deposition (PLD) using a Nd-YAG laser (fourth harmonic-266 nm) instead of the popular KrF excimer laser. The growth window to obtain superconducting films is laser energy 350-450 mJ and vacuum pressure with Ar-buffer gas of 1-8/10 Pa (initial background vacuum 0.5-1 x 10 -3 Pa). Films were deposited at room temperature and post-annealed in situ and ex situ at temperatures of 500-780 0 C and up to 1 h. Films are randomly oriented with maximum critical temperature (offset of resistive transition) of 27 K. SEM/TEM/EDS investigations show that they are mainly composed of small sphere-like particles (≤20 nm), and contain oxygen and some carbon, uniformly distributed in the flat matrix, but the amount of Mg and/or oxygen is higher in the aggregates-droplets (100-1000 nm) observed on the surface of the film's matrix. Some aspects of the processing control and dependences on film characteristics are discussed. The technique is promising for future development of coated conductors

  2. Characteristics of a laser beam produced by using thermal lensing effect compensation in a fiber-coupled laser-diode-pumped Nd:YAG ceramic laser

    International Nuclear Information System (INIS)

    Kim, Duck-Lae; Kim, Byung-Tai

    2010-01-01

    The characteristics of a laser beam produced by using thermal lensing effect compensation in a fiber-coupled laser-diode Nd:YAG ceramic laser were investigated. The thermal lensing effect was compensated for by using a compensator, which was 25 mm away from the laser rod, with a focal length of 30 mm and an effective clear aperture of 22 mm. Using a compensator, the divergence and the beam propagation factor M 2 of the output beam were 5.5 mrad and 2.4, respectively, under a pump power of 12W. The high-frequency components in the compensated laser beam were removed.

  3. Growth and annealing effect of SrTiO{sub 3} thin films grown by pulsed laser deposition using fourth harmonic Nd:YAG pulsed laser

    Energy Technology Data Exchange (ETDEWEB)

    Takamura, Koji; Fujiwara, Takumi; Yokota, Akinobu; Nakamura, Motonori; Yoshimoto, Ken' ichi [National Institute of Technology, Asahikawa College, 2-2-1-6 Shunkodai, Asahikawa 071-8142 (Japan)

    2017-06-15

    SrTiO{sub 3} homoepitaxial films were grown by pulsed laser deposition (PLD) using a fourth harmonic Nd:YAG pulsed laser. The substrate temperature was kept constant at 600, 700, or 800 C. The laser energy was set at 9-25 mJ on the polycrystal SrTiO{sub 3} target. Post-procedure annealing was performed in the air for 24 h. The X-ray diffraction measurement results showed that the lattice constant of the film was only 0.010 Aa larger than that of the substrate and was not dependent on the annealing temperature. We demonstrated the possibility of growing near-stoichiometric SrTiO{sub 3} film by PLD using an Nd:YAG laser. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. Teaching learning algorithm based optimization of kerf deviations in pulsed Nd:YAG laser cutting of Kevlar-29 composite laminates

    Science.gov (United States)

    Gautam, Girish Dutt; Pandey, Arun Kumar

    2018-03-01

    Kevlar is the most popular aramid fiber and most commonly used in different technologically advanced industries for various applications. But the precise cutting of Kevlar composite laminates is a difficult task. The conventional cutting methods face various defects such as delamination, burr formation, fiber pullout with poor surface quality and their mechanical performance is greatly affected by these defects. The laser beam machining may be an alternative of the conventional cutting processes due to its non-contact nature, requirement of low specific energy with higher production rate. But this process also faces some problems that may be minimized by operating the machine at optimum parameters levels. This research paper examines the effective utilization of the Nd:YAG laser cutting system on difficult-to-cut Kevlar-29 composite laminates. The objective of the proposed work is to find the optimum process parameters settings for getting the minimum kerf deviations at both sides. The experiments have been conducted on Kevlar-29 composite laminates having thickness 1.25 mm by using Box-Benkhen design with two center points. The experimental data have been used for the optimization by using the proposed methodology. For the optimization, Teaching learning Algorithm based approach has been employed to obtain the minimum kerf deviation at bottom and top sides. A self coded Matlab program has been developed by using the proposed methodology and this program has been used for the optimization. Finally, the confirmation tests have been performed to compare the experimental and optimum results obtained by the proposed methodology. The comparison results show that the machining performance in the laser beam cutting process has been remarkably improved through proposed approach. Finally, the influence of different laser cutting parameters such as lamp current, pulse frequency, pulse width, compressed air pressure and cutting speed on top kerf deviation and bottom kerf

  5. Effects of electrocautery, CO/sub 2/ laser, and contact Nd:YAG laser scalpel on the healing of intestinal incision

    Energy Technology Data Exchange (ETDEWEB)

    Puolakkainen, P.; Brackett, K.; Sankar, M.Y.; Joffe, S.; Schroeder, T.

    1987-01-01

    Leakage after intestinal resection is a serious complication with a high mortality rate. A recent study claims that cutting the intestine with the CO/sub 2/ laser improves the healing of intestinal anastomoses. The present study was undertaken to analyze the effects of electrocautery, CO/sub 2/ laser, and contact Nd:YAG laser on the healing of intestinal incisions. Fifteen piglets were used and the cutting and reanastomosing were performed by using all cutting methods in each animal in randomized order. Resection sites were 50 cm, 100 cm, and 150 cm distal to the ligament of Treitz. On the seventh day the bursting pressures were measured for each anastomosis. They were 172 +/- 17 mmHg for normal bowel segment and 133 +/- 12, 135 +/- 40, and 139 +/- 17 mmHg for electrocautery, CO/sub 2/ laser, and Nd:YAG laser, respectively. There were no mortality, no anastomotic leaks, and no statistically significant differences in the bursting pressures, in histology, or in the healing of anastomotic sites, indicating that electrocautery, CO/sub 2/ laser, and contact Nd:YAG laser scalpel can safely be used in the surgery of small intestine.

  6. Comparison of treatment with an Alexandrite picosecond laser and Nd:YAG nanosecond laser for removing blue-black Chinese eyeliner tattoos.

    Science.gov (United States)

    Zhang, Mengli; Huang, Yuqing; Lin, Tong; Wu, Qiuju

    2018-02-28

    To retrospectively evaluate the efficacy of an Alexandrite picosecond laser versus Nd:YAG nanosecond laser for removing blue-black eyeliner tattoos which have existed more than 10 years. A total of 40 patients were treated with an Alexandrite picosecond laser in our department from August 2015 to July 2017, with a fluence of 1.96-6.37J/cm 2 , spot size of 2.0-3.6 mm, and pulse width of 750 ps. Another 32 patients were treated with an Nd:YAG nanosecond laser, with a fluence of 2.80-7.00 J/cm 2 , spot size of 3 mm, and pulse width of 5-20 ns. All analysed patients completed at least one treatment and follow-up. The median number of treatment for all the patients was 1 (range, 1-4). After a single session, no difference was found between the two lasers for the eyeliner removal (p > 0.05). For the people who achieved an excellent response of tattoo clearance, there was still no difference between the two groups (p > 0.05). Transient side effects were observed in two groups, but neither group had significant adverse reactions. To treat blue-black Chinese eyeliner tattoos over 10 years, Alexandrite picosecond laser does not provide better clearance than the Nd:YAG nanosecond laser.

  7. Influence of water content on the ablation of skin with a 532 nm nanosecond Nd:YAG laser

    Science.gov (United States)

    Kim, Soogeun; Eom, Tae Joong; Jeong, Sungho

    2015-01-01

    This work reports that the ablation volume and rate of porcine skin changed significantly with the change of skin water content. Under the same laser irradiation conditions (532 nm Nd:YAG laser, pulse width=11.5 ns, pulse energy=1.54 J, beam radius=0.54 mm), the ablation volume dropped by a factor of 4 as the skin water content decreased from 40 wt. % (native) to 19 wt. % with a change in the ablation rate below and above around 25 wt. %. Based on the ablation characteristics observed by in situ shadowgraph images and the calculated tissue temperatures, it is considered that an explosive rupture by rapid volumetric vaporization of water is responsible for the ablation of the high water content of skin, whereas thermal disintegration of directly irradiated surface layer is responsible for the low water content of skin.

  8. Long-pulsed Nd:YAG laser vs. intense pulsed light for hair removal in dark skin: a randomized controlled trial.

    Science.gov (United States)

    Ismail, S A

    2012-02-01

    Although several lasers meet the wavelength criteria for selective follicular destruction, the treatment of darker skin phototypes is particularly challenging because absorption of laser energy by the targeted hairs is compromised by an increased concentration of epidermal melanin. To compare satisfaction level, safety and effectiveness of a long-pulsed Nd:YAG laser and intense pulsed light (IPL) in axillary hair reduction in subjects with dark skin. The study design was a within-patient, right-left, assessor-blinded, comparison of long-pulsed Nd:YAG laser and IPL. Fifty women (skin phototypes IV-VI) volunteered for removal of axillary hair. Five sessions at 4- to 6-week intervals were performed. Hair counts at both sides were compared at baseline and 6months after the last session. Final overall evaluations were performed by subjects and clinician at the end of the study. Satisfaction was scored for both devices. Thirty-nine women completed the study. At 6months, the decrease in hair counts on the laser side (79·4%, Pvs. pretreatment) was significantly (Pvs. pretreatment). Only temporary adverse effects were reported at both sides. Higher pain scores and more inflammation were reported with Nd:YAG laser; however, it was preferred by 29 volunteers (74%). Volunteers reported higher satisfaction score with Nd:YAG laser (PDark skin can be treated by both systems safely and effectively; however, long-pulsed (1064 nm) Nd:YAG laser is more effective as reported by both subjects and clinician. © 2011 The Authors. BJD © 2011 British Association of Dermatologists.

  9. AIR FLOW AND ENVIRONMENTAL WIND VISUALIZATION USING A CW DIODE PUMPED FREQUENCY DOUBLED Nd:YAG Laser

    Directory of Open Access Journals (Sweden)

    Mircea UDREA

    2009-09-01

    Full Text Available Preliminary results obtained in developing a visualisation technique for non-invasive analysis of air flow inside INCAS subsonic wind tunnel and its appendages are presented. The visualisation technique is based on using a green light sheet generated by a continuous wave (cw longitudinally diode pumped and frequency doubled Nd:YAG laser. The output laser beam is expanded on one direction and collimated on rectangular direction. The system is tailored to the requirements of qualitative analysis and vortex tracking requirements inside the INCAS 2.5m x 2.0m subsonic wind tunnel test section, for measurements performed on aircraft models. Also the developed laser techniques is used for non-invasive air flow field analysis into environmental facilities settling room (air flow calming area. Quantitative analysis is enabled using special image processing tools upon movies and pictures obtained during the experiments. The basic experimental layout in the wind tunnel takes advantage of information obtained from the investigation of various aircraft models using the developed visualisation technique. These results are further developed using a Particle Imaging Velocimetry (PIV experimental technique.The focus is on visualisation techniques to be used for wind flow characterization at different altitudes in indus-trial and civil buildings areas using a light sheet generated by a Nd:YAG cw pumped and doubled laser at 532 nm wave-length. The results are important for prevention of biological/chemical disasters such as spreading of extremely toxic pol-lutants due to wind. Numerical simulations of wind flow and experimental visualisation results are compared. A good agreement between these results is observed.

  10. Nd:YAG laser annealing investigation of screen-printed CIGS layer on PET: Layer annealing method for photovoltaic cell fabrication process

    KAUST Repository

    Alsaggaf, Ahmed; Alarousu, Erkki; Boulfrad, Samir; Rothenberger, Alexander

    2014-01-01

    by heat treatment using a Nd:YAG laser. The structure and morphology of the heated thin films were studied. The characterization of the CIGS powder, ink, and film was done using TGA, SEM, FIB, EDS, and XRD. TGA analysis shows that the CIGS ink is drying

  11. An injection seeded single frequency Nd:YAG Q-switched laser with precisely controllable laser pulse firing time

    Science.gov (United States)

    Wu, Frank F.; Khizhnyak, Anatoliy; Markov, Vladimir

    2010-02-01

    We have realized a single frequency Q-switched Nd:YAG laser with precisely controllable lasing time and thus enabled synchronization of multi-laser systems. The use of injection seeding to the slave ring oscillator results in unidirectional Q-switched laser oscillation with suppression of bidirectional Q-switched oscillation that otherwise would be initiated from spontaneous emission if the seeding laser is not present. Under normal condition, the cavity is high in loss during the pumping period; then a Pockels cell opens the cavity to form the pulse build up, with a second Pockels cell to perform cavity dumping, generating the Q-switched pulse output with optimized characteristics. The two Pockels cells can be replaced by a single unit if an adjustable gated electrical pulse is applied to the Pockels cell in which the pulse front is used to open the cavity and the falling edge to dump the laser pulse. Proper selection of the pump parameters and Pockels-cell gating enables operation of the system in a mode in which the Q-switched pulse can be formed only under the seeding condition. The advantage of the realized regime is in stable laser operation with no need in adjustment of the seeded light wavelength and the mode of the cavity. It is found that the frequency of the Q-switched laser radiation matches well to the injected seeded laser mode. By using two-stage amplifiers, an output energy better than 300 mJ has been achieved in MOPA configuration without active control of the cavity length and with pulse width adjustability from several nanoseconds to 20 ns. The Q-switched oscillator operates not only at precisely controlled firing time but also can be tuned over wide range. This will enable multi-laser systems synchronization and frequency locking down each other if necessary.

  12. The regeneration of thermal wound on mice skin (Mus Musculus) after Q-Switch Nd: YAG laser irradiation for cancer therapy candidate

    Science.gov (United States)

    Apsari, R.; Nahdliyatun, E.; Winarni, D.

    2017-09-01

    The aims of this study are to investigate the regeneration of mice skin tissue (Mus Musculus) irradiated by Q-Switch Nd: YAG laser and morphological change due to Q-Switch Nd: YAG laser irradiation compared to conventional heating (hairdryer). The 2-3 month of twenty-seven mice were used for experimental animals. Mice were incised in the dorsum by the damage effect of laser energy dose (therapeutic dose) of 29.5 J/cm2 with 10 seconds of exposure time, 10 Hz of repetition rate, and 100 pulses of the given single pulse energy. The mice skin tissue was injuried by hairdryer to get burned effect. Mice were divided into three groups, Group I (control) were not treated by anything, Group II were treated by Q-Switch Nd: YAG laser irradiation and sacrificed on (0, 1, 3, 5) days, and Group III were treated by hairdryer then sacrificed on (0, 1, 3, 5) days. Pathology examination showed that the energy of 29,5 J/cm2 dose produced the hole effect (ablation) through the hypodermic layer caused by optical breakdown and collagen coagulation. Thus, the 60 °C temperature of burn showed coagulation necrosis because piknosis discovered in the injured area. The regeneration process showed that the mice skin tissue's ability to regenerate was irradiated by fast laser because of the focus of Q-Switch Nd: YAG laser. It was showed by the scab releases on third day and completely reepithelialization formation on the fifth day. The collagen fibers distribution was same as normal skin tissue on day 5 and so did angiogenesis. Therefore, Q-Switch Nd: YAG laser can be applied for problems of dermatology medical therapies, especially melasma, nevus of ota and tatto therapy. For skin cancer therapy application, energy dose of unregenerated skin tissue is chosen because the death expected effect is permanent.

  13. Ablation of CdTe with 100 μs Nd:YAG laser pulses: dependence on target preparation method

    International Nuclear Information System (INIS)

    Rzeszutek, J.; Savchuk, V.; Oszwaldowski, M.

    2008-01-01

    The results of experimental studies of the ablation of CdTe with a pulsed Nd:YAG laser (wavelength 1064 nm) performed with 100 μs pulses and repetition time of 35 Hz are presented for the pulse energy range from 0.13 to 0.25 J. The main goal is to elucidate the dependence of the ablation process on the target preparation method. The investigation of the vapour stream intensity and chemical composition and their evolution with time are performed with a quadrupole mass spectrometer synchronized with the laser pulses. These studies are performed for three kinds of targets: a target made of CdTe bulk crystal (BC target), a target made of CdTe fine powder pressed under the pressure of 700 atm (PP target), and a target made of loose CdTe powder (N-PP target). The applicability of these targets for obtaining high quality CdTe thin films is determined. The best chemical composition of the vapour stream can be obtained with the BC target. A major drawback of this target is the energetic threshold for ablation with Nd:YAG laser and resulting delay in the ablation process above the threshold. The advantage of powder targets over BC target is the lack of any ablation threshold or delay. Weaker angular dependence of the particle emission (associated with the surface roughness), if confirmed in further experiments, can be the most important advantage of PP and N-PP targets. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  14. Long pulsed Nd: YAG laser with inbuilt cool sapphire tip for long term hair reduction on type- IV and V skin: A prospective analysis of 200 patients

    Directory of Open Access Journals (Sweden)

    Nanda Soni

    2010-01-01

    Full Text Available Background: Laser hair reduction has become a very popular means to get rid of unwanted hair. Aims: We conducted the current study to evaluate the safety and efficacy of Nd: YAG laser on dark skin. We also evaluated the effect of increasing the gap between sessions on the long term efficacy of hair reduction achieved with long pulsed Nd: YAG laser. Methods: A prospective study was conducted on 200 consecutive female patients who underwent laser hair reduction for unwanted hair over the face, at Kaya skin clinic Delhi, with long pulsed Nd: YAG laser, from May 2006 to May 2009. The gap between sessions was increased from 2 nd session itself. Results were evaluated 6 months after 6 sessions. Also a note was made of worsening of hair growth or any side effects experienced the patient during any of the sessions. Results: A total of 200 female patients (160 skin type IV and 40 skin type V were followed up. Of these, 64 enrolled for lower face, 88 for chin or upper neck and 48 for upper lip. 6 months after 6 sessions, more than 50% improvement was seen in 68.7% of lower face, 89.69% cases of chin and 59% of upper lip cases. None of the patients had any worsening. Conclusions: The current study shows that long pulsed Nd: YAG is a very safe and effective means of hair reduction in skin types IV and V. Adequate fluences and increasing the gap between sessions from the 2 nd session could be the key to achieving long term hair reduction with Nd: YAG laser. Adequate cooling and proper shaving are the key factors determining the safety.

  15. Low-Cost Real-Time Gas Monitoring Using a Laser Plasma Induced by a Third Harmonic Q-Switched Nd-YAG Laser

    Directory of Open Access Journals (Sweden)

    Syahrun Nur Abdulmadjid

    2005-11-01

    Full Text Available A gas plasma induced by a third harmonic Nd-YAG laser with relatively low pulsed energy (about 10 mJ has favorable characteristics for gas analysis due to its low background characteristics, nevertheless a high power fundamental Nd-YAG laser (100-200 mJ is widely used for laser gas breakdown spectroscopy. The air plasma can be used as a low-cost real-time gas monitoring system such that it can be used to detect the local absolute humidity, while a helium plasma can be used for gas analysis with a high level of sensitivity. A new technique using a helium plasma to improve laser ablation emission spectroscopy is proposed. Namely, the third harmonic Nd-YAG laser is focused at a point located some distance from the target in the 1-atm helium surrounding gas. By using this method, the ablated vapor from the target is excited through helium atoms in a metastable state in the helium plasma.

  16. Beam stability and warm-up effects of Nd:YAG lasers used in particle image velocimetry

    International Nuclear Information System (INIS)

    Grayson, K; De Silva, C M; Hutchins, N; Marusic, I

    2017-01-01

    The characteristics and causes of Nd:YAG laser warm-up transients and steady state beam stability effects are investigated in this study. Dynamic laser performance has a particularly noticeable impact on particle image velocimetry (PIV) and other laser-based flow visualisation techniques, where changes in beam pointing can influence the overlap between laser light sheets and thereby degrade the correlation of PIV image pairs. Despite anecdotal knowledge or experience of laser warm-up effects, they have not been formally documented or quantified to date for PIV applications. In this study, the nature of these laser transients are analysed and compared among a selection of typical PIV laser equipment. An investigation into the cause of these transients during the laser warm-up sequence is also presented. Furthermore, the degree of dual cavity transient coupling within a PIV laser system is analysed to determine a practical limit to the laser light sheet overlap that can be expected from PIV experiments. Finally, the results from this study inform a series of recommendations for PIV best practice, which aim to minimise the impact of laser transients on experimental data. (paper)

  17. Metallography of a pulsed Nd:YAG laser weld in a RS/PM Al-8Fe-2Mo alloy

    International Nuclear Information System (INIS)

    Krishnaswamy, S.; Baeslack, W.A. III

    1990-01-01

    This paper reports the microstructure of a pulsed Nd:YAG laser weld in a rapid solidification/powder metallurgy (RS/PM) Al-8.0 wt.% Fe-2.3 wt.% Mo (Al-8Fe-2Mo) alloy investigated using light microcopy, canning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. This analysis revealed significant microstructure variations across the weld fusion zone (FZ). Near the fusion boundary, a light-etching FZ microstructure was observed to contain submicron dispersoids entrapped in a matrix of fine-sized dendritic alpha aluminum. At the center of the FZ, the presence of relatively coarse-sized intermetallic particles that served as growth centers for coarser dendritic alpha aluminum promoted a dark-etching microstructure. In the boundary between successive melt zones, both a heat-affected zone (HAZ) containing acicular dispersoids and a fusion boundary region (FBR) containing irregular-shaped particles in a coarse-grained dendritic alpha aluminum matrix were observed

  18. Double-Arched LD Array Stagger Pumped Electro-Optic Q-Switched Nd:YAG Laser without Water Cooling

    International Nuclear Information System (INIS)

    Xin-Yu, Chen; Guang-Yong, Jin; Yong-Ji, Yu; Chao, Wang; Da-Wei, Hao; Yi-Bo, Wang

    2010-01-01

    We report an experimental study on a double-arched LD array stagger pumped electro-optic Q-switched Nd:YAG laser without water cooling by using a convex-concave compensate resonator. Perfect matching of the gain field inside the rod and the fundamental mode of the cavity is made by this structure. When the repetition rate is 20 Hz, A maximum output energy at 1064 nm wavelength of 176 mJ (M 2 = 1.55) and 9.6 ns FWHM pulse width in fundamental mode Q-switch operation is obtained with LD injection current 120 A. The optical-optical conversion efficiency is 14.7%, the divergence angle of the output beam is about 1.8 mrad. (fundamental areas of phenomenology(including applications))

  19. Photobiomodulation therapy on wound treatment subsequent to Q-switched Nd: YAG laser tattoo removal in rat model.

    Science.gov (United States)

    Imrigha, Nada Abusalah Almabrouk; Bidin, Noriah; Lau, Pik Suan; Musa, Nurfatin; Zakaria, Nurlaily; Krishnan, Ganesan

    2017-10-01

    Q-switched Nd: YAG laser is the most effective laser for tattoo removal. Photobiomodulation (PBM) therapy is an alternative method applied to accelerate the wound healing. This paper investigated the effects of PBM therapy using 808 nm diode laser on tattooed skin after laser tattoo removal. Forty-five rats were selected and tattooed with black ink on their dorsal, and then distributed into three groups. G0 was received non-laser irradiation. G1 was treated by laser tattoo removal using 1064 nm with energy density of 3.4 J/cm 2 without PBM therapy, while G2 was treated daily with PBM therapy using 808 nm diode laser of 5 J/cm 2 after a single session of laser tattoo removal. The effects of tattoo removal and healing progress of the wound were analyzed using histological studies. Findings showed 808 nm laser promotes the healing process through enhancing epithelialization and collagen deposition. Moreover, PBM therapy stimulated immune cells to improve phagocytosis process for removing the tattoo ink fragments effectively. The PBM therapy treated group was capable of improving the healing process and increasing the quality of skin following the laser tattoo removal. It was also found that stimulation of cellular function by PBM therapy increased tattoo clearance efficiency. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Development of an automation system for Iodine-125 brachytherapy seed encapsulated by Nd:YAG laser welding

    International Nuclear Information System (INIS)

    Somessari, S.L.; Feher, A.; Sprenger, F.E.; Rostelato, M.E.C.M.; Costa, F.E. da; Calvo, W.A.P.

    2011-01-01

    The aim of this work is to develop an automation system for iodine-125 radioactive seed production by Nd:YAG laser welding, which has been used successfully in low dose rate (LDR) brachytherapy treatment. This small seed consists of a welded titanium capsule, with 0.8 mm in diameter and 4.5 mm in length, containing iodine-125 adsorbed onto a silver rod. The iodine-125 seeds are implanted into the human prostate to irradiate the tumor for cancer treatment. Nowadays, the Radiation Technology Center, at Institute for Nuclear and Energy Research, Sao Paulo, Brazil (IPEN-CNEN/SP) imports and distributes 36,000 iodine-125 seeds per year, for the clinics and hospitals in the country. However, the Brazilian market potential is now over 8,000 iodine-125 seeds per month. The local production of these iodine-125 radioactive sources became a priority for the Institute, in order to reduce the price and the problems of prostate cancer management. It will permit to spread their use to a larger number of patients in Brazil. On the other hand, the industrial automation plays an important role for iodine-125 seeds in order to increase the productivity, with high quality and assurance, avoiding human factors, implementing and operating with good manufacturing practices (GMP). The technology consists of appliance electronic and electro-mechanical parts and components to control machines and processes. The automation system technology for iodine-125 seed production developed in this work was mainly assembled employing a programmable logic controller (PLC), a stepper motor, an Nd:YAG laser welding machine and a supervisory. The statistical repeatability of correctly encapsulated sealed sources with this automation system is greater than 95%. (authors)

  1. Densification behavior, doping profile and planar waveguide laser performance of the tape casting YAG/Nd:YAG/YAG ceramics

    Science.gov (United States)

    Ge, Lin; Li, Jiang; Qu, Haiyun; Wang, Juntao; Liu, Jiao; Dai, Jiawei; Zhou, Zhiwei; Liu, Binglong; Kou, Huamin; Shi, Yun; Wang, Zheng; Pan, Yubai; Gao, Qingsong; Guo, Jingkun

    2016-10-01

    The sintering behavior and doping concentration profile of the planar waveguide YAG/Nd:YAG/YAG ceramics by the tape casting and solid-state reaction method were investigated on the basis of densification trajectory, microstructure evolution, and Nd3+ ions diffusion. The porosity of the green body by tape casting and cold isostatic pressing is about 38.6%. And the green bodies were consolidated from 1100 °C to 1800 °C for 0.5-20 h to study the densification and the doping diffusion behaviors. At the temperature higher than 1500 °C, pure YAG phase is formed, followed by the densification and grain growth process. With the increase of temperature, two sintering stages occur, corresponding to remarkable densification and significant grain growth, respectively. The mechanism controlling densification at 1550 °C is grain boundary diffusion. The diffusion of Nd3+ ions is more sensitive to temperature than the sintering time, and the minimum temperature required for the obvious diffusion of Nd3+ ions is higher than 1700 °C. Finally, planar waveguide YAG/1.5 at.%Nd:YAG/YAG transparent ceramics with in-line transmittance of 84.8% at 1064 nm were obtained by vacuum-sintering at 1780 °C for 30 h. The fluorescence lifetime of 4F3/2 state of Nd3+ in the specimen is about 259 μs. The prepared ceramic waveguide was tested in a laser amplifier and the laser pulse was amplificated from 87 mJ to 238 mJ, with the pump energy of 680 mJ.

  2. Development of an automation system for iodine-125 brachytherapy seed production by ND:YAG laser welding

    International Nuclear Information System (INIS)

    Somessari, Samir L.; Feher, Anselmo; Sprenger, Francisco E.; Rostellato, Maria Elisa C.M.; Costa, Fabio E.; Calvo, Wilson A.P.

    2009-01-01

    The aim of this work is to develop an automation system for iodine-125 radioactive seed production by Nd:YAG laser welding, which has been used successfully in low dose rate brachytherapy treatment. This small seed consists of a welded titanium capsule, with 0.8 mm in diameter and 4.5 mm in length, containing iodine-125 adsorbed onto a silver rod. The iodine-125 seeds are implanted into the human prostate to irradiate the tumor for cancer treatment. Nowadays, the Radiation Technology Center, at IPEN-CNEN/SP imports and distributes 36,000 iodine-125 seeds per year, for the clinics and hospitals in the country. However, the Brazilian market potential is now over 8,000 iodine-125 seeds per month. The local production of these iodine-125 radioactive sources became a priority for the Institute, in order to reduce the price and the problems of prostate cancer management. It will permit to spread their use to a larger number of patients in Brazil. On the other hand, the industrial automation plays an important role for iodine-125 seeds in order to increase the productivity, with high quality and assurance, avoiding human factors, implementing and operating with good manufacturing practices. The technology consists of appliance electronic and electro-mechanical parts and components to control machines and processes. The automation system technology for iodine-125 seed production developed in this work was mainly assembled employing a Programmable Logic Controller, a stepper motor, an Nd:YAG laser welding machine and a supervisory. (author)

  3. Development of an automation system for iodine-125 brachytherapy seed production by (Nd:YAG) laser welding

    International Nuclear Information System (INIS)

    Somessari, Samir Luiz

    2010-01-01

    The aim of this work is to develop an automation system for iodine-125 radioactive seed production by (Nd:YAG) laser welding, which has been used successfully in Low Dose Rate (LDR) brachytherapy treatment. This small seed consists of a welded titanium capsule, with 0.8mm in diameter and 4.5mm in length, containing iodine-125 adsorbed onto a silver rod. The iodine-125 seeds are implanted into the human prostate to irradiate the tumor for cancer treatment. Nowadays, the Radiation Technology Center, at IPEN-CNEN/SP imports and distributes 36,000 iodine-125 seeds per year, for the clinics and hospitals in the country. However, the Brazilian market potential is now over 8,000 iodine-125 seeds per month. The local production of these iodine-125 radioactive sources becomes a priority for the Institute, in order to reduce the price and the problems of prostate cancer management. It will permit to spread their use to a largest number of patients in Brazil. On the other hand, the industrial automation plays an important role for iodine-125 seeds in order to increase the productivity, with high quality and assurance, avoiding human factors, implementing and operating with Good Manufacturing Practices (GMP). The technology consists of appliance electronic and electro-mechanical parts and components to control machines and processes. The automation system technology for iodine-125 seed production developed in this work was mainly assembled employing Programmable Logic Controller (PLC), stepper motors, drivers, (Nd:YAG) laser welding machine, photoelectric sensors and supervisory. (author)

  4. Stable TEM00-mode Nd:YAG solar laser operation by a twisted fused silica light-guide

    Science.gov (United States)

    Bouadjemine, R.; Liang, D.; Almeida, J.; Mehellou, S.; Vistas, C. R.; Kellou, A.; Guillot, E.

    2017-12-01

    To improve the output beam stability of a TEM00-mode solar-pumped laser, a twisted fused silica light-guide was used to achieve uniform pumping along a 3 mm diameter and 50 mm length Nd:YAG rod. The concentrated solar power at the focal spot of a primary parabolic mirror with 1.18 m2 effective collection area was efficiently coupled to the entrance aperture of a 2D-CPC/2V-shaped pump cavity, within which the thin laser rod was pumped. Optimum solar laser design parameters were found through ZEMAX© non-sequential ray-tracing and LASCAD© laser cavity analysis codes. 2.3 W continuous-wave TEM00-mode 1064 nm laser power was measured, corresponding to 1.96 W/m2 collection efficiency and 2.2 W laser beam brightness figure of merit. Excellent TEM00-mode laser beam profile at M2 ≤ 1.05 and very good output power stability of less than 1.6% were achieved. Heliostat orientation error dependent laser power variation was considerably less than previous solar laser pumping schemes.

