Sample records for yag photodisruptors american

  1. Tape casting fabrication and properties of planar waveguide YAG/Yb:YAG/YAG transparent ceramics

    Zhao, Yu; Liu, Qiang; Ge, Lin; Wang, Chao; Li, Wenxue; Yang, Chao; Wang, Juntao; Yuan, Lei; Xie, Tengfei; Kou, Huamin; Pan, Yubai; Gao, Qingsong; Bo, Yong; Peng, Qinjun; Xu, Zuyan; Li, Jiang


    Highly transparent YAG/10at.%Yb:YAG/YAG planar waveguide ceramics were fabricated by the non-aqueous tape casting and solid-state reactive sintering technology. The tapes are relatively homogeneous and the green body shows a dense structure without distinct interfaces after the treatment of debinding and cold isostatic pressing. YAG/10at.%Yb:YAG/YAG ceramics with almost full dense structure were obtained by vacuum-sintering at 1760 °C for 30 h. For the mirror-polished sample with the thickness of 3.5 mm, the In-line transmittance was measured to be 83.6% at the visual wavelength of 400 nm. The diffusion distance of the Yb3+ ions was about 215 μm along the thickness direction of the ceramics. In the lasing experiments, the YAG/10at.%Yb:YAG/YAG planar waveguide ceramics were end-pumped by a 976 nm semiconductor diode laser and enabled efficient continuous-wave lasers, which resulted in a maximum output power of 1.6 W and a slope efficiency of 34.4% at 1030 nm.

  2. Erbium: YAG laser lithotripsy mechanism.

    Chan, Kin Foong; Lee, Ho; Teichman, Joel M H; Kamerer, Angela; McGuff, H Stan; Vargas, Gracie; Welch, Ashley J


    We tested the hypothesis that the mechanism of long pulse erbium:YAG laser lithotripsy is photothermal. Human urinary calculi were placed in deionized water and irradiated with erbium:YAG laser energy delivered through a sapphire optical fiber. Erbium:YAG bubble dynamics were visualized with Schlieren flash photography and correlated to acoustic emissions measured by a polyvinylidene fluoride needle hydrophone. The sapphire fiber was placed either parallel or perpendicular to the calculus surface to assess the contribution of acoustic transients to fragmentation. Stones were irradiated using desiccated stone irradiated in air, hydrated stone irradiated in air and hydrated stone irradiated in water. Ablation crater sizes were compared. Uric acid stones were irradiated in water and the water was assayed for cyanide. During the early phase of vapor bubble expansion, acoustic transients had minimal effects on calculus fragmentation. Fragmentation occurred due to direct absorption of laser energy transmitted to the calculus through the vapor channel between the sapphire fiber tip and calculus. The forward axial expansion of the bubble occurred more rapidly than the radial expansion. A parallel oriented fiber on the calculus surface produced no fragmentation but generated larger amplitude acoustic transients compared to perpendicular orientation. In perpendicular orientation the erbium:YAG laser did not generate any collapse acoustic waves but fragmentation occurred. Crater width was greatest for desiccated stones irradiated in air (p <0.03). Cyanide production increased as erbium:YAG irradiation of uric acid calculi increased, (r2 = 0.98). The erbium:YAG laser fragments stones through a photothermal mechanism.

  3. Ceramic planar waveguide laser of non-aqueous tape casting fabricated YAG/Yb:YAG/YAG.

    Wang, Chao; Li, Wenxue; Yang, Chao; Bai, Dongbi; Li, Jiang; Ge, Lin; Pan, Yubai; Zeng, Heping


    Ceramic YAG/Yb:YAG/YAG planar waveguide lasers were realized on continuous-wave and mode-locked operations. The straight waveguide, fabricated by non-aqueous tape casting and solid state reactive sintering, enabled highly efficient diode-pumped waveguide continuous-wave laser with the slope efficiency of 66% and average output power of more than 3 W. The influence of the waveguide structure on the wavelength tunability was also experimentally investiccgated with a dispersive prism. Passively mode-locked operation of the ceramic waveguide laser was achieved by using a semiconductor saturable absorber mirror (SESAM), output 2.95 ps pulses with maximum power of 385 mW at the central wavelength of 1030 nm.

  4. Synthesis and microstructure analysis of composite Nd: YAG/YAG transparent ceramics

    Benxue Jiang; Tongde Huang; Yusong Wu; Wenbin Liu; Yubai Pan


    Transparent Nd:YAG/YAG composite ceramics are synthesized by solid-state reaction method using highpurity Y2O3,Al2O3,and Nd2O3 powders as raw materials.The mixed powder compacts are sintered at 1780 ℃ for 10 h under vacuum and annealed at 1450 ℃ for 20 h in air.The Nd:YAG/YAG ceramics exhibit a pore free structure with an average grain size of about 30 μm.The microstructure of the Nd:YAG/YAG composite transparent ceramics is studied and there is no interface between Nd:YAG and YAG ceramics.The Nd ion distribution in one grain is also studied,which shows that there is no segregation of Nd ions as in Nd:YAG crystals.

  5. Scintillation properties of YAG:Yb crystals

    Antonini, P; Carugno, Giovanni; Iannuzzi, D


    We report on measurements of the light yield, emission spectrum, and time response of YAG:Yb crystals. The temperature dependence of light yield was investigated. Data show that YAG:Yb crystals are good scintillators, suitable for applications to neutrino detection and spectroscopy.

  6. Laser properties of yag: Nd, Cr, Ce

    Kvapil, J.; Kvapil, Jos; Perner, B.; Kubelka, J.; Mánek, B.; Kubeček, V.


    Transient absorption of a long lifetime (≧ 20 s) of YAG: Nd is typical of pure material. It is the main reason of thermal deformation of the laser rods accompanied with power decreases at higher CW input. It may be prevented by an admixture of Fe, Ti or Cr. Using a small admixture (≦ 10-3 wt.%) of Ti or Cr the energy transfer among Nd ions and the gain coefficient may be increased. Cr in a higher concentration absorbs the pumping light and serves as earlier described coactivator (sensitizer) only. Fe impurity fully prevents any increase of the gain of YAG: Nd containing Ti or Cr and causes slow but irreversible degradation of the active parameters. Ce favourably modifies properties of YAG: Nd, Cr. YAG: Nd, Cr, Ce free of iron impurity is advisable active material for powerfull CW lasers.

  7. Densification behavior, doping profile and planar waveguide laser performance of the tape casting YAG/Nd:YAG/YAG ceramics

    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


    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.

  8. Preparation and Characterization of Yb - doped YAG Ceramics


    Rare-earth doped yttrium aluminum garnet (YAG) ceramics are among the most widely produced transparent ceramics for laser applications. Yb:YAG ceramics are an interesting IR laser material [1], which allows significantly higher doping compared to the generally more used Nd:YAG [2,3]. This work presents the preparation of polycrystalline Yb:YAG ceramics with dopant concentration from 0 up to 20 at.% via solid state reactive sintering. Samples were prepared via cold isostatic pressing of spray ...

  9. Laser properties of YAG:Nd, Ti

    Kvapil, J.; Kvapil, J.; Kubelka, K. J.; Perner, B.


    YAG:Nd containing about 0.001 wt percent Ti showed slightly increased losses at 1.064 micron but a substantially increased gain coefficient if compared with a material containing no Ti. The increased losses may be attributed to the increased absorption near 1.064 nm and the increased gain to the better energy coupling among Nd(3+) ions occupying nonequivalent sites due to the presence of Ti(3+) ions. YAG:Nd, Ti may be used as a high performance pulsed laser.

  10. YAG laser welding with surface activating flux

    樊丁; 张瑞华; 田中学; 中田一博; 牛尾诚夫


    YAG laser welding with surface activating flux has been investigated, and the influencing factors and mechanism are discussed. The results show that both surface activating flux and surface active element S have fantastic effects on the YAG laser weld shape, that is to obviously increase the weld penetration and D/W ratio in various welding conditions. The mechanism is thought to be the change of weld pool surface tension temperature coefficient, thus, the change of fluid flow pattern in weld pool due to the flux.

  11. Pre-pumped passively Q-switched Nd:YAG/Cr:YAG microchip laser

    Xinning Tian(田信宁); Ping Yan(闫平); Qiang Liu(柳强); Mali Gong(巩马理); Yun Liao(廖云)


    A pre-pumped passively Q-switched Nd:YAG/Cr:YAG microchip laser is demonstrated with a peak power of 7.5 kW at pulse repetition rate of serveral kilohertzs. The full-width at half-maximum(FWHM)is 734 ps, and the pulse energy is 5.5 μJ with a fundamental spatial mode. In this system, the pre-pumped microchip laser of Nd:YAG/Cr:YAG wafer which is bonded through the thermal-bonding technique has achieved a time jitter value of 12 μs and a Q-switched amplitude instability of 1.26%(15)through the pre-pumped modulation technique.

  12. Stone Retropulsion with Ho: YAG and Tm: YAG Lasers: A Clinical Practice-Oriented Experimental Study.

    Kamal, Wissam; Kallidonis, Panagiotis; Koukiou, Georgia; Amanatides, Lefteris; Panagopoulos, Vasileios; Ntasiotis, Pantelis; Liatsikos, Evangelos


    To compare the retropulsion of stones with the use of holmium: yttrium aluminum garnet (Ho: YAG) laser and thulium: yttrium aluminum garnet (Tm: YAG) laser in settings that could be used in clinical practice. The experimental configuration included a glass tube set in a water bath filled with physiologic saline. Plaster of Paris stones were inserted in the tube. Tm: YAG and Ho: YAG laser systems were used along with a high-speed slow-motion camera. The lasers were activated with different settings. The displacement of the stone was measured according to a custom-made algorithm. Ho: YAG: the retropulsion of stones was the lowest with the energy setting of 0.5 J and the frequency of 20 Hz with long pulse duration. The highest retropulsion was observed in the case of 3 J, 5 Hz, and short pulse. Tm: YAG: the retropulsion of stones was the lowest with the energy setting of 1 J and the frequency of 10 Hz with either long or short pulse duration. Practically, there was no retropulsion at all. The highest retropulsion was observed in the case of 8 J, 5 Hz, and short pulse. Ho: YAG laser has a linear increase in stone retropulsion with increased pulse energy. On the other hand, the retropulsion rate was kept to the minimum with Tm: YAG as much as the energy level of 8 J. The activation of lasers with short pulse resulted in further displacement of the stone. Lower frequency with the same power setting seemed to result in further stone retropulsion. Higher power with the same frequency setting resulted in further displacement of the stone.

  13. Microchip laser based on Yb:YAG/V:YAG monolith crystal

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


    V:YAG crystal was investigated as a passive Q-switch of longitudinally diode-pumped microchip laser, emitting radiation at wavelength 1030.5 nm. This laser was based on diffusion bonded monolith crystal (diameter 3 mm) which combines in one piece an active laser part (Yb:YAG crystal, 10 at.% Yb/Y, 3 mm long) and saturable absorber (V:YAG crystal, 2 mm long, initial transmission 86 % @ 1031 nm). The microchip resonator consisted of dielectric mirrors directly deposited on the monolith surfaces (pump mirror HT @ 968 nm and HR @ 1031 nm on Yb:YAG part, output coupler with reflection 55 % @ 1031 nm on the V:YAG part). For longitudinal CW pumping of Yb:YAG part, a fibre coupled (core diameter 100 μm, NA = 0.22, emission @ 968 nm) laser diode was used. The laser threshold was 3.8W. The laser slope efficiency for output mean in respect to incident pumping was 16 %. The linearly polarized generated transversal intensity beam profile was close to the fundamental Gaussian mode. The generated pulse length, stable and mostly independent on pumping power, was equal to 1.3 ns (FWHM). The single pulse energy was increasing with the pumping power and for the maximum pumping 9.7W it was 78 μJ which corresponds to the pulse peak-power 56 kW. The maximum Yb:YAG/V:YAG microchip laser mean output power of 1W was reached without observable thermal roll-over. The corresponding Q-switched pulses repetition rate was 13.1 kHz.

  14. CO2, Er: YAG and Nd:YAG lasers in endodontic surgery

    Daniel Humberto Pozza


    Full Text Available OBJECTIVES: CO2, Er:YAG and Nd:YAG lasers have been used in endodontic surgery. This in vitro study evaluated 1% Rhodamine B dye penetration using computer-assisted morphometry (ImageTool Software® of 108 endodontically treated human permanent canines. MATERIAL AND METHODS: Teeth were divided into 9 groups according to the technique used: A: 90-degree apicoectomy with bur, root-end cavity preparation with ultrasound and filled with MTA; B: 90-degree apicoectomy with bur, root-end cavity prepared with ultrasound and filled with MTA, and treatment of apical surface with CO2 laser (1 W, CW/CW; C: 90-degree apicoectomy with bur, and treatment of apical surface with Nd:YAG laser (150 mJ, 10 Hz; D: 90-degree apicoectomy with bur, and treatment of apical surface with CO2 laser,(1 W, CW/CW; E: apicoectomy with Er:YAG laser (400 mJ, 10 Hz, root-end cavity prepared with ultrasound and filled with MTA; F: apicoectomy with Er:YAG laser (400 mJ, 10 Hz and treatment of apical surface with Nd:YAG laser (150 mJ, 10Hz; G: apicoectomy with CO2 laser (5W, CW/SP, root-end cavity prepared with ultrasound and filled with MTA; H: irradiation of apical end with CO2 laser (1 W, CW/CW; I: irradiation of apical end with Nd:YAG laser (150 mJ, 10 Hz. RESULTS: Dye penetration was found in all specimens at different rates, the lowest penetration occurring in groups C (16.20%, B (17.24% and F (17.84%. CONCLUSIONS: Groups B, C and F represent the best technical sequences to perform endodontic surgery.


    Pozza, Daniel Humberto; Fregapani, Patrícia Wehmeyer; Xavier, Cristina Braga; Weber, João Batista Blessmann; de Oliveira, Marília Gerhardt


    Objectives: CO2, Er:YAG and Nd:YAG lasers have been used in endodontic surgery. This in vitro study evaluated 1% Rhodamine B dye penetration using computer-assisted morphometry (ImageTool Software®) of 108 endodontically treated human permanent canines. Material and methods: Teeth were divided into 9 groups according to the technique used: A: 90-degree apicoectomy with bur, root-end cavity preparation with ultrasound and filled with MTA; B: 90-degree apicoectomy with bur, root-end cavity prepared with ultrasound and filled with MTA, and treatment of apical surface with CO2 laser (1 W, CW/CW); C: 90-degree apicoectomy with bur, and treatment of apical surface with Nd:YAG laser (150 mJ, 10 Hz); D: 90-degree apicoectomy with bur, and treatment of apical surface with CO2 laser (1 W, CW/CW); E: apicoectomy with Er:YAG laser (400 mJ, 10 Hz), root-end cavity prepared with ultrasound and filled with MTA; F: apicoectomy with Er:YAG laser (400 mJ, 10 Hz) and treatment of apical surface with Nd:YAG laser (150 mJ, 10Hz); G: apicoectomy with CO2 laser (5W, CW/SP), root-end cavity prepared with ultrasound and filled with MTA; H: irradiation of apical end with CO2 laser (1 W, CW/CW); I: irradiation of apical end with Nd:YAG laser (150 mJ, 10 Hz). Results: Dye penetration was found in all specimens at different rates, the lowest penetration occurring in groups C (16.20%), B (17.24%) and F (17.84%). Conclusions: Groups B, C and F represent the best technical sequences to perform endodontic surgery. PMID:20027433

  16. CO(2), Er: YAG and Nd:YAG lasers in endodontic surgery.

    Pozza, Daniel Humberto; Fregapani, Patrícia Wehmeyer; Xavier, Cristina Braga; Weber, João Batista Blessmann; Oliveira, Marília Gerhardt de


    CO(2), Er:YAG and Nd:YAG lasers have been used in endodontic surgery. This in vitro study evaluated 1% Rhodamine B dye penetration using computer-assisted morphometry (ImageTool Software) of 108 endodontically treated human permanent canines. Teeth were divided into 9 groups according to the technique used: A: 90-degree apicoectomy with bur, root-end cavity preparation with ultrasound and filled with MTA; B: 90-degree apicoectomy with bur, root-end cavity prepared with ultrasound and filled with MTA, and treatment of apical surface with CO(2) laser (1 W, CW/CW); C: 90-degree apicoectomy with bur, and treatment of apical surface with Nd:YAG laser (150 mJ, 10 Hz); D: 90-degree apicoectomy with bur, and treatment of apical surface with CO(2) laser,(1 W, CW/CW); E: apicoectomy with Er:YAG laser (400 mJ, 10 Hz), root-end cavity prepared with ultrasound and filled with MTA; F: apicoectomy with Er:YAG laser (400 mJ, 10 Hz) and treatment of apical surface with Nd:YAG laser (150 mJ, 10Hz); G: apicoectomy with CO(2) laser (5W, CW/SP), root-end cavity prepared with ultrasound and filled with MTA; H: irradiation of apical end with CO(2) laser (1 W, CW/CW); I: irradiation of apical end with Nd:YAG laser (150 mJ, 10 Hz). Dye penetration was found in all specimens at different rates, the lowest penetration occurring in groups C (16.20%), B (17.24%) and F (17.84%). Groups B, C and F represent the best technical sequences to perform endodontic surgery.

  17. Properties of Yb:YAG scintillators

    Antonini, P; Bressi, G; Carugno, Giovanni; Santilli, P


    Relative light yield (LY) dependence on temperature for Yb:YAG crystals containing from 10% to 100% of Yb dopant is studied for gamma and alpha excitations. The maximum LY is achieved at 120 KYAG. Linearity of the light output is checked. alpha/gamma ratio is found to be 0.42+-0.02. Pulse shapes induced by gamma and alpha particles and cosmic rays are investigated by analyzing a set of single events recorded. Gamma events are fast tau<4 ns), while other kinds of radiation give rise to more complicated and longer profiles, allowing particle discrimination. Dependence of scintillation properties on concentration of Yb and purity is discussed.

  18. End-Pumped Tm:YAG Ceramic Slab Lasers

    CHENG Xiao-Jin; XU Jian-Qiu; ZHANG Wen-Xin; JIANG Sen-Xue; PAN Yu-Bai


    Lasers from a Tm:YAG ceramic aare reported for the first time to our best knowledge. The Tm:YAG ceramic slab is end-pumped by a laser diode with central wavelength 792nm. At room temperature, the maximum continuous-wave output power is 4.5 W, and the sloping efficiency is obtained to be 20.5%. The laser spectrum of the Tm: YAG ceramic is centered at 2015 nm.

  19. Cryogenic Yb:YAG thin-disk laser

    Vretenar, N.; Carson, T.; Lucas, T.; Newell, T.; Latham, W. P.; Peterson, P.; Bostanci, H.; Lindauer, J. J.; Saarloos, B. A.; Rini, D. P.


    At cryogenic temperatures, Yb:YAG behaves as a 4-level laser. Its absorption and emission cross-sections increase, and its thermal conductivity improves. Yb:YAG thin disk laser performance at room and cryogenic (80°K) temperatures will be presented. The Yb:YAG gain media is cooled using either a pressurized R134A refrigerant system or by a two-phase liquid nitrogen spray boiler. Interchangeable mounting caps allow the same Yb:YAG media to be switched between the two systems. This allows direct comparison of lasing, amplified spontaneous emission, and temperature performance between 20°C and -200°C.

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

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


    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)

  1. Improvement of thermal management in the composite Yb:YAG/YAG thin-disk laser

    Kuznetsov, I. I.; Mukhin, I. B.; Palashov, O. V.


    To improve the thermal management in the composite Yb:YAG/YAG thin-disk laser a new design of laser head is developed. Thermal-induced phase distortions, small signal gain and lasing in the upgraded laser head are investigated and compared with previously published results. A substantial decrease of the thermal lens optical power and phase aberrations and increase of the laser slope efficiency are observed. A continuous-wave laser with 440 W average power and 44% slope efficiency is constructed.

  2. Investigations of YAG:Er(3+),Yb(3+) and YAG:Co(2+) Crystals for Laser Applications


    doped YAG crystals are given. Erbium and ytterbium doped YAG single crystals were obtained by the Czochralski method . The spectral properties and laser...relaxation time of 290 Rts14 2. CRYSTAL GROWTH The crystals were obtained by the Czochralski method , using iridium crucibles of external dimensions...YAG:Co 2+ single crystal grown by Czochralski method is presented. In all obtained crystals the core area of the characteristic threefold symmetry was

  3. High-efficiency lasing and spectroscopy of domestic 1%Nd:YAG and 1%Ho:YAG ceramics

    Vatnik, S. M.; Vedin, I. A.; Kurbatov, P. F.; Osipov, V. V.; Luk'yashin, K. E.; Maksimov, R. N.; Solomonov, V. I.


    We report on spectroscopy and high-efficiency lasing of YAG ceramics synthesized at the Institute of Electrophysics, Ural Branch, Russian Academy of Sciences. The best slope efficiency is to be 36% for 1%Nd:YAG ceramics and 40% for 1%Ho:YAG ceramics, in the latter case the emission was centred at 2090 nm. Internal losses in the samples of domestic ceramics were estimated.

  4. Apical sealing quality of in vitro apicectomy procedures after using both Er:YAG and Nd:YAG.

    Leonardi, Denise Piotto; Sivieri-Araujo, Gustavo; Zielak, Joao Cesar; Baratto-Filho, Flares; Moriyama, Lilian Tan; Berbert, Fabio Luiz Camargo Villela


    The aim of this study was to evaluate the apical sealing of dentinal tubules after root-end surface cutting by using Er:YAG and Nd:YAG lasers. After root-canal instrumentation and filling, apices of 50 extracted maxillary canine human teeth were resected by Er:YAG with 400 mJ, 10 Hz, for 30 sec. The samples were randomly assigned to five groups (n = 10): (GI) treated without root-end cavity, but with Nd:YAG (1.0 W, 10 Hz, 20 sec) for dentinal tubules sealing; (GII) treated with root-end cavity without the use of Nd:YAG; (GIII) treated with root-end cavity and Nd:YAG application; (GIV) treated with root-end cavity made by Er:YAG with no focus and without Nd:YAG application; and (GV) treated without root-end cavity and without Nd:YAG application. The root-end cavities were performed by using Er:YAG at 300 mJ, 10 Hz, for 20 sec. Subsequently, all teeth were waterproofed and immersed in 2% methylene blue for 48 h in a vacuum environment. The samples were longitudinally sectioned, and microleakage was measured. ANOVA and the Fisher LSD test showed that GIV was less susceptible to microleakage than were the other groups (p < 0.05). Interestingly, the use of the Er:YAG with no focus showed superior dentinal tubule sealing in comparison with the other groups, even with or without root-end cavity and Nd:YAG application.

  5. 340 W average power output of diode-pumped composite ceramic YAG/Nd:YAG disk laser

    Jia, Kai; Jiang, Yong; Yang, Feng; Deng, Bo; Hou, Tianjin; Guo, Jiawei; Chen, Dezhang; Wang, Hongyuan; Yang, Chuang; Peng, Chun


    We report on a diode-pumped composite ceramic disk laser in this paper. The composite ceramic YAG/Nd:YAG disk consists of 4 mm thick pure YAG and 2 mm thick Nd:YAG with 1.0 at.% doping concentration. The slope efficiency of the composite ceramic disk laser is 36.6% corresponding to the maximum optical-optical efficiency of 29.2%. Furthermore, 340 W average power output was achieved at the absorbed pump power of 1290 W.

  6. The possibility of clinical application of the solid state lasers: Nd:YAG, Ho:YAG, and Er:YAG in otolaryngology - head and neck surgery

    Tomaszewska, M.; Kukwa, A.; Tulibacki, M.; Wójtowicz, P.; Olędzka, I.; Jeżewska, E.


    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.

  7. Role of iron ions in YAG and YAP

    Kvapil, J.; Kvapil, J.; Kubelka, J. (Monokrystaly, Turnov (Czechoslovakia)); Autrata, R. (Ceskoslovenska Akademie Ved, Brno. Ustav Pristrovoje Techniky)


    Spectroscopic properties of YAG doped with Fe were compared. YAG:Fe crystals grown under reducing atmosphere showed strong colouration whereas similar colouration in YAP:Fe was found after oxygen treatment. Nd/sup 3 +/ luminescence was effectively quenched by Fe ions in YAP, whereas Ce/sup 3 +/ luminescence was quenched by Fe ions in both the materials.

  8. Flash-lamp-pumped picosecond Nd:YAG regenerative amplifier

    Bingyuan Zhang; Gang Li; Meng Chen; Guoju Wang; Yonggang Wang; Xiaoyu Ma


    @@ A flash-lamp-pumped Nd:YAG regenerative amplifier has been developed at 1.06 μm, seeded with 10-ps pulses from a diode-end-pumped and mode-locked Nd:YAG oscillator with homemade semiconductor saturable absorber mirror(SESAM).

  9. YAG Laser Treatment of Tinea Pedis

    Ueda, Masahiro; KAGAWA, Kiichiro


    A clinical experiment on the treatment of tinea pedis infections (common as an athlete’s foot) was conducted using a pulsed Nd-YAG laser with an output energy of 0.5 joule/pulse and duration of 1 millisecond. The experiment was supported by 13 volunteers for skin samples used in this experiment. The treatment was performed with the following irradiation condition; an energy density of 400 joule/cm2 at a skin sample surface, a spot diameter of the laser beam on the surface of 0.4 mm and a re...

  10. Ion beam luminescence of Nd:YAG

    Khanlary, M. [Science and Technology, Pevensey Building, University of Sussex, Brighton BN1 9QH (United Kingdom); Department of Physics, Imam Khomeini International University, Qazvin, Iran (Iran, Islamic Republic of); Hole, D.E. [Science and Technology, Pevensey Building, University of Sussex, Brighton BN1 9QH (United Kingdom); Townsend, P.D. [Science and Technology, Pevensey Building, University of Sussex, Brighton BN1 9QH (United Kingdom)]. E-mail:


    Luminescence recorded during ion beam implantation of Nd:YAG has proved valuable in sensing structural and local crystal field changes caused by waveguide fabrication in this laser material. The relative line intensities from Nd are sensitive to excitation rate and so the spectra differ strongly between H{sup +} and H2+ excitation, with further changes in the examples using He{sup +} and N{sup +} ions. The overall intensities are reduced at lower temperatures, as well as showing variations in relative line patterns. Some suggestions of component lines and weak broad bands are offered in terms of trace rare earth and other impurities.