  5. In vitro effect of Q-switched Nd:YAG laser exposure on morphology, hydroxyapatite composition and microhardness properties of human dentin

    Directory of Open Access Journals (Sweden)

    Retna Apsari

    2011-12-01

    Full Text Available Background: A Q-switched Nd:YAG laser was employed as a source of ablation. The fundamental wavelength of the laser is 1064 nm, with pulse duration of 8 nanosecond operates with uniphase mode of TEM00. In the following experiments, dentin samples (without caries and plaque are exposed to pulse laser with Q-switching effect at various energy dose. Purpose: The aim of this study was to investigate the effect of laser ablation on dentin samples using Q-switched Nd:YAG laser exposure. Methods: The laser was operated in repetitive mode with frequency of 10 Hz. The energy dose of the laser was ranging from 13.9 J/cm2, 21.2 J/cm2 and 41.7 J/cm2. The target material comprised of human dentin. The laser was exposed in one mode with Q-switched Nd:YAG laser. Energy delivered to the target through free beam technique. The exposed human dentin was examined by using x-ray diffraction (XRD and fluoresence scanning electron microscopy for energy dispersive (FESEM-EDAX. Microhardness of human dentin were examined by using microhardness vickers test (MVT. Results: The result obtained showed that the composition of hydroxyapatite of the dentin after exposed by Q-switched Nd:YAG laser are 75.02% to 78.21%, with microhardness of 38.7 kgf/mm2 to 86.6 kgf/mm2. This indicated that exposed pulsed Nd:YAG laser on the human dentin attributed to the phototermal effect. The power density created by the Q-switched Nd:YAG laser enables the heat to produce optical breakdown (melting and hole associated with plasma formation and shock wave propagation, from energy dose of 21.2 J/cm2. From XRD analysis showed that the exposure of Nd:YAG laser did not involve in changing the crystal structure of the dentin, but due to photoablation effect. Conclusion: In conclusion, the application of Q-switched Nd:YAG laser as contactless drills in dentistry should be regarded as an alternative to the classical mechanical technique to improve the quality of the dentin treatment.Latar belakang

  6. Perspectives of transurethral robotic laser resection of the prostate: vaporization and coagulation effects with the Nd:YAG laser

    Science.gov (United States)

    Ho, Gideon; Teo, Ming Y.; Kwoh, Chee K.; Ng, Wan S.; Cheng, Wai S.

    2000-05-01

    A longer operating time and steeper learning curve in mastering the techniques for transurethral laser resection of the prostate are the main problems faced by surgeons compared to standard transurethral resection of the prostate (TURP). However, these disadvantages can be solved with the introduction of a treatment modality designed and developed based on an integrated system of computer, robotics and laser technology. In vitro experiments were carried out to determine variables affecting the vaporization and coagulation lesions, in order to identify the parameters that could optimize this modality. Human cadaveric prostate and fresh chicken breast tissues were irradiated with different parameters using continuous wave Nd:YAG laser fiber in contact with the tissue. The effects of irrigant flowrate, fiber/tissue angle of inclination, number of passes, direction, speed and power of lase on the volume of tissue vaporized and coagulated, were assessed. A non-contact optical coordinate measuring machine was used to measure the depth and width of the vaporized and coagulated lesion. Results reveal that for each directional vaporization path (forward, clockwise and counter-clockwise), power and speed of lase are the most significant parameters influencing the volume of the vaporized and coagulated lesion. Optimized values of the power and speed of lase at 100 W and 1 - 3 mm/s respectively were obtained from the experiments when the tissues were irradiated in the forward, clockwise and counter-clockwise directions. It was concluded from our study to quantify tissue removal and damage, optimized values of irradiation power and speed could be obtained and implemented in the procedure of transurethral robotic laser resection of the prostate.

  7. Industrial applications of high-average power high-peak power nanosecond pulse duration Nd:YAG lasers

    Science.gov (United States)

    Harrison, Paul M.; Ellwi, Samir

    2009-02-01

    Within the vast range of laser materials processing applications, every type of successful commercial laser has been driven by a major industrial process. For high average power, high peak power, nanosecond pulse duration Nd:YAG DPSS lasers, the enabling process is high speed surface engineering. This includes applications such as thin film patterning and selective coating removal in markets such as the flat panel displays (FPD), solar and automotive industries. Applications such as these tend to require working spots that have uniform intensity distribution using specific shapes and dimensions, so a range of innovative beam delivery systems have been developed that convert the gaussian beam shape produced by the laser into a range of rectangular and/or shaped spots, as required by demands of each project. In this paper the authors will discuss the key parameters of this type of laser and examine why they are important for high speed surface engineering projects, and how they affect the underlying laser-material interaction and the removal mechanism. Several case studies will be considered in the FPD and solar markets, exploring the close link between the application, the key laser characteristics and the beam delivery system that link these together.

  8. Q-switched Nd:YAG/V:YAG microchip 1338 nm laser for laser-induced breakdown spectroscopy

    Science.gov (United States)

    Šulc, Jan; Jelínková, Helena; Nejezchleb, Karel; Škoda, Václav

    2017-12-01

    Q-switched microchip laser emitting radiation at wavelength 1338nm was tested as a radiation source for laser induced breakdown spectroscopy (LIBS). This laser used sandwich crystal which combined in one piece the cooling part (undoped YAG crystal 4mm long), the active laser part (Nd:YAG crystal 12mm long), and the saturable absorber (V:YAG crystal 0.7mm long). The diameter of this crystal was 5 mm. The microchip resonator consisted of dielectric mirrors directly deposited on the monolith crystal surfaces. The pump mirror (HT @ 808 nm, HR @ 1.3 ¹m) was placed on the undoped YAG part. The output coupler (R = 90% @ 1338 nm) was placed on the V:YAG part. The fibre-coupled 808nm pumping laser diode was operating in pulsed regime (rep. rate 250 Hz, pulse width 300 ¹s, pulse energy 6 mJ). Using this pumping, stable and high reproducible Q-switched pulses were generated at wavelength 1338 nm. Pulse length was 6.2 ns (FWHM) and the mean output power was 33mW. The single pulse energy and peak power was 0.13mJ and 21kW, respectively. Laser was operating in fundamental TEM00 mode. The laser radiation was focused on a tested sample using single plano-convex lens (focal length 75 mm). The focal spot radius was 40 ¹m. The corresponding peak-power density was 0.83GW/cm2. The laser induced break-down was successfully reached and corresponding laser-induced plasma spectra were recorded for set of metallic elements (Cu, Ag, Au, In, Zn, Al, Fe, Ni, Cr) and alloys (Sn-Pb solder, duralumin, stainless-steel, brass). To record the spectra, StellarNet BLACK-Comet concave grating CCD-based spectrometer was used without any special collimation optics. Thanks to used laser wavelength far from the detector sensitivity, no special filtering was needed to overcome the CCD dazzling. The constructed laser could significantly improve repletion-rate of up-to-date LIBS devices.

  9. Use of the 2-μm cw laser as addition and/or alternative for the Nd:YAG in urology

    Science.gov (United States)

    de Boorder, Tjeerd; Verdaasdonk, Rudolf; Lock, Tycho; Grimbergen, Matthijs; Klaessens, John

    2007-02-01

    Recently, 2 μm cw laser systems have been introduced for surgery. The 2 μm wavelength is predominantly absorbed by water and enables effective cutting and ablation of tissue similar to the cw CO II laser. In contrast to the CO II laser, the 2 μm wavelength is delivered through fiber optics and available for endoscopic procedures. After many years of experience with the 1.06 μm Nd:YAG laser, we started to use the 2 μm cw laser as alternative for various urological treatments. The treatments strategies and optimal settings were examined in the lab comparing the two 1.06 and 2 μm wavelengths performing thermal measurements. Consequently, the laser was applied for various urological cases. Penile tumors were resected with haemostatic effects and good aesthetic healing comparable with the Nd:YAG laser. Although the Nd:YAG has initially a deeper penetration, the blackening of the fiber during tissue cutting, provides a more superficial effect like the 2 μm laser. Bladder (pre)malignancies were ablated after biopsy. Only with higher stage tumors, coagulation depth of the Nd:YAG might be preferable for adequate treatment. Strictures in the urethra were incised and stents were effectively desobstructed: one patient with a stent implanted after a pelvic trauma, and one patient with catheterizable apedico stoma stenoses. The thermal damage during incision to deeper layers is minimal so recurrence due to scarring is not expected. Also hair grow in patients who underwent urethroplasty was effectively treated and scrotal atheromata cysts were effectively resected without recurrence. Laparoscopic nefrectomies are being considered using the 2 μm cw laser. The 2 μm cw laser has shown to be a versatile instrument for effective treatment of various urological indications. More patients and long term results are needed to prove the clinical significance compared to other treatment modalities

  10. Efficiency increase in solar-pumped Nd:YAG laser with a nonimaging concentrator; Taiyoko reiki Nd:YAG laser no kokoritsuka

    Energy Technology Data Exchange (ETDEWEB)

    Arashi, H.; Cooke, D.; Naito, H.; Katagiri, T. [Tohoku University, Sendai (Japan). Faculty of Engineering

    1994-12-08

    A solar pumped laser is reported, and the effect of the use of a CPC concentrator is experimentally investigated. In the experiment, a CPC corresponding to a 4 mm diameter 10 cm length laser rod is fabricated, and for collection of solar light a heliostat and a 10 m diameter, 3.2 m focal length parabolic mirror is employed. The experiment is performed in a time zone where energy of direct solar light is constant, i.e., at about 660 W/m{sup 2} and the maximum allowable angle of the CPC is at 53 degrees. Energy sent from the parabolic mirror is estimated to be 10.4 kW in total and is entirely collected on a 4 cm diameter focal flat plane. The utility of the energy is 0.13 % without the use of the CPC while being 0.46 with use of the CPC, and effective energy for use in the pumping is estimated to be 190 W, 670 W. As a result of the experiment, a laser output upon the use of the CPC is increased by 5 times, i.e., up to 10 W compared with 2 W without the use of the CPC. 2 figs., 1 tab.

  11. Study and development of 22 kW peak power fiber coupled short pulse Nd:YAG laser for cleaning applications

    Science.gov (United States)

    Choubey, Ambar; Vishwakarma, S. C.; Vachhani, D. M.; Singh, Ravindra; Misra, Pushkar; Jain, R. K.; Arya, R.; Upadhyaya, B. N.; Oak, S. M.

    2014-11-01

    Free running short pulse Nd:YAG laser of microsecond pulse duration and high peak power has a unique capability to ablate material from the surface without heat propagation into the bulk. Applications of short pulse Nd:YAG lasers include cleaning and restoration of marble, stones, and a variety of metals for conservation. A study on the development of high peak power short pulses from Nd:YAG laser along with its cleaning and conservation applications has been performed. A pulse energy of 1.25 J with 55 μs pulse duration and a maximum peak power of 22 kW has been achieved. Laser beam has an M2 value of ~28 and a pulse-to-pulse stability of ±2.5%. A lower value of M2 means a better beam quality of the laser in multimode operation. A top hat spatial profile of the laser beam was achieved at the exit end of 200 μm core diameter optical fiber, which is desirable for uniform cleaning. This laser system has been evaluated for efficient cleaning of surface contaminations on marble, zircaloy, and inconel materials for conservation with cleaning efficiency as high as 98%. Laser's cleaning quality and efficiency have been analysed by using a microscope, a scanning electron microscope (SEM), and X-ray photon spectroscopy (XPS) measurements.

  12. Bindi tattoo on forehead: success with modified R-20 technique using low fluence q-switched nd yag laser: a case report.

    Science.gov (United States)

    Zawar, Vijay; Sarda, Aarti; De, Abhishek

    2014-01-01

    Bindi tattoo on the forehead, is one of the cultural practice in Indian women from rural areas. Many patients are not pleased with the appearance of their tattoo and thus seek removal. The development of quality-switched lasers has revolutionized the removal of unwanted tattoos. However, despite multiple treatment sessions, the efficacy is often found to be limited. We herein report a case of green-blue bindi tattoo which failed to clear after 8 sessions of Q-switched Nd YAG laser. The tattoo significantly cleared with R-20 method using low fluence Q-switched Nd YAG Laser. R-20 technique seems to be an effective method of tattoo removal and might be a boon for patients who are reluctant to pursue laser treatment because of fear of expenditure, side effects and uncertainty of result. We report efficacy of R-20 technique for a bindi tattoo on forehead.

  13. Chemical composition of dome-shaped structures grown on titanium by multi-pulse Nd:YAG laser irradiation

    International Nuclear Information System (INIS)

    Gyoergy, E.; Perez del Pino, A.; Serra, P.; Morenza, J.L.

    2004-01-01

    The specific dome-shaped structures were grown by multi-pulse Nd:YAG (λ=1.064 μm, τ=∼300 ns, and ν=30 kHz) laser irradiation of titanium targets in air at atmospheric pressure. The laser intensity values were chosen below the single-laser-pulse melting threshold of titanium. The chemical composition of the structures was studied as a function of laser pulse number as well as laser intensity, both at the outer surface layer and in depth. Micro-Raman spectroscopy, Auger electron spectroscopy (AES), and wavelength dispersive X-ray spectroscopy (WDX) were used as diagnostic techniques. Morphological investigations were performed by scanning electron microscopy. The obtained results revealed a lower oxygen concentration in the centre of the structures as compared to the borders and a lower concentration on the surface than in the depth. Moreover, it was found that the stoichiometry of the formed TiO 2-x oxides increases from the structures centre towards the border and from the surface towards the depth

  14. An in vitro study of the Nd-YAG laser in the permeability of the cervical dentin; Estudo in vitro do uso do laser Nd-YAG na permeabilidade dentinaria cervical

    Energy Technology Data Exchange (ETDEWEB)

    Magalhaes, Manoelita Figueiredo de

    2001-07-01

    The purpose of this in vitro study was to verify the efficacy of the Nd:YAG pulse laser, with 1064 nm emission, in sealing the dentinal tubules for the treatment of dentin hypersensitivity, a very frequent complaint in the dental office. In spite of the existence of many articles over this subject, no fast, efficient and long lasting treatments for this problem were found yet. The obliteration of the opening of the dentinal tubules stops its inner fluid displacement and the consequent painful response (BRAENNSTROEM' S Hydrodynamics Theory). Twenty freshly and healthy extracted human teeth were used as samples, kept in saline solution. The cervical cement was removed with a 57FG Carbide bur in order to expose the dentin in an area of approximately 4 mm{sup 2}, two of which were in the buccal aspect: Groups A and S, and one in the lingual: Group C (control). A thickness plier was used to measure, directly in each sample, the thickness of the remaining dentin that was standardized, and only the samples with dentinal thickness between 1 and 1,5 mm were selected. The irradiation parameters were: 30 mJ energy per pulse; O,21 W power (Group A) and 40 mJ; O,28 W (Group B); 7 Hz frequency in both groups, in two applications of 43 seconds each with a 10 seconds interval between them. Subsequently, 10 of the samples were submitted to SEM (Screening Electronic Microscopy) examination, where it was detected a melting of the superficial dentin and a sealing of the dentinal tubules opening, besides the recrystallization of the dentin. It was then concluded that the use of the Nd:YAG laser was shown to be a very effective measure in melting and sealing the dentinal tubules and can use in treating dentin hypersensitivity, with the right parameters. The other 10 samples were cleaved in the center of the irradiated area in order to investigate the laser penetration depth in the dentin (SEM), with an approximate variation of up to 5Jlm in the center of the samples irradiated with

  15. An in vitro study of the Nd-YAG laser in the permeability of the cervical dentin; Estudo in vitro do uso do laser Nd-YAG na permeabilidade dentinaria cervical

    Energy Technology Data Exchange (ETDEWEB)

    Magalhaes, Manoelita Figueiredo de

    2001-07-01

    The purpose of this in vitro study was to verify the efficacy of the Nd:YAG pulse laser, with 1064 nm emission, in sealing the dentinal tubules for the treatment of dentin hypersensitivity, a very frequent complaint in the dental office. In spite of the existence of many articles over this subject, no fast, efficient and long lasting treatments for this problem were found yet. The obliteration of the opening of the dentinal tubules stops its inner fluid displacement and the consequent painful response (BRAENNSTROEM' S Hydrodynamics Theory). Twenty freshly and healthy extracted human teeth were used as samples, kept in saline solution. The cervical cement was removed with a 57FG Carbide bur in order to expose the dentin in an area of approximately 4 mm{sup 2}, two of which were in the buccal aspect: Groups A and S, and one in the lingual: Group C (control). A thickness plier was used to measure, directly in each sample, the thickness of the remaining dentin that was standardized, and only the samples with dentinal thickness between 1 and 1,5 mm were selected. The irradiation parameters were: 30 mJ energy per pulse; O,21 W power (Group A) and 40 mJ; O,28 W (Group B); 7 Hz frequency in both groups, in two applications of 43 seconds each with a 10 seconds interval between them. Subsequently, 10 of the samples were submitted to SEM (Screening Electronic Microscopy) examination, where it was detected a melting of the superficial dentin and a sealing of the dentinal tubules opening, besides the recrystallization of the dentin. It was then concluded that the use of the Nd:YAG laser was shown to be a very effective measure in melting and sealing the dentinal tubules and can use in treating dentin hypersensitivity, with the right parameters. The other 10 samples were cleaved in the center of the irradiated area in order to investigate the laser penetration depth in the dentin (SEM), with an approximate variation of up to 5Jlm in the center of the samples irradiated with the

  16. The possibility of clinical application of the solid state lasers: Nd:YAG, Ho:YAG, and Er:YAG in otolaryngology - head and neck surgery

    Science.gov (United States)

    Tomaszewska, M.; Kukwa, A.; Tulibacki, M.; Wójtowicz, P.; Olędzka, I.; Jeżewska, E.

    2007-02-01

    The purpose of this study was to summarize our experiences in clinical application of Nd:YAG, Ho:YAG and Er:YAG in otolaryngology- head and neck surgery. Choosing the laser type and parameters for the particular procedures was based on our previous research on tissue effects of those lasers. During the period of 1993-2006 we performed 3988 surgical procedures with the Nd:YAG laser. Over 87% of those were made for the nasal cavity pathologies as polyps, hyperplasia of inferior nasal turbinate, granulation tissue, postoperative adhesions, vascular malformations, under the local anesthesia conditions. In our experience Nd:YAG laser gives the possibility of good clinical control and low risk of side effects for disorders of high recurrence and frequent interventions necessity, as nasal polyps or respiratory papillomatosis. Nd:YAG assisted uvulopalatoplasty gives an interesting alternative for surgical procedures for snoring and slight/mild OSA-recognized patients. Due to its good hemostatic properties, it is a perfect tool for removal of the chemodectoma from meddle ear. During the period of 1995-2006 we performed 229 surgical procedures with the Ho:YAG laser, mostly for larynx pathologies (adhesion and scar tissue removal). In our experience Ho:YAG laser can serve as a precise laser knife for both soft and bony tissue. The ER:YAG laser still remain under clinical trial. Since 2001 year we performed 24 procedures of removing stone deposits from salivary glands. We believe it may become a promising method to cope with sialolithiasis which allows for glandule function preservation. All of the laser types mentioned above, can be easily coupled with endoscopes, what makes them available for all of the head and necklocalized disorders.

  17. Laser reduction of specific microorganisms in the periodontal pocket using Er:YAG and Nd:YAG lasers: a randomized controlled clinical study.

    Science.gov (United States)

    Grzech-Leśniak, K; Sculean, A; Gašpirc, Boris

    2018-05-15

    The objective of this study was to evaluate the microbiological and clinical outcomes following nonsurgical treatment by either scaling and root planing, combination of Nd:YAG and Er:YAG lasers, or by Er:YAG laser treatment alone. The study involved 60 patients with generalized chronic periodontitis, randomly assigned into one of three treatment groups of 20 patients. The first group received scaling and root planing by hand instruments (SRP group), the second group received Er:YAG laser treatment alone (Er group), and the third group received combined treatment with Nd:YAG and Er:YAG lasers (NdErNd group). Microbiological samples, taken from the periodontal pockets at baseline and 6 months after treatments, were assessed with PET Plus tests. The combined NdErNd laser (93.0%), followed closely by Er:YAG laser (84.9%), treatment resulted in the highest reduction of all bacteria count after 6 months, whereas SRP (46.2%) failed to reduce Treponema denticola, Peptostreptococcus micros, and Capnocytophaga gingivalis. Full-mouth plaque and bleeding on probing scores dropped after 6 months and were the lowest in both laser groups. The combination of NdErNd resulted in higher probing pocket depth reduction and gain of clinical attachment level (1.99 ± 0.23 mm) compared to SRP (0.86 ± 0.13 mm) or Er:YAG laser alone (0.93 ± 0.20 mm) in 4-6 mm-deep pockets. Within their limits, the present results provide support for the combination of Nd:YAG and Er:YAG lasers to additionally improve the microbiological and clinical outcomes of nonsurgical periodontal therapy in patients with moderate to severe chronic periodontitis.

  18. Removal of Verrucaria nigrescens from Carrara marble artefacts using Nd:YAG lasers: comparison among different pulse durations and wavelengths

    Science.gov (United States)

    Osticioli, I.; Mascalchi, M.; Pinna, D.; Siano, S.

    2015-03-01

    The periodical removal of biodeteriogens is a fundamental need for the preservation of outdoor stone cultural heritage, which is stimulating significant efforts toward the development of low-impact conservation strategies. In the present work, the potential of laser removal of Verrucaria nigrescens Pers. from Carrara marble and the evaluation of the associated biocide effect on the organism residues embedded in the surface texture and through the outer porosities of the stone substrate were investigated. The fundamental wavelength of Nd:YAG laser (1,064 nm), commonly used in stone cleaning, and its second harmonic (532 nm) were comparatively tested. The phenomenology of laser treatments carried out in different irradiation conditions was characterized using optical, epifluorescence, and electron microscopes along with chlorophyll fluorescence with pulsed amplitude-modulated imaging. The results achieved show that 532 nm can provide significant advantages with respect to 1,064 nm. The potential of the latter against the biodeteriogens appears rather limited because of the low optical absorption, whereas the former can allow effective and practicable laser treatments, which disclose a significant application perspective.

  19. Effects of the Nd:YAG laser on DNA synthesis and collagen production in human skin fibroblast cultures

    Energy Technology Data Exchange (ETDEWEB)

    Castro, D.J.; Abergel, R.P.; Meeker, C.; Dwyer, R.M.; Lesavoy, M.A.; Uitto, J.

    1983-09-01

    Human skin fibroblasts were subjected to treatment with a Neodymium:YAG laser at 1060 nm with varying levels of energy determined by a reproducible method of dosimetry. DNA synthesis in the cells was measured by the incorporation of (3H)thymidine, and collagen production was monitored by the synthesis of nondialyzable (3H)hydroxyproline after incubation of cells with (3H)proline. Using energy levels equal to 1.7 X 10(3) J/cm2, a significant reduction in DNA synthesis was noted, while the cells remained viable as tested by the trypan blue exclusion test. With energy levels higher or equal to 2.3 X 10(3) J/cm2, the suppression of DNA synthesis was accompanied by cell nonviability. The collagen production, when measured immediately following the treatment with 1.7 X 10(3) J/cm2, was markedly reduced, and similar effects were observed with higher energy levels. However, when the cells were tested for collagen production at 20 hours following laser treatment, there was a significant decrease in collagen production at energy levels as low as 1.1 X 10(3) J/cm2, a dose that did not affect DNA synthesis or cell viability. Thus, the results indicate that the Nd:YAG laser can selectively suppress collagen production without affecting cell proliferation. These observations suggest that laser treatment could potentially be used to reduce collagen deposition in conditions such as keloids and hypertrophic scars.

  20. High speed ink aggregates are ejected from tattoos during Q-switched Nd:YAG laser treatments.

    Science.gov (United States)

    Murphy, Michael J

    2018-03-25

    Dark material has been observed embedded within glass slides following Q-switched Nd:YAG laser treatment of tattoos. It appears that these fragments are ejected at high speed from the skin during the treatment. Light microscopic analysis of the slides reveals aggregates of dark fragmented material, presumably tattoo ink, with evidence of fractured/melted glass. Photomicrographs reveal that the sizes of these aggregates are in the range 12 μm to 0.5 mm. Tattoo ink fragments were clearly observed on the surface and embedded within glass slides. Surface aggregates were observed as a fine dust and were easily washed off while deeper fragments remained in situ. The embedded fragments were not visible to the unaided eye. Some fragments appeared to have melted yielding an "insect-like" appearance. These were found to be located between approximately 0.2 and 1 mm deep in the glass. Given the particle masses and kinetic energies attained by some of these aggregates their velocities, when leaving the skin, may be hundreds to thousands of metres per second. However, the masses of the aggregates are minuscule meaning that laser operators may be subjected to these high-speed aggregates without their knowledge. These high-speed fragments of ink may pose a contamination risk to laser operators. Lasers Surg. Med. 9999:1-7, 2018. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

  1. Low-threshold ablation of enamel and dentin using Nd:YAG laser assisted with chromophore with different pulse shapes

    Science.gov (United States)

    Bonora, Stefano; Benazzato, Paolo; Stefani, Alessandro; Villoresi, Paolo

    2004-05-01

    Neodimium laser treatment has several drawbacks when used in the hard tissue cutting, because of the low absorption of the dental tissues at its wavelength. This investigation proved that the Nd:YAG radiation is a powerful ablation tool if it is used with the dye assisted method. Several in vitro tests on enamel and dentin were accomplished changing some laser parameters to have different pulse shapes and durations from 125μs up to 1.4ms. The importance of short time high power peaks, typical of crystal lasers, in the ablation process was investigated. The pulse shapes were analyzed by their intensity in space and time profiles. A first set of results found the optimum dye concentration be used in all the following tests. Furthermore the ablation threshold for this technique was found for each different pulse shapes and durations. A low energy ablation method was found to avoid temperature increase and surface cracks formation. In vitro temperature analysis was reported comparing the differences between no dye application laser treatment and with a dye spray applied. A strong reduction of the temperature increase was found in the dye assisted method. A discussion on the general findings and their possible clinical applications is presented.

  2. A Visualization Method for Corrosion Damage on Aluminum Plates Using an Nd:YAG Pulsed Laser Scanning System.

    Science.gov (United States)

    Lee, Inbok; Zhang, Aoqi; Lee, Changgil; Park, Seunghee

    2016-12-16

    This paper proposes a non-contact nondestructive evaluation (NDE) technique that uses laser-induced ultrasonic waves to visualize corrosion damage in aluminum alloy plate structures. The non-contact, pulsed-laser ultrasonic measurement system generates ultrasonic waves using a galvanometer-based Q-switched Nd:YAG laser and measures the ultrasonic waves using a piezoelectric (PZT) sensor. During scanning, a wavefield can be acquired by changing the excitation location of the laser point and measuring waves using the PZT sensor. The corrosion damage can be detected in the wavefield snapshots using the scattering characteristics of the waves that encounter corrosion. The structural damage is visualized by calculating the logarithmic values of the root mean square (RMS), with a weighting parameter to compensate for the attenuation caused by geometrical spreading and dispersion of the waves. An intact specimen is used to conduct a comparison with corrosion at different depths and sizes in other specimens. Both sides of the plate are scanned with the same scanning area to observe the effect of the location where corrosion has formed. The results show that the damage can be successfully visualized for almost all cases using the RMS-based functions, whether it formed on the front or back side. Also, the system is confirmed to have distinguished corroded areas at different depths.

  3. Studies of diode-pumped solid-state lasers based on Nd:KGW and Nd:YAG

    International Nuclear Information System (INIS)

    Ibrahim, Akram Yousif

    1996-01-01

    The experimental part of the thesis was dedicated to the studies of diode-pumped solid- state lasers. it includes experiments with end-pumped continuous wave (CW) Nd-doped crystals. In particular, we have concentrated to Nd:KGW, a relatively new and not studied in the literature about the laser materials. We have performed some basics measurements of this material. A fibre bundle coupled laser diode array was used as a pump source. We have investigated two main optical arrangements for the pump, allowing operation in two regimes: 1- Low pump power operation using selected output power from a single of the fibre bundle. 2- high pump power operation using the total output power from the bundle. The main parameters of the cavities we use (e.g. the cavity mode and the pumping spot size), were determined using the matrix approach and the equations for the propagation of the Gaussian beams. The highest output power obtained in this work for Nd:KGW with a transverse electromagnetic (TEM 0 0) single-mode, continuous (CW) operation, was 400 mW for 1700 mW pumping power from the diode laser. We present also data about the performance of a diode pumped Nd:YAG crystal. Our experiment shows that Nd:KGW is a promising material of low and medium pumping power levels. (Author)

  4. Thermal analysis of different application techniques on Nd:YAG laser after root canal preparation of single-rooted teeth

    International Nuclear Information System (INIS)

    Archilla, Jose Ricardo de F.

    2001-01-01

    The experiment objective is to analyze temperature variation, by means of three different application techniques of Nd:YAG laser in the root canals of singlerooted anterior teeth. Three root canals were instrumented, irrigated, X-rayed to measure the remaining dentin in the apical area and submitted to laser irradiation techniques used by Gutknecht, Matsumoto and a new technique with oscillatory movement. The used laser parameters were: pulse energy 250 mJ, frequency 5 Hz, pulse fluency 354 J/cm 2 , average potency 1,25 W, pulse width 300 μs, fiber core diameter 300 μs and interval of thermal relaxation of 20 s. After temperature evaluation and interpretation of the obtained data, it was concluded: 1) the oscillatory technique provided a better heat distribution during the laser application, when analyzing the graphs separately; 2) all the used techniques are within a pattern of safety, analyzing the average and highest temperatures of the apical area and the middle third, even so, disrespecting the last application day and the middle third of root 'C'.(author)

  5. Compact Nd:YAG laser operating at 1.06, 1.32, and 1.44 μm for dental caries effective disinfection

    Science.gov (United States)

    Dostálová, Tat'jana; Jelínková, Helena; Kadlecová, Martina; Němec, Michal; Å ulc, Jan; Fibrich, Martin; Nejezchleb, Karel; Kapitch, Nickalai; Å koda, Václav

    2017-02-01

    The analysis of the disinfection effect of Nd:YAG laser radiation was investigated for patients with high concentration of Streptococcus mutans in saliva (positive result in Saliva-check mutans test). For the interaction the Nd:YAG laser system generated separate switchable wavelengths with the maximum output energies 1.1, 0.6, and 0.3 J for wavelength 1.06 μm, 1.32, μm and 1.44 μm, respectively, was used. Our study proved that after the laser irradiation the Saliva-check test showed negative presence of Streptococcus mutans. The disinfection effect was confirmed for all used radiation wavelength. For 1.44 μm this effect was reached with a smallest energy density.

  6. Nd:YAG laser irradiation on temporary teeth carious tissue using 12% diamine silver fluoride as a photo-absorber - a morphological study

    International Nuclear Information System (INIS)

    Calmon, Andrea de Avillez

    2001-01-01

    Since Nd:YAG laser radiation was first introduced in Dentistry various photo-absorbers were employed with the intent of improving its efficacy when used on dental carious tissue. The purpose of the present study was to analyze the influence of this radiation using Scanning and Optical microscopy over carious tissue of primary teeth using two photo-absorbers. 15 primary human teeth were used and, in each one, 3 cavity preparations were performed. Specimens were then submitted to an in vitro demineralizing environment during 18 days. Two of the cavities of each specimen were laser irradiated using the Nd:YAG laser with 60 mJ of energy per pulse, 10 Hz and average power of 0,6 W. The 12% diamine silver fluoride or the mineral coal were used as photo-absorbers. The third cavity of the specimens was used as a control and received no laser irradiation. Samples were transversally cut and the section analyzed by SEM and OM. Results showed that the 12% diamine silver fluoride is an efficient photo-absorber and, when used it the Nd:YAG laser, leading to melting and resolidification of the carious tissue. It can be concluded that the 12% diammine silver fluoride presents advantages over the mineral coal as a photo absorber when used in primary teeth as it promotes and improves the efficacy of laser irradiation. This substance also works as a barrier on the carie progression in deeper areas such as the infected and necrotic zones. (author)

  7. Bullet Design and Fabrication of Dual Mode Pyroelectric Sensor: High Sensitive Energymeter for Nd: YAG Laser and Detector for Chopped He-Ne Laser

    Directory of Open Access Journals (Sweden)

    S. SATAPATHY

    2008-05-01

    Full Text Available Pyroelectric sensor using TGS has been designed and fabricated which can be operated in laser energy meter mode as well as pyroelectric detector mode. The amplifying circuit configuration has very good signal to noise ratio, very high input impedance and low drift. The pyroelectric sensor has been tested using Q-switched Nd: YAG laser and chopped He-Ne laser. The sensitivity of pyroelectric sensor in energymeter mode is 421.7V/J and the voltage responsivity of the pyroelectric sensor is 3.27 V/W in detector mode.

  8. UV laser micromachining of piezoelectric ceramic using a pulsed Nd:YAG laser

    International Nuclear Information System (INIS)

    Zeng, D.W.; Xie, C.S.; Li, K.; Chan, H.L.W.; Choy, C.L.; Yung, K.C.

    2004-01-01

    UV laser (λ=355 nm) ablation of piezoelectric lead zirconate titanate (PZT) ceramics in air has been investigated under different laser parameters. It has been found that there is a critical pulse number (N=750). When the pulse number is smaller than the critical value, the ablation rate decreases with increasing pulse number. Beyond the critical value, the ablation rate becomes constant. The ablation rate and concentrations of O, Zr and Ti on the ablated surface increase with the laser fluence, while the Pb concentration decreases due to the selective evaporation of PbO. The loss of the Pb results in the formation of a metastable pyrochlore phase. ZrO 2 was detected by XPS in the ablated zone. Also, the concentrations of the pyrochlore phase and ZrO 2 increase with increasing laser fluence. These results clearly indicate that the chemical composition and phase structure in the ablated zone strongly depend on the laser fluence. The piezoelectric properties of the cut PZT ceramic samples completely disappear due to the loss of the Pb and the existence of the pyrochlore phase. After these samples were annealed at 1150 C for 1 h in a PbO-controlled atmosphere, their phase structure and piezoelectric properties were recovered again. Finally, 1-3 and concentric-ring 2-2 PZT/epoxy composites were fabricated by UV laser micromachining and their thickness modes were measured by impedance spectrum analysis and a d 33 meter. Both composites show high piezoelectric properties. (orig.)

  9. An in vitro study of the Nd-YAG laser in the permeability of the cervical dentin

    International Nuclear Information System (INIS)

    Magalhaes, Manoelita Figueiredo de

    2001-01-01

    The purpose of this in vitro study was to verify the efficacy of the Nd:YAG pulse laser, with 1064 nm emission, in sealing the dentinal tubules for the treatment of dentin hypersensitivity, a very frequent complaint in the dental office. In spite of the existence of many articles over this subject, no fast, efficient and long lasting treatments for this problem were found yet. The obliteration of the opening of the dentinal tubules stops its inner fluid displacement and the consequent painful response (BRAENNSTROEM' S Hydrodynamics Theory). Twenty freshly and healthy extracted human teeth were used as samples, kept in saline solution. The cervical cement was removed with a 57FG Carbide bur in order to expose the dentin in an area of approximately 4 mm 2 , two of which were in the buccal aspect: Groups A and S, and one in the lingual: Group C (control). A thickness plier was used to measure, directly in each sample, the thickness of the remaining dentin that was standardized, and only the samples with dentinal thickness between 1 and 1,5 mm were selected. The irradiation parameters were: 30 mJ energy per pulse; O,21 W power (Group A) and 40 mJ; O,28 W (Group B); 7 Hz frequency in both groups, in two applications of 43 seconds each with a 10 seconds interval between them. Subsequently, 10 of the samples were submitted to SEM (Screening Electronic Microscopy) examination, where it was detected a melting of the superficial dentin and a sealing of the dentinal tubules opening, besides the recrystallization of the dentin. It was then concluded that the use of the Nd:YAG laser was shown to be a very effective measure in melting and sealing the dentinal tubules and can use in treating dentin hypersensitivity, with the right parameters. The other 10 samples were cleaved in the center of the irradiated area in order to investigate the laser penetration depth in the dentin (SEM), with an approximate variation of up to 5Jlm in the center of the samples irradiated with the

  10. Surface morphology study on chromium oxide growth on Cr films by Nd-YAG laser oxidation process

    International Nuclear Information System (INIS)

    Dong Qizhi; Hu Jiandong; Guo Zuoxing; Lian Jianshe; Chen Jiwei; Chen Bo

    2002-01-01

    Grain sized (60-100 nm) Cr 2 O 3 thin films were prepared on Cr thin film surfaces by Nd-YAG laser photothermal oxidation process. Surface morphology study showed crack-free short plateau-like oxide films formed. Increase of dislocation density after pulsed laser irradiation was found. Thin film external surfaces, grain boundaries and dislocations are main paths of laser surface oxidation. Pinning and sealing of grain boundary was the reason that deeper oxidation did not produce. Grain growth and agglomeration of Cr sub-layer yielded tensile stress on the surface Cr 2 O 3 thin film. It was the reason that short plateau-like surface morphology formed and cracks appeared sometimes. In oxygen annealing at 700 deg. C, grain boundaries were considered not to be pinned at the surface, mixture diffusion was main mechanism in growth of oxide. Compression stress development in whole film led to extrusion of grains that was the reason that multiple appearances such as pyramid-like and nutshell-like morphology formed

  11. Darkening effect on AZ31B magnesium alloy surface induced by nanosecond pulse Nd:YAG laser

    Energy Technology Data Exchange (ETDEWEB)

    Guan, Y.C., E-mail: guan0013@e.ntu.edu.sg [School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, Singapore 638075 (Singapore); Zhou, W. [School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, Singapore 638075 (Singapore); Zheng, H.Y.; Li, Z.L. [Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, Singapore 638075 (Singapore)

    2013-09-01

    Permanent darkening effect was achieved on surface of AZ31B Mg alloy irradiated with nanosecond pulse Nd:YAG laser, and special attention was made to examine how surface structure as well as oxidation affect the darkening effect. Experiments were carried out to characterize morphological evolution and chemical composition of the irradiated areas by optical reflection spectrometer, Talysurf surface profiler, SEM, EDS, and XPS. The darkening effect was found to be occurred at the surface under high laser energy. Optical spectra showed that the induced darkening surface was uniform over the spectral range from 200 nm to 1100 nm. SEM and surface profiler showed that surface morphology of darkening areas consisted of large number of micron scale cauliflower-like clusters and protruding particles. EDS and XPS showed that compared to non-irradiated area, oxygen content at the darkening areas increased significantly. It was proposed a mechanism that involved trapping of light in the surface morphology and chemistry variation of irradiated areas to explain the laser-induced darkening effect on AZ31B Mg alloy.

  12. Effects of different black mediators on the shear strength of orthodontic bracket to the enamel treated with Nd-Yag laser

    Science.gov (United States)

    Huang, Shun-Te; Lin, I.-Shueng; Tsai, Chi-Cheng

    1995-04-01

    The Nd:YAG laser has ablation, crack, and crater effects on the dental enamel through black mediators which are very similar to the acid etching effects of phosphoric acid. This study was designed for searching how the different black mediators influence the shear strengths of the brackets bound to the enamel surfaces which were treated with the Nd:YAG laser. 90 bovine enamels divided into 5 groups were painted with 5 kinds of black mediators including Chinese ink, oil ink, black ball pen, water ink and black transfer paper. The enamel surfaces painted with black mediators were then radiated by Nd:YAG laser (ADL; American Dental Laser 300dl, power: 20 pps, 87.5 mj). Orthodontic brackets were bonded to the radiated surfaces. Then the shear strengths of the brackets to the enamels were measured by Instron. The results showed that the Chinese ink group and oil ink group has the strongest shear strength, ball pen group and water ink group showed the second strength, and the transfer paper group has the lowest shear strength. In addition, scanning electronic microscope also was used to observe the topographic changes of the enamel surfaces induced by the laser ablation.

  13. Comparison between pulsed Nd:YAG laser superficial treatment and ceramic coating in creep test of Ti-6Al-4V alloy

    International Nuclear Information System (INIS)

    Reis, A.G.; Reis, D.A.P.; Moura Neto, C.; Oliveira, H.S.; Couto, A.A.

    2009-01-01

    The objective of this work was evaluating the creep resistance of the Ti-6Al-4V alloy with superficial treatment of pulsed Nd:YAG laser and ceramic coating in creep test of Ti-6Al-4V alloy. It was used Ti-6Al-4V alloy as cylindrical bars under forged and annealing of 190 deg C by 6 hours condition and cooled by air. The Ti-6Al-4V alloy after the superficial treatment of pulsed Nd:YAG laser and ceramic coating was submitted to creep tests at 600°C and 125 at 319 MPa, under constant load mode. In the Nd:YAG pulsed laser treatment was used an environment of 40 % N and 60 % Ar, with 2.1 W of power and 10 m/s of speed. Yttria (8 wt.%) stabilized zirconia (YSZ) with a CoNiCrAlY bond coat was atmospherically plasma sprayed on Ti-6Al-4V substrates by Sulzer Metco Type 9 MB. The obtained results suggest the laser treatment on Ti-6Al-4V alloy improved its creep resistance. (author)

  14. Efficient second harmonic generation of a diode-laser-pumped CW Nd:YAG laser using monolithic MgO:LiNbO3 external resonant cavities

    Science.gov (United States)

    Kozlovsky, William J.; Nabors, C. D.; Byer, Robert L.

    1988-01-01

    56-percent efficient external-cavity-resonant second-harmonic generation of a diode-laser pumped, CW single-axial-mode Nd:YAG laser is reported. A theory of external doubling with a resonant fundamental is presented and compared to experimental results for three monolithic cavities of nonlinear MgO:LiNbO3. The best conversion efficiency was obtained with a 12.5-mm-long monolithic ring cavity doubler, which produced 29.7 mW of CW, single-axial model 532-nm radiation from an input of 52.5 mW.

  15. Irradiation of root cervical dentin by using the Nd:YAG laser in vitro study and scanning electron microscopy

    International Nuclear Information System (INIS)

    Britto, Cynthia Tannure Coelho

    2003-01-01

    The dentin hypersensitivity occurs as a result of the dentine exposition to the oral environment, due to loss or removal of enamel or cementum, or both. The hypersensitivity can persist, unless the sealing of the dentin tubules be carried out. Several treatments have been considered, but with less satisfactory and only temporary results. Among these treatments we can cite methods that promote the mechanical occlusion by deposition of substances inside of tubules, by topic application. Nowadays, among the treatments studied, there is the use of lasers, which leads to better clinical efficiency by promoting fusion and re-solidification of the dentin surface, obliterating total or partially the dentin tubules. This in-vitro study was carried out in order to evaluate the efficiency of the Nd:YAG laser in promoting the fusion and re-solidification of the dentin surface, and to evaluate parameters of irradiation typically used, comparing results using photoinitiator with those without it. By observation of the dentin surface, using Scanning Electron Microscopy, it was found extensive areas of fusion and re-solidification, in those groups with photoinitiator, being this technique an efficient resource in the treatment of the dentin hypersensitivity. (author)

  16. Modificación superficial de aceros y hierros fundidos mediante láser de Nd: YAG. // Steels and cast irons superficial modification by means of laser Nd: YAG.

    Directory of Open Access Journals (Sweden)

    R. Sagaró Z.

    2001-10-01

    Full Text Available Se presentan los resultados de los autores en el tratamiento térmico superficial con técnica láser (TTSL. Con el empleo deun láser de Nd: YAG se procedió al endurecimiento superficial de los aceros AISI 1045, W1, W112 y hierros fundidos detipo laminar y nodular. Los autores prestan atención a las rutas de endurecimiento superficial atendiendo a los parámetrosoperacionales del láser: potencia incidente en la zona de interacción (P y la velocidad de barrido del haz de láser (V. Deigual forma se establecen valoraciones acerca de las estructuras metalográficas obtenidas. En todos los casos se reportanvalores de microdureza Vickers que oscilan entre los 500-900 HV (incrementos de 3-4 veces respecto al substratooriginal. Los resultados obtenidos permiten establecer en todos los casos experimentados que el incremento de lavelocidad de barrido provocó una disminución de la profundidad de la capa endurecida. Las experiencias del TTSL en losaceros ensayados muestran una tendencia a la disminución de la profundidad del endurecimiento con el incremento delcontenido de carbono.Palabras claves: Endurecimiento superficial, parámetros de operación de láser., microdureza, profundidadde capa endurecida, de fallo, vibraciones.____________________________________________________________________________AbstractThis paper expose the experiences of researchers on the laser surface heat treatment. The hardening of AISI 1045, W1,W112 steels and cast irons flake and nodular was carried out by using a Nd: YAG laser. Operation parameters of laser, likebeam power (P and traverse speed of the laser spot (V are closely with hardening depth . Authors present some analysesabout metallographic studies. In all cases are reported Vickers microhardness about 500-900 HV (three or four times higherthan original substrates. Relations between microhardness and depth of hardening are presented for the processedmaterials. Experimental results showed that the increased

  17. Infrared thermal measurements of laser soft tissue ablation as a function of air/water coolant for Nd:YAG and diode lasers

    Science.gov (United States)

    Gekelman, Diana; Yamamoto, Andrew; Oto, Marvin G.; White, Joel M.

    2003-06-01

    The purpose of this investigation was to measure the maximum temperature at the Nd:YAG and Diode lasers fiberoptic tips as a function of air/water coolant, during soft tissue ablation in pig jaws. A pulsed Nd:YAG laser (1064nm) and a Diode laser (800-830 nm) were used varying parameters of power, conditioning or not of the fiber tip, under 4 settings of air/water coolant. The maximum temperature at the fiber tip was measured using an infra-red camera and the interaction of the fiber with the porcine soft tissue was evaluated. A two-factor ANOVA was used for statistical analysis (plaser interaction with soft tissues produced temperatures levels directly proportional to power increase, but the conditioning of the fiber tip did not influence the temperature rise. On the other hand, conditioning of the fiber tip did influence the temperature rise for Diode laser. The addition of air/water coolant, for both lasers, did not promote temperature rise consistent with cutting and coagulation of porcine soft tissue. Laser parameters affect the fiberoptic surface temperature, and the addition of air/water coolant significantly lowered surface temperature on the fiberoptic tip for all lasers and parameters tested.

  18. A comparative study of pulsed Nd:YAG laser welding and TIG welding of thin Ti6Al4V titanium alloy plate

    International Nuclear Information System (INIS)

    Gao, Xiao-Long; Zhang, Lin-Jie; Liu, Jing; Zhang, Jian-Xun

    2013-01-01

    This paper reports on a study aiming at comparing properties of the Ti6Al4V titanium alloy joints between pulsed Nd:YAG laser welding and traditional fusion welding. To achieve the research purpose, Ti6Al4V titanium alloy plates with a thickness of 0.8 mm were welded using pulsed Nd:YAG laser beam welding (LBW) and gas tungsten arc welding (TIG), respectively. Residual distortions, weld geometry, microstructure and mechanical properties of the joints produced with LBW and TIG welding were compared. During the tensile test, with the aid of a high speed infrared camera, evolution of the plastic strain within tensile specimens corresponding to LBW and TIG welding were recorded and analyzed. Compared with the TIG, the welded joint by LBW has the characters of small overall residual distortion, fine microstructure, narrow heat-affected zone (HAZ), high Vickers hardness. LBW welding method can produce joints with higher strength and ductility. It can be concluded that Pulsed Nd:YAG laser welding is much more suitable for welding the thin Ti6Al4V titanium alloy plate than TIG welding.

  19. Low-threshold, nanosecond, high-repetition-rate vortex pulses with controllable helicity generated in Cr,Nd:YAG self-Q-switched microchip laser

    Science.gov (United States)

    He, Hong-Sen; Chen, Zhen; Li, Hong-Bin; Dong, Jun

    2018-05-01

    A high repetition rate, nanosecond, pulsed optical vortex beam has been generated in a Cr,Nd:YAG self-Q-switched microchip laser pumped by the annular-beam formed with a hollow focus lens. The lasing threshold for vortex pulses is 0.9 W. A pulse width of 6.5 ns and a repetition rate of over 330 kHz have been achieved. The average output power of 1 W and the slope efficiency of 46.6% have been obtained. The helicity of the optical vortices has been controlled by adjusting the tilted angle between Cr,Nd:YAG crystal and output coupler. The work provides a new method for developing pulsed optical vortices for potential applications on quantum communication and optical trapping.

  20. Spectrochemical analysis of powder using 355 nm Nd-YAG laser-induced low-pressure plasma.

    Science.gov (United States)

    Lie, Zener S; Pardede, M; Hedwig, R; Suliyanti, M M; Kurniawan, Koo Hendrik; Munadi; Lee, Yong-Inn; Kagawa, Kiichiro; Hattori, Isamu; Tjia, May On

    2008-04-01

    The applicability of spectrochemical analysis of minute amounts of powder samples was investigated using an ultraviolet Nd-YAG laser (355 nm) and low-pressure ambient air. A large variety of chemical powder samples of different composition were employed in the experiment. These included a mixture of copper(II) sulfate pentahydrate, zinc sulfide, and chromium(III) sulfate n-hydrate powders, baby powder, cosmetic powders, gold films, zinc supplement tablet, and muds and soils from different areas. The powder samples were prepared by pulverizing the original samples to an average size of around 30 microm in order to trap them in the tiny micro holes created on the surface of the quartz subtarget. It was demonstrated that in all cases studied, good quality spectra were obtained with low background, free from undesirable contamination by the subtarget elements and featuring ppm sensitivity. A further measurement revealed a linear calibration curve with zero intercept. These results clearly show the potential application of this technique for practical qualitative and quantitative spectrochemical analysis of powder samples in various fields of study and investigation.

  1. Influence of Nd:YAG laser on the bond strength of self-etching and conventional adhesive systems to dental hard tissues.

    Science.gov (United States)

    Marimoto, A K; Cunha, L A; Yui, K C K; Huhtala, M F R L; Barcellos, D C; Prakki, A; Gonçalves, S E P

    2013-01-01

    The aim of this study was to investigate the influence of Nd:YAG laser on the shear bond strength to enamel and dentin of total and self-etch adhesives when the laser was applied over the adhesives, before they were photopolymerized, in an attempt to create a new bonding layer by dentin-adhesive melting. One-hundred twenty bovine incisors were ground to obtain flat surfaces. Specimens were divided into two substrate groups (n=60): substrate E (enamel) and substrate D (dentin). Each substrate group was subdivided into four groups (n=15), according to the surface treatment accomplished: X (Xeno III self-etching adhesive, control), XL (Xeno III + laser Nd:YAG irradiation at 140 mJ/10 Hz for 60 seconds + photopolymerization, experimental), S (acid etching + Single Bond conventional adhesive, Control), and SL (acid etching + Single Bond + laser Nd:YAG at 140 mJ/10 Hz for 60 seconds + photopolymerization, experimental). The bonding area was delimited with 3-mm-diameter adhesive tape for the bonding procedures. Cylinders of composite were fabricated on the bonding area using a Teflon matrix. The teeth were stored in water at 37°C/48 h and submitted to shear testing at a crosshead speed of 0.5 mm/min in a universal testing machine. Results were analyzed with three-way analysis of variance (ANOVA; substrate, adhesive, and treatment) and Tukey tests (α=0.05). ANOVA revealed significant differences for the substrate, adhesive system, and type of treatment: lased or unlased (penamel groups were X=20.2 ± 5.61, XL=23.6 ± 4.92, S=20.8 ± 4.55, SL=22.1 ± 5.14 and for the dentin groups were X=14.1 ± 7.51, XL=22.2 ± 6.45, S=11.2 ± 5.77, SL=15.9 ± 3.61. For dentin, Xeno III self-etch adhesive showed significantly higher shear bond strength compared with Single Bond total-etch adhesive; Nd:YAG laser irradiation showed significantly higher shear bond strength compared with control (unlased). Nd:YAG laser application prior to photopolymerization of adhesive systems

  2. Stable continuous-wave single-frequency Nd:YAG blue laser at 473 nm considering the influence of the energy-transfer upconversion.

    Science.gov (United States)

    Wang, Yaoting; Liu, Jianli; Liu, Qin; Li, Yuanji; Zhang, Kuanshou

    2010-06-07

    We report a continuous-wave (cw) single frequency Nd:YAG blue laser at 473 nm end-pumped by a laser diode. A ring laser resonator was designed, the frequency doubling efficiency and the length of nonlinear crystal were optimized based on the investigation of the influence of the frequency doubling efficiency on the thermal lensing effect induced by energy-transfer upconversion. By intracavity frequency doubling with PPKTP crystal, an output power of 1 W all-solid-state cw blue laser of single-frequency operation was achieved. The stability of the blue output power was better than +/- 1.8% in the given four hours.

  3. Differential effects of Nd-YAG laser on collagen and elastin production by chick embryo aortae in vitro. Relevance to laser angioplasty for removal of atherosclerotic plaques

    International Nuclear Information System (INIS)

    Abergel, R.P.; Zaragoza, E.J.; Dwyer, R.M.; Uitto, J.

    1985-01-01

    Aortae from 17-day old chick embryos were subjected to irradiation with a Nd:YAG laser at energy densities varying from 1.2 - 4.7 X 10(3) J/cm2. The aortae were pulse-labeled in vitro with [ 3 H]proline or [ 14 C]valine, and the synthesis of collagenous polypeptides and soluble elastin was examined by SDS-polyacrylamide gel electrophoresis, followed by fluorography and quantitative scanning densitometry. Irradiation of the aortae with Nd:YAG laser resulted in inhibition of the synthesis of the extracellular matrix proteins. The production of collagen was inhibited to a considerably larger degree than the production of elastin. Thus, the biosynthetic pathway for collagen production appears to be more susceptible to laser inhibition than the corresponding pathway for elastin production. These observations may have relevance to laser angioplasty which has been proposed to be applicable for removal of atherosclerotic plaques in human vessels. Specifically, the results suggest that inhibition of the extracellular matrix production may result in weakening of the vessel wall with subsequent aneurysm formation and rupture

  4. Effect of Nd:YAG and Diode Lasers on Apical Seal of Root Canals Filled with AH Plus and Mineral Trioxide Aggregate-Based Sealers

    Directory of Open Access Journals (Sweden)

    Elham Khoshbin

    2018-01-01

    Full Text Available Objectives: Laser irradiation, as an adjunct to root canal preparation, may increase the success rate of endodontic treatments. This study aimed to assess the effect of neodymium-doped yttrium aluminum garnet (Nd:YAG and diode lasers on the apical seal of the root canals filled with AH Plus® and mineral trioxide aggregate (MTA-based sealers.Materials and Methods: This in-vitro experimental study was conducted on 96 single-rooted, single-canal extracted human teeth with closed apices. The root canals were prepared by using ProTaper® rotary instruments and were randomly divided into six groups (n=16: 940-nm diode laser and AH Plus® sealer (group 1, Nd:YAG laser and AH Plus® sealer (group 2, AH Plus® sealer (group 3, 940-nm diode laser and MTA-based sealer (group 4, Nd:YAG laser and MTA-based sealer (group 5, MTA-based sealer (group 6, as well as positive and negative control groups. A bacterial leakage model was used for microleakage assessment. Qualitative assessment was done by using a scanning electron microscope (SEM. Data were analyzed by two-way analysis of variance (ANOVA at the significance level of 0.05.Results: There were statistically significant differences between the experimental and control groups (P=0.002. The laser-treated groups showed a lower apical microleakage compared to the non-laser-treated groups, although the difference was not statistically significant (P>0.05. No significant differences were noted between the two lasers in terms of the apical microleakage, irrespective of the type of sealer (P>0.05.Conclusions: Laser irradiation, as an adjunct to root canal preparation, has no significant effect on the level of apical microleakage.

  5. Resultados de la capsulotomía Nd-YAG láser Results of the capsulotomy Nd-YAG LASER

    Directory of Open Access Journals (Sweden)

    Mirlanea López Torres

    2009-12-01

    means of laser; the current technique nowadays. Showing the results after laser capsulotomy in patients operated by the Blumenthal Technique (2007-2008 at "Abel Santamaria Cuadrado" University Hospital, in Pinar del Rio Cuba was the purpose of this paper. Age, sex, implant and non- implant of the intraocular lenses (IOL, complications during trans and post laser therapy, as well as the visual acuity before and after treatment were the variables considered, all patients were older than 60 years (80, 2 % and in 96, 8 % an intraocular lens was placed into the posterior chamber, 65.9 % of the eyes showed transient increasing of the intraocular pressure, and only 3, 2 % showed splintering of the IOL, but needing no extraction. Complications were not so important if it is considered that 93, 2 % of the eyes reached to a visual acuity > 0, 7.

  6. Research of the welding of amorphous Co-based alloys in shape of foils with Nd: YAG-LASER

    International Nuclear Information System (INIS)

    Runchev, Dobre

    1996-01-01

    In this study the results concerning the research of the welding of amorphous Co-based alloys in form of foils, with impulsive Nd: YAG LASER are given. The welding was effected on alloys with manufactured sign VAC 6025, VAC 6030, VAC 6150 as well as with different chemical structure and dimensions. Two overlapped foils of the same alloy have been connected with 6 welded spots, under laboratory conditions and in air surrounding. The welding was effected only with negative focus position (-Def.). The basic aim of the researches is the production of a spot welded joints by preserving the amorphous structure of the material. To achieve this purpose, examinations of the optical characteristics of the welded alloys were effected, by measuring the reflective energy of the laser beam from the surface of the AMF. The quality of the spot welded joint is established by shearing examination, measuring of the microhardness, metallographic examinations of the structure by both light microscope and SEM, as well as measuring of the welded spot diameter. After the examinations and the analysis of the achieved results, it is defined that the welding of AMF A and B the established aim was achieved. The welded spots ware with good quality, the structure remained amorphous and the mechanical characteristics, such as Rm and HV0, 2 were at the level of the basic materials. During the welding of AMF C, D and E, the established aim was not achieved. The welded spots ware with bad quality, as a result of the appeared crystal structure in the welded spots. The experimental researches presented in this study, have been carried out in the Technical University in Berlin. (author)

  7. Synthesis of SiC nanoparticles by SHG 532 nm Nd:YAG laser ablation of silicon in ethanol

    Science.gov (United States)

    Khashan, Khawla S.; Ismail, Raid A.; Mahdi, Rana O.

    2018-06-01

    In this work, colloidal spherical nanoparticles NPs of silicon carbide SiC have been synthesized using second harmonic generation 532 nm Nd:YAG laser ablation of silicon target dipped in ethanol solution at various laser fluences (1.5-5) J/cm2. X-Ray diffraction XRD, scanning electron microscopy SEM, transmission electron microscope TEM, Fourier transformed infrared spectroscopy FT-IR, Raman spectroscopy, photoluminescence PL spectroscopy, and UV-Vis absorption were employed to examine the structural, chemical and optical properties of SiC NPs. XRD results showed that all synthesised SiC nanoparticles are crystalline in nature and have hexagonal structure with preferred orientation along (103) plane. Raman investigation showed three characteristic peaks 764,786 and 954 cm-1, which are indexing to transverse optic TO phonon mode and longitudinal optic LO phonon mode of 4H-SiC structure. The optical absorption data showed that the values of optical energy gap of SiC nanoparticles prepared at 1.5 J/cm2 was 3.6 eV and was 3.85 eV for SiC synthesised at 5 J/cm2. SEM investigations confirmed that the nanoparticles synthesised at 5 J/cm2 are agglomerated to form larger particles. TEM measurements showed that SiC particles prepared at 1.5 J/cm2 have spherical shape with average size of 25 nm, while the particles prepared at 5 J/cm2 have an average size of 55 nm.

  8. Three-Rod Resonator for Krypton Lamp Pumped 1.8 kW Continuous-Wave Nd:YAG Laser

    Institute of Scientific and Technical Information of China (English)

    LI Qiang; FANG Ming-Xing; WANG Zhi-Yong; YU Zhen-Sheng; LEI Hong; GUO Jiang; LI Gang; ZUO Tie-Chuan

    2004-01-01

    @@ A three-rod series resonator cw Nd:YAG laser suitable for the industrial applications is presented. The symmetrical resonator laser has been developed and is rated at 1820-W output power with beam parameter product 24 mm.mrad. By utilizing the symmetrical resonator design, the characteristic of beam with multi-rod is not obviously decreased compared with that of a single one. The system total electro-optics efficiency of lamp pumped YAG crystal is as high as 4.0%. The main factors, which affect output power and beam quality of high power solid-state laser module, are theoretically analysed.

  9. A High-Energy Good-Beam-Quality Krypton-Lamp-Pumped Nd:YAG Solid-State Laser with One Pump Cavity

    Institute of Scientific and Technical Information of China (English)

    LIU Xue-Sheng; WANG Zhi-Yong; YAN Xin; CAO Ying-Hua

    2008-01-01

    We investigate a high-energy good-beam-quality krypton-lamp-pumped pulsed Nd:YAG solid-state laser with one pump cavity.The symmetrical resonator laser is developed and is rated at 80 J with beam parameter product 12mm mrad.The total system electro-optics efficiency of the lamp-pumped YAG laser is as high as 3.3% and the stability of output energy is ±2% with pulse width tunable between 0.1 ms and 10ms.The experimental results are consistent with the theoretical analysis and simulation.