  11. Cryogenic Yb: YAG Thin-Disk Laser


    Spitzberg, "Cryogenic Yb3+-Doped Solid-State Lasers," IEEE Journ. of Sel. Topics in Quant. Elect., 13(3), 448-459 (2007). [3] S. Tokita, J. Kawanaka, M...Europe ( IEEE ,2005) ,CTu3 (2005). [4] D. C. Brown, J. M. Singley, E. Yager, J. W. Kuper, B. J. Lotito, L. L. Bennett, "Innovative high-power CW...Y. Sun, and R. W. Equall, "Yb:YAG Absorption at Ambient and Cryogenic Temperatures," IEEE Journ. Sel. Topics Quant. Elect. 11(3), 604-612 (2005

  12. Combustion synthesis of YAG:Ce and related phosphors

    Gupta, K. V. K.; Muley, A.; Yadav, P.; Joshi, C. P.; Moharil, S. V.


    YAG:Ce is an important phosphor having applications in various fields ranging from solid state lighting to scintillation detectors. YAG phosphors doped with activators are mainly synthesized by solid state reaction techniques that require high sintering temperatures (above 1500°C) to eliminate YAM and YAP phases. Though several soft chemical routes have been explored for synthesis of YAG, most of these methods are complex and phase pure materials are not obtained in one step, but prolonged annealing at temperatures around 1000°C or above become necessary. One step combustion synthesis of YAG:Ce3+ and related phosphors carried out at 500°C furnace temperature is reported here. Activation with Ce3+ could be achieved during the synthesis without taking recourse to any post-combustion thermal treatment. LEDs prepared from the combustion synthesized YAG:Ce3+, exhibited properties comparable to those produced from the commercial phosphor.

  13. Molecular dynamics simulation of thermodynamic properties of YAG

    Chen Jun; Chen Dong-Quan; Zhang Jing-Lin


    In this paper we study the thermodynamic properties of Y3Al5O12 (YAG) by using molecular dynamic method combined with two- and three-body potentials. The dependences of melting process, elastic constant and diffusion coefficient on temperature of crystal YAG are simulated and compared with the experimental results. Our results show that anion O has the biggest self-diffusivity and cation Y has the smallest self-diffusivity in a crystal YAG. The calculated diffusion activation energies of ions O, Al and Y are 282.55, 439.46, 469.71k J/mol, respectively. Comparing with experimental creep activation energy of YAG confirms that cation Y can restrict the diffusional creep rate of crystal YAG.

  14. Scaling and passively Q-switch operation of a Nd:YAG laser pumped laterally through a YAG prism

    Dascalu, T.; Salamu, G.; Sandu, O.; Dinca, M.; Pavel, N.


    We report on scaling of a laser configuration in which a YAG prism is used to couple the pump beam from a fiber-coupled diode laser directly into a Nd:YAG medium. Several resonator geometries have been investigated. In free generation regime laser pulses at 1.06 μm with energy of 22.1 mJ for the pump energy of 44.6 mJ were obtained from a 10.0 mm long, 1.0-at% Nd:YAG single crystal that had the high-reflectivity mirror coated directly on one of the laser crystal surface. The slope efficiency was 0.51. A similar uncoated Nd:YAG crystal placed in a plane-plane resonator delivered laser pulses with 17.8 mJ energy under the pump with 45.4 mJ energy, at 0.40 slope efficiency. Further, a passively Q-switched Nd:YAG/Cr4+:YAG composite ceramic laser pumped through a YAG prism has been built. Using a Cr4+:YAG saturable absorber of 0.85 initial transmission the device delivered laser pulses with 0.29 mJ energy and 11 ns duration. The output performances are compared to those obtained in a classical end-pumping scheme.

  15. Combined effect of fluoride varnish to Er:YAG or Nd:YAG laser on permeability of eroded root dentine.

    Chiga, Sandra; Toro, Carmen Victoria Torres; Lepri, Taísa Penazzo; Turssi, Cecília Petroso; Colucci, Vivian; Corona, Silmara Aparecida Milori


    This study evaluated the combined effect of fluoride varnish to Er:YAG or Nd:YAG laser on permeability of eroded root dentine. Sixty slabs of bovine root dentine (2×2×2mm) were eroded with citric acid 0.3% (pH 3.2) during 2h and then kept in artificial saliva during 24h. Specimens were randomly assigned in 6 groups (n=10), to receive the following treatments: fluoride varnish; fluoride varnish+Er:YAG laser; fluoride varnish+Nd:YAG laser; non-fluoride varnish; non-fluoride varnish+Er:YAG laser; non-fluoride varnish+Nd:YAG laser. The Er:YAG (100mJ, 3Hz) and Nd:YAG (70mJ, 15Hz) were applied for 10s. Specimens were subjected to further erosive challenges with citric acid 0.3% 4×/day, during 1min, for 5 days, remaining in artificial saliva between cycles. Dentin permeability was then assessed. Two-way ANOVA demonstrated no significant interaction between laser and varnish (p=0.858). No effect was also detected for the main factor varnish (p=0.768), while permeability of eroded root dentin was significantly lower when such substrate was laser-irradiated, no matter the laser source (pfluoride varnish application. Copyright © 2016. Published by Elsevier Ltd.

  16. Diode pumped Nd:YAG laser development

    Reno, C. W.; Herzog, D. G.


    A low power Nd:YAG laser was constructed which employs GaAs injection lasers as a pump source. Power outputs of 125 mW TEM CW with the rod at 250 K and the pump at 180 K were achieved for 45 W input power to the pump source. Operation of the laser, with array and laser at a common heat sink temperature of 250 K, was inhibited by difficulties in constructing long-life GaAs LOC laser arrays. Tests verified pumping with output power of 20 to 30 mW with rod and pump at 250 K. Although life tests with single LOC GaAs diodes were somewhat encouraging (with single diodes operating as long as 9000 hours without degradation), failures of single diodes in arrays continue to occur, and 50 percent power is lost in a few hundred hours at 1 percent duty factor. Because of the large recent advances in the state of the art of CW room temperature AlGaAs diodes, their demonstrated lifetimes of greater than 5,000 hours, and their inherent advantages for this task, it is recommended that these sources be used for further CW YAG injection laser pumping work.

  17. The growth of Nd: YAG single crystals



    Full Text Available Y3Al5O12 doped with 0.8 % wt. Nd (Nd:YAG single crystals were grown by the Czochralski technique under an argon atmosphere. The conditions for growing the Nd: YAG single crystals were calculated by using a combination of Reynolds and Grashof numbers. The critical crystal diameter and the critical rate of rotation were calculated from the hydrodynamics of the melt. The crystal diameter Dc = 1.5 cm remained constant during the crystal growth, while the critical rate of rotation changed from wc = 38 rpm after necking to wc = 13 rpm at the end of the crystal. The value of the rate of crystal growth was experimentally found to be 0.8–1.0 mm/h. According to our previous experiments, it was confirmed that 20 min exposure to conc. H3PO4 at 603 K was suitable for chemical polishing. Also, one-hour exposure to conc. H3PO4 at 493 K was found to be suitable for etching. The lattice parameter a = 1.201 (1 nm was determined by X-ray powder diffraction. The obtained results are discussed and compared with published data.

  18. Ablation of porcine ligamentum flavum with Ho:YAG, q-switched Ho:YAG, and quadrupled Nd:YAG lasers.

    Johnson, Matt R; Codd, Patrick J; Hill, Westin M; Boettcher, Tara


    Ligamentum flavum (LF) is a tough, rubbery connective tissue providing a portion of the ligamentous stability to the spinal column, and in its hypertrophied state forms a significant compressive pathology in degenerative spinal stenosis. The interaction of lasers and this biological tissue have not been thoroughly studied. Technological advances improving endoscopic surgical access to the spinal canal makes selective removal of LF using small, flexible tools such as laser-coupled fiber optics increasingly attractive for treatment of debilitating spinal stenosis. Testing was performed to assess the effect of Ho:YAG, Q-switched Ho:YAG, and frequency quadrupled Nd:YAG lasers on samples of porcine LF. The objective was to evaluate the suitability of these lasers for surgical removal of LF. LF was resected from porcine spine within 2 hours of sacrifice and stored in saline until immediately prior to laser irradiation, which occurred within an additional 2 hours. The optical absorbance of a sample was measured over the spectral band from 190 to 2,360 nm both before and after dehydration. For the experiments using the Ho:YAG (λ = 2,080 nm, tp  = 140 µs, FWHM) and Q-Switched Ho:YAG (λ = 2,080 nm, tp  = 260 ns, FWHM) lasers, energy was delivered to the LF through a laser-fiber optic with 600 µm core and NA = 0.39. For the experiment using the frequency quadrupled Nd:YAG laser (λ = 266 nm, tp  = 5 ns FWHM), rather than applying the laser energy through a laser-fiber, the energy was focused through an aperture and lens directly onto the LF. Five experiments were conducted to evaluate the effect of the given lasers on LF. First, using the Ho:YAG laser, the single-pulse laser-hole depth versus laser fluence was measured with the laser-fiber in direct contact with the LF (1 g force) and with a standoff distance of 1 mm between the laser-fiber face and the LF. Second, with the LF remaining in situ and the spine bisected

  19. Method of preparation and structural properties of transparent YAG nanoceramics

    Fedyk, Robert; Hreniak, Dariusz; Łojkowski, Witold; Stręk, Wiesław; Matysiak, Hubert; Grzanka, Ewa; Gierlotka, Stanisław; Mazur, Piotr


    Transparent Nd:YAG nanoceramics composed of nanosized grains were fabricated by high-pressure low temperature sintering technique (HPLT). Structural and morphological studies of the sintered pellets were carried out using X-ray powder diffraction and Transmission Electron Microscopy. The hardness of nanoceramics, extinction coefficient and transmittance spectra were measured and analyzed. The initial grain size of the YAG powder was 30 nm and no grain growth has taken place during the consolidation process. The density of the obtained nanoceramics was close to the theoretical density of YAG.

  20. Solvothermal synthesis of spherical YAG powders via different precipitants

    Wu Zuogui [Department of Materials Science and Engineering, Shandong Institute of Light Industry, Jinan, Shandong 250353 (China); Zhang Xudong [Department of Materials Science and Engineering, Shandong Institute of Light Industry, Jinan, Shandong 250353 (China)], E-mail:; He Wen; Du Yuanwei; Jia Naitao; Liu Pengcheng; Bu Fanqing [Department of Materials Science and Engineering, Shandong Institute of Light Industry, Jinan, Shandong 250353 (China)


    Yttrium aluminum garnet (YAG) powders were synthesized by a solvothermal method under mild conditions with inexpensive aluminum and yttrium nitrates as the starting materials, and the ethylenediamine (EDA) solution as the solvent. Hydroxide precursors were synthesized by two different precipitating processes, in which urea or ammonium hydrogen carbonate was used as precipitant. The formation of YAG particle was investigated by means of Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The TEM results showed that spherical YAG powders were successfully synthesized when ammonium hydrogen carbonate was used as precipitant.

  1. Lasing and thermal characteristics of Yb:YAG/YAG composite with atomic diffusion bonding

    Sankar Nagisetty, Siva; Severova, Patricie; Miura, Taisuke; Smrž, Martin; Kon, Hitoe; Uomoto, Miyuki; Shimatsu, Takehito; Kawasaki, Masato; Higashiguchi, Takeshi; Endo, Akira; Mocek, Tomáš


    We demonstrated the laser performance of an Yb:YAG/YAG composite ceramic laser medium mounted on an aluminium heatsink via atomic diffusion bonding (ADB) technique using nanocrystalline metal films at room temperature in air. The surface temperature rise of the ADB bonded laser medium was linear with 57 °C lower than that of the commercially available soldered Yb:YAG thin disk at the pump power of 280 W. Moreover, the ADB disk was pumped 1.5 times higher (7.3 kW cm-2) than the typical damage threshold of the soldered disk without any sign of damage. The undoped capping may be effective for the suppression of ASE heating; however, according to the in situ OPD measurement it induces strong thermal lensing. The CW laser output power of 177 W was obtained at the pump power of 450 W with the optical-to-optical efficiency of 40% using V-shape cavity.

  2. Pulsed Nd-YAG laser in endodontics

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


    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.

  3. Crystallography of Alumina-YAG-Eutectic

    Farmer, Serene C.; Sayir, Ali; Dickerson, Robert M.; Matson, Lawrence E.


    Multiple descriptions of the alumina-YAG eutectic crystallography appear in the ceramic literature. The orientation between two phases in a eutectic system has direct impact on residual stress, morphology, microstructural stability, and high temperature mechanical properties. A study to demonstrate that the different crystallographic relationships can be correlated with different growth constraints was undertaken. Fibers produced by Laser-Heated Float Zone (LHFZ) and Edge-defined Film-fed Growth (EFG) were examined. A map of the orientation relationship between Al2O3 and Y3Al5O12 and their relationship to the fiber growth axis as a function of pull rate are presented. Regions in which a single orientation predominates are identified.

  4. Demining with Nd:YAG laser

    Rothacher, Thomas; Lüthy, Willy; Weber, Heinz P.


    Laser neutralization of antipersonnel (AP) mines offers the enormous advantage to work from a safe distance. In this article the interaction of Nd:YAG laser radiation and four different types of blast AP mines is investigated. For this purpose, a very compact laser system for mine neutralization is developed. The incident power on the mine surfaces is varied from 20 to 70 W. Neutralization of all mines is achieved from a safe distance up to 50 m. The mines burn and finally detonate after an irradiation time of a few minutes. Detonation of the irradiated burning mines is considerably weaker compared to fully functional mines. Therefore, expected damage in the surrounding area is significantly reduced.

  5. Crystal structure and luminescent properties of nanocrystalline YAG and YAG:Nd synthesized by sol-gel method

    Zhydachevskii, Ya.; Syvorotka, I. I.; Vasylechko, L.; Sugak, D.; Borshchyshyn, I. D.; Luchechko, A. P.; Vakhula, Ya. I.; Ubizskii, S. B.; Vakiv, M. M.; Suchocki, A.


    The work describes results of synthesis of undoped and Nd-doped YAG nanopowders by sol-gel method using different complexing agents (ethylene glycol and citric acid) and characterization of the material by X-ray powder diffraction, scanning electron microscopy, photoluminescence and thermoluminescence techniques. Utilization of citrate sol-gel procedure using yttrium and aluminum nitrate nonahydrates as starting substances allowed to obtain highly stoichiometric and non-defected YAG and YAG:Nd nanocrystalline samples with good luminescence performance and low radiation storage efficiency.

  6. Er:YAG laser radiation etching of enamel

    Dostalova, Tatjana; Jelinkova, Helena; Krejsa, Otakar; Hamal, Karel; Kubelka, Jiri; Prochazka, Stanislav


    This study compares the effects of acid treatment and Er:YAG laser radiation on the enamel. The permanent human molars were used. Oval cavities in the buccal surface were prepared and the edges of cavities were irradiated by Er:YAG radiation. The energy of laser was 105 mJ and repetition rate 1 Hz. The radiation was focused by CaF2 lens and the sample was placed in the focus. Ten samples were etched by 35 percent phosphoric acid during 60 s. Than cavities were filled with composite resin following manufacturers directions. By laser etching the structure enamel in section was rougher. The optimal connection between the enamel and composite resin was achieved in 75 percent by acid etching and in 79.2 percent by Er:YAG laser etching. Er:YAG laser etching could be alternative method for etching of enamel.

  7. Optical properties of epitaxial YAG:Yb films

    Ubizskii, S. B.; Matkovskii, A. O.; Melnyk, S. S.; Syvorotka, I. M.; Müller, V.; Peters, V.; Petermann, K.; Beyertt, A.; Giesen, A.


    This work deals with the investigation of the optical properties of epitaxial YAG:Yb films and their suitability as gain media for thin disk lasers. Epitaxial films of YAG:Yb were grown by the liquid phase epitaxy method in air on the (111)-oriented YAG substrates. The thickness of the grown layers was from 30 to 260 m. The melt composition was varied to obtain the desired doping level from 10 to 15% and to optimize the optical properties. The best epitaxial films were colourless and had an Yb3+ luminescence lifetime of more than 950 s, which is very close to the intrinsic lifetime of the Yb ions in the bulk YAG single crystals. These films were tested in a thin disk laser setup with 24 absorption passes of the 940 nm pumping beam. The maximum output power at 1.03 m wavelength in CW operation reached more than 60 W and the optical efficiency was close to 30%.

  8. Growth and characterization of YAG:Cr4+epitaxial films

    Ubizskii, Sergii B.; Syvorotka, Igor M.; Melnyk, Sergii S.; Matkovskii, Andrej O.; Kopczynski, Krzysztof; Mierczyk, Zygmunt; Frukacz, Zygmunt


    Epitaxial films with thickness of 10 - 250 micrometers of yttrium aluminum garnet (YAG) doped with Cr were grown by liquid phase epitaxy technique on YAG:Nd substrates. Co-doping with Mg2+ is used to force the Cr4+ valent state formation. Dependence of absorption spectra of obtained films on melt-solution composition, growth conditions and thermal treatment in reducing and oxidizing atmospheres is studied. A very intensive absorption band in UV region with maximum at 275 nm was found both in co-doped and YAG:Mg2+ epifilms caused probably by oxygen vacancies compensating the excess charge of Mg2+. Its intensity correlates with Cr4+ content in the film in that way: it decreases with Cr4+ entering in the film. The absorption being characteristic for YAG:Cr4+ crystals is found in co-doped films grown at higher temperatures (1000 - 1100 degree(s)C). The processes occurring during annealing are discussed.

  9. Effect of Additive on Microstructure of Transparent YAG Ceramics

    Sun Xudong; Wen Lei; Xiu Zhimeng; Huo Di; Li Xiaodong; Chi-Tay Tsai


    Transparent YAG (yttrium aluminum garnet) ceramics were fabricated by solid-state reaction method. Effect of additive (tetraethyl orthosilicate, TEOS) on microstructure of YAG ceramics was investigated. If the addition of TEOS is more than 3% (mass fraction), large amount of liquid phase can be yielded at grain boundaries, resulting in the formation of second phase particles at grain boundaries. If the addition is less than 0.05% (mass fraction), pores are entrapped in the grains. The suitable amount is 0.5% (mass fraction). A fully transparent YAG ceramic was fabricated by vacuum sintering at 1700 ℃ for 5 h. Optical transmittance of the YAG ceramic is 63% in the visible light wavelengths and 70% in the infrared wavelengths.

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

    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 intermedi

  11. The bactericidal effect of a Genius Nd: YAG laser

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


    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 intermedi

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

    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 intermedi

  13. 600-W lamp pumped CW Nd:YAG laser

    Qiang Li(李强); Zhimin Wang(王志敏); Zhiyong Wang(王智勇); Zhensheng Yu(于振声); Hong Lei(雷訇); Jiang Guo(郭江); Gang Li(李港); Tiechuan Zuo(左铁钏)


    A lamp pumped CW Nd:YAG laser is presented in this paper for the requirement of industrial application.The main factors, which affect output power and beam quality of high power solid-state laser module, are theoretically analyzed. Total electro-optics efficiency of lamp pumped Nd:YAG crystal as high as 4.0% is obtained, and output power is higher than 647 W with beam parameter product 22 mm.mrad.

  14. Ho:YAG Single Crystal Fiber: Fabrication and Optical Characterization


    diameter variations, two feedback systems are employed. First, a standard proportional-integral-derivative ( PID ) controller provides feedback from...broad emission band from 2050 – 2150 nm, and previous papers confirm the wavelength tuning capability of Ho:YAG solid state lasers [23]. Ho:YAG SCF... tuned across the spectral band, then the gain was measured and plotted as markers in Fig. 4 for the 10.5 cm piece, along with the measured emission

  15. Deicing with Nd:YAG and CO2 lasers

    Qi, Lijun; Zhu, Xiao; Zhu, Changhong; Guo, Fei; Zhu, Guangzhi; Gu, Shanqiang


    A model of deicing with Nd:YAG and CO2 lasers for simulation using ANSYS software is presented. Experiments with a 300-W, 1-ms, 60-Hz Nd:YAG laser and a 500- to 2000-W cw CO2 laser are reported. The Nd:YAG laser is considered as a volume thermal source, and the CO2 laser as a plane thermal source. The model and the simulation results can describe both Nd:YAG and CO2 laser deicing well. The results of the simulation and experiments suggest that the melting rates for the two lasers are almost equal at the same laser power density. So are the melting efficiencies. The hard and transparent ice irradiated by the Nd:YAG laser becomes opaque and loose, because the thermal stress is distributed in the body of the ice, while the ice irradiated by the CO2 laser is still transparent and hard, because thermal stress hardly occurs. So the laser with characteristics of high output power and large ice absorbing length can be selected for the power line laser deicing system, and Nd:YAG laser is more appropriate for power-line deicing than CO2 laser.

  16. Passive mode locking of a Nd:YAG laser with co-doped Nd, Cr:YAG as saturable absorber

    Yang Lin(杨林); Feng Bao-Hua(冯宝华); Zhang Zhi-Guo(张治国); Gaebler Volker; Liu Bai-Ning(刘百宁); Eichler Hans


    We demonstrate the characteristics of relatively low saturation intensity using co-doped Nd, Cr:YAG as saturable absorber for passively mode locking the Nd:YAG laser. The difference of the saturation intensity between Q-switched and mode-locked operation in co-doped Nd, Cr:YAG was only one to two orders of magnitude, while Cr:YAG was generally reported at a difference of five orders of magnitude. More than 80% mode locking modulation depth was achieved at an incident pump power of 4.4W, corresponding to an intracavity intensity of 6 × 104W/cma2, using a 68cm long plano-concave cavity.

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

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


    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.

  18. Nd:YAG Laser Posterior Capsulotomy and Visual Outcome

    Khaleda Nazneen Bari


    Full Text Available Background: Neodymium-doped yttrium aluminum garnet (Nd:YAG laser capsulotomy is a relatively noninvasive procedure that is used in the treatment of posterior capsular opacification (PCO. PCO is caused by proliferation of lens epithelial cells which causes fibrotic changes and wrinkling of the posterior capsule and results in decreased vision, glare, and other symptoms similar to that of the original cataract.Objective: To find out the visual outcome after performing Nd:YAG laser capsulotomy for PCO.Materials and method: A prospective clinical trial was carried out in National Institute of Ophthalmology (NIO, Dhaka, Bangladesh from January 2010 to June 2011 on purposively selected 70 adult subjects of both sexes who developed PCO within 2 months to more than 2 years after extracapsular cataract extraction with posterior chamber intra ocular lens implant. After thorough pre laser assessment Nd:YAG laser capsulotomy was carried out with Zeis VISULAS YAG II through Zeiss slit lamp under topical anesthesia. Data were recorded and expressed as proportion.Results: Out of the 70 subjects 40 were male and 30 were female. The average time interval of cataract surgery and Nd: YAG laser capsulotomy was 23 months. Capsular fibrosis (57.04% was the predominant type of PCO. The pre laser visual acuity (VA of more than 61.06% of eyes was 6/36 or below while 41.12% had VA hand movements to finger count. After Nd:YAG laser capsulotomy VA of 6/18 or better was achieved in 63.9% of eyes while 9.94% recovered to 6/9 and 11.36% achieved 6/6. None of these eyes showed further deterioration in VA.Conclusion: Nd:YAG laser capsulotomy for PCO is safe, effective and a rewarding procedure for improvement of vision.

  19. Sulcular debridement with pulsed Nd:YAG

    Harris, David M.; Gregg, Robert H., II; McCarthy, Delwin K.; Colby, Leigh E.; Tilt, Lloyd V.


    We present data supporting the efficacy of the procedure, laser sulcular debridement (laser curettage), as an important component in the treatment of inflammatory periodontal disease. Laser Assisted New Attachment Procedure (LANAP) is a detailed protocol for the private practice treatment of gum disease that incorporates use of the PerioLase pulsed Nd:YAG Dental Laser for laser curettage. Laser curettage is the removal of diseased or inflamed soft tissue from the periodontal pocket with a surgical dental laser. The clinical trial conducted at The University of Texas HSC at San Antonio, Texas, evaluated laser curettage as an adjunct to scaling and root planing. They measured traditional periodontal clinical indices and used a questionnaire to evaluate patient comfort and acceptance. The Texas data (N=10 patients) are compared with pocket depth changes following LANAP. LANAP data were obtained from a retrospective review of patient records at three private practices (N=65). No significant differences in post treatment probe depth changes were found among the four centers indicating that the procedure produced consistent, favorable outcomes, and that results from controlled scientific clinical trials can be replicated in private practices. Reduction in pocket depths following laser treatment compare well with results obtained with scalpel surgery. The use of the laser offers additional benefits. We also present quantitative evidence from digitized radiographs of increased bone density in affected areas following LANAP.

  20. Development of monolith Nd:YAG /Cr+4:YAG passively Q-switched microchip laser

    Izhnin, Ihor; Vakiv, Mykola; Izhnin, Aleksandr; Syvorotka, Igor; Ubizskii, Sergii; Syvorotka, Ihor, Jr.


    The main features of passively Q-switched microchip lasers development are considered. The active medium of laser is an epitaxial structure combining an epitaxial layer of saturable absorber Cr4+:Y3Al5O12 (Cr:YAG) grown on substrate of generating crystal Nd:YAG by liquid phase epitaxy. The modulator layer has an initial optical absorption of 36 cm-1 at wavelength of lasing (1064 nm). The epitaxial layer grown on unworking side was mechanically removed and this substrate side was optically polished. The other one was processed precisely to needed thickness. The cavity's mirrors were deposited by electron beam technique directly on each side of the structure to form a rugged, monolithic resonator. Diode laser Model ATC-C4000 with lasing wavelength 808 nm provided the CW end pumping. The output pulses parameters were investigated by means of test bench consisting of photoelectric transducer FEK-15 and Digital Phosphor Oscilloscope TDS 5052B. The obtained laser parameter are as follows: pulse width (FWHM) about 1.3 ns, repetition rate 5.5 kHz, average output power about 10 mW, pulse energy 1.0 μJ, pick power 1.2 kW. The possible solutions for laser parameter improving and optimization are discussed.

  1. Er:YAG laser debonding of porcelain veneers

    Buu, Natalie; Morford, Cynthia; Finzen, Frederick; Sharma, Arun; Rechmann, Peter


    The removal of porcelain veneers using Er:YAG lasers has not been previously described in the scientific literature. This study was designed to systematically investigate the efficacy of an Er:YAG laser on veneer debonding without damaging the underlying tooth structure, as well as preserving a new or misplaced veneer. Initially, Fourier Transform Infrared Spectroscopy (FTIR) was used on flat porcelain veneer samples (IPS Empress Esthetic; Ivoclar Vivadent, Amherst, NY) to assess which infrared laser wavelengths are transmitted through the veneer. Additionally, FTIR spectra from a veneer bonding cement (RelyX Veneer Cement A1; 3M ESPE, St. Paul, MN) were obtained. While the veneer material showed no characteristic water absorption bands in the FTIR, the bonding cement has a broad H2O/OH absorption band coinciding with the ER:YAG laser emission wavelength. Consequently Er:YAG laser energy transmission through different veneer thicknesses was measured. The porcelain veneers transmitted 11 - 18 % of the incident Er:YAG laser energy depending on their thicknesses (Er:YAG laser: LiteTouch by Syneron; wavelength 2,940 nm, 10 Hz repetition rate, pulse duration 100 μs at 133 mJ/pulse; straight sapphire tip 1,100 μm diameter; Syneron, Yokneam, Israel). Initial signs of cement ablation occurred at approximately 1.8 - 4.0 J/cm2. This can be achieved by irradiating through the veneer with the fiber tip positioned at a distance of 3-6 mm from the veneer surface, and operating the Er:YAG laser with 133 mJ output energy. All eleven veneers bonded on extracted anterior incisor teeth were easily removed using the Er:YAG laser. The removal occurred without damaging underlying tooth structure as verified by light microscopic investigation (Incident Light Microscope Olympus B 50, Micropublisher RTV 3.3 MP, Image Pro software, Olympus). The debonding mainly occurred at the cement/veneer interface. When the samples were stored in saline solution for 5 days and/or an air-waterspray was

  2. Clinical application of erbium:YAG laser in periodontology.

    Ishikawa, Isao; Aoki, Akira; Takasaki, Aristeo Atsushi


    Various lasers have been introduced for the treatment of oral diseases and their applications in dental clinics have become a topic of much interest among practitioners. Technological advances and improvements have increased the choices of the available laser systems for oral use. Among them, a recently developed erbium-doped:yttrium aluminum garnet (Er:YAG) laser system possesses suitable characteristics for oral soft and hard tissue ablation. Due to its high absorption in water, an effective ablation with a very thin surface interaction occurs on the irradiated tissues without any major thermal damage to the irradiated and surrounding tissues. In the field of periodontics, the application of Er:YAG laser for periodontal hard tissue has begun with studies from Japanese and German researchers. Several in vitro and clinical studies have already demonstrated an effective application of the Er:YAG laser for calculus removal and decontamination of the diseased root surface in periodontal non-surgical and surgical procedures. However, further studies are required to better understand the various effects of Er:YAG laser irradiation on biological tissues for its safe and effective application during periodontal and implant therapy. Randomized controlled clinical trials and more basic studies have to be encouraged and performed to confirm the status of Er:YAG laser treatment as an adjunct or alternative to conventional mechanical periodontal therapy. In this paper, the advantages and current clinical applications of this laser in periodontics and implant dentistry are summarized based on current scientific evidence.

  3. Bond Strength of Resin Cement and Glass Ionomer to Nd:YAG Laser-Treated Zirconia Ceramics.

    Asadzadeh, Nafiseh; Ghorbanian, Foojan; Ahrary, Farzaneh; Rajati Haghi, Hamidreza; Karamad, Reza; Yari, Amir; Javan, Abdollah


    To investigate the effect of neodymium-doped yttrium aluminum garnet (Nd:YAG) laser irradiation on the surface properties and bond strength of zirconia ceramics. Forty-eight zirconia ceramic pieces (4 × 4 × 1 mm(3) ) were divided into four groups according to surface treatment as follows: two control groups (no treatment) for resin bonding (CRC) and glass ionomer (GI) bonding (CGC); two laser treatment groups (Nd:YAG irradiation, 3 W, 200 MJ, 10 Hz, 180 μs) for resin bonding (LRC) and GI bonding (LGC). The ceramics in the control groups and the laser groups were distinguished by the application of different cements (resin cement and GI). Following surface treatments, the specimens were cemented to human dentin with resin cement and GI. After bonding, the shear bond strength (SBS) of the ceramic to dentin was measured, and the failure mode of each specimen was analyzed using a stereomicroscope. A one-way ANOVA compared the average bond strength of the four groups. Pairwise comparisons among the groups were performed using the Games-Howell test. The level of significance was set at 0.05. The means (± standard deviation) of SBS values in the CRC, CGC, LRC, and LGC groups were 3.98 ± 1.10, 1.66 ± 0.59, 10.24 ± 2.46, and 2.21 ± 0.38 MPa, respectively. Data showed that the application of the Nd:YAG laser resulted in a significantly greater SBS of the resin cement to the zirconia ceramics (p nd 83.3% in the LRC and LGC groups, respectively. In the CGC group, all failures were adhesive. Pretreatment of zirconia ceramic via Nd:YAG laser improves the bond strength of the resin cement to the zirconia ceramic. GI cement does not provide sufficient bond strength of zirconia ceramics to dentin. © 2017 by the American College of Prosthodontists.

  4. Comparison of Er:YAG laser and surgical drill for osteotomy in oral surgery: an experimental study.

    Gabrić Pandurić, Dragana; Bago, Ivona; Katanec, Davor; Zabkar, Janez; Miletić, Ivana; Anić, Ivica


    High-energy lasers have been proposed as an alternative to the conventional surgical drill in oral and maxillofacial surgery. The aims of this study were to compare thermal changes of the bone surface, procedure time, and volume of the removed bone after drilling with an erbium (Er):yttrium-aluminum-garnet (YAG) laser versus a low-speed surgical drill. The bone sections were observed under light microscopy and examined histologically. Thirty bone blocks were prepared from porcine ribs. On each block 2 holes (tunnel preparations) were performed using a low-speed, 1.0-mm-wide, surgical pilot drill and an Er:YAG laser (pulse energy, 1,000 mJ; pulse duration, 300 μs; frequency, 20 Hz). The temperature induced by the preparation techniques was measured using an infrared camera. The removed bone volume was calculated by a modified mathematical algorithm. The time required for the preparation was measured with a digital stopwatch and a time-measurement instrument integrated within the computer program. The cortical and spongiose surfaces of the specimens were examined microscopically and histologically under a light microscope with a high-resolution camera. The Er:YAG laser removed significantly more bone tissue than the drill (P time (P laser preparation (P laser were regular with clear sharp edges and knifelike cuts. In the drill group, the preparations exhibited irregular edges full of bone fragments and fiberlike debris. Histologic examination of the laser sides showed a 30-μm-thick altered sublayer. The tissue in the drill group was covered with a smear layer without any alterations. The Er:YAG laser produced preparations with regular and sharp edges, without bone fragments and debris, in a shorter time, and with less generated heat. Thermal alterations in the treated surface were minimal. Copyright © 2012 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  5. Pump beam waist-dependent pulse energy generation in Nd:YAG/Cr4+:YAG passively Q-switched microchip laser

    Li, Chao-yu; Dong, Jun


    The incident pump beam waist-dependent pulse energy generation in Nd:YAG/Cr4+:YAG composite crystal passively Q-switched microchip laser has been investigated experimentally and theoretically by moving the Nd:YAG/Cr4+:YAG composite crystal along the pump beam direction. Highest pulse energy of 0.4 mJ has been generated when the Nd:YAG/Cr4+:YAG composite crystal is moved about 6 mm away from the focused pump beam waist. Laser pulses with pulse width of 1.7 ns and peak power of over 235 kW have been achieved. The theoretically calculated effective laser beam area at different positions of Nd:YAG/Cr4+:YAG composite crystal along the pump beam direction is in good agreement with the experimental results. The highest peak power can be generated by adjusting the pump beam waist incident on the Nd:YAG/Cr4+:YAG composite crystal to optimize the effective laser beam area in passively Q-switched microchip laser.

  6. Sintering of transparent Nd:YAG ceramics in oxygen atmosphere

    HUANG Yihua; JIANG Dongliang; ZHANG Jingxian; LIN Qingling; HUANG Zhengren


    Yttrium aluminum garnet (YAG) transparent ceramics were fabricated by sintering at oxygen atmosphere.Tetraethyl orthosilicate (TEOS) was added as the sintering additive to control the grain growth and densification.Pores were eliminated clearly at temperature lower than 1700 ℃,while grain size was around 3 μm.The in-line transmittance was 80% at 1064 nm when samples vere sintered at 1710 ℃.The effect of TEOS was studied in oxygen atmosphere sintering for Nd:YAG transparent ceramics.At higher temperature like 1710 ℃,the grain growth mechanism was solute drag,while at 1630 and 1550 ℃ the grain growth was controlled by liquid phase sintering mechanism.And 0.5 wt.% TEOS was the best adding content for Nd:YAG sintered in oxygen atmosphere.

  7. Growth of single-crystal YAG fiber optics.

    Nie, Craig D; Bera, Subhabrata; Harrington, James A


    Single-crystal YAG (Y3Al5O12) fibers have been grown by the laser heated pedestal growth technique with losses as low as 0.3 dB/m at 1.06 μm. These YAG fibers are as long as about 60 cm with diameters around 330 μm. The early fibers were grown from unoriented YAG seed fibers and these fibers exhibited facet steps or ridges on the surface of the fiber. However, recently we have grown fibers using an oriented seed to grow step-free fibers. Scattering losses made on the fibers indicate that the scattering losses are equal to about 30% of the total loss.

  8. Electrically Tunable Nd:YAG waveguide laser based on Graphene

    Ma, Linan; Tan, Yang; Akhmadaliev, Shavkat; Zhou, Shengqiang; Chen, Feng


    We demonstrate a tunable hybrid Graphene-Nd:YAG cladding waveguide laser exploiting the electro-optic and the Joule heating effects of Graphene. A cladding Nd:YAG waveguide was fabricated by the ion irradiation. The multi-layer graphene were transferred onto the waveguide surface as the saturable absorber to get the Q-switched pulsed laser oscillation in the waveguide. Composing with appropriate electrodes, graphene based capacitance and heater were formed on the surface of the Nd:YAG waveguide. Through electrical control of graphene, the state of the hybrid waveguide laser was turned on or off. And the laser operation of the hybrid waveguide was electrically tuned between the continuous wave laser and the nanosecond pulsed laser.

  9. A Coprecipitation Coating Synthesis of SiC/YAG Composites

    Ning ZHANG; Hongqiang RU; Xudong SUN; Qingkui CAI


    The α-SiC in 0.5 μm size powders were coated with Al2O3 and Y2O3 by a coprecipitation coating (CPC) method for fabrication of SiC/YAG composites. The same powder preparation was carried out by conventional mechanical mixing (MM) method for comparison. Two kinds of SiC/YAG composites were manufactured by pressureless sintering using the different powders, named CPC composite and MM composite thereafter respectively. It is shown that the CPC composite has the advantages of homogeneous distribution of YAG phase and of being sintered to high density at a low temperature, 100℃ lower than that of MM composite. The strength (573 Mpa) and hardness (23.3 Gpa) of the CPC composite are significantly higher than those (323 Mpa and 13.5 Gpa) of the MM composite, respectively.

  10. Can YAG screen accept LEReC bunch train?

    Seletskiy S.; Thieberger, P.; Miller, T.


    LEReC RF diagnostic beamline is supposed to accept 250 us long pulse trains of 1.6 MeV – 2.6 MeV (kinetic energy) electrons. This beamline is equipped with YAG profile monitor. Since we are interested in observing only the last macro bunch in the train, one of the possibilities is to install a fast kicker and a dedicated dump upstream of the YAG screen (and related diagnostics equipment). This approach is expensive and challenging from engineering point of view. Another possibility is to send the whole pulse train to the YAG screen and to use a fast gated camera (such as Imperex B0610 with trigger jitter under 60ns) to observe the image from the last pulse only. In this paper we study the feasibility of the last approach.

  11. 21 CFR 886.4392 - Nd:YAG laser for posterior capsulotomy and peripheral iridotomy.


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nd:YAG laser for posterior capsulotomy and...:YAG laser for posterior capsulotomy and peripheral iridotomy. (a) Identification. The Nd:YAG laser for... laser intended for disruption of the posterior capsule or the iris via optical breakdown. The...

  12. Transient absorption and laser output of YAG : Nd

    Kvapil, Jiří; Kvapil, Jos; Kubelka, J.; Kubeček, V.


    YAG : Nd grown under 98% Ar 2% H2 protective atmosphere free of nitrogen or hydrocarbons showed after UV irradiation broad absorption peaked at ˜1·9×104 cm-1 which disappeared relatively slowly at room temperature. It was more intensive in oxygen treated samples than in those annealed in hydrogsn. Transient absorption suppresses laser output by the increase of absorption at 0·94×104 cm-1 (1064 nm) and, particularly in CW mode, by the anomalous rod deformation. YAG : Nd containing Fe ions (≲2·10-4 wt%) showed no transient absorption.


    A. M. Ivashko


    Full Text Available The theoretical and experimental results of longitudinally continuous-wave diode-pumped Yb:Y3Al5O12 (YAG laser performance for compact field-condition measuring systems were demonstrated. Optimization of laser setup in terms of operation condition in the range of -40 ˚С – +65 ˚С without active thermal stabilization was carried out. Using Yb (10 ат.%:YAG crystal with the length of 3 mm the maximal output power more than 2 W was obtained in the whole of temperature range.

  14. THC:YAG, Ultrasonic, And Electrohydraulic Gallstone Lithotriptors

    Johnson, Jeffrey P.; Oz, Mehmet C.; Treat, Michael R.; Chuck, Roy S. H.; Trokel, Stephen L.


    There is considerable interest in methods of dealing with gallstones that would be less invasive than traditional gallbladder surgery. Our group has been especially interested in percutaneous endoscopic or transcatheter methods for performing biliary lithotripsy. We performed an in vitro comparison of three methods for lithotripsy, the thulium-holmium-chromium:YAG laser (THC:YAG), the ultrasonic lithotriptor (UL) and the electrohydraulic lithotriptor (EHL). We concluded that no one modality is clearly superior to the others, but rather that these methods are complementary with each modality having a preferred role.

  15. Experimental 511 W Composite Nd:YAG Ceramic Laser

    LI Hai-Feng; XU De-Gang; YANG Yang; WANG Yu-Ye; ZHOU Rui; ZHANG Tie-Li; ZHAO Xin; WANG Peng; YAO Jian-Quan


    @@ We demonstrate a 511 W laser diode pumped composite Nd:YAG ceramic laser. The optical pumping system is consisted of five laser diode stacked arrays arranged in a pentagonal shape around the ceramic rod whose size is φ6.35×144mm. When the pumping power is 1600W, the cw laser output up to 511 W at 1064nm can be obtained with a linear plano-plano cavity, and the optical-to-optical efficiency is 31.9%. To our knowledge, this is the highest value of laser output by using a newly invented composite Nd:YAG ceramic rod as the gain medium.

  16. Holmium:YAG laser coronary angioplasty in acute myocardial infarction

    Topaz, On; Luxenberg, Michael; Schumacher, Audrey


    Patients who sustain complicated acute myocardial infarction in whom thrombolytic agents either fail or are contraindicated often need mechanical revascularization other than PTCA. In 24 patients with acute infarction complicated by continuous chest pain and ischemia who either received lytics or with contraindication to lytics, a holmium:YAG laser (Eclipse Surgical Technologies, Palo Alto, CA) was utilized for thrombolysis and plaque ablation. Clinical success was achieved in 23/24 patients, with 23 patients (94%) surviving the acute infarction. Holmium:YAG laser is very effective and safe in thrombolysis and revascularization in this complicated clinical setting.

  17. Absorption of some powder materials to YAG laser



    Laser powder alloying is widely used for tribological applications. As one of the key pa-rameters , absorptivity of powder materials to laser plays an important role in the processing. Themeasurement of laser absorptivity is essential for absorptivity research. In present work, lumpedmethod based on heat transfer is established for laser absorptivity measurement. The absorptivityof some powder materials as Cu, Fe, Al, NiO, Al2O3, ZrO2, SiC, to YAG laser, are investigated.The results show that the absorptivity of powder materials to YAG laser is generally larger thanthat of bulk materials.

  18. Fabrication of transparent YAG ceramics by traditional solid-state-reaction method

    LI Chang-qing; ZUO Hong-bo; ZHANG Ming-fu; HAN Jie-cai; MENG Song-he


    Transparent polycrystalline YAG ceramics were fabricated by solid-state reaction method using commercial ultrafine yttria and α-Al2O3 powders. The starting materials were milled and calcined at 1 400 ℃, and sintered into transparent YAG ceramics at 1 750 ℃ in the vacuum for 4 h. Neither the starting materials as-milled or those calcined into YAG phase at 1 500 ℃ can be sintered into transparent ceramics. Wide grain boundaries emerge in the YAG ceramics sintered at 1 850 ℃ for 4 h, at the edge of which YAG phases decompose into perovskite YAlO3(YAP) and α-Al2O3.

  19. Highly efficient Nd: YAG ceramic CW laser with 59.8% slope-efficiency

    Yunfeng Qi; Qihong Lou; Haixia Ma; Jingxing Dong


    @@ In this paper, a highly efficient Ti:sapphire end-pumped 1 at.-% Nd:YAG ceramic laser that is comparable in efficiency with Nd:YAG single crystal lasers has been developed. Optical absorption and emission spectra for Nd:YAG ceramics have been measured. With 673-mW pumping, 295-mW laser output at 1064 nm has been obtained. The laser threshold is only 13 mW. Deducted the transmitted light, the corresponding optical-to-optical conversion efficiency is 58.4%. The lasing characteristics of Nd:YAG ceramic are nearly equal to those of Nd:YAG single crystal.

  20. Comparison of spectroscopic properties of Yb:YAP and Yb:YAG crystals

    Xiaoming He; Guangjun Zhao; Xiaodong Xu; Xionghui Zeng; Jun Xu


    The Yb:YAG and Yb:YAP crystals have been grown by Czochralski method. The absorption spectra and the fluorescence spectra of Yb:YAG and Yb:YAP crystals have been investigated. It is shown that the Yb:YAG crystal has better laser properties and smaller threshold power than Yb:YAP crystal. In addition, the absorption cross-section of the Yb:YAP crystal is 2.16 times of that of the Yb:YAG crystal,so laser diode pumped Yb:YAG lasing can be easily realized. Because YAP single crystal is anisotropic, it is provided with polarization characteristics.

  1. Coating of SiC Powder with Nano YAG Phase

    Zhang Ning; Cai Qingkui; Ru Hongqiang; Li Ying; Qiu Guanming; Sun Xudong


    SiC-YAG(Y3Al5O12) ceramic composite powders were prepared by co-precipitation coating method. Mechanism of co-precipitation coating of SiC powders with Y3+ and Al3+ precursors was investigated. If the concentration of [OH-] ion in the solution is controlled within the range between critical values for heterogeneous nucleation and homogeneous nucleation, Y3+ and Al3+ precipitation precursors can be coated on the surface of SiC particles. Y3+ and Al3+ precipitation precursors transform into YAG phase after calcining at 1000 ℃ without the formation of YAM and YAP phases. The formation temperature of YAG phase is about 600 ℃ lower than that of conventional powder mixing method. The effect of pH value of the solution and precipitant titration rate on coating quality of SiC-YAG composite powders was also studied. The results show that co-precipitation coating can be realized at a final pH of 9 and a precipitant titration rate of 5 ml·min-1.

  2. Dichroic mirror for diode pumped YAG:Nd-laser

    Dinca, Andreea; Skettrup, Torben; Lupei, V.


    The paper describes the design and realization of a dichroic mirror for a diode pumped YAG:Nd laser. The mirror is deposed on an optical glass substrate and works in optical contact with the laser crystal. The design was performed by admittance matching of the basic stack with the adjacent media...

  3. Er:YAG and adhesion in conservative dentistry : clinical overview

    Fornaini, Carlo


    The notion of utilizing laser technology in conservative dentistry was proposed in 1990 by Hibst and Keller, who introduced the possibility of using an Er:YAG laser as alternative to conventional instruments such as the turbine and micro-motor. In subsequent years a continuing effort has been made by clinicians, researchers and commercial companies to improve the technology.

  4. Optical properties of epitaxial YAG:Yb films

    Ubizskii, S.B. [Institute for Telecommunication, Radioelectronics and Electronic Engineering, Lviv Polytechnic National University, 12, Bandera St., Lviv, 79013 (Ukraine); Matkovskii, A.O. [Institute for Telecommunication, Radioelectronics and Electronic Engineering, Lviv Polytechnic National University, 12, Bandera St., Lviv, 79013 (Ukraine); Institute of Physics, University Rzezsow, 16 Rejtana St., Rzeszow, 35310 (Poland); Melnyk, S.S.; Syvorotka, I.M. [R and D Institute for Materials, Scientific Research Company ' ' Carat' ' , 202, Stryjska St., Lviv, 79031 (Ukraine); Mueller, V.; Peters, V.; Petermann, K. [Institut fuer Laser-Physik, Universitaet Hamburg, Jungiusstrasse 9a, 20355 Hamburg (Germany); Beyertt, A.; Giesen, A. [Institut fuer Strahlwerkzeuge, Universitaet Stuttgart, Pfaffenwaldring 43, 70569 Stuttgart (Germany)


    This work deals with the investigation of the optical properties of epitaxial YAG:Yb films and their suitability as gain media for thin disk lasers. Epitaxial films of YAG:Yb were grown by the liquid phase epitaxy method in air on the (111)-oriented YAG substrates. The thickness of the grown layers was from 30 to 260 {mu}m. The melt composition was varied to obtain the desired doping level from 10 to 15% and to optimize the optical properties. The best epitaxial films were colourless and had an Yb{sup 3+} luminescence lifetime of more than 950 {mu}s, which is very close to the intrinsic lifetime of the Yb ions in the bulk YAG single crystals. These films were tested in a thin disk laser setup with 24 absorption passes of the 940 nm pumping beam. The maximum output power at 1.03 {mu}m wavelength in CW operation reached more than 60 W and the optical efficiency was close to 30%. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  5. Low-power pulsed Nd:YAG laser irradiation for pre-emptive anaesthesia: A morphological and histological study.

    Chan, Ambrose; Punnia-Moorthy, Arumugam; Armati, Patricia


    To determine if tooth structure or dental pulp of normal healthy human premolar teeth to be extracted for orthodontic reasons exhibit morphological or histological changes following dental anaesthesia by pulsed Nd:YAG laser and subsequent cavity preparation (CP). Materials (Subjects) and Methods: 54 bilateral paired of human, healthy premolar teeth identified for inclusion in a clinical trial of Nd:YAG-induced anaesthesia and subsequently extracted for orthodontic reasons, were randomly divided into 4 treatment groups: Group 1 - teeth (n=44) were irradiated with 150 µs pulsed Nd:YAG laser-1064 nm (American Dental Laser, dLase300, Sunrise Technologies Inc., Folsom, CA, USA; Average power: 1.1 ± 0.2 W, power density: 39+ 0.7 W/cm(2), area 0.28 cm(2), 15 Hz; energy density:0. 260+ 0.047 J/cm(2)) +Sham EMLA (cream without active component) followed by cavity preparation (CP); Group 2 - Teeth (n=44) - were treated with EMLA + Sham Laser (1 mW 632.8-nm He:Ne laser aiming beam only) with CP; Group 3 Teeth (n=10) - were irradiated with pulsed Nd:YAG laser as above but minus CP; Group 4 (n=10)- was a Control group with teeth untreated (no Laser, EMLA or CP). Clinical anaesthesia was assessed by electric pulp testing (EPT) and CP. Teeth in each of the 4 groups were processed for examination by i) scanning electron microscopy (SEM); ii) longitudinal undecalcified ground sectioning (LUGS); iii) light microscopy of pulpal tissues or iv) dye penetration. Both Laser and EMLA groups demonstrated no alteration to mineralized tooth structure and dentinal permeability. Mild superficial pulpal changes were found in both groups (3/18 teeth) and of no statistical difference (p>0.99, the McNemar test). Neither Laser nor the Control groups minus CP, showed pulpal changes. Low-power pulsed Nd:YAG laser dose, as used in the clinical trial to induce anaesthesia, does not cause morphological damage to the mineralized tooth structure. Both Laser and EMLA groups showed minor superficial

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

    Shahabi, Sima; Fekrazad, Reza; Johari, Maryam; Chiniforoush, Nasim; Rezaei, Yashar


    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. PMID:28096945

  7. Er:YAG and Nd:YAG laser in treatment of patients with contraindications of conventional dental and maxillofacial surgery

    Smucler, Roman; Mazanek, Jiri


    In clinical praxis we must treat patients with some relative or absolute contraindications every day. Need of hospitalization, antibiotics, hemostyptics and complex examinations makes dentoalveolar and maxillofacial surgery in those cases quite expensive. Combination of Nd:YAG and Er:YAG laser gives us new possibilities. We can help some untreatable patients or transfer care from hospital to dental office. We have been trying to solve contraindications for laser therapy five years. In the center of our work are disorders of blood coagulation, immunity and metabolism. Nd:YAG laser is very useful in coagulation and vaporization of dental gum hypertrophies, benign and malign tumors in case of chronic anticoagulation therapy and immunosupress / in combination for example- after heart transplantation /. Special chapter is the care of patients with disseminated tumors. Er:YAG laser large solve big lesions because of minimal invasivity of course but for small benign tumors are recidives is ideal. Better and quicker healing make new standard of patients' cooperation. Generally fashionable and more comfortable laser treatment minimize need of general anesthesia. After five years we use complex laser therapy in our routine. Aim of our new work is to find ideal combination of cutting lasers to minimize classical complications of laser surgery / carbonization, long and secondary healing /.

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

    Sima Shahabi


    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.