  10. Process and application of shock compression by nanosecond pulses of frequency-doubled Nd:YAG laser

    Science.gov (United States)

    Sano, Yuji; Kimura, Motohiko; Mukai, Naruhiko; Yoda, Masaki; Obata, Minoru; Ogisu, Tatsuki

    2000-02-01

    The authors have developed a new process of laser-induced shock compression to introduce a residual compressive stress on material surface, which is effective for prevention of stress corrosion cracking (SCC) and enhancement of fatigue strength of metal materials. The process developed is unique and beneficial. It requires no pre-conditioning for the surface, whereas the conventional process requires that the so-called sacrificial layer is made to protect the surface from damage. The new process can be freely applied to water- immersed components, since it uses water-penetrable green light of a frequency-doubled Nd:YAG laser. The process developed has the potential to open up new high-power laser applications in manufacturing and maintenance technologies. The laser-induced shock compression process (LSP) can be used to improve a residual stress field from tensile to compressive. In order to understand the physics and optimize the process, the propagation of a shock wave generated by the impulse of laser irradiation and the dynamic response of the material were analyzed by time-dependent elasto-plastic calculations with a finite element program using laser-induced plasma pressure as an external load. The analysis shows that a permanent strain and a residual compressive stress remain after the passage of the shock wave with amplitude exceeding the yield strength of the material. A practical system materializing the LSP was designed, manufactured, and tested to confirm the applicability to core components of light water reactors (LWRs). The system accesses the target component and remotely irradiates laser pulses to the heat affected zone (HAZ) along weld lines. Various functional tests were conducted using a full-scale mockup facility, in which remote maintenance work in a reactor vessel could be simulated. The results showed that the system remotely accessed the target weld lines and successfully introduced a residual compressive stress. After sufficient training

  11. 21 CFR 886.4392 - Nd:YAG laser for posterior capsulotomy and peripheral iridotomy.

    Science.gov (United States)

    2010-04-01

    ... or in close proximity to the target tissue. (b) Classification. Class II (special controls). Design... laser generates short pulse, low energy, high power, coherent optical radiation. When the laser output is combined with focusing optics, the high irradiance at the target causes tissue disruption via...

  12. Shift and broadening of emission lines in Nd :YAG laser crystal ...

    Indian Academy of Sciences (India)

    1Department of Optics and Laser Engineering, Estahban Branch, Islamic Azad ... Nd3+:YAG crystal; heat generation; three-level emission lines; four-level emission ... Modelling of high-power solid-state lasers requires precise knowledge of ...

  13. Morphological Alterations of the Surfaces of Enamel and Dentin of Deciduous Teeth Irradiated with Nd:YAG, C0(2)and Diode Lasers

    OpenAIRE

    Souza, Mónica Rodrigues de; Watanabe, Ii-Sei; Azevedo, Luciane H; Tanji, Edgar Y

    2009-01-01

    In this work, we studied the effects of C0(2), Nd:YAG and diode lasers on the enamel and dentin of deciduous human teeth. After the irradiations, the samples were duly prepared and set up on metallic bases, covered with gold and examined in the scanning electron microscope. The results showed that the irradiation with the C0(2) mode locked laser with 1.0 W power caused melting and irregularities with small cavities on the surface of the enamel. The irradiated area on the dentin surface appear...

  14. The effect of Nd:YAG laser treatment of posterior capsule opacification on anterior chamber depth and refraction in pseudophakic eyes

    Directory of Open Access Journals (Sweden)

    Khambhiphant B

    2015-03-01

    Full Text Available Bharkbhum Khambhiphant,1 Chayata Liumsirijarern,2 Piyada Saehout1 1Department of Ophthalmology, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, 2Department of Ophthalmology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand Purpose: This was a prospective descriptive study to determine the changes in intraocular lens (IOL position after neodymium-doped yttrium–aluminum–garnet (Nd:YAG laser posterior capsulotomy by measuring anterior chamber depth (ACD and refraction, including the spherical equivalent (SE and cylinder. Materials and methods: Forty-seven pseudophakic eyes with posterior capsule opacification of 29 patients were included. Nd:YAG laser posterior capsulotomy was performed. Patients’ ACD and refraction were measured before the treatment, as well as after the treatment at 1 week and 3 months. IOLMaster® and an automated refractometer were used at the Department of Ophthalmology, King Chulalongkorn Memorial Hospital, Bangkok, Thailand. Results: There were no statistically significant differences in ACD and SE before and after laser treatment at 1 week and 3 months (repeated analysis of variance, P=0.582 and P=0.269, respectively. Both backward IOL movement (number [n]=29 and forward IOL movement (n=18 were found. Some changes in cylindrical refraction were found at 1 week, but decreased at 3 months after capsulotomy (baseline cylinder: -1.16; cylinder at 1 week and 3 months: -1.00 and -1.14, respectively; P=0.012. These changes were the same with one-piece and three-piece IOLs. Conclusion: Nd:YAG laser posterior capsulotomy did not significantly change ACD and SE. It led to cylinder change at 1 week after laser, but the effect decreased at 3 months. This effect was small and may not be clinically significant. Keywords: posterior capsule opacification, neodymium-doped yttrium–aluminum–garnet, anterior chamber depth, pseudophakia, refraction

  15. Comparison of endoscopic Nd:YAG laser therapy and oesophageal tube in palliation of oesophagogastric malignancy

    Energy Technology Data Exchange (ETDEWEB)

    Hahl, J.; Salo, T.; Ovaska, J.; Haapiainen, R.; Kalima, T.; Schroeder, T. (Helsinki Univ. Central Hospital (Finland). Meilahti Clinic)

    1991-01-01

    The clinical results of 96 patients with upper gastrointestinal malignancy have been evaluated retrospectively. 69 patients with a mean age of 72 years (35 men and 34 women) were treated with endoscopic laser therapy, and 27 patients with a mean age of 67 years (16 men and 11 women) with insertion of an oesophageal tube. After laser therapy the bulk of the tumour was reduced in 87%, and in 55% clear signs of relieved dysphagia were seen. The insertion of an esophageal tube was successful in 89%. In the laser group no fatal complications occurred, and the overall complication risk was 8.7%. The first-year survival in all laser patients was 12%, and in patients with impassable tumour stenosis the survival was 6%. The mortality related to the insertion of an oesophageal tube was 11%, and complications occurred in 48% of the patients. The first-year survival of the tube group was nil. It is concluded that endoscopic laser therapy and insertion of oesophageal tube are both effective methods in palliation of oesophagogastric malignancy, but the mortality and risk for complications were markedly lower after laser therapy. 20 refs., 1 fig., 3 tabs.

  16. Mechanical response of agar gel irradiated with Nd:YAG nanosecond laser pulses

    Science.gov (United States)

    Pérez-Gutiérrez, Francisco G.; Evans, Rodger; Camacho-López, Santiago; Aguilar, Guillermo

    2010-02-01

    Nanosecond long laser pulses are used in medical applications where precise tissue ablation with minimal thermal and mechanical collateral damage is required. When a laser pulse is incident on a material, optical energy will be absorbed by a combination of linear and nonlinear absorption according to both: laser light intensity and material properties. In the case of water or gels, the first results in heat generation and thermoelastic expansion; while the second results in an expanding plasma formation that launches a shock wave and a cavitation/boiling bubble. Plasma formation due to nonlinear absorption of nanosecond laser pulses is originated by a combination of multiphoton ionization and thermionic emission of free electrons, which is enhanced when the material has high linear absorption coefficient. In this work, we present measurements of pressure transients originated when 6 ns laser pulses are incident on agar gels with varying linear absorption coefficient, mechanical properties and irradiation geometry using laser radiant exposures above threshold for bubble formation. The underlying hypothesis is that pressure transients are composed of the superposition of both: shock wave originated by hot expanding plasma resulting from nonlinear absorption of optical energy and, thermoelastic expansion originated by heat generation due to linear absorption of optical energy. The objective of this work is to evaluate the relative contribution of each absorption mechanism to mechanical effects in agar gel. Real time pressure transients are recorded with PVDF piezoelectric sensors and time-resilved imaging from 50 μm to 10 mm away from focal point.

  17. Nd:YAG laser annealing investigation of screen-printed CIGS layer on PET: Layer annealing method for photovoltaic cell fabrication process

    KAUST Repository

    Alsaggaf, Ahmed

    2014-06-01

    Cu(In, Ga)Se2 (CIGS) ink was formulated from CIGS powder, polyvinyl butyral PVB, terpineol and polyester/polyamine co-polymeric dispersant KD-1. Thin films with different thicknesses were deposited on PET substrate using screen-printing followed by heat treatment using a Nd:YAG laser. The structure and morphology of the heated thin films were studied. The characterization of the CIGS powder, ink, and film was done using TGA, SEM, FIB, EDS, and XRD. TGA analysis shows that the CIGS ink is drying at 200 °C, which is well below the decomposition temperature of the PET substrate. It was observed by SEM that 20 pulses of 532nm and 60 mJ/cm2 Nd:YAG laser annealing causes atomic diffusion on the near surface area. Furthermore, FIB cross section images were utilized to monitor the effect of laser annealing in the depth of the layer. Laser annealing effects were compared to as deposited layer using XRD in reference to CIGS powder. The measurement shows that crystallinity of deposited CIGS is retained while EDS quantification and atomic ratio result in gradual loss of selenium as laser energy increases. The laser parameters were tuned in an effort to utilize laser annealing of screen-printed CIGS layer as a layer annealing method for solar cell fabrication process.

  18. In vitro studies of morphological changes in enamel surface after Er:YAG and Nd:YAG laser irradiation, by SEM

    International Nuclear Information System (INIS)

    Verlangieri, Eleonora Jaeger

    2001-01-01

    The caries prevention by using laser irradiation has been investigated by many authors using various lasers with different irradiations conditions. The purpose of this study was to investigated the morphological changes in enamel surface after Er:YAG and Nd:YAG laser irradiation, in vitro, by SEM. Fifteen freshly extracted, intact, caries-free, human third molars, were used in this study. The coronary portions were sectioned, from buccal to lingual direction, in two half-parts. Each one was irradiated by a different laser. The first one was irradiated with water-air spray, by a Nd:YAG laser, at 1.084 nm wave length, at 10 W, 10 Hz, 100 mJ for 60 sec., with an optical fiber in contact mode (0,32 mm of diameter); and the other half, with water-air spray by an Er:YAG laser at 2,94 micrometers wave length at the parameters of 4 Hz, 80 mJ, 24.95 J/cm 2 for 60 sec. The results of this study suggested that both lasers promoted morphological changes in the enamel surface enhancing resistance and can be an alternative clinical method for caries preventions. (author)

  19. Long-term efficacy of Nd:YAG laser photocoagulation vs. liquid paraffin plus antiseptic cream in the treatment of recurrent epistaxis.

    Science.gov (United States)

    Zhang, Jing; Qiu, Rongxing; Wei, Chunsheng

    2015-12-01

    The objective of this study was to evaluate the long-term efficacy of Nd:YAG laser photocoagulation with that of liquid paraffin plus antiseptic cream in the management of recurrent epistaxis. Eighty consecutive patients who suffered from recurrent anterior epistaxis presented to the Otolaryngology Department at the Eye and ENT Hospital, Fudan University between February 2011 and June 2011. These patients with histories of recurrent epistaxis were randomly assigned to receive treatment in an outpatient setting consisting of either a combination of liquid paraffin plus antiseptic cream (Group 1) or Nd:YAG laser photocoagulation (Group 2). the following outcome measures were assessed: bleeding intensity; bleeding frequency 2 years after treatment (0 = no bleeding, 1 = reduced bleeding, 2 = the same, 3 = worse), participant's perception of discomfort during the management (grade 0-10, where 10 is the worst pain), and complications. Finally, 70 patients remain in our study. At 2 years, 86 % of laser patients versus 31 % of control patients had no reported bleeding. The outcome score at 2 years after treatment showed a significant difference between the two groups (P = 0.000, P < 0.01). The median and mean ± SD pain levels experienced were 5.0 and 5.2 ± 2.2. Both groups had no complications. It can be further concluded that Nd:YAG laser photocoagulation is a preferable therapy in the treatment of recurrent epistaxis in long-term efficacy. The level of pain associated with the procedure was well tolerated. It is a simple, easy, safe and rapid therapy, which can be performed in an office setting.

  20. Investigation of droplet formation in pulsed Nd:YAG laser deposition of metals and silicon

    Energy Technology Data Exchange (ETDEWEB)

    Siew, Wee-Ong; Lee, Wai-Keat; Wong, Hin-Yong; Tou, Teck-Yong [Multimedia University, Faculty of Engineering, Cyberjaya, Selangor (Malaysia); Yong, Thian-Khok [Multimedia University, Faculty of Engineering, Cyberjaya, Selangor (Malaysia); Universiti Tunku Abdul Rahman, Faculty of Engineering and Science, Kuala Lumpur (Malaysia); Yap, Seong-Shan [Multimedia University, Faculty of Engineering, Cyberjaya, Selangor (Malaysia); Norwegian University of Science and Technology, Institute of Physics, Trondheim (Norway)

    2010-12-15

    In the process of pulsed laser deposition of nickel (Ni) and ruthenium (Ru) thin films, the occurrence of phase explosion in ablation was found to affect the deposition rate and enhance the optical emissions from the plasma plume. Faster thin-film growth rates coincide with the onset of phase explosion as a result of superheating and/or sub-surface boiling which also increased the particulates found on the thin-film surface. These particulates were predominantly droplets which may not be round but flattened and also debris for the case of silicon (Si) ablation. The droplets from Ni and Ru thin films were compared in terms of size distribution and number density for different laser fluences. The origins of these particulates were correlated to the bubble and ripple formations on the targets while the transfer to the thin film surface was attributed to the laser-induced ejection from the targets. (orig.)

  1. Investigation of droplet formation in pulsed Nd:YAG laser deposition of metals and silicon

    International Nuclear Information System (INIS)

    Siew, Wee-Ong; Lee, Wai-Keat; Wong, Hin-Yong; Tou, Teck-Yong; Yong, Thian-Khok; Yap, Seong-Shan

    2010-01-01

    In the process of pulsed laser deposition of nickel (Ni) and ruthenium (Ru) thin films, the occurrence of phase explosion in ablation was found to affect the deposition rate and enhance the optical emissions from the plasma plume. Faster thin-film growth rates coincide with the onset of phase explosion as a result of superheating and/or sub-surface boiling which also increased the particulates found on the thin-film surface. These particulates were predominantly droplets which may not be round but flattened and also debris for the case of silicon (Si) ablation. The droplets from Ni and Ru thin films were compared in terms of size distribution and number density for different laser fluences. The origins of these particulates were correlated to the bubble and ripple formations on the targets while the transfer to the thin film surface was attributed to the laser-induced ejection from the targets. (orig.)

  2. Optimization of Nd: YAG Laser Marking of Alumina Ceramic Using RSM And ANN

    International Nuclear Information System (INIS)

    Peter, Josephine; Doloi, B.; Bhattacharyya, B.

    2011-01-01

    The present research papers deals with the artificial neural network (ANN) and the response surface methodology (RSM) based mathematical modeling and also an optimization analysis on marking characteristics on alumina ceramic. The experiments have been planned and carried out based on Design of Experiment (DOE). It also analyses the influence of the major laser marking process parameters and the optimal combination of laser marking process parametric setting has been obtained. The output of the RSM optimal data is validated through experimentation and ANN predictive model. A good agreement is observed between the results based on ANN predictive model and actual experimental observations.

  3. Aluminium alloys welding with high-power Nd:YAG lasers

    International Nuclear Information System (INIS)

    Garcia Orza, J.A.

    1998-01-01

    Aluminium alloys have good mechanical properties (high strength-to-weight ratio, corrosion resistance) and good workability. their applications are growing up, specially in the transportation industry. Weldability is however poorer than in other materials; recent advances in high power YAG laser are the key to obtain good appearance welds and higher penetration, at industrial production rates. Results of the combination of high power YAG beams with small fiber diameters and specific filler wires are presented. It is also characterized the air bone particulate material, by-product of the laser process: emission rates, size distribution and chemical composition are given for several aluminium alloys. (Author) 6 refs

  4. Diffractive optics for reduction of hot cracking in pulsed mode Nd:YAG laser welding

    DEFF Research Database (Denmark)

    Bagger, Claus; Olesen, Søren; Roos, Sven-Olov

    2001-01-01

    In order to reduce the susceptibility to hot cracking in pulsed mode laser welding of austenitic stainless steel, an optical system for reduction of the cooling rate is sought developed. Based on intensive numerical simulations, an optical system producing three focused spots is made. In a number...

  5. Nd: YAG laser treatment of aluminium-TiB2 coated: optimization of corrosion properties

    CSIR Research Space (South Africa)

    Popoola, PAI

    2011-06-01

    Full Text Available . Eutectics of TiB2/Al and TiB2/Ti were observed. The results of the tests indicate that TiB2 reinforcement does not give significant increase in microhardness of aluminium. The corrosion resistance of a single laser trackline MMC in a 3.65 % NaCl solution...

  6. Does performance status influence the outcome of Nd:YAG laser therapy of proximal esophageal tumors?

    NARCIS (Netherlands)

    Alexander, G. L.; Wang, K. K.; Ahlquist, D. A.; Viggiano, T. R.; Gostout, C. J.; Balm, R.

    1994-01-01

    The value of endoscopic palliative therapy for malignant obstruction in the proximal esophagus has been questioned. To assess the importance of pre-treatment performance status on treatment outcome, we reviewed the records of patients with tumors of the proximal esophagus undergoing endoscopic laser

  7. Split lesion randomized comparative study between long pulsed Nd:YAG laser 532 and 1,064 nm in treatment of facial port-wine stain.

    Science.gov (United States)

    Al-Dhalimi, Muhsin A; Al-Janabi, Murtadha H

    2016-11-01

    Lasers have been the treatment of choice for Port-wine stain (PWS). However, only one type of laser is not a panacea for all PWS malformations. This is may be due to the great heterogeneity of phenotypic presentation of this congenital anomaly as color, depth, and the site of the lesion. For the treatment of PWS, flash lamp-pumped pulsed dye laser, carbon dioxide, argon, krypton, copper bromide, frequency-doubled neodymium:yttrium-aluminum-garnet (Nd:YAG), and also intense pulsed light sources can be used. To assess and compare the effectiveness of wavelength 532 and 1,064 nanometers (nm) long pulse Nd:YAG laser in the treatment of facial port-wine stain. This was a comparative therapeutic study for the treatment of facial port-wine stain. We divided the lesion into two halves, medial and lateral, and then each half was treated by 532 or 1,064 nm Nd:YAG. The sessions were done every 4 weeks for six sessions and follow-up after 3 months, then assess the response before and after the sessions and at the end follow-up period objectively (degree of improvement, Photo comparison) and subjectively (Patient satisfaction). Fourteen out of nineteen patients completed all sessions of the treatment, and the other five patients were defaulted from the study due to different causes, including marriage, poor compliance for treatment, and for unknown causes. They were 13 (92.85%) females and 1 (7.15%) male. The mean age of patients was 22.07 ± 9.003 years (range 8-44 years). Three patients (21.4%) were Fitzpatrick's skin type III and four patients (78.6%) were typed IV. There was no hypertrophy in any of the lesions. All facial PWSs lie along the distribution of the trigeminal nerve. Four patients (28.6%) have V1 (ophthalmic), 12 patients (85.7%) have V2 (maxillary), and 9 (64.3%) have V3 (mandibular). The color of PWSs was pink-red in eight patients (57.1%), dark-red in four patients (28.6%), and purple-dark two patients (14.3%). The improvement score for the halves of

  8. A diode-pumped continuous-wave Nd:YAG laser with an average output power of 1 kW

    International Nuclear Information System (INIS)

    Lee, Sung Man; Cha, Byung Heon; Kim, Cheol Jung

    2004-01-01

    A diode-pumped Nd:YAG laser with an average output power of 1 kW is developed for industrial applications, such as metal cutting, precision welding, etc. To develop such a diode-pumped high power solid-state laser, a series of laser modules have been used in general with and without thermal birefringence compensation. For example, Akiyama et al. used three laser modules to obtain a output power of 5.4 kW CW.1 In the side-pumped Nd:YAG laser, which is a commonly used pump scheme to obtain high output power, the crystal rod has a short thermal focal length at a high input pump power, and the short thermal focal length in turn leads to beam distortion within a laser resonator. Therefore, to achieve a high output power with good stability, isotropic beam profile, and high optical efficiency, the detailed analysis of the resonator stability condition depending on both mirror distances and a crystal separation is essential

  9. SPF-RR sequential photothermal fractional resurfacing and remodeling with the variable pulse Er:YAG laser and scanner-assisted Nd:YAG laser.

    Science.gov (United States)

    Marini, Leonardo

    2009-12-01

    Many different lasers, polychromatic high-intensity light sources (PCLs), and RF devices have claimed clinical efficacy in rejuvenating the skin. In this study, the sequential combination of two different laser wavelengths was evaluated to produce reliably significant clinical improvements optimizing treatment parameters. The left volar aspects of the forearms of four volunteers were treated with nine different parameter settings using a variable pulsewidth fractional Er:YAG 2940-nm laser with and without air cooling. The pain perception level was recorded on a 0-10 point scale (0=No pain; 10=Most severe pain). Three evaluations were made: during treatment, immediately after treatment, and 5 minutes after treatment. The same investigation was made on the right volar aspects of the same four volunteers using a short-pulse, random pattern, 3-mm spot, scanner-assisted Nd-YAG 1064-nm laser at 0.3 ms pulsewidth at seven different parameter settings. Clinical evaluations were made concerning erythema and edema 3 days after treatment, as well as pre-operative and 60 days postoperative skin texture plus color uniformity. Considering that the majority of cosmetic patients are willing to accept a relatively short and uneventful downtime (2-4 days according to a study we are presently conducting) and do prefer to limit their intra- and postoperative pain to a minimum, the best combination of clinical improvement matching these two important parameters were selected for our study. A treatment strategy combining two sequential passes of long-pulse Nd:YAG laser (Nd:YAG-LP) at 0.3 and 35 ms followed by two passes of long-pulse fractional Er:YAG laser (Er:YAG-FT) at 600 micros was designed to treat the facial regions of 10 volunteers affected by a combination of intrinsic (chrono-) and extrinsic (mostly photo-) aging. The pain perception level was recorded on a 0-10 scale (0=No pain; 10=Most severe pain). Three evaluations were made: during, immediately after, and 5 minutes after

  10. Short-pulse-width micromachining of hard materials using DPSS Nd:YAG lasers

    Science.gov (United States)

    Heglin, Michael; Govorkov, Sergei V.; Scaggs, Michael J.; Theoharidis, Haris; Schoelzel, T.

    2002-06-01

    The material processing of an industrial, short-pulse duration DPPS YAG laser producing peak powers greater than 0.2MW is discussed in this paper. This peak power provides sufficient materials processing capability to meet the micro machining needs in the automotive, semiconductor, micro- electronic, medical and telecommunication industries. All hard and soft materials including: plastics, metals, ceramics, diamond and other crystalline materials are suitable candidates for the processing capability of this laser. Micro level features can be machined in these materials to a depth in excess of 1mm with high quality results. In most applications feature sizes can be achieved that are not possible or economical with existing technologies. The optical beam delivery system requirements, and overall micro-machining set-up are also described. The drilling and cutting versatility down to feature sizes of less than 7 micrometers , as well as, complex shapes are shown. The wavelength, pulse length, and peakpower are described and relate to their effect on recast, micro-cracking and material removal rates. Material removal effects related to progressive penetration into the material will be reviewed. The requirements of this DPSS laser technology to meet the operational requirements for high duty cycle operation in industrial environments is covered along with processing flexibility and lower operating cost.

  11. Cascade conical refraction for annular pumping of a vortex Nd:YAG laser and selective excitation of low- and high-order Laguerre–Gaussian modes

    Science.gov (United States)

    Wu, Yongxiao; Wang, Zhongyang; Chen, Sanbin; Shirakwa, Akira; Ueda, Ken-ichi; Li, Jianlang

    2018-05-01

    We proposed an efficient and vortex Nd:YAG laser for selective lasing of low- and high-order vortex modes, in which multiple-ring pump light was originated from cascaded conical refraction of multiple biaxial crystals. In our proof of concept demonstration, we used two-crystal cascade conical refraction to generate two-ring pump light; the mutual intensity ratio and relative separation of the inner ring and outer ring were controlled by rotating the second biaxial crystal and by moving the imaging lens, respectively. As a result, we obtained selective excitation of Laguerre–Gaussian (LG01 and LG03) vortex modes in the end-pump Nd:YAG laser. For LG01-mode output, the laser power reached 439 mW with 52.5% slope efficiency; for LG03-mode output, the laser power reached 160 mW with 41.3% slope efficiency. Our results revealed that the multiple-ring pumping technique based on cascaded conical refraction would pave the way for realization of the efficient and switchable excitation of low- and high-order LG modes in an end-pumped solid-state laser.

  12. [A case of polypoid bronchial neurofibroma originating from right B2b successfully treated by bronchoscopic snaring forceps and Nd-YAG laser therapy].

    Science.gov (United States)

    Takiguchi, Y; Uchiyama, T; Sato, K; Tatsumi, K; Kimura, H; Nagao, K; Fujisawa, T; Ohwada, H; Hiroshima, K; Kuriyama, T

    1993-12-01

    A 34-year-old man with persistent cough was admitted to our hospital. Bronchoscopic examination revealed a polypoid tumor with smooth surface which almost completely obstructed the right main bronchus. The tumor was removed by transbronchial snaring forceps and histologically confirmed as neurofibroma. Residual tumor was excised by biopsy forceps and further endoscopic Nd-YAG laser vaporization was performed. This is the first case in our country in which bronchoscopic treatment was performed for bronchial neurofibroma. Bronchoscopic removal might be the preferred treatment in the present case, although long-term follow-up is also required.

  13. Mode-locking operation of a flash-lamp-pumped Nd:YAG laser at 1.064 μm with Zakharov-Manakov solitons

    International Nuclear Information System (INIS)

    Andreana, M; Tonello, A; Couderc, V; Baronio, F; Conforti, M; De Angelis, C

    2011-01-01

    We report experimental results on the mode-locked operation of a flash-lamp-pumped Nd:YAG laser at 1.064 μm. The KTP crystal, which induces passive mode-locking, exploits the existence and properties of spatial Zakharov-Manakov soliton dynamics. A train of pulses with duration close to 100 ps, repetition rate of 136 MHz and modulation depth almost 100% has been produced. The mode-locked pulses are modulated with a longer 180 ns pulse envelope with repetition rate of 10 Hz

  14. Characterisation of the light pulses of a cavity dumped dye laser pumped by a cw mode-locked and q-switched Nd:YAG laser

    International Nuclear Information System (INIS)

    Geist, P.; Heisel, F.; Martz, A.; Miehe, J.A.; Miller, R.J.D.

    1984-01-01

    The frequency doubled pulses (of 532 nm) obtained, with the help of a KTP crystal, from those delivered by either a continuous wave mode-locked (100 MHz) or mode-locked Q-switched (0-1 KHz) Nd: YAG laser, are analyzed by means of a streak camera, operating in synchroscan or triggered mode. In the step-by-step measurements the pulse stability, concerning form and amplitude, is shown. In addition, measurements effectuated with synchronously pumped and cavity dumped dye laser (Rhodamine 6G), controlled by a Pockels cell, allows the obtention of stable and reproducible single pulses of 30 ps duration, 10 μJ energy and 500Hz frequency [fr

  15. Gain measurement in a CW medium-power diode pumped Nd:YAG laser amplifier by ASE analysis

    International Nuclear Information System (INIS)

    Razzaghi, D; Hajiesmaeilbaigi, F; Ruzbehani, M

    2014-01-01

    Using the relation between amplified spontaneous emission intensity and gain, a set of formulas is derived for gain evaluation by comparing fluorescence yield in two different lengths of the active medium. Experimental measurements are carried out and gain is calculated by solving the derived formula. For comparison, measurements are also carried out using the probe beam method, which shows good agreement between the two methods in a typical CW medium-power diode pumped Nd:YAG amplifier. (paper)

  16. 25  W/m2 collection efficiency solar-pumped Nd:YAG laser by a heliostat-parabolic mirror system.

    Science.gov (United States)

    Liang, D; Almeida, J; Vistas, C R

    2016-09-20

    A large aspheric fused silica lens was used to couple efficiently the concentrated solar radiation from the focal zone of a 1.5-m-diameter primary concentrator into a 4-mm-diameter, 35-mm-long Nd:YAG single-crystal rod within a conical pump cavity. Continuous-wave laser power of 29.3 W was measured, attaining 25.0  W/m2 solar laser collection efficiency, corresponding to a 19% increase over the previous record. Its laser beam figure of merit-the ratio between laser power and the product of Mx2, My2 beam quality factors-of 0.01 W is 1.6 times higher than that of a direct tracking solar laser with 30  W/m2 collection efficiency. A strong dependency of solar laser power on laser resonator cavity length was found.

  17. Controlling phase formation during aluminium/steel Nd:YAG laser brazing

    Directory of Open Access Journals (Sweden)

    Rodriguez, L.

    2006-12-01

    Full Text Available The reduction of fuel consumption of internal combustion motors, imposed by the new anti-pollution and energy saving laws may be attained by reducing the weight of vehicles, introducing, for example, aluminium sections into the main steel car-body. Laser brazing is a process which can be used to perform such a junction. The main problem of welding this kind of materials combination with conventional processes is the potential formation of inter-metallic phases, which reduces the good performance of the joint. Laser brazing allows a very good control of the thermal development of the joint, with a limited precipitation of these brittle phases. This paper presents the results of a feasibility study made with ZnAl-30 as filler metal. The study shows that the type of configuration used for the assembly has a particular influence on the formation of brittle phases and consequently on the mechanical performance of the joint.

    La reducción en el consumo de combustibles fósiles y las emergentes leyes mundiales anti-contaminación, obligan a prever una reducción en el peso de los vehículos de transporte. Esta condición se puede cumplir por ejemplo, introduciendo componentes de Aluminio en el cuerpo de la carrocería principal de acero de los mencionados vehículos. El principal problema que se presenta al realizar este tipo de ensamblaje es la formación de fases íntermetálicas frágiles que pueden comprometer el buen desenvolvimiento de la unión. La soldadura con rayo láser permite un buen control de calor aportado y una formación muy limitada de este tipo de fases. Este trabajo presenta los resultados preliminares de los estudios realizados en uniones soldadas con ZnAl-30 como material de aportación. El estudio muestra que el tipo de configuración utilizada para realizar la soldadura tiene una influencia importante sobre la posibilidad de formación de estas fases ínter-metálicas.

  18. Theoretical and experimental study on the Nd:YAG/BaWO4/KTP yellow laser generating 8.3 W output power.

    Science.gov (United States)

    Cong, Zhenhua; Zhang, Xingyu; Wang, Qingpu; Liu, Zhaojun; Chen, Xiaohan; Fan, Shuzhen; Zhang, Xiaolei; Zhang, Huaijin; Tao, Xutang; Li, Shutao

    2010-06-07

    A diode-side-pumped actively Q-switched intracavity frequency-doubled Nd:YAG/BaWO(4)/KTP Raman laser is studied experimentally and theoretically. Rate equations are used to analyze the Q-switched yellow laser by considering the transversal distributions of the intracavity photon density and the inversion population density. An 8.3 W 590 nm laser is obtained with a 125.8 W 808 nm pump power and a 15 kHz pulse repetition frequency. The corresponding optical conversion efficiency from diode laser to yellow laser is 6.57%, much higher than that of the former reported side-pumped yellow laser. The output powers with respect to the incident pump power are in agreement with the theoretical results on the whole.