  9. Tissue damage by laser radiation: an in vitro comparison between Tm:YAG and Ho:YAG laser on a porcine kidney model.

    Huusmann, Stephan; Wolters, Mathias; Kramer, Mario W; Bach, Thorsten; Teichmann, Heinrich-Otto; Eing, Andreas; Bardosi, Sebastian; Herrmann, Thomas R W


    The understanding of tissue damage by laser radiation is very important for the safety in the application of surgical lasers. The objective of this study is to evaluate cutting, vaporization and coagulation properties of the 2 µm Tm:YAG laser (LISA Laser Products OHG, GER) in comparison to the 2.1 µm Ho:YAG laser (Coherent Medical Group, USA) at different laser power settings in an in vitro model of freshly harvested porcine kidneys. Laser radiation of both laser generators was delivered by using a laser fiber with an optical core diameter of 550 µm (RigiFib, LISA Laser GER). Freshly harvested porcine kidneys were used as tissue model. Experiments were either performed in ambient air or in aqueous saline. The Tm:YAG laser was adjusted to 5 W for low and 120 W for the high power setting. The Ho:YAG laser was adjusted to 0.5 J and 10 Hz (5 W average power) for low power setting and to 2.0 J and 40 Hz (80 W average power) for high power setting, accordingly. The specimens of the cutting experiments were fixed in 4 % formalin, embedded in paraffin and stained with Toluidin blue. The laser damage zone was measured under microscope as the main evaluation criteria. Laser damage zone consists of an outer coagulation zone plus a further necrotic zone. In the ambient air experiments the laser damage zone for the low power setting was 745 ± 119 µm for the Tm:YAG and 614 ± 187 µm for the Ho:YAG laser. On the high power setting, the damage zone was 760 ± 167 µm for Tm:YAG and 715 ± 142 µm for Ho:YAG. The incision depth in ambient air on the low power setting was 346 ± 199 µm for Tm:YAG, 118 ± 119 µm for Ho:YAG. On the high power setting incision depth was 5083 ± 144 µm (Tm:YAG) and 1126 ± 383 µm (Ho:YAG) respectively. In the saline solution experiments, the laser damage zone was 550 ± 137 µm (Tm:YAG) versus 447 ± 65 µm (Ho:YAG), on the low power setting and 653 ± 137 µm (Tm:YAG) versus 677 ± 134 µm (Ho:YAG

  10. 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

    Goya, Claudia


    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)

  11. Effect of dental surface treatment with Nd:YAG and Er:YAG lasers on bond strength of resin composite to recently bleached enamel.

    Rocha Gomes Torres, Carlos; Caneppele, Taciana Marco Ferraz; Del Moral de Lazari, Regina; Ribeiro, Carolina Ferraz; Borges, Alessandra Buhler


    The aim of this work is to evaluate the effect of surface treatment with Er:YAG and Nd:YAG lasers on resin composite bond strength to recently bleached enamel. In this study, 120 bovine incisors were distributed into two groups: group C: without bleaching treatment; group B: bleached with 35% hydrogen peroxide. Each group was divided into three subgroups: subgroup N: without laser treatment; subgroup Nd: irradiation with Nd:YAG laser; subgroup Er: irradiation with Er:YAG laser. The adhesive system (Adper Single Bond 2) was then applied and composite buildups were constructed with Filtek Supreme composite. The teeth were sectioned to obtain enamel-resin sticks (1 × 1 mm) and submitted to microtensile bond testing. The data were statistically analyzed by the ANOVA and Tukey tests. The bond strength values in the bleached control group (5.57 MPa) presented a significant difference in comparison to the group bleached and irradiated with Er:YAG laser (13.18 MPa) or Nd:YAG (25.67 MPa). The non-bleached control group presented mean values of 30.92 MPa, with statistical difference of all the others groups. The use of Nd:YAG and Er:YAG lasers on bleached specimens was able to improve the bond strengths of them.

  12. Bonding Strength of Ceromer with Direct Laser Sintered, Ni-Cr-Based, and ZrO2 Metal Infrastructures After Er:YAG, Nd:YAG, and Ho:YAG Laser Surface Treatments-A Comparative In Vitro Study.

    Gorler, Oguzhan; Ozdemir, Ali Kemal


    Laser modalities instead of conventional surface treatment techniques have been suggested to obtain an adequate micromechanical bonding between dental super- and infrastructures. The present study was undertaken to assess the effect of surface treatment with Ho:YAG, Er:YAG, and Nd:YAG laser modalities on the shear bond strength (SBS) of ceromer to different types of metal infrastructures in in vitro settings. The study specimens consisted of 40 direct laser sintered (DLS), 40 Ni-Cr-based, and 40 zirconium oxide (ZrO2) infrastructures. In each infrastructure group, the specimens were divided randomly into five treatment modalities (n = 8): no treatment (controls), sandblasting, Er:YAG, Nd:YAG, and Ho:YAG lasers. The DLS, Ni-Cr-based, and ZrO2 infrastructures were prepared in the final dimensions of 7 mm in diameter and 3 mm in thickness in line with the ISO 11405 standard. Ceromer as superstructure was applied to all the infrastructures after their surface treatments according to the selected treatment modality. SBS test was performed to test the effectiveness of surface treatments. A stereomicroscope was used to determine the changes in the surface morphology of specimens. Among the laser modalities and sandblasting, Ho:YAG laser caused the most important increase in the DLS and Ni-Cr-based infrastructures but sandblasting caused the most important increase in the ZrO2 infrastructure. In all the infrastructures, Nd:YAG laser has the least effectiveness, and Er:YAG laser makes an intermediate success. The stereomicroscopy images presented that the applications of laser surface treatments altered the surface in all the infrastructures. Overall, in current experimental settings, Ho:YAG, Nd:YAG, and Er:YAG lasers, in order of strength, are effective in improving the bonding of ceromer to all the infrastructures. Ho:YAG laser is more effective in the DLS and Ni-Cr-based infrastructures, but sandblasting is more effective in the ZrO2 infrastructure. The studied

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

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


    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.

  14. Amplification of complex fields in Nd:YAG amplifiers

    Chen, Xudong; Chang, Chengcheng; Pu, Jixiong


    High energy nanosecond vortex beams and cylindrically polarized beams are generated in Nd:YAG amplifiers. Vortex seed beams and cylindrically polarized seed beams are converted from a conventional Nd:YAG laser by spiral phase plate and polarization converter, respectively. Maximum output energy of optical vortex up to 995 mJ and cylindrically polarized beams up to 772 mJ have been achieved at 10 Hz in a 10-ns pulse, respectively. The amplification efficiency, the beam quality and pulse width of the amplification output are studied. Both the topological charge of the vortex seed beams and polarization state of cylindrically polarized beams are confirmed to be conserved during the amplification. The generation of high energy vortex beams and cylindrically polarized beams would be beneficial to laser material processing.

  15. Development behavior of liquid plasma produced by YAG laser

    Yamada, J; Yamada, Jun; Tsuda, Norio


    The laser induced plasma in liquid hasn't been studied enough. In liquid, the laser induced plasma may be able to resolve the hazardous material called the environment material. Then, the plasma produced in liquid by the laser light is studied and the plasma development is observed by a streak camera. The ultra pure water or the ultra pure water with a melted NaCl is used as a test liquid. The liquid plasma is produced by the fundamental wave of YAG laser. When NaCl concentration is varied, the plasma development behavior is obserbed by streak camera. The liquid plasma develops backward. The plasma is produced from many seeds and It consists of a group of plasmas. However, the liquid plasma produced by second harmonic wave of YAG laser develops as a single plasma. The development mechanism is investigated from the growth rate of backward plasma. The backward plasma develops by breakdown wave and radiation supported shock wave.

  16. Hollow polycarbonate fiber for Er:YAG laser light delivery.

    Nakazawa, Masayuki; Shi, Yi-Wei; Matsuura, Yuji; Iwai, Katsumasa; Miyagi, Mitsunobu


    We developed hollow fibers with polycarbonate (PC) capillaries for use as a supporting tube. The PC capillaries were prepared by using a glass-drawing technique. Hollow PC fibers are safer and more flexible than hollow glass fibers because no fragments are released when the fibers are broken in various applications. Inner coating layers of silver and cyclic olefin polymer (COP) enhanced the reflection rate at the Er:YAG laser light wavelength. Using these fibers, we attained low loss for Er:YAG laser light transmission. By adjusting the drawing temperature in the fabrication of the PC capillaries, we created a smooth inner surface and uniform PC capillaries. We also demonstrated low-loss properties for visible pilot beams.

  17. Synthesis and characterization of yttrium aluminium garnet (YAG powders

    Magdalena Zarzecka-Napierala


    Full Text Available In this paper synthesis and characterization of YAG powders, prepared by a process based on complexing properties of citric acid, was reported. Influence of citric acid estrification induced by 2-propanol or ethylene glycol on the system homogeneity was investigated. These reagents were introduced to aqueous solution of yttrium and aluminium nitrates. A variety of powders from Al2O3-Y2O3 system with different phase composition were obtained by altering the citrate to nitrate ratio. Evolution of the powders phase composition vs. temperature was investigated using DTA/TG, XRD, and FT-IR methods. The most interesting results were observed in case of the citric acid–propanol–relative nitrates system. The mole ratio of these reagents equal to 1:2.5:2.5 (nitrates (Al,Y:citric acid:2-propanol allowed to synthesize pure YAG phase powders at temperature as low as 950°C.

  18. Effects of Er:YAG laser irradiation on human cartilage

    Glinkowski, Wojciech; Brzozowska, Malgorzata; Ciszek, Bogdan; Rowinski, Jan; Strek, Wieslaw


    Irradiation of the hyaline or fibrous cartilage excised from the body of a human cadaver with Er:YAG laser beam, single pulse with a dose of 1 J, produces a crater with a depth of approximately 500 micrometers and a diameter varying from 5 to 300 micrometers. Histological examination has revealed that the laser-made craters were surrounded by a thin rim (2-10 micrometer) of charred and coagulated tissue. No damage was observed in the cartilage surrounding the rim. The presence of sharp demarcation between the tissue areas ablated by laser energy and the undamaged areas argues for the potential usefulness of the Er:YAG laser in surgery of cartilages.

  19. Pulsed Tm:YAG laser ablation of knee joint tissues

    Shi, Wei-Qiang; Vari, Sandor G.; Duffy, J. T.; Miller, J. M.; Weiss, Andrew B.; Fishbein, Michael C.; Grundfest, Warren S.


    We investigated the effect of a free-running 2.01 micron pulsed Tm:YAG laser on bovine knee joint tissues. Ablation rates of fresh fibrocartilage, hyaline cartilage, and bone were measured in saline as a function of laser fluence (160 - 640 J/cm2) and fiber core size (400 and 600 microns). All tissues could be effectively ablated and the ablation rate increased linearly with the increasing fluence. Use of fibers of different core sizes, while maintaining constant energy fluence, did not result in significant difference in ablation rate. Histology analyses of the ablated tissue samples reveal average Tm:YAG radiation induced thermal damage (denatunalization) zones ranging between 130 and 540 microns, depending on the laser parameters and the tissue type.

  20. Investigation of bulk laser damage in transparent YAG ceramics controlled with microstructural refinement

    Kamimura, T.; Kawaguchi, Y.; Arii, T.; Shirai, W.; Mikami, T.; Okamoto, T.; Aung, Yan Lin; Ikesue, A.


    We have investigated a relationship among the bulk laser-induced damage threshold (LIDT) and YAG ceramics with various structural defects. The correlation of scattering defect density and laser damage resistance was clearly observed. A high-quality YAG ceramic having a low-scattering density showed a higher LIDT than that of a low-quality YAG ceramic. Laser damage threshold (LIDT) of high-quality YAG ceramic was almost the same as that of a single crystal. In addition, the high-quality Nd:YAG ceramics with low-defect density showed an excellent oscillation efficiency which was comparable to that of a single crystal. Thus, high-quality YAG ceramic with low-defect density is more reliable as a material which is highly resistant to laser damage.

  1. Cryogenic Tm: YAG Laser in the Near Infrared


    REPLACE THIS LINE WITH YOUR PAPER IDENTIFICATION NUMBER (DOUBLE-CLICK HERE TO EDIT) < Cryogenic Tm:YAG Laser in the Near Infrared* Tso Yee Fan...therefore limits operation. However, operation at cryogenic temperature depopulates the lower laser level, reduces laser threshold, increases...efficiency, and greatly mitigates thermo-optic effects in crystalline host materials [21]-[23]. Here, we have used cryogenic cooling to enable laser

  2. Neodymium YAG Lasers. Citations from the NTIS data base

    Carrigan, B.


    Federally funded research reports on lasing of neodymium doped yttrium aluminum garnet are cited. Studies on design, fabrication, quantum efficiency, light pulses, stabilization, and testing are covered. Optical pumping, mode locking, frequency conversion, and modulation of these lasers are discussed. Laser applications such as optical communication, range finding, and tracking are included. Safety hazards and radiation damage related to neodymium YAG lasers are also covered. This updated bibliography contains 181 citations, 15 of which are new entries to the previous edition.

  3. Diode-pumped 1123-nm Nd:YAG laser

    Xiaoping Guo(郭晓萍); Meng Chen(陈檬); Gang Li(李港); Bingyuan zhang(张炳元); Jiandong Yang(杨建东); Zhigang Zhang(张志刚); Yonggang Wang(王勇刚)


    We demonstrated a diode-pumped Nd:YAG laser with a plano-concave resonator. When the pump power is 1.57 W, the output power of 1123-nm laser is 132 mW at the temperature of 20 ℃, and the power change is less than 2% in an hour. A periodically poled LiNbOa (PPLN) was used as outer cavity frequency-doubling crystal and 561-nm laser was observed.

  4. Experimental study of thermal lensing of Nd:YAG laser

    HU Shao-yun; ZHONG Ming; ZUO Yan; FAN Hong-ying


    A wavefront method of measuring the thermal lensing of solid-state lasers is proposed.This method is easy to implement and has a high spatial resolution for diagnosing thermal lensing.By this method,the thermal lensing of Nd:YAG laser is studied in detail.And this work provides a means for studying the thermal effects of laser medium and many instructional parameters for optimizing the design of the laser cavity.

  5. The Effects of Er:YAG, Nd:YAG, and Ho:YAG Laser Surface Treatments to Acrylic Resin Denture Bases on the Tensile Bond Strength of Silicone-Based Resilient Liners.

    Gorler, Oguzhan; Dogan, Derya Ozdemir; Ulgey, Melih; Goze, Aysegul; Hubbezoğlu, Ihsan; Zan, Recai; Ozdemir, Ali Kemal


    The present study was to assess the effect of surface treatments of Er:YAG, Nd:YAG, and Ho:YAG lasers on the tensile bond strength of a silicone-based resilient liner to an acrylic denture in an in vitro setting. Experimental dumbbell-shaped specimens (75 mm) were produced by combining two acrylate pieces fabricated from heat-polymerized acrylic resin (36 mm) with 3 mm of Molloplast(®)-B filling between them. The specimens (n=200) were randomly divided in half for thermocycling, and each 100 specimen set was randomized into five groups (n=20) with different surface treatments: control (no surface treatment), sandblasting, Er:YAG laser, Nd:YAG laser, and Ho:YAG laser. A tensile bond strength test was performed. The effect of the laser surface treatments was examined with scanning electron microscopy. Only the Er:YAG laser increased the tensile bond strength compared with the other treatments. The other laser groups showed lower bond strengths. The Ho:YAG laser resulted in considerably reduced tensile bond strength. The scanning electron microscopy images showed that applying laser surface treatments modified the surface of the denture base resin. There was not an overall improvement with the use of the studied laser modalities in the adhesion quality of resilient denture liner to acrylic resin, although Er:YAG laser showed a potential to improve their adhesion. These laser modalities need to be subjected to further studies to determine optimal setup for use in prosthodontics.

  6. Emerging blue-UV luminescence in cerium doped YAG nanocrystals

    Shirmane, Liana [Institute of Solid State Physics, University of Latvia, Riga (Lithuania); Pankratov, Vladimir [Research Center of Molecular Materials, University of Oulu (Finland)


    Time-resolved luminescence properties of Ce{sup 3+} doped Y{sub 3}Al{sub 5}O{sub 12} (YAG) nanocrystals have been studied by means of vacuum-ultraviolet excitation spectroscopy. It was discovered that additionally to the regular Ce{sup 3+} yellow-green emission which is well-known luminescence in YAG, new emission covering a broad spectral range from 2.7 eV to 3.5 eV was revealed in the luminescence spectra for all YAG:Ce nanocrystals studied. This blue-UV emission has fast decay time about 7 ns as well as intensive well-resolved excitation band peaking at 5.9 eV and, in contrast to green Ce{sup 3+} emission, practically is not excited at higher energies. The origin of the blue-UV emission is tentatively suggested and discussed. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

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

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


    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.

  8. Temperature variation during apicectomy with Er:YAG laser.

    Bodrumlu, Emre; Keskiner, Ilker; Sumer, Mahmut; Sumer, A Pinar; Telcıoglu, N Tuba


    The purpose of this in vitro study was to evaluate the generated temperature of the Er:YAG laser, with three different pulse durations for apicectomy, compared with tungsten bur and surgical saw. Apicectomy is an endodontic surgery performed to remove the root apex and curette adjacent periapical tissue because of lesions of the apical area that are not healing properly. Sixty single-rooted extracted human teeth were resected by three cutting methods: tungsten bur, surgical saw, and Er:YAG laser irradiation with three different pulse durations; pulse duration 50 μs, pulse duration 100 μs, and pulse duration 300 μs. Teflon-insulated, type K thermocouples were used to measure temperature changes during the apicectomy process. Data were analyzed using the general linear models procedure of the SPSS statistical software program. Although there was no statistically significant difference for the mean values of temperature changes at 1 mm away to the cutting site of teeth, there was statistically significant difference among groups for the mean values of temperature changes at 3 mm away to the cutting site of teeth. Additionally, there was statistically significant difference among groups for the total time required for apicectomy. The laser irradiation with pulse duration 50 μs appears to have the lowest temperature rise and the shortest time required for apicectomy of the three pulse durations. However, Er:YAG laser for apicectomy in all pulse durations could be used safely for resection in endodontics in the presence of sufficient water.

  9. Holmium:YAG laser in dentistry: photoconditioning of dentinal surfaces

    Holt, Raleigh A.; Nordquist, Robert E.


    This in vitro study was undertaken to determine energy levels necessary to produce tubule closure and surface smoothing on dentinal surfaces of human teeth and their resultant temperature increases within the pulpal canals with the Holmium:YAG laser. An optimal working spot size and even absorption pattern were produced by defocusing the laser beam and evaluated by images produced on light exposed and developed photographic paper. The surface effects on dentin were examined by scanning electron microscopy. A thermocouple was positioned in the canals of fresh dissected dog jaws and attached to a recorder which produced a graph of the temperature changes. The in vitro research model for intrapulpal temperatures changes was verified by comparing premortem and postmortem temperature readings. The same protocol was used to evaluate temperature changes in fresh human extracted teeth. In vivo histological studies were conducted to evaluate the effects of HO:YAG laser energy on pulpal tissues. The results of these studies indicate the HO:YAG laser at a wavelength of 2.12 microns can be safely and effectively used for photoconditioning of the dentinal surfaces of teeth in clinical conditions.

  10. Accidental macular hole following Neodymium:YAG posterior capsulotomy

    Munteanu Mihnea


    Full Text Available Introduction. Posterior capsular opacification (PCO is the commonest complication of cataract surgery, occurring in up to one-third of patients in a period of five years. The treatment of choice is the Neodymium:YAG laser posterior capsulotomy. This treatment can be associated with several complications, some of them severe. A rare complication of this procedure is the accidental induced macular hole. Case Outline. A 54-year-old female patient was referred to our Department because of a severe loss of vision and a central scotoma at the right eye. The patient underwent a Nd:YAG posterior capsulotomy 2 days ago, for a PCO. The fundus examination at presentation revealed a round retinal defect in the macular region, a massive inferior preretinal hemorrhage and a mild vitreous hamorrhage. A 6-months follow-up of the case, including retinography and fluorescein angiography, is presented. Conclusion. Although the Nd:YAG laser capsulotomy is a safe, noninvasive, and effective outpatient procedure to improve vision hindered by PCO, it must be recognized that it carries a low but definite risk of serious complications. Physicians and patients should be aware of these rare but severe complications regarding this otherwise safe procedure. Fortunately, most of the complications related to this procedure are transient and can be managed by proper medication.

  11. A Multicenter Study for Cellulite Treatment Using a 1440-nm Nd:YAG Wavelength Laser with Side-Firing Fiber.

    DiBernardo, Barry E; Sasaki, Gordon H; Katz, Bruce E; Hunstad, Joseph P; Petti, Christine; Burns, A Jay


    Treatment of cellulite using a 1440-nm YAG wavelength laser with side-firing fiber has proven safe and effective, lasting at least 6 months. The authors evaluate the safety and efficacy of a single, subdermal procedure to treat the underlying structure of cellulite for at least 1 year. Fifty-seven patients underwent a 3-step cellulite treatment with a 1440-nm Nd:YAG laser with a side-firing fiber and temperature-sensing cannula. Efficacy was measured by the blinded evaluators to distinguish baseline photos from those taken at 12 months posttreatment, with results on a 5-point, 2-category ordinal photonumeric scale when comparing baseline photos to 12 months posttreatment. Subject and physician satisfaction was assessed based on completion of a satisfaction survey. Adverse events (AE) were recorded throughout the study. Twelve month data were analyzed and compared to 6 month data. Evaluators chose baseline photographs 97% on average from 6 (-1, +2) months and 91% from the 12 (-3, +2) months posttreatment photographs. At 6 (-1, +2) months, the average improvement score was 1.7 for dimples and 1.1 for contour irregularities. At 12 (-3, +2) months, the average improvement score was 1.4 for dimples and 1.0 for contour irregularities. The average satisfaction score for the physician was 5.6 and the patient was 5.3 on a 6-point scale. A single, 3-step, minimally invasive laser treatment using a 1440-nm Nd:YAG laser, side-firing fiber, and temperature-sensing cannula to treat the underlying structure of cellulite proved to be safe and maintained effectiveness at least 1 year post treatment. LEVEL OF EVIDENCE 2: Therapeutic. © 2016 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission:

  12. Amalgam Surface Treatment by Different Output Powers of Er:YAG Laser:SEM Evaluation.

    Hosseini, Mohammad Hashem; Hassanpour, Mehdi; Etemadi, Ardavan; Ranjbar Omrani, Ladan; Darvishpour, Hojat; Chiniforush, Nasim


    The purpose of this study was to evaluate amalgam surfaces treated by different output powers of erbium-doped yttrium aluminum garnet (Er:YAG) laser by scanning electron microscope (SEM). Twenty-one amalgam blocks (8 mm × 8 mm, 3 mm thickness) were prepared by condensing silver amalgam (into putty impression material. After keeping them for 24 hours in distilled water, they were divided into 7 groups as follow: G1: Er:YAG laser (1 W, 50 mJ), G2: Er:YAG laser (2 W, 100 mJ), G3: Er:YAG laser (3 W, 150 mJ), G4: Sandblast, G5: Sandblast + Er:YAG laser (1 W, 50 mJ), G6: Sandblast +Er:YAG laser (2 W, 100 mJ) and G7: Sandblast +Er:YAG laser (3 W, 150 mJ). Then after preparation of all samples, they were examined by SEM. The SEM results of amalgam surfaces treated by different output powers of Er:YAG laser showed some pitting areas with non-homogenous irregularities Conclusion: It seems that the application of sandblasting accompanied by Er:YAG laser irradiation can provide proper surface for bonding of orthodontic brackets.

  13. All solid-state diode pumped Nd:YAG MOPA with stimulated Brillouin phase conjugate mirror

    Offerhaus, H.L.; Godfried, H.P.; Witteman, W.J.


    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 μ

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

    Danqing Xia


    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.

  15. Effect of Nd:YAG laser capsulotomy on refraction in multifocal apodized diffractive pseudophakia.

    Vrijman, V.; Linden, J.W.M. van der; Nieuwendaal, C.P.; Meulen, I.J. van der; Mourits, M.P.; Lapid-Gortzak, R.


    PURPOSE: To evaluate the effect on refraction of neodymium:YAG (Nd:YAG) laser posterior capsulotomy for posterior capsule opacification (PCO), and to evaluate the correlation between automated and subjective refraction in multifocal apodized diffractive pseudophakia. METHODS: A retrospective study

  16. Histological and TEM examination of early stages of bone healing after Er:YAG laser irradiation.

    Pourzarandian, Amir; Watanabe, Hisashi; Aoki, Akira; Ichinose, Shizuko; Sasaki, Katia M; Nitta, Hiroshi; Ishikawa, Isao


    The aim of this study was to analyze the early healing process of bone tissue irradiated by Er:YAG laser and compare it with that treated by mechanical drilling and CO(2) laser. Er:YAG laser has a great potential for cutting hard tissues as it is capable of ablation with less thermal damage. Twenty-four male Wistar rats were used for this study. The calvarial bone of rats was exposed and straight grooves were prepared by Er:YAG laser, mechanical bur and continuous wave CO(2) laser. Four rats each were sacrificed at six time points: 10 min, 6 and 24 h and 3, 7, and 14 days post-surgery. Sections were prepared for light and transmission electron microscopic (TEM) observations. Compared to mechanical bur and CO(2) groups, the inflammatory cell infiltration adjacent to the irradiated bone surface, fibroblastic reaction, and revascularization were more pronounced in the Er:YAG laser-irradiated tissues. A cell-rich granulation tissue with fibroblasts and osteoblasts was predominant in 7-day specimens of Er:YAG laser group. Histopathological analysis of 14-day specimens in the Er:YAG group also revealed significantly greater new bone formation, compared with the mechanical bur and CO(2) laser groups. Initial bone healing following Er:YAG laser irradiation occurred faster than that after mechanical bur and CO(2) laser. Er:YAG laser treatment may be advantageous for wound healing of bone tissue, presumably by providing a favorable surface for cell attachment.