  19. Modelling and optimization of cut quality during pulsed Nd:YAG laser cutting of thin Al-alloy sheet for straight profile

    Science.gov (United States)

    Sharma, Amit; Yadava, Vinod

    2012-02-01

    Thin sheets of aluminium alloys are widely used in aerospace and automotive industries for specific applications. Nd:YAG laser beam cutting is one of the most promising sheetmetal cutting process for cutting sheets for any profile. Al-alloy sheets are difficult to cut by laser beam because of its highly reflective nature. This paper presents modelling and optimization of cut quality during pulsed Nd:YAG laser cutting of thin Al-alloy sheet for straight profile. In the present study, four input process parameters such as oxygen pressure, pulse width, pulse frequency, and cutting speed and two output parameters such as average kerf taper ( Ta) and average surface roughness ( Ra) are considered. The hybrid approach comprising of Taguchi methodology (TM) and response surface methodology (RSM) is used for modelling whereas multi-objective optimization is performed using hybrid approach of TM and grey relational analysis (GRA) coupled with entropy measurement methodology. The entropy measurement methodology is employed for the calculation of weight corresponding to each quality characteristic. The results indicate that the hybrid approaches applied for modelling and optimization of the LBC process are reasonable.

  20. Potential role of S100A8 in skin rejuvenation with the 1064-nm Q-switched Nd:YAG laser.

    Science.gov (United States)

    Qin, Yan; Qin, Xiaofeng; Xu, Peng; Zhi, Yuanting; Xia, Weili; Dang, Yongyan; Gu, Jun; Ye, Xiyun

    2018-04-01

    The 1064-nm Q-switched Nd:YAG laser is demonstrated to be effective for non-ablative skin rejuvenation, but the molecular mechanism by which dermis responses to laser-induced damage and initiates skin remodeling is still unclear. HaCaT cells and 3T3 skin fibroblasts were irradiated with the 1064-nm Q-switched Nd:YAG laser at the different doses. Then, cells were collected and lysed for PCR and Western blot analysis. Cell viability was detected by Cell Counting Kit-8 (CCK-8) before and after laser irradiation. The expressions of S100A8, advanced glycosylation end product-specific receptor (RAGE) and inflammatory cytokines in two cell lines were markedly upregulated after laser treatments. The PCR, Western blot, and ELISA analysis showed the significant increase of type I and III procollagen in the 3T3 cells treated with the 1064-nm laser. Interestingly, si S100A8 effectively inhibited the expression of cytokines and collagen, while S100A8 treatments significantly increased them. P-p38 and p-p65 levels were also elevated after the 1064-nm laser irradiation, which is positively related with S100A8. Cell viability and reactive oxygen species (ROS) levels were not changed, while the content of superoxidase dismutase (SOD) in two cells was increased after laser irradiation. Our results demonstrated that the overexpression of S100A8 induced by the 1064-nm laser irradiation triggered inflammatory reactions in skin cells. The inflammatory microenvironment and improvement of skin antioxidant capacity contribute to new collagen synthesis in the skin cells. Thus, S100A8 was required for laser-induced new collagen synthesis in skin cells. p38/MAPK and NF-κB signal pathways were involved in S100A8-mediated inflammatory reactions in response to laser irradiation.

  1. Single-mode pulsed dye laser pumped by using a diode-pumped Nd:YAG laser with a long pulse width

    CERN Document Server

    Yi, J H; Moon, H J; Rho, S P; Han, J M; Rhee, Y J; Lee, J M

    1999-01-01

    The lasing characteristics of a single-mode dye laser pumped by using a diode-pumped solid-state laser (DPSSL) with a high repetition rate is described. A 45-mm-long Nd:YAG rod was pumped by three CW diode arrays and it was acousto-optically Q-switched. A KTP crystal was used for intracavity frequency doubling. The pulse width of the laser ranged from 90 ns to 200 ns, depending on the diode current and the Q-switching frequency. The single-mode dye laser had a grazing incidence configuration. The pulse width of the dye laser was reduced to about 1/8 of the pumping laser pulse width. The effects of the DPSSL Q-switching frequency, the driving current, and the cavity loss on the dye laser pulse width were investigated by using a simple plane-parallel cavity. From the measured pulse width of the dye laser as a function of the reflectivity of the dye laser output coupler, we found that the cavity loss due to the frequency selection elements and the output coupler should be less than 70 % in order to avoid a drast...

  2. Single-mode pulsed dye laser pumped by using a diode-pumped Nd:YAG laser with a long pulse width

    International Nuclear Information System (INIS)

    Yi, Jong Hoon; Kim, Jin Tae; Moon, Hee Jong; Rho, Si Pyo; Han, Jae Min; Rhee, Yong Joo; Lee, Jong Min

    1999-01-01

    The lasing characteristics of a single-mode dye laser pumped by using a diode-pumped solid-state laser (DPSSL) with a high repetition rate is described. A 45-mm-long Nd:YAG rod was pumped by three CW diode arrays and it was acousto-optically Q-switched. A KTP crystal was used for intracavity frequency doubling. The pulse width of the laser ranged from 90 ns to 200 ns, depending on the diode current and the Q-switching frequency. The single-mode dye laser had a grazing incidence configuration. The pulse width of the dye laser was reduced to about 1/8 of the pumping laser pulse width. The effects of the DPSSL Q-switching frequency, the driving current, and the cavity loss on the dye laser pulse width were investigated by using a simple plane-parallel cavity. From the measured pulse width of the dye laser as a function of the reflectivity of the dye laser output coupler, we found that the cavity loss due to the frequency selection elements and the output coupler should be less than 70 % in order to avoid a drastically reduced pulse width

  3. High-power narrow-linewidth quasi-CW diode-pumped TEM00 1064 nm Nd:YAG ring laser.

    Science.gov (United States)

    Liu, Yuan; Wang, Bao-shan; Xie, Shi-yong; Bo, Yong; Wang, Peng-yuan; Zuo, Jun-wei; Xu, Yi-ting; Xu, Jia-lin; Peng, Qin-jun; Cui, Da-fu; Xu, Zu-yan

    2012-04-01

    We demonstrated a high average power, narrow-linewidth, quasi-CW diode-pumped Nd:YAG 1064 nm laser with near-diffraction-limited beam quality. A symmetrical three-mirror ring cavity with unidirectional operation elements and an etalon was employed to realize the narrow-linewidth laser output. Two highly efficient laser modules and a 90° quartz rotator for birefringence compensation were used for the high output power. The maximum average output power of 62.5 W with the beam quality factor M(2) of 1.15 was achieved under a pump power of 216 W at a repetition rate of 500 Hz, corresponding to the optical-to-optical conversion efficiency of 28.9%. The linewidth of the laser at the maximum output power was measured to be less than 0.2 GHz.

  4. Diode-side-pumped intracavity frequency-doubled Nd:YAG/BaWO4 Raman laser generating average output power of 3.14 W at 590 nm.

    Science.gov (United States)

    Li, Shutao; Zhang, Xingyu; Wang, Qingpu; Zhang, Xiaolei; Cong, Zhenhua; Zhang, Huaijin; Wang, Jiyang

    2007-10-15

    We report a linear-cavity high-power all-solid-state Q-switched yellow laser. The laser source comprises a diode-side-pumped Nd:YAG module that produces 1064 nm fundamental radiation, an intracavity BaWO(4) Raman crystal that generates a first-Stokes laser at 1180 nm, and a KTP crystal that frequency doubles the first-Stokes laser to 590 nm. A convex-plane cavity is employed in this configuration to counteract some of the thermal effect caused by high pump power. An average output power of 3.14 W at 590 nm is obtained at a pulse repetition frequency of 10 kHz.

  5. Treatment of resistant tattoos using a new generation Q-switched Nd:YAG laser: influence of beam profile and spot size on clearance success.

    Science.gov (United States)

    Karsai, Syrus; Pfirrmann, Gudrun; Hammes, Stefan; Raulin, Christian

    2008-02-01

    Multiple treatments of resistant tattoos often result in fibrosis and visible textural changes that lessen response to subsequent treatments. The aim of this study is to evaluate the influence of beam profile and spot size on clearance rates and side effects in the setting of resistant tattoos. Thirty-six professional, black tattoos (32 patients) were treated unsuccessfully with a Q-switched Nd:YAG laser (MedLite C3, HoyaConBio Inc., Fremont, CA). Because of therapy resistance all tattoos were re-treated using a new generation Nd:YAG laser (MedLite C6, HoyaConBio Inc.). Maximum energy fluence (E (max)), mean energy fluence, mean spot size, level of clearance, side effects and beam profile (irradiance distribution) of both laser systems were assessed and evaluated in a retrospective study. All tattoos were previously treated with the C3 laser at 1,064 nm using a mean E(max) of 5.8+/-0.8 J/cm(2) (range 3.8-7.5 J/cm(2)) as compared with a mean E(max) of 6.4+/-1.6 J/cm(2) (range 3.2-9.0 J/cm(2)) during the C6 treatment course. Corresponding spot sizes were larger during C6 treatments as compared with C3 (5.0+/-0.9 and 3.6+/-0.2 mm, respectively). The C6 laser had a "flat top" and homogenous profile regardless of the spot size. For the C3 laser the beam shape was "Gaussian," and the homogeneity was reduced by numerous micro-spikes and micro-nadirs. After the C6 treatment course 33.3% of the tattoos showed clearance of grade 1 (0-25%), 16.7% of grade 2 (26-50%), 16.7% of grade 3 (51-75%), 30.5% of grade 4 (76-95%), 2.8% of grade 5 (96-100%). The total rate of side effects due to C6 treatment was 8.3% in all tattoos (hyperpigmentation 5.6%, hypopigmentation 2.7%, textural changes/scars 0%). This clinical study documents for the first time the impact of a 1,064-nm Nd:YAG laser with a more homogenous beam profile and a larger spot size on the management of resistant tattoos. Only a few treatment sessions were necessary to achieve an additional clearance with a low rate of

  6. Effect of laser beam conditioning on fabrication of clean micro-channel on stainless steel 316L using second harmonic of Q-switched Nd:YAG laser

    Science.gov (United States)

    Singh, Sanasam Sunderlal; Baruah, Prahlad Kr; Khare, Alika; Joshi, Shrikrishna N.

    2018-02-01

    Laser micromachining of metals for fabrication of micro-channels generate ridge formation along the edges accompanied by ripples along the channel bed. The ridge formation is due to the formation of interference pattern formed by back reflections from the beam splitter and other optical components involved before focusing on the work piece. This problem can be curtailed by using a suitable aperture or Iris diaphragm so as to cut the unwanted portion of the laser beam before illuminating the sample. This paper reports an experimental investigation on minimizing this problem by conditioning the laser beam using an Iris diaphragm and using optimum process parameters. In this work, systematic experiments have been carried out using the second harmonic of a Q-switched Nd:YAG laser to fabricate micro-channels. Initial experiments revealed that formation of ridges along the sides of micro-channel can easily be minimized with the help of Iris diaphragm. Further it is noted that a clean micro-channel of depth 43.39 μm, width up to 64.49 μm and of good surface quality with average surface roughness (Ra) value of 370 nm can be machined on stainless steel (SS) 316L by employing optimum process condition: laser beam energy of 30 mJ/pulse, 11 number of laser scans and scan speed of 169.54 μm/s with an opening of 4 mm diameter of Iris diaphragm in the path of the laser beam.

  7. Novel Treatment Approach for Deep Palmoplantar Warts Using Long-Pulsed 1064-nm Nd:YAG Laser and a Moisturizing Cream Without Prior Paring of the Wart Surface.

    Science.gov (United States)

    Alshami, Mohammad Ali; Mohana, Mona Jameel

    2016-10-01

    The present study aimed to assess the safety and efficacy of palmoplantar wart removal using long-pulsed 1064-nm Nd:YAG laser after application of a moisturizing cream. Previously described laser treatments for wart removal are associated with negative side effects and need to pare the warts before laser treatment. Two hundred forty patients (142 males, 98 females) were treated for 1-40 palmoplantar warts by long-pulsed 1064-nm Nd:YAG laser (spot size 4-6 mm, pulse duration 20 msec, fluence 200 J/cm 2 ) after covering the wart surface with a thin film of a moisturizing cream. The endpoint was lesion graying or whitening with or without development of a hemorrhagic bulla beneath the treated wart. Color photographs were taken before and immediately after each laser session and at 1, 4, and 16 weeks after the last session. The overall clearance rate was 97%, with 90% of treated patients cured after one session, 4% after two, and 3% after three. Clearance rate after three laser sessions decreased linearly with the number of warts from 100% to 95%. Less accessible wart location in interdigital spaces also decreased the cure rate after three sessions from 100% to 95%. Additionally, warts became more difficult to eradicate as they aged. Remission lasted up to 6 years, and complications were mild and infrequent (17.5%). This novel method is effective in removing palmoplantar warts. It is easier, time-saving, and safer than other methods described in previous studies conducted with ablative or nonablative lasers.

  8. Comparison of a long-pulse Nd:YAG laser and a combined 585/1,064-nm laser for the treatment of acne scars: a randomized split-face clinical study.

    Science.gov (United States)

    Min, Seong U K; Choi, Yu Sung; Lee, Dong Hun; Yoon, Mi Young; Suh, Dae Hun

    2009-11-01

    Nonablative laser is gaining popularity because of the low risk of complications, especially in patients with darker skin. To compare the efficacy and safety of a long-pulse neodymium-doped yttrium aluminium garnet (Nd:YAG) laser and a combined 585/1,064-nm laser for the treatment of acne scars. Nineteen patients with mild to moderate atrophic acne scars received four long-pulse Nd:YAG laser or combined 585/1,064-nm laser treatment sessions at fortnightly intervals. Treatments were administered randomly in a split-face manner. Acne scars showed mild to moderate improvement, with significant Echelle d'évaluation clinique des cicatrices d'acné (ECCA) score reductions, after both treatments. Although intermodality differences were not significant, combined 585/1,064-nm laser was more effective for deep boxcar scars. In patients with combined 585/1,064-nm laser-treated sides that improved more than long-pulse Nd:YAG laser-treated sides, ECCA scores were significantly lower for combined 585/1,064-nm laser treatment. Histologic evaluations revealed significantly greater collagen deposition, although there was no significant difference between the two modalities. Patient satisfaction scores concurred with physicians' evaluations. Both lasers ameliorated acne scarring with minimal downtime. In light of this finding, optimal outcomes might be achieved when laser treatment types are chosen after considering individual scar type and response.

  9. Microstructural examination of Zr-2.5%Nb alloy welds made by pulsed Nd:YAG laser and TIG welding technique

    International Nuclear Information System (INIS)

    Bhatt, R.B.; Varma, P.V.S.; Panakkal, J.P.; Srivastava, D.; Dey, G.K.

    2009-01-01

    The paper describes the weld microstructure of Zr-2.5%Nb alloy material. Bead on plate welds were made using pulsed Nd:YAG laser and TIG welding technique at different parameters. These welds were characterized at macro and microstructural level. Weld pools of Pulsed Laser and TIG welds were not resolved by optical microscopy. SEM too did not reveal much. Orientation imaging microscopy could reveal the presence of fine martensite. It was observed that microstructure is very sensitive to welding parameters. Microhardness studies suggested formation of martensite in the weld pool. It was also observed that laser welds had very sharp weld pool boundary as compared to TIG welds. Variation in microhardness of the weldment is seen and is influenced by overlapping of weld spots causing thermal treatment of previously deposited spots. (author)

  10. Study of Nd:YAG laser annealing of electroless Ni-P film on spiegel-iron plate by Taguchi method and grey system theory

    Energy Technology Data Exchange (ETDEWEB)

    Liu, W.L. [Department of Materials Science and Engineering, National Formosa University, 64, Wunhua Road, Huwei, Yunlin 632, Taiwan (China); Chien, W.T.; Jiang, M.H. [Department of Mechanical Engineering, National Pingtung University of Science and Technology, 1, Shuehfu Road, Neipu, Pingtung 912, Taiwan (China); Chen, W.J., E-mail: chenwjau@yuntech.edu.t [Graduate School of Materials Science, National Yunlin University of Science and Technology, 123 University Road, Section 3, Douliou, Yunlin 64002, Taiwan (China)

    2010-04-09

    An electroless Ni-P film was first deposited on a spiegel-iron plate and then annealed by an Nd:YAG pulsed wave laser. In order to obtain the optimal laser annealing parameters for maximizing the hardness and minimizing the surface roughness of electroless Ni-P films, the Taguchi method and grey system theory were used to analyze the experimental data. The electroless Ni-P film was also characterized by scanning electron microscopy for the morphology, and transmission electron microscopy for the microstructure and crystal structure. The results showed that the hardness and the surface roughness of electroless Ni-P films can be, at the same time, improved to 50.8% and 68%, respectively, by the laser annealing with the optimal parameters.

  11. Study of Nd:YAG laser annealing of electroless Ni-P film on spiegel-iron plate by Taguchi method and grey system theory

    International Nuclear Information System (INIS)

    Liu, W.L.; Chien, W.T.; Jiang, M.H.; Chen, W.J.

    2010-01-01

    An electroless Ni-P film was first deposited on a spiegel-iron plate and then annealed by an Nd:YAG pulsed wave laser. In order to obtain the optimal laser annealing parameters for maximizing the hardness and minimizing the surface roughness of electroless Ni-P films, the Taguchi method and grey system theory were used to analyze the experimental data. The electroless Ni-P film was also characterized by scanning electron microscopy for the morphology, and transmission electron microscopy for the microstructure and crystal structure. The results showed that the hardness and the surface roughness of electroless Ni-P films can be, at the same time, improved to 50.8% and 68%, respectively, by the laser annealing with the optimal parameters.

  12. Wideband and high-gain frequency stabilization of a 100-W injection-locked Nd:YAG laser for second-generation gravitational wave detectors.

    Science.gov (United States)

    Ohmae, Noriaki; Moriwaki, Shigenori; Mio, Norikatsu

    2010-07-01

    Second-generation gravitational wave detectors require a highly stable laser with an output power greater than 100 W to attain their target sensitivity. We have developed a frequency stabilization system for a 100-W injection-locked Nd:YAG (yttrium aluminum garnet) laser. By placing an external wideband electro-optic modulator used as a fast-frequency actuator in the optical path of the slave output, we can circumvent a phase delay in the frequency control loop originating from the pole of an injection-locked slave cavity. Thus, we have developed an electro-optic modulator made of a MgO-doped stoichiometric LiNbO(3) crystal. Using this modulator, we achieve a frequency control bandwidth of 800 kHz and a control gain of 180 dB at 1 kHz. These values satisfy the requirement for a laser frequency control loop in second-generation gravitational wave detectors.

  13. A promising split-lesion technique for rapid tattoo removal using a novel sequential approach of a single sitting of pulsed CO(2) followed by Q-switched Nd: YAG laser (1064 nm).

    Science.gov (United States)

    Sardana, Kabir; Garg, Vijay K; Bansal, Shivani; Goel, Khushbu

    2013-12-01

    Laser tattoo removal conventionally uses Q-switched (QS) lasers, but they require multiple sittings, and the end results depend largely on the type of tattoo treated. In pigmented skin, due to the competing epidermal pigment results, laser results in tattoo are slow and inadequate. To evaluate the efficacy of a combined use of ultrapulse CO2 and QS Nd:YAG (1064 nm) laser in the treatment of tattoos in Indian skin. A split-lesion trial was carried out in five patients, with the left side of tattoos receiving the QS Nd:YAG (1064 nm) and the right side, a sequential combination of Up CO2 and QS Nd: YAG at 6 weeks interval with a maximum of six sittings. Outcome assessment was carried out by a blinded assessor using standardized photography. An assessment of physician improvement score, side-effects score, and patient satisfaction score was taken during and at the end of the study. There was a statistically significant improvement on the combination side(physician improvement score -3.7 vs. 1.87: P = 0.0019) which occurred earlier with fewer sittings (1.7 vs. 6). There was no statistically significant difference in the side effects. A combination of an Up CO2 laser with QS Nd: YAG laser is a promising tool for rapid and effective removal of blue-black/blue amateur tattoo in pigmented skin. © 2013 Wiley Periodicals, Inc.

  14. Study on the pathogenesis of transient intraocular pressure after laser iridectomy with Krypton laser combined with Q-switched Nd:YAG laser

    Directory of Open Access Journals (Sweden)

    Zhi-Juan Pei

    2017-12-01

    Full Text Available AIM: To study the pathogenesis of transient intraocular pressure(IOPafter laser iridectomy with Krypton laser combined with Q-switched Nd:YAG laser. METHODS: Totally 42 healthy rabbits(84 eyesprovided by the Animal Experimental Center of our hospital were selected, including 18 female rabbits, 24 male rabbits, average weight 2.24±0.31kg, and they were randomly divided into 6 groups, 7 rats in each group(14 eyes. We observed the change of intraocular pressure after laser iridectomy surgery at 20min, 2, 6, 18, 24h and the nitric oxide(NO, malondialdehyde(MDA, superoxide dismutase(SOD, 6-keto-prostaglandin(6-keto-PGF1αand nitric oxide synthase(NOScontent in aqueous. RESULTS: There was no significant difference in intraocular pressure, NO, NOS, SOD, MAD and 6-keto- PGF1α before operation(P>0.05. The intraocular pressure increased after operation, and the difference was statistically significant(PP>0.05. The levels of NO, NOS and SOD in the aqueous humor of the two groups decreased 20min, 2 and 6h after the operation(PP>0.05. The levels of MDA and 6-keto-prostaglandin in the aqueous humor increased after the operation, and the difference was statistically significant at 20min, 2 and 6h after operation(PP>0.05.CONCLUSION: The increase of transient intraocular pressure after laser iridectomy may relate to the increase of malondialdehyde, 6-keto-prostaglandin content and the decrease of superoxide dismutase and nitric oxide in the aqueous humor after operation.

  15. Sensitive detection and separation of fluorescent derivatives using capillary electrophoresis with laser-induced fluorescence detection with 532nm Nd:YAG laser

    International Nuclear Information System (INIS)

    Vrabel, Patrik; Taborsky, Petr; Ryvolova, Marketa; Havel, Josef; Preisler, Jan

    2006-01-01

    Capillary electrophoresis with laser-induced fluorescence detection (CELIF) is a powerful tool for separation and sensitive determination of fluorescent species. Biologically active compounds, such as amino acids, peptides and proteins may exhibit native fluorescence, which is however often low and/or an expensive laser is required for excitation in UV. Therefore, labelling of the analytes with a fluorescent dye is usually necessary. In this work, a home-built CELIF instrument with diode pumped frequency-doubled continuous wave Nd:YAG excitation laser with feedback power regulation (532nm) was constructed. The suitability of this type of laser for LIF detection in a separation method was found excellent. A limit of detection (LOD) (S/N=3) of 2x10 -13 mol/l was achieved with rhodamine B, which is comparable to those obtained using similar instruments with Ar + laser [Y.F. Cheng, N.J. Dovichi, Science 242 (1988) 562, E.S. Yeung et al., J. Chromatogr. 608 (1992) 73]. LOD of a protein derivatized according to modified procedures [M.J. Little et al., Anal. Chim. Acta 339 (1997) 279, A. Chersi et al., Biochim. Biophys. Acta 1336 (1997) 83] was determined. Detection of the derivatives was found to be limited by insufficient reaction recovery at low analyte concentration, chemical noise, separation efficiency and quality of the derivatizing reagent rather than by the detector performance. As a consequence, a huge gap between the detection ability of CELIF instruments and LOD determined in real samples is revealed

  16. Sharpening of the 6.8 nm peak in an Nd:YAG laser produced Gd plasma by using a pre-formed plasma

    Directory of Open Access Journals (Sweden)

    Yong Tian

    2016-03-01

    Full Text Available For effective use of a laser-produced-plasma (LPP light source, an LPP is desired to emit a narrow spectral peak because the reflection spectrum of multilayer mirrors for guiding emission from the source is very narrow. While a Gd plasma has been studied extensively as an extreme ultraviolet (EUV light source at around 6.8 nm, where La/B4C multilayer is reported to have a high reflectivity with a bandwidth of about 0.6 %, all previous works using an Nd:YAG laser reported very broad spectra. This paper reports the first narrowing of the 6.8 nm peak in the case of using an Nd:YAG laser to generate a Gd plasma by using a pre-pulse. The best peak narrowing is observed when a pre-formed plasma is heated by a 1064 nm main laser pulse with a duration of 10 ns at the irradiation density of 4x 1011 W/cm2 at a delay time of 50 ns after the pre-pulse irradiation. The observed spectral width of about 0.3 nm is about one fifth of the value for no pre-formed plasma. The peak wavelength of the 6.8 nm band shifted to a longer wavelength side and the peak was broadened both for lower and higher laser irradiation density. It is discussed that this robustness of the peak position of the 6.8 nm Gd peak against temperature change is suitable to achieve a narrow bandwidth from an LPP generated on solid. The observed spectra are compared with those previously reported in various conditions.

  17. 1064-nm Nd:YAG and 980-nm Diode Laser EDTA Agitation on the Retention of an Epoxy-Based Sealer to Root Dentin.

    Science.gov (United States)

    Macedo, Helena Suleiman de; Messias, Danielle Cristine Furtado; Rached-Júnior, Fuad Jacob; Oliveira, Ligia Teixeira de; Silva-Sousa, Yara Teresinha Correa; Raucci-Neto, Walter

    2016-01-01

    Root canal irrigants are used to minimize the negative effects of smear layer on endodontic sealer retention. The aim of this study was to evaluate the efficacy of agitation of 17% ethylenediaminetetraacetic acid (EDTA) with ultrasonic, 1064-nm Nd:YAG and 980-nm diode laser on the retention of an epoxy-based sealer to the root canal walls. Forty single-rooted bovine teeth were instrumented with ProTaper rotary system and divided into four groups according to the final irrigation protocol (n = 10): (1) 17% EDTA (control); (2) 17% EDTA with 50-s ultrasonic agitation; (3) 17% EDTA with 50-s diode laser (2-W) agitation; and (4) 17% EDTA with 50-s Nd:YAG (1.5-W) laser agitation. After endodontic filling with gutta-percha F5 master cone and Sealer 26, the roots were sectioned at the cervical, middle, and apical root thirds to obtain 1.5-mm slices. Push-out tests were performed using a universal testing machine at a 1 mm/min crosshead speed. Data were analyzed using two-way ANOVA and Tukey's tests (α=0.05). Apical root thirds had significant higher retention values than cervical and middle thirds (p diode laser presented the highest retention values and was significantly different from EDTA with ultrasonic agitation and EDTA only (p diode laser EDTA agitation enhanced the retention of the epoxy-based sealer to the root canal walls compared with that due to EDTA only or EDTA with ultrasonic agitation.

  18. In vitro studies of morphological changes in enamel surface after Er:YAG and Nd:YAG laser irradiation, by SEM; Estudo in vitro do efeito do laser Nd:YAG e Er:YAG sobre o esmalte dental humano atraves de microscopia eletronica de varredura

    Energy Technology Data Exchange (ETDEWEB)

    Verlangieri, Eleonora Jaeger

    2001-07-01

    The caries prevention by using laser irradiation has been investigated by many authors using various lasers with different irradiations conditions. The purpose of this study was to investigated the morphological changes in enamel surface after Er:YAG and Nd:YAG laser irradiation, in vitro, by SEM. Fifteen freshly extracted, intact, caries-free, human third molars, were used in this study. The coronary portions were sectioned, from buccal to lingual direction, in two half-parts. Each one was irradiated by a different laser. The first one was irradiated with water-air spray, by a Nd:YAG laser, at 1.084 nm wave length, at 10 W, 10 Hz, 100 mJ for 60 sec., with an optical fiber in contact mode (0,32 mm of diameter); and the other half, with water-air spray by an Er:YAG laser at 2,94 micrometers wave length at the parameters of 4 Hz, 80 mJ, 24.95 J/cm{sup 2} for 60 sec. The results of this study suggested that both lasers promoted morphological changes in the enamel surface enhancing resistance and can be an alternative clinical method for caries preventions. (author)

  19. Successful treatment of tattoo-induced pseudolymphoma with sequential ablative fractional resurfacing followed by Q-switched Nd: Yag 532 nm laser

    Directory of Open Access Journals (Sweden)

    Tan Siyun Lucinda

    2013-01-01

    Full Text Available Decorative tattooing has been linked with a range of complications, with pseudolymphoma being unusual and challenging to manage. We report a case of tattoo-induced pseudolymphoma, who failed treatment with potent topical and intralesional steroids. She responded well to sequential treatment with ablative fractional resurfacing (AFR followed by Q-Switched (QS Nd:YAG 532 nm laser. Interestingly, we managed to document the clearance of her tattoo pigments after laser treatments on histology and would like to highlight the use of special stains such as the Grocott′s Methenamine Silver (GMS stain as a useful method to assess the presence of tattoo pigment in cases where dense inflammatory infiltrates are present.

  20. Diode-pumped quasi-three-level Nd:GdV O4–Nd:YAG sum-frequency laser at 464 nm

    International Nuclear Information System (INIS)

    Lu, Jie

    2014-01-01

    We report a laser architecture to obtain continuous-wave (cw) blue radiation at 464 nm. A 808 nm diode pumped a Nd:GdV O 4 crystal emitting at 912 nm. A part of the pump power was then absorbed by the Nd:GdV O 4 crystal. The remainder was used to pump a Nd:YAG crystal emitting at 946 nm. Intracavity sum-frequency mixing at 912 and 946 nm was then realized in a LiB 3 O 5 (LBO) crystal to produce blue radiation. We obtained a cw output power of 1.52 W at 464 nm with a pump laser diode emitting 18.4 W at 808 nm. (letter)

  1. Successful Treatment of Tattoo-Induced Pseudolymphoma with Sequential Ablative Fractional Resurfacing Followed by Q-Switched Nd: YAG 532 nm Laser

    Science.gov (United States)

    Lucinda, Tan Siyun; Hazel, Oon Hwee Boon; Joyce, Lee Siong Siong; Hon, Chua Sze

    2013-01-01

    Decorative tattooing has been linked with a range of complications, with pseudolymphoma being unusual and challenging to manage. We report a case of tattoo-induced pseudolymphoma, who failed treatment with potent topical and intralesional steroids. She responded well to sequential treatment with ablative fractional resurfacing (AFR) followed by Q-Switched (QS) Nd:YAG 532 nm laser. Interestingly, we managed to document the clearance of her tattoo pigments after laser treatments on histology and would like to highlight the use of special stains such as the Grocott's Methenamine Silver (GMS) stain as a useful method to assess the presence of tattoo pigment in cases where dense inflammatory infiltrates are present. PMID:24470721

  2. 3D periodic structures grown on silicon by radiation of a pulsed Nd:YAG laser and their field emission properties

    Energy Technology Data Exchange (ETDEWEB)

    Karabutov, A.V. [A.M. Prokhorov General Physics Institute of the Russian Academy of Sciences, 38 Vavilov Street, 119991 Moscow (Russian Federation); Shafeev, G.A. [A.M. Prokhorov General Physics Institute of the Russian Academy of Sciences, 38 Vavilov Street, 119991 Moscow (Russian Federation)]. E-mail: shafeev@kapella.gpi.ru; Badi, N. [Physics Department, The University of Houston, Houston, TX 77204-5005 (United States); Nair, A.M. [TcSAM, The University of Houston, Houston, TX 77204-5004 (United States); Bensaoula, A. [Physics Department, The University of Houston, Houston, TX 77204-5005 (United States)

    2006-04-30

    Periodic three-dimensional structures were successfully grown on single crystal Si wafers either bare or Au-covered under their exposure to a pulsed radiation of a Nd:YAG laser in vacuum. The structures protrude above the initial wafer surface for 10 {mu}m while their spatial period is about 70 {mu}m. The coupling of the laser radiation to Si surface is related to the thermal non-linear absorption of the near band gap radiation. The structures exhibit an efficient field emission with an average emission current of 5 mA/cm{sup 2} and is sensitive to the post-treatment of samples. The drawbacks of the emission current densities are discussed.