  17. Er:YAG crystal temperature influence on laser output characteristics

    Němec, Michal; Å ulc, Jan; Hubka, Zbyněk.; Hlinomaz, Kryštof; Jelínková, Helena


    The main goal of this work was to investigate the influence of the temperature of the Er:YAG active medium on laser properties in eye-safe spectral region for three various pump wavelengths. The tested Er:YAG sample doped by 0.5% of Er3+ ions had a cylindrical shape with 25mm in length and 5mm in diameter. The absorption spectrum of the Er:YAG active medium in the range from 1400nm up to 1700nm for temperatures 80K and 300K was measured. The crystal was placed inside the vacuum chamber of a liquid nitrogen cooled cryostat. The temperature was controlled within the 80 - 340K temperature range. Three pump sources generating at 1535, 1452, and 1467nm were applied. The first one was flash lamp pumped Er:glass laser (repetition rate 0.5 Hz, pulse duration 1 ms, pulse energy 148 mJ). The further two sources were fiber coupled laser diodes (repetition rate 10 Hz, pulse duration 10 ms, maximum pulse energies 106mJ and 195 mJ). The semi-hemispherical laser resonator consisted of a pump curved mirror and output plan coupler with a reflectivity of 90% @ 1645 nm. The laser output characteristics were investigated in dependence on temperature of active medium for three laser pumping systems. The output energy has an optimum in dependence on active medium temperature and pump wavelengths. The maximal generated laser energies were 16.2mJ (90 K), 28.7mJ (120 K), and 33.2mJ (220 K), for pump wavelengths 1452 nm, 1467 nm, and 1535 nm, respectively.

  18. Intracorporeal lithotripsy with the holmium:YAG laser

    Denstedt, John D.; Razvi, Hassan A.; Chun, Samuel S.; Sales, Jack L.


    A variety of devices are currently available for intracorporeal stone fragmentation. Recently a new wavelength of laser, the Holmium:YAG, has demonstrated a variety of potential urologic applications including ablation of soft tissue lesions as well as stone fragmentation. This laser has a wavelength of 2100 nm and operates in a pulsed mode. Energy is delivered through a 400 um quartz end-firing fiber. In this presentation we review our clinical experience with the Holmium:YAG laser for the treatment of renal and ureteral calculi. Over a 23 month period, 63 patients underwent 67 procedures. Seven procedures consisted of percutaneous nephrolithotripsy for large or staghorn renal calculi. Sixty procedures were performed for ureteral stones. Procedures for proximal ureteral stones (6) employed a retrograde approach using flexible ureteroscopes (8.5 or 9.8). Stones in the mid ureter (12) and distal ureter (42) were approached transurethrally using a 6.9 rigid ureteroscope. Complete stone fragmentation without the need for additional procedures was achieved in 82% of cases. Treatment failures included 1 stone migration into the renal pelvis during laser activation, 6 patients who had incomplete fragmentation and 3 patients in which laser malfunction precluded complete fragmentation. Stone analysis available in 23 patients revealed calcium oxalate monohydrate (15), calcium oxalate dihydrate (2), cystine (2), uric acid (3) and calcium phosphate (1). A single complication of ureteral perforation occurred when the laser was fired without direct visual guidance. Radiographic follow-up at an average of 16 weeks is available in 22 patients and has identified 2 patients with ureteral strictures that are not believed to be related to laser lithotripsy. In summary, we have found the Holmium:YAG laser to be a reliable and versatile device for intracorporeal lithotripsy. Its safety and efficacy make it a suitable alternative for performing intracorporeal lithotripsy of urinary

  19. Vitreous humor rheology after Nd:YAG laser photo disruption.

    Abdelkawi, Salwa A; Abdel-Salam, Ahmed M; Ghoniem, Dina F; Ghaly, Sally K


    This work aimed to consider the hazardous side effect of eye floaters treatment with Q-switched Nd:YAG laser on the protein and viscoelastic properties of the vitreous humor, and evaluate the protective role of vitamin C against laser photo disruption. Five groups of New Zealand rabbits were divided as follows: control group for (n = 3) without any treatment, the second group (n = 9) treated with Q-switched Nd:YAG laser energy of 5 mJ × 100 pulse delivered to the anterior, middle, and posterior vitreous, respectively (n = 3 for each). The third group (n = 9) received a daily dose of 25 mg/kg body weight vitamin C for 2 weeks, and then treated with laser as the previous group. The fourth group (n = 9) treated with 10 mJ 9 50 pulse delivered to the anterior, middle, and posterior vitreous, respectively (n = 3 rabbits each). The fifth group (n = 9) received a daily dose of 25 mg/kg body weight vitamin C for 2 weeks, and then treated with laser as the previous group. After 2 weeks of laser treatment, the protein content, refractive index (RI), and the rheological properties of vitreous humor, such as consistency, shear stress, and viscosity, were determined. The results showed that, the anterior vitreous group exposed to of 5 mJ × 100 pulse and/or supplemented with vitamin C, showed no obvious change. Furthermore, all other treated groups especially for mid-vitreous and posterior vitreous humor showed increase in the protein content, RI and the viscosity of vitreous humor. The flow index remained below unity indicating the non-Newtonian behavior of the vitreous humor. Application of Q-switched Nd:YAG laser should be restricted to the anterior vitreous humor to prevent the deleterious effect of laser on the gel state of the vitreous humor.

  20. Transmission of Er:YAG laser through different dental ceramics.

    Sari, Tugrul; Tuncel, Ilkin; Usumez, Aslihan; Gutknecht, Norbert


    The aim of this study was to determine the erbium-doped yttrium aluminum garnet (Er:YAG) laser transmission ratio through different dental ceramics with different thicknesses. Laser debonding procedure of adhesively luted all-ceramic restorations is based on the transmission of laser energy through the ceramic and the ablation of resin cement, because of the transmitted laser energy. Five different dental ceramics were evaluated in this study: sintered zirconium-oxide core ceramic, monolithic zirconium-oxide ceramic, feldspathic ceramic, leucite-reinforced glass ceramic, and lithium disilicate-reinforced glass ceramic. Two ceramic discs with different thicknesses (0.5 and 1 mm) were fabricated for each group. Ceramic discs were placed between the sensor membrane of the laser power meter and the tip of the contact handpiece of an Er:YAG laser device with the aid of a custom- made acrylic holder. The transmission ratio of Er:YAG laser energy (500 mJ, 2 Hz, 1 W, 1000 μs) through different ceramic discs was measured with the power meter. Ten measurements were made for each group and the results were analyzed with two way analysis of variance (ANOVA) and Tukey honestly significant difference (HSD) tests. The highest transmission ratio was determined for lithium disilicate-reinforced ceramic with 0.5 mm thickness (88%) and the lowest was determined for feldspathic ceramic with 1 mm thickness (44%). The differences among the different ceramics and between the different thicknesses were significant (pCeramic type and thickness should be taken into consideration to adjust the laser irradiation parameters during laser debonding of adhesively luted all-ceramic restorations.

  1. Influence of the Ce:YAG Amount on Structure and Optical Properties of Ce:YAG-PMMA Composites for White LED

    Armetta, Francesco; Sibeko, Motshabi A.; Luyt, Adriaan S.; Chillura Martino, Delia F.; Spinella, Alberto; Saladino, Maria Luisa


    Ce:YAG-poly(methyl methacrylate) (PMMA) composites were prepared by using a melt compounding method, adding several amounts of Ce:YAG in the range 0.1-5 wt. %. The optical properties of the obtained composites and of the composites combined with a blue LED were measured to investigate the effect of the amount of Ce:YAG on the resulting emitted light in view of possible application in white LED manufacture. An increase in Ce:YAG amount caused an increase in the emission and a shift of 15 nm, influencing the white LED performance. The structure and morphology of the composites were studied. The results show that the interaction between the two components, observed by using solid state NMR experiments, are the responsible for the observed shift.

  2. Ignition of an automobile engine by high-peak power Nd:YAG/Cr⁴⁺:YAG laser-spark devices.

    Pavel, Nicolaie; Dascalu, Traian; Salamu, Gabriela; Dinca, Mihai; Boicea, Niculae; Birtas, Adrian


    Laser sparks that were built with high-peak power passively Q-switched Nd:YAG/Cr(4+):YAG lasers have been used to operate a Renault automobile engine. The design of such a laser spark igniter is discussed. The Nd:YAG/Cr(4+):YAG laser delivered pulses with energy of 4 mJ and 0.8-ns duration, corresponding to pulse peak power of 5 MW. The coefficients of variability of maximum pressure (COV(Pmax)) and of indicated mean effective pressure (COV(IMEP)) and specific emissions like hydrocarbons (HC), carbon monoxide (CO), nitrogen oxides (NO(x)) and carbon dioxide (CO2) were measured at various engine speeds and high loads. Improved engine stability in terms of COV(Pmax) and COV(Pmax) and decreased emissions of CO and HC were obtained for the engine that was run by laser sparks in comparison with classical ignition by electrical spark plugs.

  3. Neodymium YAG lasers pumped by light-emitting diodes

    Bilak, V.I.; Goldobin, I.S.; Zverev, G.M.; Kuratev, I.I.; Pashkov, V.A.; Stel' makh, M.F.; Tsvetkov, Y.V.; Solov' eva, N.M.


    The results are presented of theoretical and experimental investigations of room-temperature YAG:Nd lasers pumped by light-emitting diodes. The lasing characteristics of a laser operated at the 1.06 and 1.32 wavelengths were investigated in the cw and pulsed regimes and dependences of its parameters on the temperature, pulse repetition frequency, and other factors were studied. In the pulsed regime the laser efficiency was 0.2% and in the cw regime the radiation power reached 50 and 17 mW at the 1.06 and 1.32 wavelengths, respectively.

  4. Cooperative emission in ion implanted Yb:YAG waveguides

    Vazquez, G V; Desirena, H; De la Rosa, E [Centro de Investigaciones en Optica, Loma del Bosque 115, Lomas del Campestre, 37150 Leon, Guanajuato (Mexico); Flores-Romero, E; Rickards, J; Trejo-Luna, R [Instituto de Fisica, UNAM, Apartado Postal 20364, 01000 Mexico, D. F. (Mexico); Marquez, H, E-mail: [Departamento de Optica, CICESE, Km 107 Carr. Tijuana-Ensenada, 22860 Ensenada, B. C. (Mexico)


    In this work, we report the analysis of spectroscopic properties of waveguides fabricated by ion implantation in YAG doped with Yb{sup 3+} ions. Three emission bands were detected in the blue, green and red regions under 970-nm excitation. The strong blue-green emission can be explained by a cooperative process between ytterbium ion pairs, leading to emission centered at 514 nm. The additional blue bands as well as green and red emission bands are attributed to the presence of Tm{sup 3+} and Er{sup 3+} traces. The results include absorption and emission curves as well as decay time rates.

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

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


    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....

  6. Effect of transscleral neodymium: YAG cyclophotocoagulation on intraocular lenses

    Blomquist, P.H.; Gross, R.L.; Koch, D.D. (Baylor College of Medicine, Houston, TX (USA))


    A neodymium: YAG laser operating in the thermal mode was used to irradiate isolated intraocular lenses (IOLs) and to perform transscleral cyclophotocoagulation on pseudophakic autopsy eyes to investigate the potential damage to IOL haptics such irradiation may cause. In the isolated IOLs, 70 mJ of energy deformed and partially melted both polymethylmethacrylate (PMMA) and polypropylene haptics. One of the capsular-fixated PC-IOL haptics in an autopsy eye partially melted when irradiated with the maximum energy level (8.8 J), with the aiming beam focused 1 mm posterior to the limbus and maximal posterior focus offset.

  7. Dual-polarization mode-locked Nd:YAG laser.

    Thévenin, J; Vallet, M; Brunel, M


    A mode-locked solid-state laser containing a birefringent element is shown to emit synchronously two frequency combs associated to the two polarization eigenstates of the cavity. An analytical model predicts the polarization evolution of the pulse train, which is determined by the adjustable intracavity birefringence. Experiments realized with a Nd:YAG laser passively mode locked by a semiconductor saturable absorber mirror are in perfect agreement with the model. Locking between the two combs arises for particular values of their frequency difference, e.g., half the repetition rate, and the pulse train polarization sequence is then governed by the relative overall phase offset of the two combs.

  8. Neodymium YAG laser for treatment of oral cavernous hemangiomas

    Bradley, Paul F.


    Oral cavernous haemangiomas are common lesions which may require treatment due to episodes of bleeding when bitten or deformity particularly when involving the lips and/or cheeks. Surgery can be hazardous due to haemorrhage while cryosurgery tends to be tedious for large lesions and be accompanied by major oedema. Sclerosants produce hard bulky masses. Embolization is seldom helpful due to lack of arterial feeders. The Nd:YAG laser is proving a useful modality in the oro-facial region and appeared worth investigating for these lesions in a laboratory animal model, by thermography and in the clinical situation.

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

    Ekin Meşe Say


    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. Studies on Nd∶YAG Single-pass Amplifiers for High-power Q-switched Laser System

    CAO Sansong(曹三松); ZHANG Xiangyang(张向阳); HUANG Yanlin(黄燕琳); LI Guangrong(李光荣); SU Xinzhi(苏心智)


    The output of Nd∶YAG single-pass laser amplifiers is studied analytically and experimentally. Methods of analysis for single-pass Nd∶YAG laser amplifier are presented. A flashlamp-pumped Q-switched Nd∶YAG oscillator/amplifier laser system has been developed with the average output power of 121.5 W.

  11. Microstructural characteristics of Nd:YAG powders leading to transparent ceramics

    ZHANG Xiaolin; LIU Duo; LIU Hong; WANG Jiyang; QIN Haiming; SANG Yuanhua


    We reported on the successful synthesis of the Nd:YAG (Nd:Y3Al5O12) nano-powders by using urea as the precipitant with the microwave assisted homogeneous precipitation (MAHP) method. The different microstructural characteristics of the Nd:YAG nano-powders were affected by the concentrations of (Y3++Nd3+) and Al3+ ([Y3++Nd3+]=0.06 mol/L, [Al3+]=0.1 mol/L), aging time (6 d) and aging condition (in vessel). The optimum microstructural characteristics of the high quality Nd:YAG nano-powders leading to transparent Nd:YAG ceramics including the pure YAG phase, the smallest crystallite size, a uniform crystallite size distribution, less density defects, uniform micro-components and the proper molar ratio of (Y3++Nd3+) and Al3+ (0.6148) were discussed.

  12. One Step Combustion Synthesis Of YAG:Ce Phosphor For Solid State Lighting

    Yadav, Pooja; Gupta, K. Vijay Kumar; Muley, Aarti; Joshi, C. P.; Moharil, S. V.


    YAG:Ce is an important phosphor having applications in various fields ranging from solid state lighting to scintillation detectors. YAG phosphors doped with activators are mainly synthesized by solid state reaction techniques that require high sintering temperatures (above 1500°C) to eliminate YAM and YAP phases. Though several soft chemical routes have been explored for synthesis of YAG, most of these methods are complex and phase pure materials are not obtained in one step, but prolonged annealing at temperatures around 1000 C or above becomes necessary. One step combustion synthesis of YAG:Ce3+ and related phosphors carried out at 500 C furnace temperature is reported here. Activation with Ce3+ could be achieved during the synthesis without taking recourse to any post-combustion thermal treatment. LEDs prepared from the combustion synthesized YAG:Ce3+, exhibited properties comparable to those produced from the commercial phosphor.

  13. Analysis of the thermal effects in diode-pumped Tm:YAG ceramic slab lasers

    Cheng, Xiaojin; Shang, Jianhua; Jiang, Benxue


    Tm:YAG ceramics with a quasi-three-level system are sensitive to temperature. The optical and thermodynamic properties of Tm:YAG ceramics can change with changing temperature, and this affects the output power stability and beam quality of lasers. Thus temperature control is a key and difficult problem for Tm:YAG lasers, especially for high power laser output. In combination with slab structure and grad-doping techniques for composite ceramics, the temperature distributions of Tm:YAG ceramics are analyzed. It is found that the temperature difference of a rationally designed grad-doping Tm:YAG ceramic can be reduced significantly with the same absorption pump power, which results in higher output power and beam quality.

  14. Stability of a Laser-diode-pumped Cr4+∶YAG Passively Q-switched Nd3+∶YAG Laser

    ZHANG Xingyu; ZHAO Shengzhi; WANG Qingpu; ZHANG Qidi; B. Ozygus; M. Weber


    In this paper, the stability of a laser-diode-pumped Cr4+∶YAG passively Nd3+∶YAG Q-switched laser and the influence of the transversal mode structure on the stability are investigated. With the laser operating in TEM00 mode, the pulse energy fluctuation and the repetition rate fluctuation as functions of the repetition rate are measured, and semi-quantitatively and qualitatively analyzed, respectively.

  15. Periorbital rejuvenation with fractional 1,550-nm ytterbium/erbium fiber laser and variable square pulse 2,940-nm erbium:YAG laser in Asians: a comparison study.

    Wattanakrai, Penpun; Pootongkam, Suwimon; Rojhirunsakool, Salinee


    Ablative and fractional lasers are used for periorbital rejuvenation, with different downtime, side effects, and efficacy. To compare effects of fractional 1,550-nm ytterbium- and erbium-doped (Yb/Er) fiber laser and variable square pulse (VSP) 2,940-nm erbium-doped yttrium aluminum garnet (Er:YAG) laser treatment for periorbital wrinkles. This side-by-side comparison study randomized 22 women with mild to moderate periorbital rhytides to receive three treatments with fractional 1,550-nm Yb/Er fiber laser or 2,940-nm Er:YAG laser treatment on either side at 4-week intervals. A video camera was used for objective assessment of wrinkles. Standardized photographs, patient satisfaction, side effects, and pain score were recorded. Twenty subjects completed the study. The median change in wrinkle measurement 3 months after laser treatments from baseline of the fractional Yb/Er fiber laser side was -3.03 versus -3.09 on the VSP Er:YAG side (p = .63, Wilcoxon signed-rank test). There was no significant difference in degree of wrinkle improvement analyzed according to global assessment between the sides (p = .25, Wilcoxon signed-rank test). Less downtime correlated with greater patient satisfaction of the fractional laser treatment . Two subjects experienced hyperpigmentation. Fractional Yb/Er fiber and VSP Er:YAG lasers are effective in improving periorbital wrinkles in Asians, with minimal side effects. © 2012 by the American Society for Dermatologic Surgery, Inc. Published by Wiley Periodicals, Inc.

  16. Er:YAG and CTH:YAG laser radiation: contact versus non-contact enamel ablation and sonic-activated bulk composite placement

    Buckova, M.; Kasparova, M.; Dostalova, T.; Jelinkova, H.; Sulc, J.; Nemec, M.; Fibrich, M.; Bradna, P.; Miyagi, M.


    Laser radiation can be used for effective caries removal and cavity preparation without significant thermal effects, collateral damage of tooth structure, or patient discomfort. The aim of this study was to compare the quality of tissue after contact or non-contact Er:YAG and CTH:YAG laser radiation ablation. The second goal was to increase the sealing ability of hard dental tissues using sonic-activated bulk filling material with change in viscosity during processing. The artificial caries was prepared in intact teeth to simulate a demineralized surface and then the Er:YAG or CTH:YAG laser radiation was applied. The enamel artificial caries was gently removed by the laser radiation and sonic-activated composite fillings were inserted. A stereomicroscope and then a scanning electron microscope were used to evaluate the enamel surface. Er:YAG contact mode ablation in enamel was quick and precise; the cavity was smooth with a keyhole shaped prism and rod relief arrangement without a smear layer. The sonic-activated filling material was consistently regularly distributed; no cracks or microleakage in the enamel were observed. CTH:YAG irradiation was able to clean but not ablate the enamel surface; in contact and also in non-contact mode there was evidence of melting and fusing of the enamel.

  17. Optic coherence tomography measurement of choroidal and retinal thicknesses after uncomplicated YAG laser capsulotomy

    İsa Yuvacı


    Full Text Available ABSTRACT Purpose: Optic coherence tomography (OCT evaluation of the choroid, retina, and retinal nerve fiber layer after uncomplicated yttrium-aluminum-garnet (YAG laser capsulotomy. Methods: OCT analysis of retinal and choroidal structures was performed in 28 eyes of 28 patients following routine examinations before and 24 h, 72 h, 2 weeks, 4 weeks, and 12 weeks after YAG laser capsulotomy. Data were analyzed using the SPSS software. Results: Data collected before YAG capsulotomy and at the above mentioned follow-up visits are summarized as follows. Mean central subfoveal choroidal thickness before YAG capsulotomy was 275.85 ± 74.78 µm; it was 278.46 ± 83.46 µm, 283.39 ± 82.84 µm, 280.00 ± 77.16 µm, 278.37 ± 76.95 µm, and 278.67 ± 76.20 µm after YAG capsulotomy, respectively. Central macular thickness was 272.14 ± 25.76 µm before YAG capsulotomy; it was 266.53 ± 26.47 µm, 269.14 ± 27.20 µm, 272.17 ± 26.97 µm, 270.91 ± 26.79 µm, and 273 ± 26.63 µm after YAG capsulotomy, respectively. Mean retinal nerve fiber layer thickness before YAG was 99.89 ± 7.61 µm; it was 98.50 ± 8.62 µm, 98.14 ± 8.69 µm, 99.60 ± 8.39 µm, 99.60 ± 8.39 µm, and 99.60 ± 8.35 µm after YAG capsulotomy, respectively. No observed change was statistically significant. No significant changes were observed with regard to mean intraocular pressure. Conclusions: After YAG laser capsulotomy, no statistically significant changes were found in choroidal, retinal, and optical nerve fiber layer thicknesses, although slight thickness changes in these structures were observed, particularly during the first days.

  18. Holmium:YAG laser angioplasty: treatment of acute myocardial infarction

    Topaz, On


    We report our clinical experience with a group of 14 patients who presented with acute myocardial infarction. A holmium:YAG laser was applied to the infarct-related artery. This laser emits 250 - 600 mJ per pulse, with a pulse length of 250 microseconds and repetition rate of 5 Hz. Potential benefits of acute thrombolysis by lasers include the absence of systemic lytic state; a shortened thrombus clearing time relative to using thrombolytics; safe removal of the intracoronary thrombus and facilitation of adjunct balloon angioplasty. Potential clinical difficulties include targeting the obstructive clot and plaque, creation of debris and distal emboli and laser-tissue damage. It is conceivable that holmium:YAG laser can be a successful thrombolytic device as its wave length (2.1 microns) coincides with strong water absorption peaks. Since it is common to find an atherosclerotic plaque located under or distal to the thrombotic occlusion, this laser can also be applied for plaque ablation, and the patient presenting with acute myocardial infarction can clearly benefit from the combined function of this laser system.

  19. American Religion



    It is said that American religion,as a great part of American culture,plays an important role in American culture. It is hoped that some ideas can be obtained from this research paper,which focuses on analyzing the great impact is produced to American culture by American religion. Finally, this essay gives two useful standpoints to English learners:Understunding American religion will help understand the American history, culture and American people,and help you to communic.ate with them better. Understanding American religion will help you understand English better.

  20. Effect of Er:YAG laser energy on the morphology of enamel/adhesive system interface

    Delfino, Carina Sinclér; Souza-Zaroni, Wanessa Christine; Corona, Silmara Aparecida Milori; Pécora, Jesus Djalma; Palma-Dibb, Regina Guenka


    The aim of this study was to evaluate in vitro the influence of Er:YAG laser energy variation to cavity preparation on the morphology of enamel/adhesive system interface, using SEM. Eighteen molars were used and the buccal surfaces were flattened without dentine exposure. The specimens were randomly assigned to two groups, according to the adhesive system (conventional total-etching or self-etching), and each group was divided into three subgroups (bur carbide in turbine of high rotation, Er:YAG laser 250 mJ/4 Hz and Er:YAG laser 300 mJ/4 Hz) containing six teeth each. The enamel/adhesive system interface was serially sectioned and prepared for SEM. The Er:YAG laser, in general, produced a more irregular adhesive interface than the control group. For Er:YAG laser 250 mJ there was formation of a more regular hybrid layer with good tag formation, mainly in the total-etching system. However, Er:YAG laser 300 mJ showed a more irregular interface with amorphous enamel and fused areas, for both adhesive systems. It was concluded that cavity preparation with Er:YAG laser influenced on the morphology of enamel/adhesive system interface and the tissual alterations were more evident when the energy was increased.

  1. Laser Erbium: YAG no tratamento de nevos melanocíticos Erbium: YAG laser in treatment of acquired melanocytic nevi

    Mauricio Martins


    Full Text Available FUNDAMENTOS - Os nevos melanocíticos adquiridos são observados em grande parte da população e o resultado da sua excisão, dependendo da localização, extensão e fatores inerentes ao paciente, pode ser insatisfatório. OBJETIVO - Avaliar o uso do laser Erbium: YAG no tratamento de nevos melanocíticos adquiridos MÉTODOS - Foram selecionados nove pacientes, seis homens e três mulheres, brancos, com idade entre 20 e 60 anos e desejo de remover um nevo melanocítico composto no tronco. Metade do nevo foi tratada com laser, e a outra metade foi utilizada como controle. Após um mês da aplicação, foram avaliados a cicatrização, o resultado estético e a persistência de células névicas e melanina. RESULTADOS - Houve rápida cicatrização e ótimo resultado estético, no entanto, o exame histopatológico demonstrou a permanência de células névicas e melanina em sete e em nove das amostras examinadas, respectivamente. CONCLUSÃO - A utilização do laser Erbium:YAG, com os parâmetros utilizados neste estudo, não foi capaz de destruir completamente as células névicas melanocíticas e a melanina, não sendo, portanto, recomendada para o tratamento dessas lesões, dada a possibilidade de transformação maligna futura.BACKGROUND- Acquired melanocytic nevi are commonly found and the result of their excision may not be satisfactory depending on their location, extension and factors associated to the patient. OBJECTIVE - To evaluate the use of Erbium:YAG laser in treatment of acquired melanocytic nevi. METHOD - Nine white-skinned patients were selected, six men and three women with aged 20-60 years. All desired to remove one compound acquired melanocytic nevus on the trunk. Half of the nevi was treated with Erbium YAG laser while the remaining were used as control. One month after application, healing, aesthetic results and persistence of melanocytic cells and melanin were evaluated. RESULTS - All patients presented fast healing and

  2. Three-dimensional topographic scanning electron microscope and Raman spectroscopic analyses of the irradiation effect on teeth by Nd:YAG, Er: YAG, and CO(2) lasers.