  3. Sodium temperature/wind lidar based on laser-diode-pumped Nd:YAG lasers deployed at Tromsø, Norway (69.6°N, 19.2°E).

    Science.gov (United States)

    Kawahara, T D; Nozawa, S; Saito, N; Kawabata, T; Tsuda, T T; Wada, S

    2017-06-12

    An Nd:YAG laser-based sodium temperature/wind lidar was developed for the measurement of the northern polar mesosphere and lower thermosphere at Tromsø (69.6N, 19.2E), Norway. Coherent light at 589 nm is produced by sum frequency generation of 1064 nm and 1319 nm from two diode laser end-pumped pulsed Nd:YAG lasers. The output power is as high as 4W, with 4 mJ/pulse at 1000 Hz repetition rate. Five tilting Cassegrain telescopes enable us to make five-direction (zenith, north, south, east, west) observation for temperature and wind simultaneously. This highly stable laser system is first of its kind to operate virtually maintenance-free during the observation season (from late September to March) since 2010.

  4. Evaluation of the permeability and morphological alteration of the dental surface after apicoectomy, treatment and preparation with Er:YAG and Nd:YAG lasers

    International Nuclear Information System (INIS)

    Oliveira, Rodrigo Guerra de

    2001-01-01

    One of the objectives of endodontic treatment is to resolve pathological periapical processes caused by microbial contamination of the dental pulp. Correct execution of the necessary chemical preparation prior to surgery generally results in positive outcomes. However, a percentage of cases do not respond favorably and therefore require retreatment, a conservative therapeutic option. There are meanwhile a number of treatment failures which do not respond to these conservative measures and must therefore be subjected to paraendodontic surgical procedures. One of the principal problems of this therapeutic conduct is linked to the surface permeability of the dentin after apicoectomy and the lack of adequate marginal adaptation between the retrofilling material and the cavity walls. This permits the percolation of microorganisms and their metabolic by products from the system of root canals to the periapical region, thereby compromising the necessary tissue repair. The present work proposes the evaluation of the surface and marginal permeability of cut dentin after apicoectomy and treatment with Er:YAG and Nd:YAG lasers with fiber optics and then retrofilled with intermediate restorative material (IRM). A total of 24 single rooted teeth whose canals were endodontically treated were divided into 3 experimental groups: group I, whose apices were sectioned with an Er:YAG laser and the resulting cavity and the cut dental surface were irradiated with this laser via a 50/10 type fiber; in group II the apicoectomy was conducted with an Er:YAG laser and the resulting cavity and the cut surface were irradiated with a Nd:YAG laser; in group III, the samples were apicoectomized and the cavities were treated with a high speed bur (control group). Analysis of the infiltration of the dye methylene blue throughout the cut dental surface and the reconstruction demonstrated that the samples in the irradiated groups presented lower indices of infiltration than the control group. The

  5. Short-pulse neodymium:yttrium-aluminium garnet (Nd:YAG 1064nm) laser irradiation photobiomodulates mitochondria activity and cellular multiplication of Paramecium primaurelia (Protozoa).

    Science.gov (United States)

    Amaroli, Andrea; Benedicenti, Alberico; Ravera, Silvia; Parker, Steven; Selting, Wayne; Panfoli, Isabella; Benedicenti, Stefano

    2017-10-01

    Few studies exist to explore the potential photobiomodulation (PBM) effect of neodymium:yttrium-aluminium garnet (Nd:YAG) laser irradiation using a flat-top handpiece delivery system. In this study, we explored the photobiomodulation effect of that laser, on Paramecium primaurelia. The parameters for the different study groups were: 0.50W, 10Hz, 100msp, 30J/cm 2 ; 0.75W, 10Hz, 100msp, 45J/cm 2 ; 1.00W, 10Hz, 100msp, 60J/cm 2 ; 1.25W, 10Hz, 100msp, 75J/cm 2 and 1.50W, 10Hz, 100msp, 90J/cm 2 . Our results suggest that only the parameter 0.5W, 10Hz, 100msp, 30J/cm 2 positively photobiomodulates the Paramecium cells inducing an increment in oxygen consumption, endogenous ATP synthesis and fission rate rhythm. Applying the laser energy with parameters of 1.25W, 10Hz, 100msp, 75J/cm 2 and 1.50W, 10Hz, 100msp, 90J/cm 2 , induce adverse effect on the Paramecium cells, which protect themselves through the increase in Heat Shock Protein-70 (HSP70). The data presented in our work support our assumption that, when using appropriate parameters of irradiation, the 1064nm Nd:YAG laser with flat-top handpiece could be a valuable aid for effective clinical application of PBM. Copyright © 2017 Elsevier GmbH. All rights reserved.

  6. Enlarged pores treated with a combination of Q-switched and micropulsed 1064 nm Nd:YAG laser with and without topical carbon suspension: A simultaneous split-face trial

    OpenAIRE

    Chung, HJ; Goo, BC; Lee, HJ; Roh, MR; Chung, KY

    2011-01-01

    Background and aims: Enlarged facial pores remain one of the major cosmetic concerns among Asian females. This study attempted to assess and compare the efficacy of a combination of the Q-switched and quasi long-pulsed (micropulsed) Nd:YAG laser to reduce the size of the enlarged pores with and without an exogenous photoenhancer.

  7. Shear Bond Strength of Composite and Ceromer Superstructures to Direct Laser Sintered and Ni-Cr-Based Infrastructures Treated with KTP, Nd:YAG, and Er:YAG Lasers: An Experimental Study.

    Science.gov (United States)

    Gorler, Oguzhan; Hubbezoglu, Ihsan; Ulgey, Melih; Zan, Recai; Guner, Kubra

    2018-04-01

    The aim of this study was to examine the shear bond strength (SBS) of ceromer and nanohybrid composite to direct laser sintered (DLS) Cr-Co and Ni-Cr-based metal infrastructures treated with erbium-doped yttrium aluminum garnet (Er:YAG), neodymium-doped yttrium aluminum garnet (Nd:YAG), and potassium titanyl phosphate (KTP) laser modalities in in vitro settings. Experimental specimens had four sets (n = 32) including two DLS infrastructures with ceromer and nanohybrid composite superstructures and two Ni-Cr-based infrastructures with ceromer and nanohybrid composite superstructures. Of each infrastructure set, the specimens randomized into four treatment modalities (n = 8): no treatment (controls) and Er:YAG, Nd:YAG, and KTP lasers. The infrastructures were prepared in the final dimensions of 7 × 3 mm. Ceromer and nanohybrid composite was applied to the infrastructures after their surface treatments according to randomization. The SBS of specimens was measured to test the efficacy of surface treatments. Representative scanning electron microscopy (SEM) images after laser treatments were obtained. Overall, in current experimental settings, Nd:YAG, KTP, and Er:YAG lasers, in order of efficacy, are effective to improve the bonding of ceromer and nanohybrid composite to the DLS and Ni-Cr-based infrastructures (p laser is more effective in the DLS/ceromer infrastructures (p laser, as second more effective preparation, is more effective in the DLS/ceromer infrastructures (p laser modalities, in order of success, Nd:YAG, KTP, and Er:YAG, are effective to increase bonding of these structures.

  8. Treating onychomycoses of the toenail: clinical efficacy of the sub-millisecond 1,064 nm Nd: YAG laser using a 5 mm spot diameter.

    Science.gov (United States)

    Kimura, Utako; Takeuchi, Kaori; Kinoshita, Ayako; Takamori, Kenji; Hiruma, Masataro; Suga, Yasushi

    2012-04-01

    Onychomycosis is a relatively common fungal infection. Current treatments have limited applicability and low cure rates. Recently introduced laser therapy has shown to be a safe and effective treatment for onychomycosis. In this study, we evaluate a submillisecond Nd:YAG 1,064 nm laser for treating onychomycoses of the tonail. Thirteen subjects (9 female, 4 male) with 37 affected toenails received 1 to 3 treatments 4 and/or 8 weeks apart with a sub-millisecond 1,064 nm Nd:YAG laser. Diagnosis of onychomycosis was confirmed with microscopy. Average follow-up time was 16 weeks post-final treatment. Photos were taken and degree of turbidity was determined using a turbidity scale (ranging from "0 = clear nail" to "10 = completely turbid nail") at each visit. Improvement in turbidity was determined by comparison of turbidity scores at baseline and 16-week follow-up on average. Efficacy was assessed by an overall improvement scale (0 to 4), which combined improvement in turbidity scores and microscopic examination. Overall improvement was classified as "4 = complete clearance" if the turbidity score indicated "0 = clear nail" accompanied by a negative microscopic result. No microscopic examination was performed unless the turbidity score showed "0 = clear nail." Treatments were well tolerated by all subjects and there were no adverse events. Of the 37 toenails treated, 30 (81%) had "moderate" to "complete" clearance average of 16 weeks post-final treatment. Nineteen toenails (51%) were completely clear and all tested negative for fungal infection on direct microscopic analysis. Seven (19%) toenails had significant clearance and four (11%) had moderate clearance. The preliminary results of this study show this treatment modality is safe and effective for the treatment of onychomycosis in the short term. Additional studies are needed to more fully assess the clinical and mycological benefits as well as optimize the treatment protocol and parameters.

  9. Detection and Analytical Capabilities for Trace Level of Carbon in High-Purity Metals by Laser-Induced Breakdown Spectroscopy with a Frequency Quintupled 213 nm Nd:YAG Laser

    Directory of Open Access Journals (Sweden)

    Masaki Ohata

    2017-01-01

    Full Text Available The laser-induced breakdown spectroscopy (LIBS with a frequency quintupled 213 nm Nd:YAG laser was examined to the analysis of trace level of carbon (C in high-purity metals and its detection and analytical capabilities were evaluated. Though C signal in a wavelength of 247.9 nm, which showed the highest sensitivity of C, could be obtained from Cd, Ti, and Zn ca. 7000 mg kg−1 C in Fe could not be detected due to the interferences from a lot of Fe spectra. Alternative C signal in a wavelength of 193.1 nm could not be also detected from Fe due to the insufficient laser output energy of the frequency quintupled 213 nm Nd:YAG laser. The depth analysis of C by LIBS was also demonstrated and the C in Cd and Zn was found to be contaminated in only surface area whereas the C in Ti was distributed in bulk. From these results, the frequency quintupled 213 nm Nd:YAG laser, which was adopted widely as a commercial laser ablation (LA system coupled with inductively coupled plasma mass spectrometry (ICPMS for trace element analysis in solid materials, could be used for C analysis to achieve simultaneous measurements for both C and trace elements in metals by LIBS and LA-ICPMS, respectively.

  10. 16.7 W 885 nm diode-side-pumped actively Q -switched Nd:YAG/YVO4 intracavity Raman laser at 1176 nm

    International Nuclear Information System (INIS)

    Jiang, Pengbo; Zhang, Guizhong; Liu, Jian; Ding, Xin; Sheng, Quan; Sun, Bing; Shi, Rui; Wu, Liang; Yao, Jianquan; Yu, Xuanyi; Wang, Rui

    2017-01-01

    We proposed and experimentally demonstrated the generation of high-power 1176 nm Stokes wave by frequency shifting of a 885 nm diode-side-pumped Nd:YAG laser using a YVO 4 crystal in a Z -shaped cavity configuration. Employing the 885 nm diode-side-pumped scheme and the Z -shaped cavity, for the first time to our knowledge, we realized the thermal management effectively, achieving excellent 1176 nm Stokes wave consequently. With an incident pump power of ∼190.0 W, a maximum average output power of 16.7 W was obtained at the pulse repetition frequency of 10 kHz. The pulse duration and spectrum linewidth of the Stokes wave at the maximum output power were 20.3 ns and ∼0.08 nm, respectively. (paper)

  11. Experimental study of the effect of Nd:YAG laser on dental hard tissues: comparison between multi-pulse and free-generation emission code

    International Nuclear Information System (INIS)

    Carballosa Amor, A.; Tellez Jimenez, H.; Ponce Flores, E.; Flores Reyes, T.

    2016-01-01

    The aim of this study is to compare and contrast the morphological changes on dental hard tissue when irradiated with a Nd: YAG laser both on multi-pulse mode, with a Q: Switch of Cr: YAG passive, and on free generation mode. The experimental sample consisted of 6 healthy third molars which were divided equally and randomly between the two emission methods. The depths of each perforation were measured by optical coherence tomography (OCT). It was noted that, despite being less energy in the multi-pulse mode, the first three shots in this achieved deeper cavities than the ones on the free generation mode. Also, less damage to surrounding tissue were obtained on multi-pulse mode. (Author)

  12. A study on the formation of the sharp corner on the cutting of Inconel 718 sheet using CW Nd:YAG laser

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Dong Gyu; Byun, Kyung Won; Yoo, Young Tae [Chosun Univ., Gwangju (Korea, Republic of)

    2008-07-01

    The objective of this paper is to investigate into the formation of the sharp corner according to process parameters and corner angles in the cutting of Inconel 718 sheet using CW Nd:YAG laser. In order to examine the effects of corner angles and the size of loop on the melted area in the sharp corner, several angular and loop cutting experiments were performed using a six-axis controlled automatic robot cutting system. The results of angular cutting experiments showed that the melted area is minimized at 90 .deg. of the corner angle. In addition, the results of the loop cutting experiments showed that the melted area rapidly decreases to nearly zero when the corner angle is greater than 3 mm and the corner angle is 90 .deg.

  13. Influence of Er:YAG and Nd:YAG wavelengths on laser-induced breakdown spectroscopy measurements under air or helium atmosphere

    International Nuclear Information System (INIS)

    Detalle, Vincent; Sabsabi, Mohamad; St-Onge, Louis; Hamel, Andre; Heon, Rene

    2003-01-01

    Laser-induced breakdown spectroscopy (LIBS) is widely dependent on the conditions of its implementation in terms of laser characteristics (wavelength, energy, and pulse duration), focusing conditions, and surrounding gas. In this study two wavelengths, 1.06 and 2.94 μm, obtained with Nd:YAG and Er:YAG lasers, respectively, were used for LIBS analysis of aluminum alloy samples in two conditions of surrounding gas. The influence of the laser wavelength on the laser-produced plasma was studied for the same irradiance by use of air or helium as a buffer gas at atmospheric pressure. We used measurements of light emission to determine the temporally resolved space-averaged electron density and plasma temperature in the laser-induced plasma. We also examined the effect of laser wavelength in two different ambient conditions in terms of spectrochemical analysis by LIBS. The results indicate that the effect of the surrounding gas depends on the laser wavelength and the use of an Er:YAG laser could increase linearity by limiting the leveling in the calibration curve for some elements in aluminum alloys. There is also a significant difference between the plasma induced by the two lasers in terms of electron density and plasma temperature

  14. An investigation on capability of hybrid Nd:YAG laser-TIG welding technology for AA2198 Al-Li alloy

    Science.gov (United States)

    Faraji, Amir Hosein; Moradi, Mahmoud; Goodarzi, Massoud; Colucci, Pietro; Maletta, Carmine

    2017-09-01

    This paper surveys the capability of the hybrid laser-arc welding in comparison with lone laser welding for AA2198 aluminum alloy experimentally. In the present research, a continuous Nd:YAG laser with a maximum power of 2000 W and a 350 A electric arc were used as two combined welding heat sources. In addition to the lone laser welding experiments, two strategies were examined for hybrid welding; the first one was low laser power (100 W) accompanied by high arc energy, and the second one was high laser power (2000 W) with low arc energy. Welding speed and arc current varied in the experiments. The influence of heat input on weld pool geometry was surveyed. The macrosection, microhardness profile and microstructure of the welded joints were studied and compared. The results indicated that in lone laser welding, conduction mode occurred and keyhole was not formed even in low welding speeds and thus the penetration depth was so low. It was also found that the second approach (high laser power accompanied with low arc energy) is superior to the first one (low laser power accompanied with high arc energy) in hybrid laser-arc welding of Al2198, since lower heat input was needed for full penetration weld and as a result a smaller HAZ was created.

  15. A Single-Center, Randomized, Double-Blind, Placebo-Controlled Clinical Trial of the Effectiveness of ANT1 Soybean Extract Cream on Skin Recovery After Nd: YAG Laser Treatment.

    Science.gov (United States)

    Hsieh, Meng-Chien; Wu, Yi-Chia; Huang, Shu-Hung; Kuo, Yur-Ren; Lee, Su-Shin

    2018-02-01

    Nd:YAG laser has been used extensively for its versatility in treating many common aesthetic problems, but numerous adverse effects are often complained by recipients of Nd:YAG laser. This study introduces the ANT1 soybean extract cream, which was formulated to alleviate adverse effects after laser therapy. This study explores whether ANT1 enhances the repair mechanism of the postlaser skin, decreases laser-induced complication, and shortens recovery time. The study also aims to pinpoint the ANT1 concentration that is most effective in improving the skin condition after Nd-YAG laser therapy. This study was a single-center, randomized, double-blind, placebo-controlled trial. Patients eligible for the study were Asian women, aged 25 to 40 years, who were free of dermatological diseases and allergic reaction. There were a total of 45 subjects. Each subject received a session of Nd-YAG laser therapy every 2 weeks, totaling 3 sessions. Facial skin assessment was achieved via VISIA complexion analysis. VISIA complexion analysis quantitatively assessed the skin condition and tracked the recovery progress of each subject at baseline, immediately after all 3 laser sessions, and a week after the final laser treatment. Skin condition was evaluated by VISIA complexion analysis. Skin condition was recorded in aspects of pigmented spots, wrinkles, texture, pores, and red area. After Nd-YAG laser therapy, postlaser inflammation was observed in all subjects. Throughout the laser sessions and the outpatient follow-up clinic, the adverse effects of laser therapy, such as redness, spots, wrinkles, pores, and textures, decreased with the use of ANT1 cream. There has been a marked effect in wrinkle reduction in the patients who received a higher concentration of ANT1 cream (P ≤ 0.05). Statistically significant improvement in spots and pores is also seen (P ≤ 0.05). Through this study, the results suggest that the application of ANT1 soybean extract cream ameliorates the

  16. Two-photon excitation laser scanning microscopy of porcine nasal septal cartilage following Nd:YAG laser-mediated stress relaxation

    Science.gov (United States)

    Kim, Charlton C.; Wallace, Vincent P.; Rasouli, Alexandre; Coleno, Mariah L.; Dao, Xavier; Tromberg, Bruce J.; Wong, Brian J.

    2000-05-01

    Laser irradiation of hyaline cartilage result in stable shape changes due to temperature dependent stress relaxation. In this study, we determined the structural changes in chondrocytes within porcine nasal septal cartilage tissue over a 4-day period using a two-photon laser scanning microscope (TPM) following Nd:YAG laser irradiation (lambda equals 1.32 micrometer) using parameters that result in mechanical stress relaxation (6.0 W, 5.4 mm spot diameter). TPM excitation (780 nm) result in induction of fluorescence from endogenous agents such as NADH, NADPH, and flavoproteins in the 400 - 500 nm spectral region. During laser irradiation diffuse reflectance (from a probe HeNe laser, (lambda) equals 632.8 nm), surface temperature, and stress relaxation were measured dynamically. Each specimen received one, two, or three sequential laser exposures (average irradiation times of 5, 6, and 8 seconds). The cartilage reached a peak surface temperature of about 70 degrees Celsius during irradiation. Cartilage denatured in 50% EtOH (20 minutes) was used as a positive control. TPM was performed using a mode-locked 780 nm Titanium:Sapphire (Ti:Al203) beam with a, 63X, 1.2 N.A. water immersion objective (working distance of 200 mm) to detect the fluorescence emission from the chondrocytes. Images of chondrocytes were obtained at depths up to 150 microns (lateral resolution equals 35 micrometer X 35 micrometer). Images were obtained immediately following laser exposure, and also after 4 days in culture. In both cases, the irradiated and non-irradiated specimens do not show any discernible difference in general shape or auto fluorescence. In contrast, positive controls (immersed in 50% ethanol), show markedly increased fluorescence relative to both the native and irradiated specimens, in the cytoplasmic region.

  17. Combination of Q-switched and quasi long-pulsed 1064-nm Nd:YAG laser, non-ablative 1450-nm diode laser, and ablative 10 600-nm carbon dioxide fractional laser for enlarged pores.

    Science.gov (United States)

    Cho, Sung Bin; Noh, Seongmin; Lee, Sang Ju; Kang, Jin Moon; Kim, Young Koo; Lee, Ju Hee

    2010-07-01

    Currently, there is no gold standard for the treatment of enlarged facial pores. In this report, we describe a patient with enlarged nasal pores which were treated with a combination of a non-ablative 1450-nm diode laser, a Q-switched and quasi long-pulsed 1064-nm Nd:YAG laser, and an ablative 10 600-nm carbon dioxide fractional laser system. Four months after the final treatment, the condition of the patient's pores had markedly improved, and the patient was satisfied with the results.

  18. A randomized, controlled, split-face clinical trial of 1320-nm Nd:YAG laser therapy in the treatment of acne vulgaris.

    Science.gov (United States)

    Orringer, Jeffrey S; Kang, Sewon; Maier, Lisa; Johnson, Timothy M; Sachs, Dana L; Karimipour, Darius J; Helfrich, Yolanda R; Hamilton, Ted; Voorhees, John J

    2007-03-01

    There is a need for additional effective treatments for acne vulgaris. Laser therapy has been explored as a therapeutic option for acne, but rigorously designed studies in this area have been limited. We sought to examine the efficacy of an infrared laser in the treatment of acne. We conducted a randomized, controlled, single-blind, split-face clinical trial of 46 patients with facial acne. Patients received a series of 3 nonablative laser treatments using a novel neodymium:yttrium-aluminum-garnet (Nd:YAG) laser to half of the face. Serial blinded lesion counts and global acne severity rating of standardized bilateral patient photographs were performed. Sebum production was measured, and patient self-assessment surveys were administered. A transient but statistically significant improvement in lesion counts of open comedones was demonstrated in treated skin as compared with untreated skin. There were no significant differences between treated and control sides of the face in terms of changes in mean papule or pustule counts. Grading of serial photographs revealed no significant differences between treated and untreated skin. Patient surveys indicated that the majority of patients found the treatments to be at least mildly effective for both acne and oiliness. The current study only addresses the efficacy of a single laser system employing a specific treatment regimen. Infrared laser therapy may improve comedonal acne. Additional work is needed to better define the degree and duration of the effect. Patients appear to positively view such therapy for both acne and oily skin.

  19. Quantitative analysis of manganese concentration in manganese-doped glasses by laser-induced breakdown spectroscopy using a nanosecond ultraviolet Nd:YAG laser

    International Nuclear Information System (INIS)

    Unnikrishnan, V.K.; Nayak, Rajesh; Kartha, V.B.; Santhosh, C.; Sonavane, M.S.; Yeotikar, R.G.; Gupta, G.P.; Suri, B.M.

    2012-01-01

    Laser-induced breakdown spectroscopy (LIBS) has been well recognized as a simple, fast and direct analytical technique for the analysis of elemental analysis of multi-element materials by a number of research groups all over the world. It is based on the focusing of a high-power pulsed laser beam with a power density > 100 MW/cm 2 onto a sample surface followed by optical emission spectroscopy of the plasma produced over the surface. During the last two decades, LIBS has attracted a lot of attention, leading to an ever increasing list of applications, both in laboratory and in industry. In this work, the quantitative analysis of manganese in manganese-doped glass samples in air at atmospheric pressure has been carried out by the LIBS system assembled and optimized in the laboratory. The plasma is generated using a nanosecond ultraviolet Nd:YAG laser with an irradiance of 1x10 9 W/cm 2 on the sample surface. The spatially integrated plasma light emission was collected and imaged on to the spectrograph slit using an optical-fibre-based collection system. An Echelle spectrograph-ICCD system (Andor Mechelle ME5000-DH734-18U-03PS150) was used to record the emission spectrum. The spectrograph with an Echelle grating covers 200-975 nm spectral range in a single shot with a good wavelength resolution (0.05 nm). The detector was gated in synchronization with the laser pulse to get maximum signal-to-background (S/B) ratio. The detector gate width of 2 μs and the detector gate delay of 2 μs were chosen for recording the plasma emission signals, discriminating the continuum radiation which is intense at initial delay time less than 300 ns and decreases at later time

  20. Nd:YAG laser irradiation effects on electrical properties of polycrystalline Li{sub 0.5}Fe{sub 2.5}O{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Mane, Maheshkumar L., E-mail: mane.maheshkumar@hotmail.com [Department of physics, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad (M.S.) 431 004 (India); Dhage, V.N.; Shirsath, Sagar E. [Department of physics, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad (M.S.) 431 004 (India); Sundar, R.; Ranganathan, K.; Oak, S.M. [Solid State Laser Division, Raja Ramanna Centre for Advanced Technology, Indore (M.P.) (India); Jadhav, K.M. [Department of physics, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad (M.S.) 431 004 (India)

    2012-01-15

    Highlights: > Standard double sintering ceramic method. > Infrared and electrical properties of spinel ferrite. > Laser irradiation study. > Conduction mechanism. > Temperature dependence dielectric properties. - Abstract: The polycrystalline spinel structured Li{sub 0.5}Fe{sub 2.5}O{sub 4} ferrite have been prepared by conventional double sintering ceramic method. The samples were palletized and irradiated by Nd:YAG laser with different laser fluencies and characterized by infrared spectroscopy and DC electrical resistivity in order to obtain phase, crystal structure and conduction mechanism in pristine and irradiated samples. The infrared spectroscopy is employed to study the local symmetry and conduction mechanism in crystalline solids before and after irradiation. The DC electrical resistivity measured by two-probe technique from room temperature to beyond Curie temperature with steps of 10 K increases after laser irradiation. Variation of dielectric properties like dielectric constant and dielectric loss tangent is also measured as a function of temperature. A significant reduction in the values of dielectric constant and dielectric loss tangent has been observed with the increase of laser dose.

  1. Tattoo removal in micropigs with low-energy pulses from a Q-switched Nd:YAG laser at 1064 nm

    Science.gov (United States)

    Hu, Xin-Hua; Wooden, W. A.; Cariveau, Mickael J.; Fang, Qiyin; Bradfield, J. F.; Kalmus, Gerhard W.; Vore, S. J.; Sun, Y.

    2001-05-01

    Treatment of pigmented lesions in skin with visible or near- infrared nanosecond (ns) laser pulses often causes significant collateral tissue damage because the current approach uses pulses with energy of 300 mJ or larger. Additionally, this requires large Q-switched laser systems. To overcome these disadvantages, we have investigated a different approach in delivering ns laser pulses for cutaneous lesion treatment. Tattoo removal in an animal model with a focused laser beam from a Q-switched Nd:YAG laser has been investigated in two Yucatan micropigs tattooed with blue, black, green and red pigments. The tattoos were treated with a focused beam of 12-ns pulses at 1064 nm, with different depth under the skin surface, while the micropig was translated to achieve an effect of single pulse per ablation site in the skin. With the pulse energy reduced to a range from 38 to 63 mJ, we found that nearly complete clearance was achieved for blue and black tattoos while clearance of red and green tattoos was incomplete. Analysis of the skin appearance suggested that the pulse energy can be decreased to below 20 mJ which may lead to further reduction of the collateral tissue damage and improve the clearance of red and green tattoos.

  2. Identification and Removal of High Frequency Temporal Noise in a Nd:YAG Macro-Pulse Laser Assisted with a Diagnostic Streak Camera

    International Nuclear Information System (INIS)

    Kent Marlett; Ke-Xun Sun

    2004-01-01

    This paper discusses the use of a reference streak camera (SC) to diagnose laser performance and guide modifications to remove high frequency noise from Bechtel Nevada's long-pulse laser. The upgraded laser exhibits less than 0.1% high frequency noise in cumulative spectra, exceeding National Ignition Facility (NIF) calibration specifications. Inertial Confinement Fusion (ICF) experiments require full characterization of streak cameras over a wide range of sweep speeds (10 ns to 480 ns). This paradigm of metrology poses stringent spectral requirements on the laser source for streak camera calibration. Recently, Bechtel Nevada worked with a laser vendor to develop a high performance, multi-wavelength Nd:YAG laser to meet NIF calibration requirements. For a typical NIF streak camera with a 4096 x 4096 pixel CCD, the flat field calibration at 30 ns requires a smooth laser spectrum over 33 MHz to 68 GHz. Streak cameras are the appropriate instrumentation for measuring laser amplitude noise at these very high frequencies since the upper end spectral content is beyond the frequency response of typical optoelectronic detectors for a single shot pulse. The SC was used to measure a similar laser at its second harmonic wavelength (532 nm), to establish baseline spectra for testing signal analysis algorithms. The SC was then used to measure the new custom calibration laser. In both spatial-temporal measurements and cumulative spectra, 6-8 GHz oscillations were identified. The oscillations were found to be caused by inter-surface reflections between amplifiers. Additional variations in the SC spectral data were found to result from temperature instabilities in the seeding laser. Based on these findings, laser upgrades were made to remove the high frequency noise from the laser output

  3. Improvement of the surface finish obtained by laser ablation with a Nd: YAG laser on pre-ablated tool steel

    CSIR Research Space (South Africa)

    Steyn, J

    2007-01-01

    Full Text Available . In recent years, these lasers have been used in other fields, such as laser ablation of small tools for plastics injection moulding. Laser ablation is a technology that is investigated as a method to improve the surface finish in tool steel. Different...

  4. Treatment of melasma with low fluence, large spot size, 1064-nm Q-switched neodymium-doped yttrium aluminum garnet (Nd:YAG) laser for the treatment of melasma in Fitzpatrick skin types II-IV.

    Science.gov (United States)

    Brown, Alia S; Hussain, Mussarat; Goldberg, David J

    2011-12-01

    Melasma is a common condition affecting over six million American women. Treatment of dermal or combined melasma is difficult and does not respond well to conventional topical therapies. Various light sources have been used recently in the treatment of melasma including fractionated ablative and non-ablative lasers as well as intense pulse light. We report the use of low fluence, large spot size Q-switched, Nd:Yag laser for the treatment of melasma in skin types II-IV.

  5. Experimental Study of The Physical Properties of The Laser Diode (AlGaAs/GaAs) (Arsenic Gallium Aluminum) To Use as a Pumping Source of Laser Nd:YAG

    International Nuclear Information System (INIS)

    Dayoub, N.; Altwel, E.

    2009-01-01

    The research includes an experimental study of the physical properties of the laser diode (AlGaAs/GaAs). We have made a detailed display of the structure of diode and mechanism of its operation, as well as its convenience as a pumping source for Solid-state laser Nd:YAG. Then we studied the changes of potential difference (expressing the capacity of laser diode) by the dependence of diode temperature, for variant intensity of the injection current, and the changes of potential by dependence of the injection current; and finally, we made a study of the capacity of laser diode output by dependence of the injection current. (author)

  6. Fluorescence imaging of lattice re-distribution on step-index direct laser written Nd:YAG waveguide lasers

    Energy Technology Data Exchange (ETDEWEB)

    Martínez de Mendívil, Jon; Pérez Delgado, Alberto; Lifante, Ginés; Jaque, Daniel [Departamento de Física de Materiales, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid 28049 (Spain); Ródenas, Airán [Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Tarragona 43007 (Spain); Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom); Benayas, Antonio, E-mail: antonio.benayas@emt.inrs.ca [Departamento de Física de Materiales, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid 28049 (Spain); Institut National de la Recherche Scientifique, Centre – Énergie Matériaux et Télécommunications, 1650, Boul. Lionel Boulet Varennes, Quebec J3X 1S2 (Canada); Aguiló, Magdalena; Diaz, Francesc [Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Tarragona 43007 (Spain); Kar, Ajoy K. [Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom)

    2015-01-14

    The laser performance and crystalline micro-structural properties of near-infrared step-index channel waveguides fabricated inside Neodymium doped YAG laser ceramics by means of three-dimensional sub-picosecond pulse laser direct writing are reported. Fluorescence micro-mapping of the waveguide cross-sections reveals that an essential crystal lattice re-distribution has been induced after short pulse irradiation. Such lattice re-distribution is evidenced at the waveguide core corresponding to the laser written refractive index increased volume. The waveguides core surroundings also present diverse changes including slight lattice disorder and bi-axial strain fields. The step-index waveguide laser performance is compared with previous laser fabricated waveguides with a stress-optic guiding mechanism in absence of laser induced lattice re-distribution.

  7. Preliminary panoramic study of river calm muscle using neodymium:yttrium-aluminum-garnet (Nd: YAG) laser-induced breakdown spectroscopy (LIBS)

    Science.gov (United States)

    Idris, N.; Lahna, K.; Usmawanda, T. N.; Herman; Ramli, M.; Hedwig, R.; Marpaung, A. M.; Kurniawan, K. H.

    2018-04-01

    A wide coverage spectral investigation on the muscle of river calm sample has been carried out using laser-induced breakdown spectroscopy for examining the overall profile of the emission spectra from the produced plasma. The basic apparatus of LIBS system used is a Nd-YAG laser and wide coverage optical multichannel analyzer (OMA) system. The river clam samples used is collected from Panga River in Aceh Jaya Regency, Aceh, Indonesia up streaming in a mountain of Gunong Ujeun, which is used as a location of the intensive traditional mining activity. Assuming that heavy metal accumulated in the clam muscle, LIBS experiments were carried out on the muscle of the calm. The sample used was fresh muscle sliced and attached to a copper plate. Plasma was generated by focusing the laser beam on the sample surface under air surrounding gas at 1 atmosphere. It is found that there are only major elements of host organic, namely C, H, O, N and the minor element of salts can be detected from fresh the clam sample when using a high pulse laser energy under air surrounding at high pressure of 1 atmosphere. There is no emission lines from any metal can be detected. Several experimental parameters were explored to study the panoramic dynamic of the emission spectra. It is found that the lower energy and the lower pressure is better for obtaining better emission spectra showing the possibility for determination of the analyte.

  8. Parametric Study On The CW Nd: YAG Laser Cutting Quality Of 1.25 mm Ultra Low Carbon Steel Sheets Using O2 Assist Gas

    International Nuclear Information System (INIS)

    Salem, Hanadi G.; Abbas, Wafaa A.; Mansour, Mohy S.; Badr, Yehia A.

    2007-01-01

    There are many non-linear interaction factors responsible for the performance of the laser cutting process. Identification of the dominant factors that significantly affect the cut quality is important. In the current research, the gas pressure, laser power and scanning speed were selected as the cutting parameters. Effect of the cutting parameters on the cut quality was investigated, by monitoring the variation in hardness, oxide layer width and microstructural changes within the heat affected zone (HAZ). Results revealed that good quality cuts can be produced in ultra low carbon steel thin sheets, using CW Nd:YAG laser at a window of scanning speed ranging from 1100-1500 mm/min at a minimum heat input of 337watts under an assisting O2 gas pressure of 5 bar. Higher laser power resulted in either strengthening or softening in the HAZ surrounding the cut kerf. The oxide layer width is not affected by the energy density input but rather affected by the O2 gas pressure due to exothermal reaction

  9. Characteristics of a Ti:sapphire laser pumped by a Nd:YAG laser and its analysis. Nd:YAG laser reiki Ti:sapphire laser no dosa tokusei to sono kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Okada, T.; Masumoto, J.; Mizunami, T.; Maeda, M.; Muraoka, K. (Kyushu Univ., Fukuoka (Japan). Faculty of Engineering)

    1991-06-29

    Although Ti: Sapphire expects of a possibility of being a light source much superior to a dye laser having been used as a wavelength variable laser for spectral analyses, it has a limitation that it does not oscillate directly in the visible and ultraviolet regions. In order to develop a light source that is synchronizable over ultraviolet-near infrared regions, by means of combining a Ti: Sapphire laser of a high peak power, comprising an oscillator and a multistage amplifier, with a non-linear frequency conversion method for harmonic generation and Raman conversion, a prototype Ti:Sapphire laser that is excited by YAG laser second harmonic, and that synchronizes with a prism was fabricated, and its operational characteristics were investigated. As a result, an output energy of 35.6 mJ at a maximum was obtained at a wavelength of 773 nm against an excitation energy of 129 mJ, a conversion efficiency of 38.2% was obtained against the absorption energy of the crystals, and a continuous synchronism was achieved over 750 to 900 nm. 4 refs., 9 figs., 1 tab.

  10. Transformation of medical grade silicone rubber under Nd:YAG and excimer laser irradiation: First step towards a new miniaturized nerve electrode fabrication process

    International Nuclear Information System (INIS)

    Dupas-Bruzek, C.; Robbe, O.; Addad, A.; Turrell, S.; Derozier, D.

    2009-01-01

    Medical grade silicone rubber, poly-dimethylsiloxane (PDMS) is a widely used biomaterial. Like for many polymers, its surface can be modified in order to change one or several of its properties which further allow this surface to be functionalized. Laser-induced surface modification of PDMS under ambient conditions is an easy and powerful method for the surface modification of PDMS without altering its bulk properties. In particular, we profit from both UV laser inducing surface modification and of UV laser micromachining to develop a first part of a new process aiming at increasing the number of contacts and tracks within the same electrode surface to improve the nerve selectivity of implantable self sizing spiral cuff electrodes. The second and last part of the process is to further immerse the engraved electrode in an autocatalytic Pt bath leading in a selective Pt metallization of the laser irradiated tracks and contacts and thus to a functionalized PDMS surface. In the present work, we describe the different physical and chemical transformations of a medical grade PDMS as a function of the UV laser and of the irradiation conditions used. We show that the ablation depths, chemical composition, structure and morphology vary with (i) the laser wavelength (using an excimer laser at 248 nm and a frequency-quadrupled Nd:YAG laser at 266 nm), (ii) the conditions of irradiation and (iii) the pulse duration. These different modified properties are expected to have a strong influence on the nucleation and growth rates of platinum which govern the adhesion and the thickness of the Pt layer on the electrodes and thus the DC resistance of tracks.

  11. Evaluation of the permeability and morphological alteration of the dental surface after apicoectomy, treatment and preparation with Er:YAG and Nd:YAG lasers; Avaliacao da permeabilidade e da alteracao morfologica da superficie dentinaria apos apicectomia, tratamento e retropreparo com os lasers de Er:YAG e Nd:YAG

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Rodrigo Guerra de

    2001-07-01

    One of the objectives of endodontic treatment is to resolve pathological periapical processes caused by microbial contamination of the dental pulp. Correct execution of the necessary chemical preparation prior to surgery generally results in positive outcomes. However, a percentage of cases do not respond favorably and therefore require retreatment, a conservative therapeutic option. There are meanwhile a number of treatment failures which do not respond to these conservative measures and must therefore be subjected to paraendodontic surgical procedures. One of the principal problems of this therapeutic conduct is linked to the surface permeability of the dentin after apicoectomy and the lack of adequate marginal adaptation between the retrofilling material and the cavity walls. This permits the percolation of microorganisms and their metabolic by products from the system of root canals to the periapical region, thereby compromising the necessary tissue repair. The present work proposes the evaluation of the surface and marginal permeability of cut dentin after apicoectomy and treatment with Er:YAG and Nd:YAG lasers with fiber optics and then retrofilled with intermediate restorative material (IRM). A total of 24 single rooted teeth whose canals were endodontically treated were divided into 3 experimental groups: group I, whose apices were sectioned with an Er:YAG laser and the resulting cavity and the cut dental surface were irradiated with this laser via a 50/10 type fiber; in group II the apicoectomy was conducted with an Er:YAG laser and the resulting cavity and the cut surface were irradiated with a Nd:YAG laser; in group III, the samples were apicoectomized and the cavities were treated with a high speed bur (control group). Analysis of the infiltration of the dye methylene blue throughout the cut dental surface and the reconstruction demonstrated that the samples in the irradiated groups presented lower indices of infiltration than the control group. The

  12. Current treatments of acne: Medications, lights, lasers, and a novel 650-μs 1064-nm Nd: YAG laser.

    Science.gov (United States)

    Gold, Michael H; Goldberg, David J; Nestor, Mark S

    2017-09-01

    The treatment of acne, especially severe acne, remains a challenge to dermatologists. Therapies include retinoids, antibiotics, hormones, lights, lasers, and various combinations of these modalities. Acne is currently considered a chronic rather than an adolescent condition. The appropriate treatment depends on the patient and the severity of disease. The purpose of this study was to review current therapies for acne of all severities and to introduce the 650-μs 1064-nm laser for the treatment of acne. © 2017 Wiley Periodicals, Inc.

  13. Nd: YAG laser irradiation effects on structural and magnetic properties of Ni1+xZrxFe2-2xO4 nanoparticles

    Science.gov (United States)

    Saraf, Tukaram S.; Kounsalye, Jitendra S.; Birajdar, Shankar D.; Shamkuwar, N. R.

    2018-05-01

    The effect of 112 mJ Nd: YAG laser irradiation on structural, morphological, infrared and magnetic properties of Ni1+xZrxFe2-2xO4 spinel ferrite nanoparticles has been systematically investigated in the present work. The sol-gel auto combustion synthesis method was successfully executed for the synthesis of the present system. All the samples were characterized by X-ray diffraction technique (XRD), scanning electron microscopy (SEM) and infrared spectroscopy (IR) technique. The magnetic properties of the present samples were measured by pulse field hysteresis loop technique. All the properties were measured for laser irradiated samples as well, to understand the effect of irradiation on the properties. The single-phase cubic spinel structure was confirmed by X-ray diffraction patterns of all samples and the disordered structure was observed for irradiated samples. The two principle absorption bands in IR spectra also confirm the formation of the spinel structure. Spherical and agglomerated morphology was observed for Zr4+ substituted nickel ferrite, whereas scratched morphology was observed for the irradiated samples. The grain size confirms the nanocrystalline nature, the crystallite size also evident the same. The magnetic parameters decreased after Zr4+ ion doping and strongly influenced by the irradiation.

  14. Review of progress in pulsed laser deposition and using Nd:YAG laser in processing of high Tc superconductors

    International Nuclear Information System (INIS)

    Chen, C.W.; Mukherjee, K.

    1993-01-01

    The current progress in pulsed laser ablation of high-temperature superconductors is reviewed with emphasis on the effect of pulse-width and wavelength, nature of the plasma plume, post-annealing and methods to improve quality of films grown at low temperature. An ion beam assisted millisecond pulsed laser vapor deposition process has been developed to fabricate YBa 2 Cu 3 O x high T. superconductor thin films. Solution to target overheating problem, effects of oxygen ion beam, properties of deposited films, and effect of silver buffer layer on YSZ substrate are presented. A new laser calcining process has been used to produce near single phase high T c superconductors of Bi-Pb-Sr-Ca-Cu-0 system. The total processing time was reduced to about 100 hours which is about half of that for conventional sintering. For this compound both resistance and magnetic susceptibility data showed an onset of superconducting transition at about 110K. A sharp susceptibility drop was observed above 106K. The zero resistance temperature was about 98K. High T c phase was formed via a different kinetic path in laser calcined sample compare with the conventionally processed sample

  15. Experimental Investigations on Pulsed Nd:YAG Laser Welding of C17300 Copper-Beryllium and 49Ni-Fe Soft Magnetic Alloys

    International Nuclear Information System (INIS)

    Mousavi, S. A. A. Akbari; Ebrahimzadeh, H.

    2011-01-01

    Copper-beryllium and soft magnetic alloys must be joined in electrical and electro-mechanical applications. There is a high difference in melting temperatures of these alloys which cause to make the joining process very difficult. In addition, copper-beryllium alloys are of age hardenable alloys and precipitations can brittle the weld. 49Ni-Fe alloy is very hot crack sensitive. Moreover, these alloys have different heat transfer coefficients and reflection of laser beam in laser welding process. Therefore, the control of welding parameters on the formation of adequate weld puddle composition is very difficult. Laser welding is an advanced technique for joining of dissimilar materials since it can precisely control and adjust the welding parameters. In this study, a 100W Nd:YAG pulsed laser machine was used for joining 49Ni-Fe soft magnetic to C17300 copper-beryllium alloys. Welding of samples was carried out autogenously by changing the pulse duration, diameter of beam, welding speed, voltage and frequency. The spacing between samples was set to almost zero. The ample were butt welded. It was required to apply high voltage in this study due to high reflection coefficient of copper alloys. Metallography, SEM analysis, XRD and microhardness measurement was used for survey of results. The results show that the weld strength depends upon the chemical composition of the joints. To change the wells composition and heat input of the welds, it was attempted to deviate the laser focus away from the weld centerline. The best strength was achieved by deviation of the laser beam away about 0.1mm from the weld centerline. The result shows no intermetallic compounds if the laser beam is deviated away from the joint.

  16. Local Effects on Lung Parenchyma Using a 600 µm Bare Fiber with the Diode-Pumped Nd:YAG Laser LIMAX® 120

    Directory of Open Access Journals (Sweden)

    Peter Rexin

    2015-12-01

    Full Text Available Lung metastases are frequently removed with an Nd:YAG laser. The aim is to perform a non-anatomic resection of all intraoperatively palpable lung metastases completely in order to preserve the largest possible amount of healthy lung parenchyma. The surgeon can either work with a focusing handpiece or use a laser fiber of the so-called bare fiber with direct contact to the lung parenchyma. We currently use a 600 µm bare fiber for applications involving the lung parenchyma. Precise data on the local effect of the laser fiber on the lung parenchyma are not available, especially with regard to an increase in the laser energy. We want to study this question within the scope of an experimental model in pig lungs by means of systematic and reproducible tests. The lung lobes were removed from animals recently slaughtered in the abattoir and taken to the laboratory immediately, where the lobes were stored such that the surface of the lungs was parallel to the floor. A 600 µm bare fiber was attached to a mounting bracket vertically above the lung surface at a distance of either 0, 5, or 10 mm. This mounting bracket was in turn connected to a hydraulic feed motor. The feed motor is capable of moving the bare fiber forward across the lungs consistently at three different speeds (5 mm/s, 10 mm/s, or 20 mm/s. The bare fiber itself was connected to the diode-pumped Nd: YAG Laser LIMAX® 120 (Gebrüder Martin GmbH & Co KG, Tuttlingen, Germany. We carried out the tests using three different laser powers: 20 W, 60 W, and 120 W. The lung lesions caused by the laser in each of the lungs were resected and sent in for histological analysis. The exact size of the vaporization and coagulation zone was measured using the HE sections, and the respective mean values (with standard deviations were ascertained. For all laser powers, the extent of the vaporization was greatest with a motion speed of 5 mm/s for the respective laser power: 756.4 ± 1.2 µm (20 W, 1411.0 ± 2

  17. Enlarged pores treated with a combination of Q-switched and micropulsed 1064 nm Nd:YAG laser with and without topical carbon suspension: A simultaneous split-face trial.

    Science.gov (United States)

    Chung, Hj; Goo, Bc; Lee, Hj; Roh, Mr; Chung, Ky

    2011-01-01

    Enlarged facial pores remain one of the major cosmetic concerns among Asian females. This study attempted to assess and compare the efficacy of a combination of the Q-switched and quasi long-pulsed (micropulsed) Nd:YAG laser to reduce the size of the enlarged pores with and without an exogenous photoenhancer. In twenty five female subjects mean age 34.04 yr and skin type II-IV, a carbon lotion as a photoenhancer was applied on one side of the face (Method 1) and the other side was used as the control (Method 2). The entire face was then treated with a single pass of the 1064 nm Nd:YAG laser in the micropulsed mode, pulse fluence and width of 2.3 J/cm(2) and 300 µsec, respectively. Multiple passes were then delivered in the Q-switched mode (2.5 J/cm(2) and 5 nsec). Three weeks after the final treatment, 75% of the subjects showed improvement with method 1 whereas 67% showed improvement with method 2. No adverse side effects were reported with either method. Although histological confirmation was not performed, we were able to prove both subjectively and objectively that the use of the combination of the micropulsed and Q-switched modes of the Nd:YAG laser was useful in reducing pore size, and that the photoenhancer improved the efficacy.

  18. All solid-state diode pumped Nd:YAG MOPA with stimulated Brillouin phase conjugate mirror

    NARCIS (Netherlands)

    Offerhaus, Herman L.; Godfried, Herman; Godfried, H.P; Witteman, W.J.

    1996-01-01

    At the Nederlands Centrum voor Laser Research (NCLR) a 1 kHz diode-pumped Nd:YAG Master Oscillator Power Amplifier (MOPA) chain with a Stimulated Brillouin Scattering (SBS) Phase Conjugate mirror is designed and operated. A small Brewster angle Nd:YAG slab (2 by 2 by 20 mm) is side pumped with 200

  19. Pulsed Nd:YAG laser deposition of indium tin oxide thin films in different gases and organic light emitting device applications

    International Nuclear Information System (INIS)

    Yong, T.Y.; Tou, T.Y.; Yow, H.K.; Safran, G.

    2008-01-01

    The microstructures, electrical and optical properties of indium-doped tin oxide (ITO) films, deposited on glass substrates in different background gases by a pulsed Nd:YAG laser, were characterized. The optimal pressure for obtaining the lowest resistivity in ITO thin film is inversely proportional to the molecular weight of the background gases, namely the argon (Ar), oxygen (O 2 ), nitrogen (N 2 ) and helium (He). While substrate heating to 250 deg. C decreased the ITO resistivity to -4 Ω cm, obtaining the optical transmittance of higher than 90% depended mainly on the background gas pressure for O 2 and Ar. Obtaining the lowest ITO resistivity, however, did not beget a high optical transmittance for ITO deposition in N 2 and He. Scanning electron microscope pictures show distinct differences in microstructures due to the background gas: nanostructures when using Ar and N 2 but polycrystalline for using O 2 and He. The ITO surface roughness varied with the deposition distance. The effects on the molecularly doped, single-layer organic light emitting device (OLED) operation and performance were also investigated. Only ITO thin films prepared in O 2 and Ar are suitable for the fabrication OLED with performance comparable to that fabricated on the commercially available, magnetron-sputtered ITO

  20. Effects of Nd:YAG laser irradiation on structural, morphological, cation distribution and magnetic properties of nanocrystalline CoFe{sub 2}O{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Mane, Maheshkumar L., E-mail: mane.maheshkumar@hotmail.com [Department of Physics, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad (M.S.) 431004 (India); Dhage, Vinod N. [Department of Physics, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad (M.S.) 431004 (India); Sundar, R.; Ranganathan, K.; Oak, S.M. [Solid State Laser Division, Raja Ramanna Center for Advanced Technology, Indore (M.P.) (India); Shengule, D.R.; Jadhav, K.M. [Department of Physics, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad (M.S.) 431004 (India)

    2011-08-01

    The cobalt ferrite nanoparticles of 20 nm size were synthesized by sol-gel auto-combustion technique. The samples were irradiated with Nd:YAG laser to understand the effects of irradiation on structural, cation distribution and magnetic properties. The virgin and irradiated samples were characterized by X-ray diffraction technique. The X-ray diffraction studies at room temperature shows that defects were created in the lattice after irradiation which causes effects on structural, cation distribution and magnetic properties. The energy dispersive analysis of X-rays (EDAX) showed the chemical composition is as per the expected stichiometry. The lattice constant observed from XRD data for virgin and irradiated samples shows increasing trend after irradiation. Cation distribution was investigated by using X-ray diffraction method. We observe decrease in magnetization of the samples after irradiation. The observed reduction in the saturation magnetization after irradiation can be understood on the basis of the partial formation of paramagnetic centers and rearrangement of cations in the lattice.

  1. Effect of the overlapping factor on the microstructure and mechanical properties of pulsed Nd:YAG laser welded Ti6Al4V sheets

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Xiao-Long; Liu, Jing; Zhang, Lin-Jie, E-mail: zhanglinjie@mail.xjtu.edu.cn; Zhang, Jian-Xun

    2014-07-01

    The effect of the overlapping factor on the microstructures and mechanical properties of pulsed Nd:YAG laser welded Ti6Al4V alloy sheets was investigated by microstructural observations, microhardness tests, tensile tests and fatigue tests. A microstructural examination shows that by increasing the overlapping factor, the grains in the fusion zone become coarser, and the width of the heat affected zone increases. As overlapping factor increases, the width of region composed completely of martensite α′ and the secondary α phase in the heat affected zone increases, consequently the gradient of microstructure along the direction from the fusion zone to base metal decreases, so does the gradient of microhardness. The results of tensile and fatigue tests reveal that the joints made using medium overlapping factor exhibit better mechanical properties than those welded with low and high overlapping factors. Based on the experimental results, it can be stated that a sound weld of Ti6Al4V alloy can be obtained if an appropriate overlapping factor is used. - Highlights: • The weld quality of Ti6Al4V alloy under various overlapping factors was assessed. • Tensile and fatigue tests were conducted with as-welded specimen. • Localized strain across the weld was measured using DIC photogrammetry system. • A sound weld of Ti6Al4V alloy is obtained by using right overlapping factor.

  2. Plasma emission induced by an Nd-YAG laser at low pressure on solid organic sample, its mechanism, and analytical application

    International Nuclear Information System (INIS)

    Suliyanti, Maria Margaretha; Sardy, Sar; Kusnowo, Anung; Hedwig, Rinda; Abdulmadjid, Syahrun Nur; Kurniawan, Koo Hendrik; Lie, T.J.; Pardede, Marincan; Kagawa, Kiichiro; Tjia, M.O.

    2005-01-01

    An Nd-YAG laser (1064 nm, 120 mJ, 8 ns) was focused on various types of solid organic samples such as a black acrylic plate, a black polyvinyl chloride plastic sheet, and a methoxy polyaniline film coated on the surface of a glass substrate, under a surrounding air pressure of 2 Torr. A modulated plasma technique was used to study the mechanism of excitation of the emission of the organic material. As a result, we conclude that ablated atoms and molecules are excited by a shock-wave mechanism, similar to the case of hard samples such as metal. The ablation speed of hydrogen emission (H I 656.2 nm) was examined and the results show that the release speed of the ablated atoms is relatively low (less than Mach 10) and persists for a longer period of time (around 1 μs); this phenomenon can be understood by assuming that the soft target absorbs recoil energy, causing a low release speed of ablated atoms which would form the shock wave. This was overcome by placing a subtarget on the back of the soft sample so as to enhance the repelling force, thus increasing the release speed of the atoms. A possible application of the low-pressure plasma on an organic solid was demonstrated in the detection of chlorine in a black polyvinyl chloride plastic sheet

  3. Stress analysis and optimization of Nd:YAG pulsed laser processing of notches for fracture splitting of a C70S6 connecting rod

    International Nuclear Information System (INIS)

    Kou, Shuqing; Gao, Yan; Zhao, Yong; Lin, Baojun

    2017-01-01

    The pulsed laser pre-processing of a notch as the fracture initiation source for the splitting process is the key mechanism of an advanced fracture splitting technology for C70S6 connecting rods. This study investigated the stress field of Nd:YAG pulsed laser grooving, which affects the rapid fracture initiation at the notch root and the controlled crack extension in the critical fracture splitting quality, to improve manufacturing quality. Thermal elastic-plastic incremental theory was applied to build the finite element analysis model of the stress field of pulsed laser grooving for fracture splitting based on the Rotary-Gauss body heat source. The corresponding numerical simulation of the stress field was conducted. The changes and distributions of the stress during pulsed laser grooving were examined, the influence rule of the primary technological parameters on the residual stress was analyzed, and the analysis results were validated by the corresponding cutting experiment. Results showed that the residual stress distribution was concentrated in the Heat-affected zone (HAZ) near the fracture splitting notch, which would cause micro-cracks in the HAZ. The stress state of the notch root in the fracture initiation direction was tensile stress, which was beneficial to the fracture initiation and the crack rapid extension in the subsequent fracture splitting process. However, the uneven distribution of the stress could lead to fracture splitting defects, and thus the residual stress should be lowered to a reasonable range. Decreasing the laser pulse power, increasing the processing speed, and lowering the pulse width can lower the residual stress. Along with the actual production, the reasonable main technological parameters were obtained.

  4. Stress analysis and optimization of Nd:YAG pulsed laser processing of notches for fracture splitting of a C70S6 connecting rod

    Energy Technology Data Exchange (ETDEWEB)

    Kou, Shuqing; Gao, Yan; Zhao, Yong; Lin, Baojun [Jilin University, Changchun (China)

    2017-05-15

    The pulsed laser pre-processing of a notch as the fracture initiation source for the splitting process is the key mechanism of an advanced fracture splitting technology for C70S6 connecting rods. This study investigated the stress field of Nd:YAG pulsed laser grooving, which affects the rapid fracture initiation at the notch root and the controlled crack extension in the critical fracture splitting quality, to improve manufacturing quality. Thermal elastic-plastic incremental theory was applied to build the finite element analysis model of the stress field of pulsed laser grooving for fracture splitting based on the Rotary-Gauss body heat source. The corresponding numerical simulation of the stress field was conducted. The changes and distributions of the stress during pulsed laser grooving were examined, the influence rule of the primary technological parameters on the residual stress was analyzed, and the analysis results were validated by the corresponding cutting experiment. Results showed that the residual stress distribution was concentrated in the Heat-affected zone (HAZ) near the fracture splitting notch, which would cause micro-cracks in the HAZ. The stress state of the notch root in the fracture initiation direction was tensile stress, which was beneficial to the fracture initiation and the crack rapid extension in the subsequent fracture splitting process. However, the uneven distribution of the stress could lead to fracture splitting defects, and thus the residual stress should be lowered to a reasonable range. Decreasing the laser pulse power, increasing the processing speed, and lowering the pulse width can lower the residual stress. Along with the actual production, the reasonable main technological parameters were obtained.

  5. Effect of Nd:YAG laser light on post-extractive socket healing in rats treated with zoledronic acid and dexamethasone

    Science.gov (United States)

    Mergoni, Giovanni; Merigo, Elisabetta; Passerini, Pietro; Corradi, Domenico; Maestri, Roberta; Bussolati, Ovidio; Bianchi, Massimiliano; Sala, Roberto; Govoni, Paolo; Namour, Samir; Vescovi, Paolo

    2016-03-01

    Introduction The effect of low level laser therapy (LLLT) on the healing process could be useful for the prevention of post-extractive Bisphosphonate-related Osteonecrosis of the Jaws (BRONJ). The aim of the study was to investigate the effect of LLLT on the post-extractive socket healing in rats treated with zoledronic acid and dexamethasone. Material and Methods Thirty male Sprague-Dawley rats were divided in 4 groups: control group (C, n = 5), laser group (L, n = 5), treatment group (T, n = 10) and treatment plus laser group (T+L, n = 10). Rats of group T and T+L received zoledronate 0,1 mg/Kg and dexamethasone 1 mg/Kg every 2 days for 10 weeks. Rats of group C and L were infused with vehicle. After 9 weeks the first maxillary molars were extracted in all rats. Rats of groups L and T+L received laser therapy (Nd:YAG, 1064 nm, 1.25W, 15Hz, 5 min, 14.37 J/cm2) in the socket area at days 0, 2, 4 and 6 after surgery. At 8 days from extraction, the sockets were clinically assessed with a grading score and the wound area was measured with a dedicate software. Histomorphometric evaluation and western blot analysis of osteopontin and osteocalcin expression were performed. Results Group T+L showed a trend toward a better clinical grading score compared to group T (grade I 22% Vs 28 % - grade II 56% Vs 28% - grade III 22% Vs 44%, respectively). The average wound area was similar among the groups. Inhibition of osteoclastic alveolar bone resorption was found in groups T and T+L (Phealing in conditions at risk for MRONJ development.

  6. Clinical study on the removal of gingival melanin pigmentation: comparison between Nd:YAG laser ablation and mechanical abrasion; Estudo clinico comparativo entre as tecnicas de despigmentacao melanica gengival: laser neodimio (1064 nm) e gengivoabrasao

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Luis Mario de Melo

    2002-07-01

    Melanin pigmentation occurs as a result of excessive deposition of melanin, produced by the melanocytes present in the basal layer of the epithelium. This study compares clinical parameters such as inflammation and/or hemorrhage, healing process and re-pigmentation, caused by the Nd:YAG laser ablation and the mechanical abrasion of the melanin, by means of photographic images, taken during the first 30 days after the treatment. The patients comfort was monitored during the first ten days after the treatment using the method of the Visual Analog Scale to measure the pain. Six patients with gingival melanin pigmentation were selected. The left upper gingival quadrant was treated with the Nd:YAG laser using 125 mJ per pulse and 20 Hz, the right upper gingival quadrant received mechanical abrasion and the lower quadrants served for control. Both techniques did not result in inflammation and/or hemorrhage. The healing process was slower with the laser. Using mechanical abrasion, ali patients showed remaining pigmentation or re-pigmentation of varying intensity after a period of 30 days. With the laser 50 % of the patients did not show any re-pigmentation after this period. The pain analysis showed that the pain sensed 24 hours after the treatment with the laser is higher than using mechanical abrasion. (author)

  7. Early intraocular pressure change after peripheral iridotomy with ultralow fluence pattern scanning laser and Nd:YAG laser in primary angle-closure suspect: Kowloon East Pattern Scanning Laser Study Report No. 3.