    Yamada, Magda K; Uo, Motohiro; Ohkawa, Shoji; Akasaka, Tsukasa; Watari, Fumio


    A three-dimensional analyzer installed in a scanning electron microscope was used to evaluate the morphology and surface roughness using noncontact profilometry. Observations were carried out on the enamel and dentin surface irradiated by three different lasers: Nd:YAG (wavelength 1.06 microm), Er:YAG (2.94 microm), and CO(2) (10.6 microm). Spectroscopic analysis was done by Raman spectroscopy for nonirradiated and laser-irradiated surfaces. The lasers were applied perpendicularly to vertically sectioned and polished human extracted caries-free molars. The tooth was sectioned at each cavity for cross-section analysis after laser irradiation. Irradiation by Nd:YAG and CO(2) lasers of the enamel surface showed an opaque white color, different from dentin where the surface turned black. The Er:YAG laser induced no changes in color of the dentin. Numerous cracks associated with thermal stress were observed in the CO(2) laser-irradiated dentin. Noncontact surface profile analysis of Er:YAG laser-irradiated enamel and dentin showed the deepest cavities, and direct cross-sectional observations of them showed similar cavity outlines. The CO(2) laser-irradiated dentin had the least surface roughness. Raman spectroscopic analysis showed that fluorescence from the laser-irradiated tooth was generally greater than from nonirradiated teeth. Bands in dentin attributed to organic collagen matrix were lost after Nd:YAG and CO(2) laser irradiation, and a broad peak due to amorphous carbon appeared. The Er:YAG laser-irradiated dentin showed no sign of a carbon band and had more suitable results for dental ablation. Noncontact surface profile analysis was effective to evaluate the structural change in the tooth in the microarea of study after laser irradiation.

  3. Effect of Er:YAG laser on enamel demineralization around restorations.

    Colucci, Vivian; de Souza Gabriel, Aline Evangelista; Scatolin, Renata Siqueira; Serra, Mônica Campos; Corona, Silmara Aparecida Milori


    This study evaluates in situ the effect of erbium-doped yttrium aluminum garnet (Er:YAG) laser parameters on the development of caries-like lesions adjacent to dental restorations. One hundred fifty bovine enamel slabs were randomly allocated among 15 volunteers. The specimens were subdivided into ten groups: nine experimental groups prepared with Er:YAG laser (300 mJ output, frequency of 2, 4 or 6 Hz, water flow rate of 2.0, 5.0, or 8.0 mL/min) and one control group (high-speed handpiece). The prepared cavity was restored with a composite resin, and the slabs were mounted on palatal appliance to be installed in the volunteers to the cariogenic challenge. After this, the specimens were sectioned to the longitudinal microhardness measurements. Data were submitted to Friedman and Wilcoxon paired tests. All groups prepared with Er:YAG laser demonstrated microhardness values higher than those prepared with high-speed handpiece, which showed the lowest microhardness values (24.86). The group prepared with Er:YAG laser (2 Hz-2.0 mL/min) showed the highest microhardness values (152.43), followed by those prepared with Er:YAG laser (2 Hz-5.0 mL/min) (133.08) and Er:YAG laser (2 Hz-8.0 mL/min) (91.61), respectively. The groups Er:YAG laser with 4 and 6 Hz of frequency and water flow rates of 2.0, 5.0, and 8.0 mL/min showed microhardness values lower than the groups cited above and showed statistical similarity among them. The Er:YAG laser parameters employed to cavity preparation influenced the acid resistance of the irradiated substrate, and the Er:YAG laser was capable to control the development of caries-like lesions around composite resin restorations.

  4. High-energy nanosecond radially polarized beam output from Nd:YAG amplifiers

    Chang, Chengcheng; Chen, Xudong; Pu, Jixiong


    Radially polarized laser beam amplification up to the 772 mJ using flash-lamp-pumped Nd:YAG amplifiers was demonstrated. In the experiments, a nanosecond radially polarized seed beam was converted from a conventional Q-switched Nd:YAG laser output with a polarization converter and then amplified with two Nd:YAG amplifier stages. A maximum amplification output energy up to 772 mJ was achieved at 10 Hz with a 10-ns pulse, corresponding to an amplification factor of 323%. Excellent conservation of polarization was also obtained during the amplification.

  5. Laser dyes excited by high PRR Nd:YAG laser second-harmonic radiation

    Soldatov, A. N.; Donin, V. I.; Jakovin, D. V.; Reimer, I. V.


    The lasing characteristics of red-emitting dyes in ethanol excited by Nd:YAG laser second-harmonic radiation are examined. The Nd:YAG laser was pumped by a diode matrix. The pump pulse repetition rates (PRRs) were 2.5 - 10 kHz and the pulse duration was 60 - 300 ns. The following dyes were evaluated: oxazine 17, DCM, DCM sp, and pyridine 1. The conversion efficiency for oxazine was 25 % without wavelength selection and 15 % with wavelength selection over the tuning range from 630 to 700 nm. The Nd:YAG and dye laser designs used are described elsewhere [1,2].

  6. Comparison of Dentin Permeability After Tooth Cavity Preparation with Diamond Bur and Er:YAG Laser

    Masoumeh Hasani Tabatabaei; Sara Shirmohammadi; Esmaeil Yasini; Mansoureh Mirzaei; Sakineh Arami; Hamid Kermanshah; Ladan Ranjbar Omrani; Azar Alimi; Nasim Chiniforush; Afrooz Nakhostin; Mahdi Abbasi


    Objectives: The aim of this study was to compare the permeability of dentin after using diamond bur and Er:YAG laser.Materials and Methods: Seventy-two recently extracted, intact, and restoration-free human permanent molars were used in this study. The samples were randomly divided into three groups of 24 each and class I cavities were prepared as follows. Group 1: High speed diamond bur with air and water spray. Group 2: Er:YAG laser. Group 3: Er:YAG laser followed by additional sub-ablative...

  7. Preserving a diffraction-limited beam in Ho:YAG laser using coherent polarization locking.

    Tan, L H; Chua, C F; Phua, P B


    We overcome several thermal issues present in Ho:YAG lasers by distributing the gain over a larger volume and achieve a diffraction-limited beam using coherent polarization locking. Increased single-pass absorption, suppression of output power saturation, and improvement in beam quality were shown using the coherent polarization locking technique as compared to a conventional Ho:YAG laser cavity with the same pump and cavity configuration. Ten watts of CW Ho:YAG laser power was generated with >96% coherent combining efficiency.

  8. Morphological assessment of dentine and cementum following apicectomy with Zekrya burs and Er:YAG laser associated with direct and indirect Nd:YAG laser irradiation.

    de Moura, Abilio Albuquerque Maranhão; Moura-Netto, Cacio; Barletta, Fernando Branco; Vieira-Júnior, Nilson Dias; Eduardo, Carlos de Paula


    This study aimed to assess the apical surface morphology of maxillary central incisors resected 3.0 mm from the tooth apex using Zekrya burs or Er:YAG laser, with or without subsequent direct Nd:YAG laser irradiation (apical and buccal surfaces) and indirect irradiation (palatal surface). Forty maxillary central incisors were instrumented and obturated. The roots were divided into 4 groups according to the root resection method (Zekrya bur or Er:YAG laser - 1.8 W, 450 mJ, 4 Hz, 113 J/cm(2)) and further surface treatment (none or Nd:YAG laser - 2.0 W, 100 mJ, 20 Hz, 124 J/cm(2)). The teeth were prepared for SEM analysis. Scores ranging from 1 to 4 were attributed to cut quality and morphological changes. The data were analyzed by the Kruskal-Wallis test and by Dunn's test. SEM images showed irregular surfaces on the apical portions resected with Zekrya burs, with smear layer and grooves in the resected dentine and slight gutta-percha displacement and plasticization. On the other hand, apicectomies carried out with Er:YAG laser showed morphological changes compatible with ablated dentine, with rough surfaces and craters. In spite of the presence of plasticized gutta-percha, with the presence of bubbles, an irregular adaptation of the filling material to the root walls was also observed. Direct Nd:YAG laser irradiation of the apical and buccal surfaces of the resected roots resulted in areas of resolidification and fusion in the dentine and cementum, with a vitrified aspect; indirect Nd:YAG laser irradiation of the palatal surfaces yielded a lower number of changes in the cementum, with irregular resolidification areas. There were no differences in terms of cut quality between the use of burs and Er:YAG laser or between the 2 surfaces (apical and buccal) treated with Nd:YAG laser with direct irradiation. However, morphological changes were significantly less frequent on surfaces submitted to indirect irradiation (palatal) when compared with those directly irradiated

  9. Ho:YAG laser arthroscopy of the knee

    Sisto, Domenick J.; Blazina, Martin E.; Hirsh, Linda C.


    The HO:YAG laser is a near-contact laser with a capacity to ablate or cut tissues. The ablation function allows the surgeon to remove meniscal tissue, lyse and resect adhesions, melt loose bodies, and dissolve inflamed synovium. The cutting function of the laser is utilized to perform a lateral release or resect torn menisci. The laser can also be utilized to drill holes in Grade IV chondromalacic lesions to initiate a healing response. The laser has been embraced by orthopaedic surgeons because of its shape and versatility. The tip is only 2 mm wide and can be delivered into the tight posterior compartments of the knee with no damaging contact with the articular surfaces. The laser coagulates as it works and bleeding is minimized. The laser can function both as a cutting and ablating tool. The laser can also drill holes into subchondral bone to, hopefully, initiate a healing response.

  10. Clinical evaluation of Er:YAG laser caries treatment

    Dostalova, Tatjana; Jelinkova, Helena; Kucerova, Hana; Krejsa, Otakar; Hamal, Karel; Kubelka, Jiri; Prochazka, Stanislav


    To prepare the enamel, the energy used was mainly 345 mJ and repetition rate 2 Hz, for dentine the optimal energy of Er:YAG drilling machine was 200 mJ and repetition rate from 1 to 2 Hz, depending on cavity depth. Subject of treatment were caries of enamel and dentine and it was possible to remove the old insufficient fillings. The average number of pulses was 111.22, ranging from 16 to 489. During preparation, vibrations of microexplosions were felt by 8 patients, however, neither pain or unpleasant sensations were experienced. The filling materials used were composite resins and glassionomer cements. Their clinical evaluation 6 months post insertion was similar to that of the classical drilling system.

  11. Numerical simulation of a battlefield Nd:YAG laser

    Henriksson, Markus; Sjoqvist, Lars; Uhrwing, Thomas


    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.

  12. Q-switched Nd:YAG optical vortex lasers.

    Kim, D J; Kim, J W; Clarkson, W A


    Q-switched operation of a high-quality Nd:YAG optical vortex laser with the first order Laguerre-Gaussian mode and well-determined helical wavefronts using a fiber-based pump beam conditioning scheme is reported. A simple two-mirror resonator incorporating an acousto-optic Q-switch was employed, along with an etalon and a Brewster plate to enforce the particular helicity of the output. The laser yielded Q-switched pulses with ~250 μJ pulse energy and ~33 ns pulse duration (FWHM) at a 0.1 kHz repetition rate for 5.1 W of absorbed pump power. The handedness of the helical wavefronts was preserved regardless of the repetition rates. The prospects of further power scaling and improved laser performance are discussed.

  13. LED pumped Nd:YAG laser development program

    Farmer, G. I.; Kiang, Y. C.; Lynch, R. J.


    The results of a development program for light emitting diode (LED) pumped Nd:YAG lasers are described. An index matching method to increase the coupling efficiency of the laser is described. A solid glass half-cylinder of 5.0 by 5.6 centimeters was used for index matching and also as a pumping cavity reflector. The laser rods were 1.5 by 56 millimeters with dielectric coatings on both end surfaces. The interfaces between the diode array, glass cylinder, and laser rod were filled with viscous fluid of refractive index n = 1.55. Experiments performed with both the glass cylinder and a gold coated stainless steel reflector of the same dimensions under the same operating conditions indicate that the index matching cylinder gave 159 to 200 percent improvement of coupling efficiency over the metal reflector at various operating temperatures.

  14. Er:YAG laser for endodontics: efficiency and safety

    Hibst, Raimund; Stock, Karl; Gall, Robert; Keller, Ulrich


    Recently it has been shown that bacterias can be sterilized by Er:YAG laser irradiation. By optical fiber transmission the bactericidal effect can also be used in endodontics. In order to explore potential laser parameters, we further investigated sterilization of caries and measured temperatures in models simulating endodontic treatment. It was found out that the bactericidal effect is cumulative, with single pulses being active. This offers to choose all laser parameters except pulse energy (radiant exposure) from technical, practical or safety considerations. For clinical studies the following parameter set is proposed for efficient and safe application (teeth with a root wall thickness > 1 mm, and prepared up to ISO 50): pulse energy: 50 mJ, repetition rate: 15 Hz, fiber withdrawal velocity: 2 mm/s. With these settings 4 passes must be performed to accumulate the total dose for sterilization.

  15. Random Laser Action in Nd:YAG Crystal Powder

    Jon Azkargorta


    Full Text Available This work explores the room temperature random stimulated emission at 1.064 μm of a Nd:YAG crystal powder (Neodymium-doped yttrium aluminum garnet in a very simple pump configuration with no assistance from an internal mirror. The laser threshold energy as a function of pump beam area and pump wavelength has been measured, as well as the temporal dynamics of emission pulses. The absolute energy of stimulated emission and the absolute laser slope efficiency have been measured by using a method proposed by the authors. The results show a surprising high efficiency that takes the low Nd3+ ion concentration of the crystal powder into account.

  16. Use of the holmium:YAG laser in urology

    Mattioli, Stefano


    The Holmium-YAG is a versatile laser with multiple soft- tissue applications including tissue incision and vaporization, and pulsed-laser applications such as lithotripsy. At 2140 nanometers, the wavelength is highly absorbed by tissue water. Further, like CO2 laser, the Holmium produces immediate tissue vaporization while minimizing deep thermal damage to surrounding tissues. It is an excellent instrument for endopyelotomy, internal urethrotomy, bladder neck incisions and it can be used to resect the prostate. The Holmium creates an acute TUR defect which gives immediate results like the TURP. More than 50 patients were treated from Jan. 1996 to Jan. 1997 for obstructive symptoms due to benign prostatic hyperplasia, bladder neck stricture, urethral stenosis, and superficial bladder tumors.

  17. SEM investigation of Er:YAG laser apical preparation

    Bǎlǎbuc, Cosmin; Todea, Carmen; Locovei, Cosmin; RǎduÅ£ǎ, Aurel


    Endodontic surgery involves the incision and flap elevation, the access to the root tip, its resection, the cavity retrograde preparation and filling it with biocompatible material that provides a good seal of the apex[1]. Apicoectomy is compulsory in endodontic surgery. The final stage involves the root retropreparation and the carrying out of the retrograde obturation. In order to perform the retrograde preparation the endodontist can use various tools such as lowspeed conventional handpieces, sonic and ultrasonic equipment. The ideal depth of the preparation should be 3 mm, exceeding this value may affect the long-term success of the obturation [2]. Resection at the depth of 3 mm reduces apical ramifications by 98% and lateral root canals by 93%. The ultrasonic retropreparation has numerous advantages compared to the dental drill. Firstly, the cavity will be in the axis of the tooth which implies a minimum destruction of the root canal morphology. The preparations are precise, and the cutting pattern is perpendicular to the long axis of the root, the advantage being the reduction in the number of dentinal tubules exposed at the resected area [3]. Therefore, the retrograde filling is the procedure when an inert and non-toxic material is compacted in the apically created cavity.[4,5]. The Er:YAG laser is the most common wavelength indicated for dental hard tissue preparation. Its natural selectivity offers a significant advantage compared to the conventional hard tissue preparation [6-9].The purpose of this in vitro study was to investigate the quality of Er:YAG laser apical third preparation using Scanning Electron Microscopy (SEM), in comparison with the conventional ultrasonic method.

  18. High-average-power diode-pumped Yb: YAG lasers

    Avizonis, P V; Beach, R; Bibeau, C M; Emanuel, M A; Harris, D G; Honea, E C; Monroe, R S; Payne, S A; Skidmore, J A; Sutton, S B


    A scaleable diode end-pumping technology for high-average-power slab and rod lasers has been under development for the past several years at Lawrence Livermore National Laboratory (LLNL). This technology has particular application to high average power Yb:YAG lasers that utilize a rod configured gain element. Previously, this rod configured approach has achieved average output powers in a single 5 cm long by 2 mm diameter Yb:YAG rod of 430 W cw and 280 W q-switched. High beam quality (M{sup 2} = 2.4) q-switched operation has also been demonstrated at over 180 W of average output power. More recently, using a dual rod configuration consisting of two, 5 cm long by 2 mm diameter laser rods with birefringence compensation, we have achieved 1080 W of cw output with an M{sup 2} value of 13.5 at an optical-to-optical conversion efficiency of 27.5%. With the same dual rod laser operated in a q-switched mode, we have also demonstrated 532 W of average power with an M{sup 2} < 2.5 at 17% optical-to-optical conversion efficiency. These q-switched results were obtained at a 10 kHz repetition rate and resulted in 77 nsec pulse durations. These improved levels of operational performance have been achieved as a result of technology advancements made in several areas that will be covered in this manuscript. These enhancements to our architecture include: (1) Hollow lens ducts that enable the use of advanced cavity architectures permitting birefringence compensation and the ability to run in large aperture-filling near-diffraction-limited modes. (2) Compound laser rods with flanged-nonabsorbing-endcaps fabricated by diffusion bonding. (3) Techniques for suppressing amplified spontaneous emission (ASE) and parasitics in the polished barrel rods.

  19. Noncontact Er:YAG laser ablation: clinical evaluation.

    Dostálová, T; Jelínková, H; Kucerová, H; Krejsa, O; Hamal, K; Kubelka, J; Procházka, S


    The aim of this study is to evaluate the quality of laser ablation in comparison with the classical drilling preparation. For the experiment, the Er:YAG laser drilling machine was used. The system had a laser head, water cooler, and power supply with automatic control. Spot size of 300-350 microns was used for the preparation. Repetition rate of 1-4 Hz, and pulse energies of 100-400 mJ with water spray were chosen. Cavity shape in comparison with classical drill, time of preparation, and influence of cavity shape on filling materials retention in accordance with the U.S. Public Health Service System were used. The evaluation criteria for noncontact Er:YAG ablation were done. The cavity shape is irregular, but spot surface has larger area and microretentive appearance. Caries of enamel and dentin were treated with a noncontact preparation. It was possible to remove the old insufficient fillings, except for amalgam or metal alloys. The average number of pulses was 111.22 (SE 67.57). Vibrations of microexplosions during preparation were felt by patients on 14 cavities; however, nobody felt unpleasant pain. The qualities of filling materials in laser cavities were very stable; however, cavo surface margin discoloration of 82-86% of Alfa rating could be a problem. Changes of the color and anatomic form of the tooth were observed in 4-8%. In comparison with the classical treatment, it could be said that the retention and quality of filling materials is the same or very similar.

  20. High power CW diode-side-pumped Nd:YAG rod laser

    Hailin Wang(王海林); Weiling Huang(黄维玲); Zhuoyou Zhou(周卓尤); Hongbing Cao(曹红兵)


    We report on the characterization of a diode-side-pumped Nd:YAG rod laser operating at high CW output power. A four-fold pump configuration is designed and the pump light is directly coupled into the Nd:YAG rod without the help of any cylindrical lenses. The distribution of pump light in the Nd:YAG rod has been calculated by using ray tracing program. The thermal lens effect of the Nd:YAG rod has been experimentally measured. A maximum output power of 800 W at 1064 nm in multimode operation is obtained for a pump power of 2400 W with 33% optical-optical efficiency. At the same time, the maximum beam parameter product of 25 mm.mrad is achieved.

  1. Up Conversion Measurements in Er:YAG; Comparison with 1.6 Micrometer Laser Performance

    Barnes, Norman P.; Walsh, Brian M.; Amzajerdian, Farzin; Reichle, Donald J.; Busch, George E.; Carrion, William A.


    Up conversion significantly affects Er:YAG lasers. Measurements performed here for low Er concentration are significantly different than reported high Er concentration. The results obtained here are used to predict laser performance and are compared with experimental results.

  2. Erbium:YAG laser as a method of deepithelization in corrective and reductive breast surgery.

    Trelles, Mario A; Pardo, Lourdes; Chamorro, Juan José; Bonanad, Enrique; Allones, Inés; Buil, Carmen; Luna, Ricardo


    Deepithelization of the breast in breast ptosis surgery is important, being associated with risks which could affect the clinical outcome. The role of Er:YAG laser deepithelization was investigated. A total of 12 bilateral mammoplasties were performed, randomly assigned to 2 groups, one of experienced and one of less-experienced surgeons. Results were compared between the 2 groups of surgeons for scalpel deepithelization on one breast and the Er:YAG laser on the contralateral breast. No complications; less edema, pain, and erythema; and quicker wound healing were observed in the laser-deepithelized breasts, with a shorter operation time even for the less-experienced surgeons. The authors do not suggest that the Er:YAG laser should replace the scalpel in the hands of the expert surgeon for breast deepithelization in breast ptosis surgery, but the results of the study suggest that Er:YAG laser ablation is a safe, precise, effective and complication-free method.

  3. Optoelectronic characteristics of YAG phosphor-incorporated ZnO films deposited by ultrasonic spray pyrolysis


    This work presents a novel white light device. An yttrium aluminum garnet (YAG) phosphor-incorporated zinc oxide (ZnO) film is deposited on a slide glass substrate by ultrasonic spray pyrolysis. A nanoflower consisting of a hexagonal nanopetal is formed on the surfaces of the samples, and the sizes of the nanopetal are approximately 200 to 700 nm. Additionally, the nanopetal becomes blunted with an increasing incorporated amount of YAG. As the incorporated amount is 1.5 and 2.5 wt.%, the photoluminescence color of the YAG-incorporated ZnO film is nearly white, possibly contributing to the YAG emission and the band-to-deep level transition in the ZnO film. PMID:23151219

  4. Coherent polarization locking: an approach to mitigating optical damage in a pulsed Ho:YAG laser.

    Tan, L H; Chua, C F; Phua, P B


    Intracavity optical damage is mitigated in a pulsed Ho:YAG laser cavity using the coherent polarization locking (CPL) technique. By splitting the available pump power into two individual Ho:YAG laser rods, we passively coherently locked two orthogonal polarization lasers with 9.13 mJ output pulse energies and 14 ns pulsewidths, and operating at 800 Hz repetition rate. A conventional Ho:YAG laser cavity with the same pump and cavity configuration results in severe optical damage when operating at <2 kHz repetition rate, thus limiting the output pulse energies to <5 mJ. We also demonstrated, to the best of our knowledge, the first pulsed operation within the entire CPL Ho:YAG laser cavity by Q-switching in one of the polarization arms, producing nanosecond pulses with no sign of pulse instability.

  5. Application of Stereology on Neodymium-Doped Yttrium Aluminum Garnet (Nd: YAG) Transparent Ceramics


    Nd: YAG precursor powders were synthesized by homogeneous precipitation, and Nd: YAG transparent ceramics were prepared by vacuum sintering at 1700 ℃ for 5 h. The ceramic materials were characterized by light transmittance and field emission gun-environment scanning microscope. Using statistics and stereology theory, study was carried out on the quantitative relationships between light transmittance and stereological parameters in three-dimensional Euclidean space. It is found that the transmittance of Nd:YAG with 1 mm in thickness is about 45% and 58% in visible and near-infrared wavelength, respectively. The transmittance linearly increases with increasing equivalent sphere diameter and reaches the theoretical value of single crystal when the equivalent sphere diameter is 20μm. The transmittance decreases with the increasing of mean specific area per unit volume of grain and discrete grains, and the transmittance decreases with increasing mean free distance of grains in Nd:YAG ceramics.

  6. High energy single frequency Yb:YAG crystalline fiber waveguide master oscillator power amplifier Project

    National Aeronautics and Space Administration — The overall objective is to demonstrate the concept of Yb:YAG crystalline fiber MOPA laser and investigation the technical feasibility toward 50 mJ single frequency...

  7. Nd: YAG Laser Treatment for Keloids and Hypertrophic Scars: An Analysis of 102 Cases

    Sachiko Koike, MD


    Conclusions: Hypertrophic scars responded significantly better to 1064 nm Nd:YAG laser treatment than keloids. However, keloid recurrence occurred when there was remaining redness and induration, even if only a small part of the scar was affected.

  8. A Continuous-Wave Diode-Side-Pumped Tm:YAG Laser with Output 51 W

    ZHANG Xiao-Fu; CUI DaFu; XU Zu-Yan; XU Yi-Ting; LI Cheng-Ming; ZONG Nan; XU Jia-Lin; CUI Qian-Jin; LU Yuan-Fu; BO Yong; PENG Qin-Jun


    A compact diode-side-pumped Tm:YAG laser is presented, which can output 51 W of cw power at 2.02μm. The Tm:YAG rod is side pumped by nine diode arrays with the central wavelength of 783nm and the with bandwidth of about 2.5 nm at 25℃. To decrease the thermal effect on the both ends and dissipate the heat effectively, one composite Tm:YAG rod with the undoped YAG end caps and the screw threads on the side surface of the rod is used as the laser crystal. The maximum optical-to-optical conversion efficiency of the 2.02-μm laser output is 14.2%, with a slope efficiency of 26.8%.

  9. Analysis on the effect of urethra caruncle treated by Ho:YAG laser

    Zhang, Mei-Jue; Zhu, Jing; Shi, Hong-Min


    Objective: To observe the effect of Ho:YAG laser in treatment of urethra cauncle. Methods: The patients suffering from urethra cauncle were treated by Ho:YAG laser, the energy of per pulse is 0.5J. The frequency of pulse is 5~15Hz, and the average power of the laser is 2.5~7.5W. Results: Among the patients 188 cases of urethra cauncle were only cured for one time, twice for12 cases. No stricture on the peristome of urethra or urethrovaginal fistula was observed. Conclusions: The technique of treatment of urethra cauncle with Ho:YAG laser is an effect and safe therapeutics with the merit of excellent homeostasis, improved visualization, minimal thermal damage to surrounding tissue, shorter period of recovery and easy to operate. It is better than CO2 laser and Nd:YAG laser.