    Science.gov (United States)

    Chan, Jeffrey Chi Wang; Choy, Bonnie Nga Kwan; Chan, Orlando Chia Chieh; Li, Kenneth Kai Wang

    2018-02-01

    Our purpose was to assess the early intraocular pressure (IOP) changes of ultralow fluence laser iridotomy using pattern scanning laser followed by neodymium:yttrium-aluminum-gamet (Nd:YAG) laser. This is a prospective interventional study. Thirty-three eyes of 33 adult Chinese primary angle-closure suspect subjects were recruited for prophylactic laser peripheral iridotomy. Sequential laser peripheral iridotomy was performed using pattern scanning laser followed by Nd:YAG laser. Visual acuity (VA) and IOP were measured before treatment, at 1 h, 1 day, 1 week, 1 month, 3 months and 6 months after laser. Laser energy used and complications were documented. Corneal endothelial cell count was examined at baseline and 6 months. Patency of the iridotomy was assessed at each follow-up visit. All subjects achieved patent iridotomy in a single session. The mean energy used was 0.335+/-0.088 J for the pattern scanning laser, and 4.767+/-5.780 mJ for the Nd:YAG laser. The total mean energy was 0.339+/-0.089 J. None of the eyes developed a clinically significant IOP spike (≥ 8 mmHg) at 1 h and 1 day after laser use. Only four eyes developed higher IOP at 1 h and all were ≤3 mmHg compared to baseline. The mean IOP was 13.8+/-2.5 mmHg at 1 h and 11.5+/-2.2 mmHg at 1 day, both were significantly lower than baseline (15.8+/-2.1 mmHg) (P laser compared to baseline (0.23 vs 0.26). There was also no statistically significant difference in mean VA at other follow-up visits compared to baseline. Peripheral iridotomy closure was encountered in two (6.1%) eyes, one at 1 month and another at 6 months follow-up. There were no complications including hyphema, peripheral anterior synechia formation nor prolonged inflammation throughout the follow-up period. There was no significant loss in corneal endothelial cell counts at 6 months (2255+/-490) compared to baseline (2303+/-386) (P = 0.347). Sequential LPI using an ultralow fluence pattern scanning laser

  8. Nanosecond Nd-YAG laser induced plasma emission characteristics in low pressure CO{sub 2} ambient gas for spectrochemical application on Mars

    Energy Technology Data Exchange (ETDEWEB)

    Lie, Zener Sukra; Kurniawan, Koo Hendrik, E-mail: kurnia18@cbn.net.id [Research Center of Maju Makmur Mandiri Foundation, 40/80 Srengseng Raya, Jakarta 11630 (Indonesia); Pardede, Marincan [Department of Electrical Engineering, University of Pelita Harapan, 1100 M.H. Thamrin Boulevard, Lippo Village, Tangerang 15811 (Indonesia); Tjia, May On [Research Center of Maju Makmur Mandiri Foundation, 40/80 Srengseng Raya, Jakarta 11630 (Indonesia); Physics of Magnetism and Photonics Group, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, 10 Ganesha, Bandung 40132 (Indonesia); Kagawa, Kiichiro [Fukui Science Education Academy, Takagi Chuou 2 choume, Fukui 910-0804 (Japan); Research Center of Maju Makmur Mandiri Foundation, 40/80 Srengseng Raya, Jakarta 11630 (Indonesia)

    2015-08-28

    An experimental study is conducted on the possibility and viability of performing spectrochemical analysis of carbon and other elements in trace amount in Mars, in particular, the clean detection of C, which is indispensible for tracking the sign of life in Mars. For this study, a nanosecond Nd-YAG laser is employed to generate plasma emission from a pure copper target in CO{sub 2} ambient gas of reduced pressure simulating the atmospheric condition of Mars. It is shown that the same shock wave excitation mechanism also works this case while exhibiting remarkably long cooling stage. The highest Cu emission intensities induced by 4 mJ laser ablation energy is attained in 600 Pa CO{sub 2} ambient gas. Meanwhile the considerably weaker carbon emission from the CO{sub 2} gas appears relatively featureless over the entire range of pressure variation, posing a serious problem for sensitive trace analysis of C contained in a solid sample. Our time resolved intensity measurement nevertheless reveals earlier appearance of C emission from the CO{sub 2} gas with a limited duration from 50 ns to 400 ns after the laser irradiation, well before the initial appearance of the long lasting C emission from the solid target at about 1 μs, due to the different C-releasing processes from their different host materials. The unwanted C emission from the ambient gas can thus be eliminated from the detected spectrum by a proper time gated detection window. The excellent spectra of carbon, aluminum, calcium, sodium, hydrogen, and oxygen obtained from an agate sample are presented to further demonstrate and verify merit of this special time gated LIBS using CO{sub 2} ambient gas and suggesting its viability for broad ranging in-situ applications in Mars.

  9. Laser Application in Dentistry: Irradiation Effects of Nd:YAG 1064 nm and Diode 810 nm and 980 nm in Infected Root Canals—A Literature Overview

    Science.gov (United States)

    Kuypers, Thorsten; Gutknecht, Norbert

    2016-01-01

    Objective. In endodontics, Nd:YAG laser (1064 nm) and diode laser (810 nm and 980 nm) devices are used to remove bacteria in infected teeth. A literature review was elaborated to compare and evaluate the advantages and disadvantages of using these lasers. Methods. Using combined search terms, eligible articles were retrieved from PubMed and printed journals. The initial search yielded 40 titles and 27 articles were assigned to full-text analysis. The studies were classified based upon laser source, laser energy level, duration/similarity of application, and initial and final bacterial count at a minimum of 20 prepared root canals. Part of the analysis was only reduced microorganisms and mechanically treated root canals upon preparation size of ISO 30. All studies were compared to evaluate the most favorable laser device for best results in endodontic therapy. Results. A total of 22 eligible studies were found regarding Nd:YAG laser 1064 nm. Four studies fulfilled all demanded criteria. Seven studies referring to the diode laser 980 nm were examined, although only one fulfilled all criteria. Eleven studies were found regarding the diode laser 810 nm, although only one study fulfilled all necessary criteria. Conclusions. Laser therapy is effective in endodontics, although a comparison of efficiency between the laser devices is not possible at present due to different study designs, materials, and equipment. PMID:27462611

  10. Laser Application in Dentistry: Irradiation Effects of Nd:YAG 1064 nm and Diode 810 nm and 980 nm in Infected Root Canals-A Literature Overview.

    Science.gov (United States)

    Saydjari, Yves; Kuypers, Thorsten; Gutknecht, Norbert

    2016-01-01

    Objective. In endodontics, Nd:YAG laser (1064 nm) and diode laser (810 nm and 980 nm) devices are used to remove bacteria in infected teeth. A literature review was elaborated to compare and evaluate the advantages and disadvantages of using these lasers. Methods. Using combined search terms, eligible articles were retrieved from PubMed and printed journals. The initial search yielded 40 titles and 27 articles were assigned to full-text analysis. The studies were classified based upon laser source, laser energy level, duration/similarity of application, and initial and final bacterial count at a minimum of 20 prepared root canals. Part of the analysis was only reduced microorganisms and mechanically treated root canals upon preparation size of ISO 30. All studies were compared to evaluate the most favorable laser device for best results in endodontic therapy. Results. A total of 22 eligible studies were found regarding Nd:YAG laser 1064 nm. Four studies fulfilled all demanded criteria. Seven studies referring to the diode laser 980 nm were examined, although only one fulfilled all criteria. Eleven studies were found regarding the diode laser 810 nm, although only one study fulfilled all necessary criteria. Conclusions. Laser therapy is effective in endodontics, although a comparison of efficiency between the laser devices is not possible at present due to different study designs, materials, and equipment.

  11. Long-term evaluation of ink clearance in tattoos with different color intensity using the 1064-nm Q-switched Nd:YAG laser.

    Science.gov (United States)

    Mankowska, Agata; Kasprzak, Wojciech; Adamski, Zygmunt

    2015-12-01

    The aim of the study was to evaluate the efficacy of tattoo removal treatments using the 1064-nm Q-switched (QS) Nd:YAG laser. Today, QS lasers appear to be the most common, effective, and safest methods to treat unwanted markings. A total of 64 patients with 75 unwanted tattoos were enrolled in the study. Tattoo clearance was evaluated according to the color intensity - concentration of pigment: group I (34) - black; group II (41) - gray. Consideration included methods of tattooing and tattoo techniques. In group I, after the first treatment session the median of clearance was 30% (10-50%), while in group II, the median was 50% (40-70%). After the second treatment session, median in group I increased to 40% (30-50%). Median of group II increased to 70% (50-80%). The highest number of treatment in group I was 7. After that, the median grew to 75%, while the highest amount of treatment in group II was 5 and a median of 90% was achieved. Effects were dependent upon the amount of ink deposited in the tissue. Old amateur tattoos and tattoos containing small quantities of ink (technique: shading and lines) demonstrated the quickest and the most efficacious results. Tattoos with large quantities of ink, obtained by filling, required the greatest number of treatment sessions. The final outcome in tattoo clearing can only be assessed following treatment completion, which may in some cases take 2-3 years. Presumably, in some cases, complete clearance is impossible. © 2015 Wiley Periodicals, Inc.

  12. Q-switched Nd: YAG laser alone or with modified Jessner chemical peeling for treatment of mixed melasma in dark skin types: A comparative clinical, histopathological, and immunohistochemical study.

    Science.gov (United States)

    Saleh, Fatma; Moftah, Noha H; Abdel-Azim, Eman; Gharieb, Marwa G

    2017-10-22

    Treatment of mixed melasma remains challenging. Promising results have been achieved with low-fluence 1064-nm Q-switched Nd-YAG laser; however, multiple sessions are necessary with occurrence of complications especially in dark skin types. So, combination methods may be recommended. To compare efficacy of Q-switched Nd-YAG laser alone or with modified Jessner's peel in mixed melasma in dark skin. Nineteen patients with mixed melasma received 6 sessions of laser on left side of face and alternating laser and modified Jessner on right side. Evaluation was carried out clinically through modified melasma area and severity index at 1 month after last session. Using histopathological, immunohistochemical, and computerized morphometric analysis, objective evaluation of melanin particle surface area and MART-1-positive cells was performed for pre- and post-treated skin biopsies. There was significant clinical improvement on both sides of face (P  .05). At the sixth laser session on left side of face, ill-defined mottled hypopigmentation was observed in 21.05% of patients. Histopathologically, melanin particle surface area and number of MART-1-positive cells (total, epidermal, and dermal) were significantly decreased after two treatment modalities (P  .05). Low-fluence Q-switched Nd-YAG laser alone and with modified Jessner's peel are equally effective regimens for mixed melasma clinically, histopathologically, and immunohistochemically. However, combined method is preferred, especially in dark skin, for obtaining better cosmetic result with fewer side effects of multiple laser sessions and decreasing cost rate of laser. © 2017 Wiley Periodicals, Inc.

  13. Self-controlled Study of Onychomycosis Treated with Long-pulsed Nd:YAG 1064-nm Laser Combined with Itraconazole

    Directory of Open Access Journals (Sweden)

    Yan Li

    2016-01-01

    Conclusions: For patients with mild or moderate onychomycosis, we recommended a pure medication treatment or combination treatment with medication and laser. For those patients with severe onychomycosis, we recommended a combination of medication and laser therapy.

  14. Solar Pumped Nd:YAG Laser with Fresnel Lens%使用菲涅耳透镜的太阳光抽运Nd:YAG激光器

    Institute of Scientific and Technical Information of China (English)

    罗萍萍; 刘诚; 徐鹏; 赵长明; 杨苏辉; 钱燕雷

    2011-01-01

    太阳能是规模最大的可再生能源,为充分利用这一资源,太阳光直接抽运激光器是一种明智的选择.提出并搭建了采用两级会聚系统的太阳光抽运激光器系统.使用菲涅耳透镜作为大口径成像型第一级会聚系统,漫反射锥形聚光腔作为非成像型第二级会聚系统提高入射太阳光到工作物质的耦合效率.采用Nd:YAG晶体作为工作物质,获得了2.85 W的激光输出,从太阳光到激光的转换效率为0.43%.从菲涅耳透镜会聚效率、聚光腔内激光棒轴线上的功率分布等会聚系统方面和激光输出特性方面分析了该太阳光抽运激光器的性能;探讨了转换效率低的原因,并提出了相应的改进措施.%Solar energy is the most abundant renewable energy among all kinds of energy sources, solar pumped laser can be the best choice in terms of the fully utilization of solar energy. The solar pumped laser with two stage sunlight concentration system is designed and constructed. A Fresnel lens with large diameter is adopted as a primary optical concentration device? And a cone type diffuse pumping chamber functions as a secondary concentrator is used to enhance the couple efficiency between the incident solar power and laser media. Output laser power is up to 2. 85 W, with the use of Nd! YAG crystal as laser media, and 0. 43% optical conversion efficiency is achieved. The performance of solar pumped laser is discussed by the concentration efficiency of Fresnel lens and the power distribution along the axis of laser rod in the cavity, as well as the laser characteristic. The reasons for low efficiency are discussed, and improvement approaches are presented.

  15. On line monitoring of a welding process by pulsed Nd-YAG laser; Controle en ligne d'un procede de soudage par laser Nd-YAG pulse

    Energy Technology Data Exchange (ETDEWEB)

    Chardon, St.; Voisin, Y.; Gorria, P. [Universite de Bourgogne, Lab. LE2I, 21 - Dijon (France); Vauzelle, Th. [CEA/Valduc, Dept. Fabrications et Technologies Nucleaires, DFTN, 21 - Is-sur-Tille (France)

    1999-07-01

    Laser weld quality inspection can be assured by the machine qualification (before and during welding), and by on line monitoring of the operation. The similarity of the signals produced by pulsed lasers (machine or interaction) leads us to develop a specific data acquisition and processing software. During a welding operation, laser-material interaction results in a characteristically emission of optical, acoustical and electrical signals. These signals are measured by different kinds of sensors (photodiode, microphone, or an electric probe), then recorded and treated with the quoted software. Signal processing tools utilization in conjunction with classification techniques (stress polytopes), introduce an innovating approach of on line inspection. Discriminant parameters determination (signals/defect correlation) become thus automatic and non subjective. (authors)

  16. NUMERICAL SIMULATION OF Q-SWITCHED Nd: YAG LASER WITH UNSTABLE RESONATOR AND OUTPUT VARIABLE REFLECTIVITY MIRROR

    Directory of Open Access Journals (Sweden)

    I. N. Dubinkin

    2017-05-01

    Full Text Available The article deals with a method of numerical simulation of laser oscillation in the radially symmetric unstable resonator with an output variable reflectivity mirror (VRM. Research results of the VRM parameters influence on the spatial and energy properties of the laser radiation are obtained. Numerical simulation of laser oscillation in active and passive Q-switching and comparative analysis of the spatial and energy radiation characteristics is done for these modes.

  17. A comparative study with a 755 nm picosecond Alexandrite laser with a diffractive lens array and a 532 nm/1064 nm Nd:YAG with a holographic optic.

    Science.gov (United States)

    Tanghetti Md, Emil; Jennings, John

    2018-01-01

    This study was performed to better understand the cutaneous effects of using a fractional picosecond laser at 755 nm with a diffractive lens array and a picosecond Nd:YAG laser at 532 mn and 1064 nm with a holographic optic. We characterized the injuries created by these devices on skin clinically and histologically over 24 hours. With this information we modeled the effects of these devices on a cutaneous target. Eight patients, representing Fitzpatrick skin types I-VI, were treated on their backs with a picosecond Alexandrite laser with a diffractive lens array, as well as a picosecond Nd:YAG laser at 532 nm and 1064 nm with a holographic optic. Photographs were taken 15 minutes and 24 hours after treatments. Punch biopsies were obtained at 24 hours and examined histologically. Treatment with the picosecond Nd:YAG laser at both 532 nm and 1064 nm with the holographic optic revealed erythema and small scatted areas of petechial hemorrhage areas immediately and in many cases at 24 hours after treatment. The 755 nm picosecond Alexandrite laser with diffractive lens array produced erythema immediately after treatment, which largely dissipated 24 hours later. Histologies revealed intra-epidermal vacuoles with all three wavelengths. Fractional picosecond Nd:YAG laser at 532 nm and 1064 nm with the holographic optic showed focal areas of dermal and intra-epidermal hemorrhage with areas of vascular damage in some patients. This study demonstrates that both fractional picosecond devices produce vacuoles in the skin, which are most likely due to areas of laser induced optical breakdown (LIOB). In the patients (skin type II-IV) we observed scatter areas of hemorrhage in the skin, due to vascular damage with the 532 nm and 1064 nm, but not with 755 nm wavelengths. Lasers Surg. Med. 50:37-44, 2018. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  18. Thermal analysis of different application techniques on Nd:YAG laser after root canal preparation of single-rooted teeth; Analise termica de diferentes tecnicas de utilizacao do laser de Nd:YAG apos o preparo quimico-cirurgico de dentes unirradiculares

    Energy Technology Data Exchange (ETDEWEB)

    Archilla, Jose Ricardo de F

    2001-07-01

    The experiment objective is to analyze temperature variation, by means of three different application techniques of Nd:YAG laser in the root canals of singlerooted anterior teeth. Three root canals were instrumented, irrigated, X-rayed to measure the remaining dentin in the apical area and submitted to laser irradiation techniques used by Gutknecht, Matsumoto and a new technique with oscillatory movement. The used laser parameters were: pulse energy 250 mJ, frequency 5 Hz, pulse fluency 354 J/cm{sup 2}, average potency 1,25 W, pulse width 300 {mu}s, fiber core diameter 300 {mu}s and interval of thermal relaxation of 20 s. After temperature evaluation and interpretation of the obtained data, it was concluded: 1) the oscillatory technique provided a better heat distribution during the laser application, when analyzing the graphs separately; 2) all the used techniques are within a pattern of safety, analyzing the average and highest temperatures of the apical area and the middle third, even so, disrespecting the last application day and the middle third of root 'C'.(author)

  19. Thermal analysis of different application techniques on Nd:YAG laser after root canal preparation of single-rooted teeth; Analise termica de diferentes tecnicas de utilizacao do laser de Nd:YAG apos o preparo quimico-cirurgico de dentes unirradiculares

    Energy Technology Data Exchange (ETDEWEB)

    Archilla, Jose Ricardo de F

    2001-07-01

    The experiment objective is to analyze temperature variation, by means of three different application techniques of Nd:YAG laser in the root canals of singlerooted anterior teeth. Three root canals were instrumented, irrigated, X-rayed to measure the remaining dentin in the apical area and submitted to laser irradiation techniques used by Gutknecht, Matsumoto and a new technique with oscillatory movement. The used laser parameters were: pulse energy 250 mJ, frequency 5 Hz, pulse fluency 354 J/cm{sup 2}, average potency 1,25 W, pulse width 300 {mu}s, fiber core diameter 300 {mu}s and interval of thermal relaxation of 20 s. After temperature evaluation and interpretation of the obtained data, it was concluded: 1) the oscillatory technique provided a better heat distribution during the laser application, when analyzing the graphs separately; 2) all the used techniques are within a pattern of safety, analyzing the average and highest temperatures of the apical area and the middle third, even so, disrespecting the last application day and the middle third of root 'C'.(author)

  20. Determination of optimum parameters effect on kerf width of 316L stainless steel tube in Nd:YAG laser cutting

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, J.M.; Kim, T.H. [Dept. of Metallurgical System Engineering, YONSEI Univ., Seoul (Korea); Kim, H.Y. [Korea Environment and Merchandise Testing Inst., Seoul (Korea)

    2005-07-01

    The effects of following four factors, which are laser power, assist gas pressure, cooling rate and scanning speed on the quality characteristics of laser cut 316L stainless steel tubes have been studied. 2{sup 4} full factorial design and central composite design were used to evaluate optimum condition of process parameters. Regression analysis was used to develop empirical models for the combined effects of the independent process parameters on laser cut quality. As the results, it was observed that laser power, assist gas pressure and scanning speeds did the major effects on kerf width. The smallest kerf width was obtained with the condition of low laser power, assist gas pressure, scanning speed and moderate cooling rate. Calculated regression model was kerf width = 64.47 + 0.91W + 1.25P + 0.41S + 0.41C{sup 2} - 0.45P{sup 2}. (orig.)

  1. Cleaning Of Black Crust From Marble Substrate By Short Free Running μs Nd: YAG Laser

    International Nuclear Information System (INIS)

    Khedr, A.; Harith, M. A.; Pouli, P.; Fotakis, C.

    2009-01-01

    One of the most important aspects in laser cleaning of artworks is the possibility for on-line monitoring the cleaning process. This ensures that the cleaning intervention is satisfactory without any damage to the underlying original surface. In this work it is shown that following and observing the integrated densities of the plumes generated during laser cleaning may be a simple, safe and straightforward methodology to monitor the removal process. A series of experiments on reference marble with simulated thick encrustation were considered to evaluate the plume monitoring technique. Parameters influencing the cleaning process and ablation threshold of the black crust (such as laser fluence, number of pulses etc.) were considered while the results were also evaluated under the microscope. The results of this study will be presented and discussed with the aim to establish accurate and reliable monitoring tools to follow the laser cleaning process.

  2. Influence of shielding gas composition on weld profile in pulsed Nd:YAG laser welding of low carbon steel

    Directory of Open Access Journals (Sweden)

    M Jokar

    2014-12-01

    Full Text Available Weld area and weld depth/width ratio can be considered to be of the most important geometrical factors in pulsed laser welding. The effects of carbon dioxide and oxygen additions to the argon shielding gas on the weld properties in pulsed laser welding of low carbon steel is investigated. Presence of carbon dioxide and oxygen up to 10 and 15 percent respectively decreases the weld geometrical factors. But, at higher levels of additions, the weld geometrical factors will increase. It is observed that the plasma plume temperature decreases from 6000K to 5500K with the addition of 15% carbon dioxide but increases to 7700K with 25% carbon dioxide addition. Increase in laser absorption coefficient, laser energy absorption, formation of oxide layer on the work-piece surface, exothermic reactions and their competitive effects can be considered as the competing phenomena involved in such a behavior in the weld profile

  3. Experimental study of mechanical response of artificial tissue models irradiated with Nd:YAG nanosecond laser pulses

    Science.gov (United States)

    Pérez-Gutiérrez, Francisco G.; Camacho-López, Santiago; Aguilar, Guillermo

    2011-07-01

    Nanosecond long laser pulses are used in medical applications where precise tissue ablation with minimal thermal and mechanical collateral damage is required. When a laser pulse is incident on a material, optical energy will be absorbed by a combination of linear and nonlinear absorption according to both: laser light irradiance and material properties. In the case of water or gels, the first results in heat generation and thermoelastic expansion; while the second results in an expanding plasma formation that launches a shock wave and a cavitation/boiling bubble. Plasma formation due to nonlinear absorption of nanosecond laser pulses is originated by a combination of multiphoton ionization and thermionic emission of free electrons, which is enhanced when the material has high linear absorption coefficient. In this work, we present three experimental approaches to study pressure transients originated when 6 ns laser pulses are incident on agar gels and water with varying linear absorption coefficient, using laser radiant exposures above and below threshold for bubble formation: (a) PVDF sensors, (b) Time-resolved shadowgraphy and (c) Time-resolved interferometry. The underlying hypothesis is that pressure transients are composed of the superposition of both: shock wave originated by hot expanding plasma resulting from nonlinear absorption of optical energy and, thermoelastic expansion originated by heat generation due to linear absorption of optical energy. The objective of this study is to carry out a comprehensive experimental analysis of the mechanical effects that result when tissue models are irradiated with nanosecond laser pulses to elucidate the relative contribution of linear and nonlinear absorption to bubble formation. Furthermore, we investigate cavitation bubble formation with temperature increments as low as 3 °C.

  4. A bio-ballistic micro-jet for drug injection into animal skin using a Nd:YAG laser

    Science.gov (United States)

    Yoh, J. J.; Jang, H.; Park, M.; Han, T.; Hah, J.

    2016-01-01

    Imaging of the abdominal skin of a guinea pig after injecting a fluorescent probe and biotin via the laser-induced ballistic technique revealed the epidermal and dermal layers which were stained well below 60 \\upmu m underneath the outer layer of the skin. An extensive network of cells was evident in the deeper layer of the stained dermis as the distributed fluorescein isothiocyanate dose was administered by repeated injection using a laser-based micro-jet. We performed optically controlled release of the drug by breaching the guinea pig's skin tissue targeting the region 10-400 \\upmu m beneath the outermost layer. Tissue damage was minimized by reducing the injection volume to approximately 100 nl per pulse. This was done using a micro-jet diameter equal to half of that of a conventional 200 \\upmu m syringe needle. Thus, the optimally controlled delivery of liquid drugs using an irradiated laser pulse was shown to be possible.

  5. Design of a high-gain laser diode-array pumped Nd:YAG alternating precessive slab amplifier (APS amplifier)

    Science.gov (United States)

    Coyle, D. B.

    1991-01-01

    In the design of space-qualifiable laser systems for ranging and altimetry, such as NASA's Geodynamic Laser Ranging System (GLRS), the transmitter must be kept small, powerful yet efficient, and must consist of as few components as possible. A novel preamplifier design is examined which requires no external beam steering optics, yielding a compact component with simple alignment procedures. The gains achieved are comparable to multipass zigzag amplifiers using two or more sets of external optics for extra passes through the amplifying medium.

  6. The Effects of the ND:YAG Laser on In vitro Fibroblast Attachment to Endotoxin Treated Root Surfaces

    Science.gov (United States)

    1991-05-01

    33 11. Cementwn Tracking (Typical)....................... 34 12. Slanted Specimen (Typical)........................ 44 13. Photoacoustic FT- IR ...suggests the possible alteration of the orientation or composition of the hydroxyapatite crystals. The laser produced three distinct zones of dentinal...showed enamel and dentin cratering with resolidified spheres of hydroxyapatite . The carbonized layer formed from lasing organic and inoraanic material

  7. Microstructure and interfacial evaluation of Co-based alloy coating on copper by pulsed Nd:YAG multilayer laser cladding

    International Nuclear Information System (INIS)

    Yan Hua; Wang Aihua; Xu Kaidong; Wang Wenyan; Huang Zaowen

    2010-01-01

    Laser cladding defect-free coatings on copper is rather difficult. The purpose of this study is to fabricate high quality Co-based alloy coating on copper substrate by laser cladding. Powder preplacement with a thickness of 0.7 mm improves the absorptivity of copper substrate to laser effectively and generates defect-free coating. Microstructures, phase constitutions and wear properties are investigated by means of scanning electronic microscopy (SEM) with X-ray energy dispersive microanalysis (EDX), transmission electron microscopy (TEM) and X-ray diffraction (XRD), as well as dry sliding wear test. Experimental results show that α-Co solution, Cr 23 C 6 , Ni 17 W 3 and Cr 4 Ni 15 W are the main phases in the Co-based coating. The Ni-based solid solutions (α-Co, Ni) and (Ni, Cu) are formed at interface, which generate metallurgical bonding by diffusion between Co-based coating and copper substrate. The average microhardness of the coating is 478HV 0.1 . Wear resistance of copper is significantly improved by laser cladding Co-based alloy multilayer coating.

  8. Contribution to the study of an on line inspection system for pulsed Nd:YAG laser welding operations

    International Nuclear Information System (INIS)

    Charton, Stephane

    1999-01-01

    This thesis deals with the study of a on line inspection system for pulsed Nd 3+ :YAG laser welding operations. During a welding operation, laser-material interaction results in the emission of signals (optical, acoustical, electrical, thermal), characteristic of its behavior. On line inspection is based on the hypothesis that the signals evolutions, measured by sensors such as photodiodes, microphones.., may be correlated with the welding defects. Laser weld quality inspection can be done by the machine qualification (before and during welding), and by on line monitoring of the welding operation. The similarity of the signals produced by pulsed lasers (machine or interaction) has led us to develop a specific data acquisition and processing software. Signal processing tools utilization (Fourier and wavelets transforms) in conjunction with classification techniques (stress polytopes), introduces an innovating on line inspection approach. Discriminant parameters determination (signals/defect correlation) becomes thus automatic and non subjective. The developed prototype is not dedicated to the detection of a particular defect because the classification operator is a supervised one and needs a learning phase. lt has been validated on welding defects which are easy to deal with, and then applied to a precise production control at the Nuclear Fabrications and Technology Division of the Valduc Center of the French Atomic Energy Agency. (author) [fr

  9. Simple synthetic route for hydroxyapatite colloidal nanoparticles via a Nd:YAG laser ablation in liquid medium

    Science.gov (United States)

    Mhin, Sung Wook; Ryu, Jeong Ho; Kim, Kang Min; Park, Gyeong Seon; Ryu, Han Wool; Shim, Kwang Bo; Sasaki, Takeshi; Koshizaki, Naoto

    2009-08-01

    Pulsed laser ablation (PLA) in liquid medium was successfully employed to synthesize hydroxyapatite (HAp) colloidal nanoparticles. The crystalline phase, particle morphology, size distribution and microstructure of the HAp nanoparticles were investigated in detail. The obtained HAp nanoparticles had spherical shape with sizes ranging from 5 to 20 nm. The laser ablation and the nanoparticle forming process were studied in terms of the explosive ejection mechanism by investigating the change of the surface morphology on target. The stoichiometry and bonding properties were studied by using XPS, FT-IR and Raman spectroscopy. A molar ratio of Ca/P of the prepared HAp nanoparticles was more stoichiometric than the value reported in the case of ablation in vacuum.

  10. Influence of Gamma-Ray Irradiation on Absorption and Fluorescent Spectra of Nd:YAG and Yb:YAG Laser Crystals

    Institute of Scientific and Technical Information of China (English)

    SUN Dun-Lu; ZHANG Qing-Li; XIAO Jing-Zhong; LUO Jian-Qiao; JIANG Hai-He; YIN Shao-Tang

    2008-01-01

    We investigate the influence of gamma-ray irradiation on the absorption and fluorescent spectra of Nd3+ : Y3Al5O12 (Nd:YAG) and Yb3+ :Y3Al5O12 (Yb:YAG) crystals grown by the Czochralski method. Two additional absorption (AA) bands induced by gamma-ray irradiation appear at 255nm and 340nm. The former is eontributed due to Fe3+ impurity, the latter is due to Fe2+ ions and F-type colour centres. The intensity of the excitation and emission spectra as well as the fluorescent lifetime of Nd:YAG crystal decrease after the irradiation of 100 Mrad gamma-ray. In contrast, the same dose irradiation does not impair the fluorescent properties of Yb: YA G crystal. These results indicate that Yb: YA G crystal possesses the advantage over Nd: YA G crystal that has better reliability for applications in harsh radiant environment.

  11. Severe unexpected adverse effects after permanent eye makeup and their management by Q-switched Nd:YAG laser.

    Science.gov (United States)

    Goldman, Alberto; Wollina, Uwe

    2014-01-01

    Permanent makeup is a cosmetic tattoo that is used to enhance one's appearance, and which has become more popular among middle-aged and elderly women. A couple of benefits seem to be associated with permanent tattoos in the elderly: saving time (wake up with makeup); poor eyesight (difficult to apply makeup); and saving money. On the other hand, cosmetic tattoos bear the same risks as other tattoo procedures. We report on fading and unintended hyperpigmentation after tattooing on eyebrows and eyelids, and discuss the scientific and anatomical background behind the possible cause. Dermatochalasis may be a possible risk factor for excessive unwanted discolorations. Q-switched neodymium-doped yttrium aluminum garnet laser is an appropriate and safe therapeutic tool that can manage such adverse effects. Consumer protection warrants better information and education of the risks of cosmetic tattoos - in particular, for elderly women.

  12. Red and orange laser operation of Pr:KYF4 pumped by a Nd:YAG/LBO laser at 469.1 nm and a InGaN laser diode at 444 nm.

    Science.gov (United States)

    Xu, B; Starecki, F; Pabœuf, D; Camy, P; Doualan, J L; Cai, Z P; Braud, A; Moncorgé, R; Goldner, Ph; Bretenaker, F

    2013-03-11

    We report the basic luminescence properties and the continuous-wave (CW) laser operation of a Pr(3+)-doped KYF(4) single crystal in the Red and Orange spectral regions by using a new pumping scheme. The pump source is an especially developed, compact, slightly tunable and intra-cavity frequency-doubled diode-pumped Nd:YAG laser delivering a CW output power up to about 1.4 W around 469.1 nm. At this pump wavelength, red and orange laser emissions are obtained at about 642.3 and 605.5 nm, with maximum output powers of 11.3 and 1 mW and associated sl