  10. Luminescence and scintillation properties of YAG:Ce single crystal and optical ceramics

    Mihóková, E; Mareš, J A; Beitlerová, A; Vedda, A; Nejezchleb, K; Blažek, K; D’Ambrosio, C


    We use various techniques to study optical and scintillation properties of Ce-doped yttrium aluminum garnet, Y3Al5O12 (YAG:Ce), in the form of a high-quality industrial single crystal. This was compared to optical ceramics prepared from YAG:Ce nanopowders. We present experimental data in the areas of optical absorption, radioluminescence, scintillation decay, photoelectron yield, thermally stimulated luminescence and radiation-induced absorption. The results point to an interesting feature—the absence of antisite (YAl, i.e. Y at the Al site) defects in optical ceramics. The scintillation decay of the ceramics is faster than that of the single crystal, but its photoelectron yield (measured with 1 μs integration time) is about 30–40% lower. Apart from the photoelectron yield value the YAG:Ce optical ceramic is fully comparable to a high quality industrial YAG:Ce single crystal and can become a competitive scintillator material.

  11. Welding of Thermomechanically Rolled Steel by Yb:YAG Disk Laser / Spawanie Stali Walcowanej Termomechanicznie Laserem Dyskowym Yb:YAG

    Lisiecki A.


    Full Text Available Autogenous laser welding of 5.0 mm thick butt joints of thermomechanically rolled steel S700MC was investigated. The Yb:YAG disk laser TruDisk 3302 emitted at 1.03 μm was used for the trials of autogenous welding. The effect of laser welding parameters and thus thermal conditions of welding on weld shape, microstructure of weld metal and heat affected zone (HAZ, tensile strength, bending angle, impact toughness and microhardness profile was determined. Studies have shown that it is advantageous to provide a high welding speed and low heat input. High cooling rate of weld metal and HAZ leads to the formation of a favorable structure characterized by a large proportion of fine-grained acicular ferrite and provides high mechanical properties of butt joints.

  12. Influence of Gamma-Ray Irradiation on Absorption and Fluorescent Spectra of Nd:YAG and Yb:YAG Laser Crystals

    SUN Dun-Lu; ZHANG Qing-Li; XIAO Jing-Zhong; LUO Jian-Qiao; JIANG Hai-He; YIN Shao-Tang


    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.

  13. The growth of Ho:YAG single crystals by Czochralski method and investigating the formed cores

    Hasani Barbaran, J., E-mail:; Ghani Aragi, M. R.; Javaheri, I.; Baharvand, B.; Tabasi, M.; Layegh Ahan, R.; Jangjo, E. [NSTRI, Laser and Optics Research School (Iran, Islamic Republic of)


    Ho:YAG single crystals were grown by Czochralski technique, and investigated by the X-ray diffraction (XRD) and optical methods. The crystals were cut and polished in order to observe and analyze their cores. It was found that the deviation of the cores formed in the Czochralski grown Ho:YAG single crystals are resulted from non-symmetrical status of thermal insulation around the Iridium crucible.

  14. Nd: YAG laser therapy of rectosigmoid bleeding due to radiation injury

    Leuchter, R.S.; Petrilli, E.S.; Dwyer, R.M.; Hacker, N.F.; Castaldo, T.W.; Lagasse, L.D.


    The Nd:YAG laser was used to treat a patient bleeding from the rectosigmoid as a result of radiation injury related to therapy for cervical carcinoma. Successful laser therapy was performed after a diverting colostomy failed to control persistent bleeding. Further surgical procedures were not required. Characteristics of Nd:YAG laser as compared with those of the carbon dioxide and argon lasers are considered.

  15. Continuous-wave operation of a room-temperature Tm: YAP-pumped Ho: YAG laser


    We report a continuous-wave (CW) 2.1-μm Ho:YAG laser operating at room temperature pumped by a diode-pumped 1.94-?m Tm:YAP laser.The maximum output power of 1.5 W is obtained from Ho:YAG laser,corresponding to Tm-to-Ho slope efficiency of 17.9% and diode-to-He conversion efficiency of 5.6%.

  16. Er:YAG laser for the surgical treatment of the carpal tunnel syndrome

    Russ, Detlef; Ebinger, Thomas; Illich, Wolfgang; Steiner, Rudolf W.


    We developed a new surgical procedure to improve the recurrence rate using an Er:YAG laser as dissection tool for the carpal ligament with the objective to ablate a small amount of the carpal ligament and to denaturate its ends. The Er:YAG Laser was transmitted to the applicator via a GeO fiber. With this system we proceeded 10 carpal ligament dissections without any complications in the follow-up period. All patients were free of pain and recurrence.

  17. Holmium:YAG laser-assisted otolaryngologic surgery: Lahey Clinic experience

    Shapshay, Stanley M.; Rebeiz, Elie E.; Pankratov, Michail M.


    The Holmium:YAG laser was used to assist in 36 rhinologic procedures including surgery for chronic sinus disease, chronic dacryocystitis, recurrent choanal stenosis, and a sphenoid sinus mucocele. There were no laser related complications. The laser permitted controlled ablation of bone and soft tissue in all cases with satisfactory results. The Ho:YAG laser can be used in otolaryngology to assist in cases where surgical access is difficult or when controlled, precise bone and soft tissue ablation is necessary.

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

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


    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.

  19. Monostatic Doppler lidar using an Nd:YAG laser for wind-velocity measurement

    Bersenev, V. I.; Kaptsov, L. N.; Priezzhev, A. V.


    A monostatic Doppler lidar using a CW Nd:YAG laser has been developed for measurements of wind velocity. A series of atmospheric measurements using this lidar was carried out. At medium turbulence levels, the limiting lidar range is 200 m. As compared with a CO2 Doppler lidar, the Nd:YAG lidar has a better spatial resolution, is more convenient to use, and does not require a cooled photodetector.

  20. Analysis of apical sealing of canals irradiated with Er: YAG and Nd: YAG lasers and filled with AH Plus®

    Celso Luis Caldeira


    Full Text Available Introduction: Laser technology is gaining increasing importance in dental practice and also in the field of Endodontics with its ability to promote disinfection and experimentally in the preparation of root canal. The action of different types of lasers results in changes representing the increase in permeability of dentinal tissue (Er: YAG or sometimes by a decrease in melting and recrystallization of dentin (Nd: YAG. Objective: this study assessed through apical dye leakage, the influence of irradiation with two types of laser, regarding to the quality of apical sealing of endodontic fillings. Material and methods: Thirty-six single-rooted teeth were used after being prepared with the ProFile system up to size #40 instrument and then divided into four experimental and two control groups. The technique used previously to the filling was as follows: G1 – not irradiated; G2 – irradiated with Er: YAG; G3 – irradiated with Nd: YAG and G4 – irradiated with Er: YAG followed by Nd: YAG. After external waterproofing and dry, the specimens were filled with a cold vertical condensation technique, using AH Plus sealer, and immediately immersed into 0.5% methylene blue solution for subsequent cleavage. The linear values of apical marginal leakage were obtained with the aid of an optical microscope connected to a computer using the Image Lab® software. Results: Data analysis showed the non-existence of statistically significant (p = 0.05 differences between different groups. Conclusion: It was concluded that the laser does not have influence on the apical sealing.

  1. Combined application of Er:YAG and Nd:YAG lasers in treatment of chronic periodontitis. A split-mouth, single-blind, randomized controlled trial.

    Sağlam, M; Köseoğlu, S; Taşdemir, I; Erbak Yılmaz, H; Savran, L; Sütçü, R


    The aim of the present study was to compare the effectiveness of combined Er:YAG and Nd:YAG laser therapy to that of scaling and root planing with hand instruments in non-surgical treatment of chronic periodontitis. Twenty-five systemically healthy patients with chronic periodontitis were selected for this study. The quadrants were randomly allocated in a split-mouth design to either combined Er:YAG (160 mJ/pulse, 10 Hz) and Nd:YAG laser (100 mJ/pulse, 20 Hz) therapy (test group) or scaling and root planing alone (control group). At baseline, 1 month and 3 months after treatment, plaque index, gingival index, probing depth, clinical attachment level and bleeding on probing (%), were recorded and gingival crevicular fluid and subgingival plaque samples were taken. The gingival crevicular fluid levels of interleukin-1β and tumor necrosis factor-α were analyzed by enzyme-linked immunosorbent assay. Quantitative analysis of red complex bacteria was performed using quantitative real-time polymerase chain reaction. The clinical parameters had significantly improved for both groups after treatment. There were statistically significant differences in probing depth and clinical attachment level between the test and control groups only for deep pockets (≥7 mm) (Pnd microbiological parameters at any time points (P>.05). The present study suggests that a combined course of Er:YAG and Nd:YAG laser therapy may be beneficial particularly in inaccessible areas such as deep pockets on a short-term basis. Further, well-designed studies are required to assess the effectiveness of the combination of these lasers. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

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

    Radmanesh, Mohammad; Rafiei, Zohreh


    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.

  3. Comparative study between Fortify and Nd:YAG laser used for marginal sealing in composite restorations

    Navarro, Ricardo S.; Esteves, Grazia V.; Oliveira, Wilson T., Jr.; Matos, Adriana B.; Turbino, Mirian L.; Youssef, Michel N.; Matson, Edmir


    The aim of this study was to evaluate microleakage of composite restorations submitted to marginal treatment. Class V preparations with walls located in enamel were performed at buccal and lingual surfaces of eighteen recently extracted, non-carious human premolars. Cavities were restored with composite resins and adhesive system. Samples were stored in distilled water for 48h and polished with Sof-Lex discs. Teeth were randomly divide in six groups: G1 - Control; G2 - marginal treatment with surface sealant; G3 - Nd:YAG 25 Hz, 80mJ, 2W; G4 - Nd:YAG 20Hz, 100mJ, 2W; G5 - Nd:YAG 30Hz, 60mJ, 1.8W; G6 - Nd:YAG 30Hz, 40mJ, 1.2W. Contact fiberoptic (300μm) pulsed (1.064 μm) Nd:YAG laser was used for 30sec, under air cooling. Teeth were impermeabilized, immersed in a dye (Rhodamine B) for 4h at 37°, and sectioned. Specimens were evaluated under light microscopy and evaluated with scores. Results were analyzed with Kruskal- Wallis test (p=0.05) and showed that there were significant differences between marginal treatments; there were no significant differences beaten groups 1, 2, 4 and 3, 5, 6; lower values of microleakage were at groups 3, 5, 6. Nd:YAG laser showed marginal sealing ability and decreased microleakage of composite resins restorations.

  4. Laser-assisted hair transplantation: histologic comparison between holmium:YAG and CO2 lasers

    Chu, Eugene A.; Rabinov, C. Rose; Wong, Brian J.; Krugman, Mark E.


    The histological effects of flash-scanned CO2 (λ=10.6μm) and pulsed Holmium:YAG (Ho:YAG, λ=2.12μm) lasers were evaluated in human scalp following the creation of hair transplant recipient channels. Ho:YAG laser irradiation created larger zones of thermal injury adjacent to the laser channels than irradiation with the CO2 laser device. When the two lasers created recipient sites of nearly equal depth, the Holmium:YAG laser caused a larger region of lateral thermal damage (589.30μm) than the CO2 laser (118.07μm). In addition, Holmium:YAG irradiated specimens exhibited fractures or discontinuities beyond the region of clear thermal injury. This shearing effect is consistent with the photoacoustic mechanism of ablation associated with pulsed mid-IR laser irradiation. In contrast, channels created with the CO2 exhibited minimal epithelial disruption and significantly less lateral thermal damage. While the Holmium:YAG laser is a useful tool for ablation soft tissue with minimal char in select applications (sinus surgery, arthroscopic surgery), this study suggests that the use of the CO2 laser for the creation of transplantation recipient channels result in significantly less lateral thermal injury for the laser parameters employed.

  5. Low temperature synthesis of monodispersed YAG:Eu crystallites by hydrothermal method

    Xu, Mengmeng [Shanghai Institute of Ceramics, Chinese Academy of Sciences, No. 1295 Dingxi Road, Shanghai, 200050 (China); University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing, 100049 (China); Zhang, Zhijun, E-mail: [School of Materials Science and Engineering, Shanghai University, No. 99 Shangda Road, Shanghai, 200072 (China); Zhao, Jingtai, E-mail: [School of Materials Science and Engineering, Shanghai University, No. 99 Shangda Road, Shanghai, 200072 (China); Zhang, Jiazhi [Shanghai Institute of Ceramics, Chinese Academy of Sciences, No. 1295 Dingxi Road, Shanghai, 200050 (China); University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing, 100049 (China); Liu, Zhiwei [Shanghai Institute of Ceramics, Chinese Academy of Sciences, No. 1295 Dingxi Road, Shanghai, 200050 (China)


    Single phase europium doped yttrium aluminum garnet (YAG:Eu) crystallites with good dispersity were successfully synthesized by a facile hydrothermal method at 300 °C for 24 h. The influences of the molar ratio of (Y + Eu) to Al (denoted by Ln/Al) in the raw material on the phase, morphology, crystallinity, local environment of Eu ions and photoluminescence properties were investigated. It was found that the monodispersed single phase YAG:Eu crystallites with terminating faces of {110} can be obtained when Ln/Al is 3:4. Eu ions in all the samples are trivalent regardless of Ln/Al, while the local environment of Eu ions is more symmetric when Ln/Al is 3:4. Moreover, the YAG:Eu crystallites obtained when Ln/Al is 3:4 exhibit improved crystallinity, which contributes to the enhanced luminescence intensity. - Highlights: • Single phase YAG:Eu was synthesized by the hydrothermal method at 300 °C. • The YAG:Eu crystallites are monodispersed and exhibit improved crystallinity. • The YAG:Eu crystallites exhibit improved luminescence intensity. • XAFS and VUV were used to investigate the local structure of Eu.

  6. Er:YAG laser irradiation to control the progression of enamel erosion: an in situ study.

    Scatolin, R S; Colucci, V; Lepri, T P; Alexandria, A K; Maia, L C; Galo, R; Borsatto, M C; Corona, S A M


    This in situ study evaluated the effect of Er:YAG laser irradiation in controlling the progression of enamel erosion-like lesions. Fifty-six enamel slabs (330 KHN ± 10 %) with one fourth of the surface covered with resin composite (control area) were submitted to initial erosion-like lesion formation with citric acid. The slabs were divided into two groups: irradiated with Er:YAG laser and non-irradiated. Fourteen volunteers used an intraoral palatal appliance containing two slabs, in two phases of 5 days each. During the intraoral phase, in a crossed-over design, half of the volunteers immersed the appliance in citric acid while the other half used deionized water, both for 5 min, three times per day. Enamel wear was determined by an optical 3D profilometer. ANOVA revealed that when deionized water was used as immersion solution during the intraoral phase, lower values of wear were showed when compared with the groups that were eroded with citric acid, whether irradiated or non-irradiated with Er:YAG laser. When erosion with citric acid was performed, Er:YAG laser was not able to reduce enamel wear. Small changes on enamel surface were observed when it was irradiated with Er:YAG laser. It may be concluded that Er:YAG laser irradiation did not reduce the progression of erosive lesions on enamel submitted to in situ erosion with citric acid.

  7. Low-temperature solution synthesis and characterization of Ce-doped YAG nanoparticles

    吉成; 冀立宇; 连刘超; 沈丽明; 张晓艳; 王一峰


    Monophasic Ce3+-doped yttrium aluminum garnet (Ce:YAG) nanoparticles with high crystallinity and tunable grain size ranging from ~19–30 nm were prepared by a modified co-precipitation process with a follow-up calcination treatment. For the syn-thesis, aluminum, yttrium, and cerium nitrates were used as starting materials, ammonium sulfate as dispersant, and a combination of ammonium bicarbonate and ammonia as precipitating agent. Influence of precipitation temperature, the pH value of precipitant solu-tions, aging period, calcination conditions, and Ce-doping level were investigated for controlling the purity, particle size, and photo-luminescence performance of the Ce:YAG nanoparticles. High-purity YAG nanoparticles were prepared at pH=10.50–11.00 and cal-cination temperatures of 850–1100 ºC with a calcination time of 3 h. With increasing Ce3+ concentration, the peak in the emission spectra of the obtained nanopowders shifted from 529 nm for the 0.67 wt.%-Ce:YAG to 544 nm for the 3.4 wt.%-Ce:YAG, while the strongest photoluminescence intensity was observed for the 1.3 wt.%-Ce:YAG nanoparticles.

  8. Adhesion of composite luting cement to Er:YAG-laser-treated dentin.

    Carrieri, Teresa C D; de Freitas, Patricia M; Navarro, Ricardo S; Eduardo, Carlos de P; Mori, Matsuyoshi


    Although some studies claim to the increase of composite resin adhesion to Er:YAG-laser-treated dentin, there are still no reports on the adhesion of composite resin cements to the irradiated surface. This in vitro study evaluated the tensile bond strength (TBS) of a composite resin cement to dentin treated with the Er:YAG laser. Sixty human dentin samples were divided into four groups (n = 15): G1 (Control)-no treatment; G2-Er:YAG laser 60 mJ, 2 Hz, with water cooling, non-contact (19 J/cm(2)); G3-Er:YAG laser 60 mJ, 10 Hz, 50/10 fiber, contact, without water cooling (40 J/cm(2)); G4-Er:YAG laser 60 mJ, 10 Hz, 50/10 fiber, contact, with water cooling (40 J/cm(2)). After the surface treatment, each sample was submitted to bonding procedures. The analysis of variance (ANOVA) and Tukey tests revealed no statistical significant difference on TBS values for groups G1 (13.73 +/- 3.05 MPa), G2 (12.60 +/- 2.09 MPa) and G4 (11.17 +/- 4.04 MPa). G4 was not statistically different from G3 (8.64 +/- 2.06 MPa). Er:YAG laser irradiation with different settings can constitute an alternative tool to the use of composite resin-luting cements.

  9. About the luminescence properties of YAG:Nd, Ce and YAG:Nd single crystals and their relation to laser properties

    Mares, Jiri A.; Kubelka, Jiri; Kvapil, Jiri


    Laser excited luminescence studies of various YAG:Nd, Ce and YAG:Nd (with an excess of yttrium) single crystals together with a testing of laser properties of rods made from the same crystals have been investigated in this paper. It was observed that laser pulse energies increase with increasing halfwidths of the luminescence spectral bands. This dependence and other observations indicate that local structure changes or Nd(3+) nonequivalent centers are present in the studied crystals. Various mechanisms leading to the formation of Nd(3+) nonequivalent centers are discussed and it seems that the more probable mechanism is oxygen segregation and diffusion.

  10. Continuous-wave and Q-switched performance of an Yb:YAG/YAG composite thin disk ceramic laser pumped with 970-nm laser diode

    Hong Cai; Jun Zhou; Hongming Zhao; Yunfeng Qi; Qihong Lou; Jingxing Dong; Yunrong Wei


    Using front face-pumped compact active mirror laser (CAMIL) structure, we have demonstrated an Yb:YAG/YAG composite ceramic disk laser with pumping wavelength at 970 nm. The laser has been operated in both continuous-wave (CW) and Q-switching modes. Under CW operation, laser output power of 1.05 W with 2% transmission output coupler was achieved at the wavelength of 1031 nm. Qswitched laser output was gotten by using an acousto-optic Q-switch. The repetition rate ranged from 1 to 30 kHz and the pulse width varied from 166 to 700 ns.

  11. Numerical Modelling of QCW-Pumped Passively Q-Switched Nd:YAG Lasers with Cr4+:YAG as Saturable Absorber

    WANG Yu-Ye; XU De-Gang; XIONG Jing-Ping; WANG Zhuo; WANG Peng; YAO Jian-Quan


    @@ Passively Q-switched quasi-continuous-wave (QCW) diode-pumped Nd:YAG laser with Cr4+:YAG as saturable absorber is numerically investigated by solving the coupled rate equations. The threshold pump rate for passively Q-switched QCW-pumped laser is derived. The effects of the pump rate and pump-pulse duration on the laser operation characteristics are studied theoretically. The pump power range can be estimated according to the number of output pulses. The numerical simulation results are in good agreement with the experimental results.

  12. Continuous-wave yellow laser generation at 578 nm by intracavity sum-frequency mixing of thin disk Yb:YAG laser and Nd:YAG laser

    Ma, Gangfei; Yang, Jianming; Tan, Huiming; Tian, Yubing; Yao, Wenming; Ju, Qiaojun; Zhang, Long; Chen, Jiansheng; Wu, Xiaodong; Gao, Jing


    We report a continuous-wave yellow laser at 578 nm obtained by doubly resonant intracavity sum-frequency mixing of thin disk Yb:YAG laser and Nd:YAG laser with a LBO nonlinear crystal. Single-wavelength laser operation at 578 nm by using a silica etalon as a wavelength selector and dual-wavelength operation at 578 nm and 582 nm are obtained with maximum output powers of 100 mW and 136 mW, respectively. The single wavelength operating power stability value in 30 min was 4.7%, which was improved ∼21.6%, compared with that of dual-wavelength operation.

  13. Evaluation of Effects on the Adhesion of Various Root Canal Sealers after Er:YAG Laser and Irrigants Are Used on the Dentin Surface.

    Ozkocak, Ismail; Sonat, Bade


    The aim of this study was to evaluate the bond strength of various root canal sealers after various irrigation solutions and Er:YAG laser irradiation were used on root canal dentin. One hundred fifty freshly extracted human maxillary single-rooted teeth were used in this study. Teeth were sectioned transversally 4 mm below the cementoenamel junction. The root canal of each specimen was prepared using a tapered bur. Teeth were divided into 3 main groups by sealer (AH Plus Jet [Dentsply DeTrey, Konstanz, Germany], EndoSequence BC Sealer [Brasseler, Savannah, GA], and Real Seal [SybronEndo, Orange, CA]) and then divided into 5 subgroups by dentin treatment (distilled water, calcium hydroxide, sodium hypochlorite, EDTA, and Er:YAG laser). The specimens were placed immediately at 37°C and 100% humidity for 1 week. Then, the push-out test was applied. The maximum failure load was recorded in newtons and was used to calculate the push-out bond strength in MPa. Then, 3 random specimens from each group were examined under scanning electron microscopy. The resin root canal sealers had higher push-out bond strength than the bioceramic sealer, and the differences were statistically significant (P < .05) except in the sodium hypochlorite groups. The EDTA and Er:YAG laser applications removed the smear layer and increased the bond strength. The highest adhesion was observed in EDTA groups when each sealer was evaluated in itself. The bonding strength of root canal sealers is influenced by their properties and various dentin surface treatments. The scanning electron microscopic study showed that although the dentinal tubules were open, at the profile examination the sealers did not penetrate into the dentin canals in all specimens. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  14. Production of dispersed nanometer sized YAG powders from alkoxide, nitrate and chloride precursors and spark plasma sintering to transparency

    Suarez, M., E-mail: m.suarez@cinn.e [Departamento de Materiales Nanoestructurados, Centro de Investigacion en Nanomateriales y Nanotecnologia (CINN), Principado de Asturias - Consejo superior de Investigaciones Cientificas (CSIC) - Universidad de Oviedo - UO, Parque Tecnologico de Asturias, 33428 Llanera, Asturias (Spain); Fernandez, A. [Fundacion ITMA, Parque Tecnologico de Asturias, 33428, Llanera (Spain); Menendez, J.L.; Torrecillas, R. [Departamento de Materiales Nanoestructurados, Centro de Investigacion en Nanomateriales y Nanotecnologia (CINN), Principado de Asturias - Consejo superior de Investigaciones Cientificas (CSIC) - Universidad de Oviedo - UO, Parque Tecnologico de Asturias, 33428 Llanera, Asturias (Spain)


    Yttrium aluminum garnet (YAG) was synthesized from different starting materials, i.e., alkoxide, nitrate and chloride precursors. The conversion steps from the precursors to crystalline YAG were studied by Raman spectroscopy. Dispersed YAG powders were formed at a relatively low temperature, around 800 {sup o}C by the chlorides route, whereas alkoxide precursors needed firing over 900 {sup o}C and nitrates even over 1100 {sup o}C. Lyophilized YAG gel was sintered to transparency by the spark plasma sintering method at 1500 {sup o}C with in-line transmittances close to 60% at 680 nm and over 80% in the infrared range.

  15. Experiment Study on Active-passive Mode-locking Using Cr4+∶YAG as Saturable Absorber

    LENG Yuxin; LU Haihe; LIN Lihuang; XU Zhizhan


    Cr4+∶YAG crystal was used as a saturable absorber in an active-passive mode-locked Nd∶YAG laser. The stable and complete mode-locked pulse train was achieved at 1064 nm. The duration of ~0.8 ns to 2.4 ns for a single pulse was obtained by using Cr4+∶YAG crystals with the different initial transmissions, and there was a shortest pulse width. The mode-locking dynamic process of Cr4+∶YAG crystal was discussed to explain the experimental result, and the effect of excited-state absorption was considered.

  16. 885-nm Pumped Ceramic Nd:YAG Master Oscillator Power Amplifier Laser System

    Yu, Anthony


    The performance of a traditional diode pumped solid-state laser that is typically pumped with 808-nm laser diode array (LDA) and crystalline Nd:YAG was improved by using 885-nm LDAs and ceramic Nd:YAG. The advantage is lower quantum defect, which will improve the thermal loading on laser gain medium, resulting in a higher-performance laser. The use of ceramic Nd:YAG allows a higher Nd dopant level that will make up the lower absorption at the 885-nm wavelength on Nd:YAG. When compared to traditional 808-nm pump, 885-nm diodes will have 30% less thermal load (or wasted heat) and will thus see a similar percentage improvement in the overall laser efficiency. In order to provide a more efficient laser system for future flight missions that require the use of low-repetition- rate (systems are numerous. The epitaxial structures of these 885-nm diodes are aluminum-free. There is a significant reduction in the thermal load generated from the Stokes shift or quantum defects. A Stokes shift is the energetic difference between the pump and laser photons. Pumping at a wavelength band closer to the lasing wavelength can reduce the thermal load by .30% compared to traditional pumping at 808 nm, and increase the optical- to-optical efficiency by the same factor. The slope efficiency is expected to increase with a reduction in the thermal load. The typical crystalline Nd:YAG can be difficult to produce with doping level >1% Nd. To make certain that the absorption at 885 nm is on the same par as the 808-nm diode, the Nd:YAG material needs to be doped with higher concentration of Nd. Ceramic Nd:YAG is the only material that can be tailored to specific needs.

  17. Power scaling estimate of crystalline fiber waveguides with rare earth doped YAG cores

    Li, Da; Hong, Pengda; Meissner, Stephanie K.; Meissner, Helmuth E.


    Power scaling analysis based on the model by Dawson et al. [1,2] for circular core fibers has been applied to estimating power scaling of crystalline fiber waveguides (CFWs) with RE3+ doped single crystalline or ceramic YAG (RE=rare earth: Yb, Er, Tm and Ho). Power scaling limits include stimulated Brillouin scattering, thermal lensing effect, and limits to coupling of pump light into CFWs. The CFW designs we have considered consist, in general, of a square doped RE3+:YAG core, an inner cladding of either undoped or laser-inactive-ion-doped YAG and an outer cladding of sapphire. The presented data have been developed for the structures fabricated using the Adhesive-Free Bonding (AFB®) technique, but the results should be essentially independent of fabrication technique, assuming perfect core/inner cladding/outer cladding interfaces. Hard power scaling limits exist for a specific CFW design and are strongly based on the physical constants of the material and its spectroscopic specifics. For example, power scaling limit was determined as ~16 kW for 2.5% ceramic Yb:YAG/YAG (core material/inner cladding material) at fiber length of 1.7 m and core diameter of 69 μm. Considering the present manufacturing limit for CFW length to be, e.g., 0.5 m, the actual maximum output power will be limited to ~4.4 kW for a Yb:YAG/YAG CFW. Power limit estimates have also been computed for Er3+, Tm3+ and Ho3+doped core based CFWs.

  18. Ablation of skin tissue by holmium:YAG laser

    Chen, Wei R.; Holt, Andrew; Nordquist, Robert E.


    Surface epithelial damage by Ho:YAG laser and recovery were studied using histology and electron microscopy. Rabbit skin was irradiated with fluence varying from 55 J/cm2 to 680 J/cm2. Laser damage was determined by histological measurement of three major injury indicators: surface lesion width, depth of photocoagulation, and depth of thermal damage. When the fluence increased, the surface lesion widened and the photocoagulation zone extended deeper into the dermis. The thermally damaged zone (60 degree(s)C muscle and nerve tissues appeared to remain intact under most of our irradiance except at 500 J/cm2 and greater. Thermally injured tissues began recovery within a short period and eventually returned to normal; electron microscopic findings indicated that severe swelling occurred in the individual collagen fibrils, but they were not disrupted and usually recovered to appear normal. A layer of new epithelium started growing underneath the photocoagulated zone around day 3. After 7 days, most photocoagulated tissue was partially, in some cases completely, separated from the skin by the new epithelium. The damage and recovery parameters established should aid in the clinical use of Holmium laser in treating lesions, benign or malignant, in hollow tubular organs and on surface epithelia.

  19. Optimization of dispersing agents for preparing YAG transparent ceramics

    BA Xuewei; LI Jiang; PAN Yubai; LIU Jing; JIANG Benxue; LIU Wenbin; KOU Huamin


    The suspensions of the powder mixture of yttria and alumina were prepared by the aqueous tape casting method.Rodia DP270,Dolapix CE64,citric acid and Dammonium 3008 were used as dispersing agents.The morphologies of the powders and the fiacture surface of the green body were observed by scanning electron microscopy (SEM).The zeta potential test was employed to characterize the surface charge states of different suspensions.The dispersion of the suspensions was analyzed by the rheological tests and the sedimentation experiments.The results indicated that the yttria and alumina powder mixtures were well dispersed by the dispersing agents.The rheological curves showed shear thinning behavior.The most efficient dispersing agent was Dammonium 3008.The optimum usage of Dammonium 3008 was 1.0 wt.%.The green body was dense and no interface between the adjacent layers was found.The in-line transmittance of the as-sintered YAG ceramic was higher than 80% between 400 and 1100 nm.

  20. Er:YAG laser technology for remote sensing applications

    Chen, Moran; Burns, Patrick M.; Litvinovitch, Viatcheslav; Storm, Mark; Sawruk, Nicholas W.


    Fibertek has developed an injection locked, resonantly pumped Er:YAG solid-state laser operating at 1.6 μm capable of pulse repetition rates of 1 kHz to 10 kHz for airborne methane and water differential absorption lidars. The laser is resonantly pumped with a fiber-coupled 1532 nm diode laser minimizing the quantum defect and thermal loading generating tunable single-frequency output of 1645-1646 nm with a linewidth of tuning range covering multiple water absorption lines, with a pulse energy of 1 mJ and a pulse repetition frequency of 1 kHz. The resonator cavity was locked to the seed wavelength via a Pound Drever Hall (PDH) technique and an analog Proportional Integral Derivative (PID) Controller driving a high-bandwidth piezoelectric (PZT)-mounted cavity mirror. Two seed sources lasing on and off the methane absorption line were optically switched to tune the resonator wavelength on and off the methane absorption line between each sequential output pulse. The cavity locking servo maintained the cavity resonance for each pulse.

  1. A multiple work mode YAG laser in derma surgery

    Sa, Yu; Zhang, Guizhong; Ye, Zhisheng; Yu, Lin


    It has been very common that a pulse laser is used in derma surgery based on the theory of "Selective Photothermolysis". This method has also been accepted as the best way to treat the pigments by the medical textbook. A kind of double-pulsed laser which gets the name by two pulse output at one pumping process is developed for derma surgery lately, and this kind of laser has been proved more effective and safe than single-pulse laser. We also develop a multiple work mode YAG laser including two double-pulsed modes at 1064nm and 532nm, two single-pulsed modes at 1064nm and 532nm, and one free-running mode at 1064nm. Considering availability, security and reliability of the laser as a surgery machine, some important subsystems of the laser are optimized carefully, such as Q-switch driver, wavelength-switching system, power supply, and control system etc. At last we get a prototype laser which can run for longer than 30 minutes continuously, and output Max10 pulse per second (pps) with Max800mJ energy at 1064nm double Q-Switch mode, or Max400mJ at 532nm. Using double pulse mode of the laser we do some removal experiments of tattoos and other pigments, and obtain good effect.

  2. Er:YAG and alexandrite laser radiation propagation in root canal and its effect on bacteria.

    Jelínková, H; Dostálová, T; Dusková, J; Krátký, M; Miyagi, M; Shoji, S; Sulc, J; Nemec, M


    The objective of this study was to compare the bactericidal effect of the Er:YAG (wavelength 2.94 microm) and the Alexandrite (wavelength 0.75 microm) laser radiation. The spreading laser energy in the surrounding hard dental tissues round the root canal was evaluated and the bactericidal effect of both these different laser wavelengths was analyzed. The use of a laser to clean and shape the root canal space is the latest method used for cleaning of root canals. The interest in laser endodontics was concentrated on the possibility to extirpate the contents of the root canal, to sterilize and to "melt" the walls of the root canals. The previous reports were performed with CO2, excimer, argon, Nd:YAG, Ho:YAG, and Er:YAG lasers. Er:YAG laser system (2.94 microm, energy 100 mJ or 300 mJ, repetition rate 1 Hz, 30 pulses) and alexandrite laser system (0.75 microm, energy 250 mJ, repetition rate 1 Hz, 30 pulses) were prepared and three experimental arrangements were used during the measurements. First the energy transport through the tooth tissue was observed (frontal and side experimental setups) and then, the bactericidal effect was evaluated. It was demonstrated that due to the absorption in the hydroxyapatite and water content in the dentin, the Er:YAG laser radiation is fully absorbed in the root canal wall. This direct influence of the radiation could be expected only close to the sapphire tip. It was found that the tissue, which was not directly affected by the laser radiation, cannot be disinfected by the subablative effect of Er:YAG laser radiation. In the second part of the experiment the real bactericidal effect of Er:YAG ablative energy (300 mJ) could be observed. It was also shown that the alexandrite laser radiation with a wavelength of 0.75 microm spreads through the canal system space and leaks into the surrounding tooth tissues. Both lasers have bactericidal effect. The pulsed Er:YAG and alexandrite lasers can be efficiently used for killing dental

  3. Effect of Nd:YAG laser capsulotomy on refraction in multifocal apodized diffractive pseudophakia.

    Vrijman, Violette; van der Linden, Jan Willem; Nieuwendaal, Carla P; van der Meulen, Ivanka J E; Mourits, Maarten P; Lapid-Gortzak, Ruth


    To evaluate the effect on refraction of neodymium:YAG (Nd:YAG) laser posterior capsulotomy for posterior capsule opacification (PCO), and to evaluate the correlation between automated and subjective refraction in multifocal apodized diffractive pseudophakia. A retrospective study of 75 pseudophakic eyes (50 patients) with multifocal apodized diffractive pseudophakia, treated for PCO with Nd:YAG laser posterior capsulotomy, was performed. Pre- and postintervention values of refractive and visual parameters were compared. The outcomes of autorefraction and subjective refraction were also compared. Uncorrected and corrected distance visual acuity improved significantly after Nd:YAG capsulotomy (Prefraction and autorefraction. Spherical equivalent changed significantly in autorefraction (P=.008), but not in subjective refraction. Autorefraction and subjective refraction were highly correlated in spherical equivalent, defocus equivalent, and blurring strength (r(2)>0.59). In approximately 7% of eyes, a change of more than 0.50 diopters in spherical equivalent in subjective refraction occurred. In most cases, Nd:YAG laser capsulotomy in patients with multifocal pseudophakia did not result in a change in refraction. However, 7% of eyes experienced a significant change in subjective refraction. Autorefraction correlated well with subjective refraction in apodized diffractive multifocal IOLs. Copyright 2012, SLACK Incorporated.

  4. Sheet metal welding using a pulsed Nd: YAG laser-robot

    Huang, Qi; Kullberg, Gunnar; Skoog, Hans

    This paper presents a pulsed Nd: YAG laser-robot system for spot and seam welding of mild steel sheets. The study evaluates the laser beams behaviour for welding, and then investigates pulsed Nd: YAG laser spot and seam welding processes. High pulse power intensity is needed to initiate the key-hole welding process and a threshold pulse energy to reach full penetration. In seam welding, a weld consists of successive overlapping spots. Both high pulse energy and high average power are needed to keep the key-hole welding going. A 70% overlap is used to define overlapping spot welding as seam welding and to optimize process parameters because a high tensile strength joint compatible with the strength of the base material can be obtained when the overlap is ≥ 70%; at the same time a smooth seam with full penetration is obtained. In these cases, the joints in pulsed Nd: YAG laser welding are comparable in strength to those obtained with CO 2 laser welding. Robot positioning and motion accuracies can meet the demands of Nd: YAG laser sheet metal welding, but its cornering accuracy affects the welding processes. The purpose of the study is to evaluate the YAG laser-robot system for production in the automotive industry.




    Full Text Available BACKGROUND: Nd: YAG laser is non-invasive and effective means to deal with the posterior capsule opacification. However safe it may have some inherent complications. Rise of intraocular pressure is frequently encountered and incompletely understood complication of YAG laser capsulotomy and documented with conflicting results. AIMS: Purpose of the study to assess the efficacy of YAG laser capsulotomy in term of visual outcome and also study the complications of the procedure, particularly on IOP. SETTING: Tertiary Centre. DESIGN: Prospective interventional study. MATERIAL AND METHODS: Present study evaluate the changes in IOP and visual acuity after Nd-YAG laser capsulotomy in 280 eyes with significant PCO after uncomplicated small incision cataract surgery with IOL implantation. Complete ocular examination including visual acuity, anterior segment examination with slit lamp, fundus and application tonometry were performed pre-and post-laser in all cases. Posterior capsulotomy was done with Q-switched Nd: YAG laser with energy used 10 mmHg was found in 5% of cases. Ninety two percent patients achieved base line pressure within 4 hours. Incidence of minor complications was 14.6% and none of patient showed major complications or deterioration of vision. CONCLUSION: Our study showed insignificant rise in IOP, and none of patient show vision threatening complication after laser capsulotomy. Hence routine antiglaucoma medicine may not be necessary in all patients following Nd: YAD laser capsulotomy.

  6. Argon laser versus erbium:YAG laser in the treatment of xanthelasma palpebrarum

    Abdelkader, Mona; Alashry, Shereen Ezzelregal


    Background Xanthelasma palpebrarum is the most common of the xanthomas with asymptomatic, symmetrical, bilateral, soft, yellow, polygonal papules around the eyelids. Though it is a benign lesion causing no functional disturbance, it is esthetically annoying. The surgical laser offers an extremely elegant and powerful solution to this problem. Objective To evaluate the effectiveness of erbium:YAG and argon lasers in the treatment of xanthelasma lesions. Patients and methods Forty patients were included in the study. Twenty patients (15 patients were bilateral with 30 eyes either in the upper or lower lid and 5 patients were unilateral) were treated with erbium:YAG laser. Another 20 patients (10 patients were bilateral with 20 eyes and 10 patients were unilateral) were treated with argon laser. Results In the majority of treated patients (either treated with erbium:YAG or argon laser), xanthelasma lesions were completely disappeared or significantly decreased in size. Two patients showed pigmentary changes in the form of hypopigmentation with erbium:YAG laser (one case), another case showed hyperpigmentation. No intraoperative complication was observed. No significant scar or recurrence was observed. Conclusion Argon laser in xanthelasma is an easy, effective, and safe method of treatment for small lesions and YAG laser is more better for large lesions than argon laser. PMID:25892929

  7. Comparative studies of YAG(Ce) and CsI(Tl) scintillators

    Bhattacharjee, T; Dey, C C; Chatterjee, M B


    The performances of YAG(Ce) and CsI(Tl) scintillators have been compared using photomultiplier tube (PMT) readout for gamma rays and alpha particles. It is found that the energy resolution of YAG(Ce) is inferior to that of CsI(Tl). With Philips XP2971 PMT, we have obtained improved energy and time resolution for YAG(Ce), compared to the same, obtained by earlier workers using XP2020/Q. The best values of energy resolution (FWHM), obtained in the present work, for 662 keV gamma ray, are 6% and 7%, respectively, for CsI(Tl) and YAG(Ce), whereas for 5.48 MeV alpha particles, the observed values are 6% and 8.4%, respectively. The pulse height response of both the scintillators has been found to be reasonably linear up to 1.3 MeV gamma energy. A prompt time resolution of 1.3 ns (FWHM) has been obtained with a BaF sub 2 - YAG(Ce) combination against 511-511 keV photopeak selection, which compares well with that obtained for a BaF sub 2 -CsI(Tl) combination, used by us.

  8. Effect of Er:YAG laser on dentin bonding durability under simulated pulpal pressure.

    Bakry, Ahmed Samir; Nakajima, Masatoshi; Otsuki, Masayuki; Tagami, Junji


    To evaluate the effects of Er:YAG laser ablation on the microtensile bond strength and the nanoleakage of Er:YAG-lased dentin bonded to a self-etching adhesive system with and without pulpal pressure. Twenty flat dentin surfaces were obtained from extracted molars. Ten specimens were irradiated by Er:YAG laser, other specimens (control group) were ground using #600 SiC paper. Direct communication to the pulp chamber was created by cutting at a level approximately 1 mm below the cementoenamel junction and parallel to the occlusal surface. The experimental groups were exposed to a simulated pulpal pressure of 15 cm H2O. Each specimen was restored using an adhesive and a photocured composite. The specimens were then sectioned vertically to obtain dentin/adhesive slabs. Ninety-six slabs were prepared for microtensile bond testing. Sixty-four slabs were immersed in ammoniacal silver nitrate tracer solution for 18 h, then rinsed thoroughly, and immersed in photodeveloping solution for 6 h prior to their examination by FE-SEM. The method of dentin preparation and the pulpal pressure storage condition significantly affected the microTBS, while the storage duration did not (p < 0.05). The nanoleakage patterns observed in the dentin/bond interface differed depending on whether the dentin was conventionally prepared or ablated by Er:YAG laser. Er:YAG laser ablation to dentin adversely affected the microTBS and the sealing ability of SE Bond bonded to dentin under simulated pulpal condition.

  9. Morphologic assessment of dental surface/ glass ionomer cement interface: influence of Er:YAG laser pretreatment

    Silmara Aparecida Milori Corona


    Full Text Available Introduction and objective: The aim of this study was to assess the surface and the substrate/glass ionomer cement (GIC interface after Er:YAG laser irradiation by means of scanning electron microcopy. Material and methods: Thirty human third molars were selected and had their roots removed. Crowns were sectioned to obtain discs that were randomly assigned to three groups according to the surface pretreatment: 40% polyacrylic acid (control; Er:YAG laser irradiation (80mJ/2Hz or Er:YAG laser followed by 40% polyacrylic acid. Two discs of each group were put aside to the surface analysis and the others were bisected. One half received Ketac-Fil and the other received Fuji II LC. Specimens were prepared for SEM and were analyzed under different magnifications. Results: Er:YAG laser group showed no adhesive interface for both enamel and dentin, but strongly damaged the interface build-up for dentin/Fuji II LC. The application of laser irradiation followed by the polyacrylic acid exhibited gaps and irregularities for both substrates. Conclusion: Er:YAG laser irradiation combined or not with 40% polyacrylic acid produced a surface unfavorable for GIC interaction, especially for the resin-modified ones.

  10. Chemical Changes Associated with Increased Acid Resistance of Er:YAG Laser Irradiated Enamel

    Jennifer Manuela Díaz-Monroy


    Full Text Available Background. An increase in the acid resistance of dental enamel, as well as morphological and structural changes produced by Er:YAG laser irradiation, has been reported. Purpose. To evaluate the chemical changes associated with acid resistance of enamel treated with Er:YAG laser. Methods. Forty-eight enamel samples were divided into 4 groups (n=12. Group I (control; Groups II, III, and IV were irradiated with Er:YAG at 100 mJ (12.7 J/cm2, 200 mJ (25.5 J/cm2, and 300 mJ (38.2 J/cm2, respectively. Results. There were significant differences in composition of irradiated groups (with the exception of chlorine and in the amount of calcium released. Conclusions. Chemical changes associated with an increase in acid resistance of enamel treated with Er:YAG laser showed a clear postirradiation pattern characterized by a decrease in C at.% and an increase in O, P, and Ca at.% and no changes in Cl at.%. An increased Ca/P ratio after Er:YAG laser irradiation was associated with the use of higher laser energy densities. Chemical changes produced by acid dissolution showed a similar trend among experimental groups. Stable or increased Ca/P ratio after acid dissolution was observed in the irradiated groups, with reduction of Ca released into the acid solution.

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

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


    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.

  12. Treatment of dentinal tubules by Nd:YAG laser

    Chmelíčkova, Hana; Zapletalova, Zdeňka; Peřina, Jan, Jr.; Novotný, Radko; Kubínek, Roman; Stranyánek, Martin


    Symptom of cervical dentine hypersensitivity attacks from 10% to 15% of population and causes an uncomfortable pain during contact with any matter. Sealing of open dentinal tubules is one of the methods to reach insensibility. Laser as a source of coherent radiation is used to melt dentine surface layers. Melted dentine turns to hard mass with a smooth, non-porous surface. Simulation of this therapy was made in vitro by means of LASAG Nd:YAG pulsed laser system KLS 246-102. Eighty human extracted teeth were cut horizontally to obtain samples from 2 mm to 3 mm thick. First experiments were done on cross section surfaces to find an optimal range of laser parameters. A wide range of energies from 30 mJ to 210 mJ embedded in 0,3 ms long pulse was tested. Motion in X and Y axes was ensured by a CNC driven table and the pulse frequency 15 Hz was chosen to have a suitable overlap of laser spots. Some color agents were examined with the aim to improve surface absorption. Scanning Electron Microscopy was used to evaluate all samples and provided optimal values of energies around 50 Next experiments were done with the beam oriented perpendicularly to a root surface, close to the real situation. Optical fibers with the diameter of 0,6 mm and 0,2 mm were used to guide a laser beam to teeth surfaces. Laser processing heads with lens F = 100 mm and F = 50 mm were used. The best samples were investigated by means of the Atomic Force Microscopy.

  13. SEM evaluation of the morphological changes in hard dental tissues prepared by Er: YAG laser and rotary instruments

    Tomov Georgi


    Full Text Available Effective ablation of dental hard tissues by means of the erbium:yttrium-aluminum garnet (Er: YAG laser has been reported recently, and its application to caries removal and cavity preparation has been expected. However, few studies have investigated the morphological changes in hard dental tissues after Er: YAG laser caries treatment. In the present study the morphological changes in hard dental tissues after Er: YAG laser caries ablation in vitro was compared with that of conventional mechanical treatment. Thirty extracted human teeth with caries were used. Ten tooth was treated with the Er: YAG laser, and the other was treated with a conventional steel and diamond burs. Laser treatment was performed by means of a non-contact irradiation modes with cooling water spray, with a new Er: YAG laser (LiteTouch. Conventional bur treatment was conducted by means of a low-speed micromotor and air turbine with water cooling. Scanning electron microscope (SEM observations were performed for each treatment. The Er: YAG laser ablated carious dentin effectively with minimal thermal damage to the surrounding intact dentin, and removed infected and softened carious dentin to the same degree as the burtreatment. In addition, a lower degree of vibration was noted with the Er: YAG laser treatment. The SEM examination revealed characteristic micro-irregularities of the lased dentin and enamel surfaces with potential benefits for adhesive restorations. Our results show that the Er: YAG laser is promising as a new technical modality for caries treatment

  14. Compact diode stack end pumped Nd:YAG amplifier using core doped ceramics.

    Denis, Thomas; Hahn, Sven; Mebben, Sandra; Wilhelm, Ralf; Kolleck, Christian; Neumann, Jörg; Kracht, Dietmar


    We report on a compact Nd:YAG amplifier emitting a maximum pulse energy of 14 mJ. By amplifying a passively Q-switched oscillator (M(2)diode pumped by an 8 bar diode stack of 800 W power and a nonimaging optic. This optic homogenizes the pump light and transfers it into a 5 mm diameter core doped rod with a centrally neodymium doped region of 3 mm and a samarium doped YAG cladding. We show that this cladding reduces parasitic effects in the laser rod compared to an undoped YAG cladding. Finally, we compare the compact amplifier with an amplifier, which is mode selectively pumped by a fiber coupled pump diode.

  15. Optimizing treatment parameters for the vascular malformations using 1064-nm Nd:YAG laser

    Gong, Wei; Lin, He; Xie, Shusen


    Near infrared Nd:YAG pulsed laser treatment had been proved to be an efficient method to treat large-sized vascular malformations like leg telangiectasia for deep penetrating depth into skin and uniform light distribution in vessel. However, optimal clinical outcome was achieved by various laser irradiation parameters and the key factor governing the treatment efficacy was still unclear. A mathematical model in combination with Monte Carlo algorithm and finite difference method was developed to estimate the light distribution, temperature profile and thermal damage in epidermis, dermis and vessel during and after 1064 nm pulsed Nd:YAG laser irradiation. Simulation results showed that epidermal protection could be achieved during 1064 nm Nd:YAG pulsed laser irradiation in conjunction with cryogen spray cooling. However, optimal vessel closure and blood coagulation depend on a compromise between laser spot size and pulse duration.

  16. Treatment of gingival hyperpigmentation for esthetic purposes by Nd:YAG laser: report of 4 cases.

    Atsawasuwan, P; Greethong, K; Nimmanon, V


    Gingival hyperpigmentation may cause esthetic problems and embarrassment, especially in patients with a gummy smile. This report presents the use of the Nd:YAG laser for gingival depigmentation. Four cases, 3 females and 1 male, ages between 24 to 28 years old, presented with the same chief complaint of unesthetic gingiva caused by melanin hyperpigmentation. The Nd:YAG laser was set at 6 watts, 60 millijoules per pulse, and 100 pulses per second. The procedures were performed with contact mode in all pigmented areas by using a handpiece with a 320 microm diameter fiber optic. Ablation of the gingival hyperpigmented areas were accomplished without any bleeding complications or significant postoperative pain. Three to 4 weeks after the procedures, the hyperpigmented gingiva appeared healthy, pink, and firm. No recurrence of hyperpigmentation had been found in 11 to 13 months of follow-up. However, in delicate areas such as the marginal gingiva, the Nd:YAG laser should be used cautiously.

  17. Selective photothermal ablation of tissue with a fiber-delivered Er:YAG laser

    Pierce, Mark C.; Dickinson, Mark R.; Devlin, Hugh


    The feasibility of using laser-induced photoemission signals to distinguish between hard and soft biological tissues during photothermal ablation with a pulsed Er:YAG laser has been investigated. Time-resolved emission spectroscopy indicated a threshold fluence of approximately 35 J/cm2 to regularly initiate photoemission from dental enamel, while no emission was detected from porcine muscle tissue with incident laser fluences of up to approximately 140 J/cm2. The delay time of an emission signal with respect to the incident, ablative Er:YAG laser pulse was found to decrease from approximately 150 microseconds near the emission threshold fluence to approximately 60 microseconds at the highest fluence level used. Optical multichannel analyzer spectroscopy of Er:YAG irradiated enamel demonstrated that photoemissions typically consisted of a broad, continuous background in the visible region, with superimposed peaks arising from the presence of elements including calcium, characteristic of plasma emission either from the sample surface or emission plume.

  18. YAG: Ce Phosphors for WLED via Nano-Pesudoboehmite Sol-Gel Route


    The sub-micron sized YAG: Ce phosphors were synthesized via a modified sol-gel method by peptizing nano-pesudoboehmite particulate. It is found that YAG phase from the dried gel powders appears at 1000 ℃ then the pure YAG phase exists at a relatively lower sintering temperature of 1400 ℃. The smaller sizes of phosphors in the ranges of 1 ~ 3 μm are obtained due to the contribution of seeding effects of nano-sized alumina particles to strengthen each step of the processes. Both the excitation and emission spectra of photoluminescence of the phosphor obtained at 1400 ℃ meet well with the spectroscopic requirements of the WLED phosphors.

  19. High-gain Yb:YAG amplifier for ultrashort pulse laser at high-average power

    Vetrovec, John; Copeland, Drew A.; Litt, Amardeep S.; Du, Detao


    We report on a Yb:YAG laser amplifier for ultrashort pulse applications at kW-class average power. The laser uses two large-aperture, disk-type gain elements fabricated from composite ceramic YAG material, and a multi-pass extraction architecture to obtain high gain in a chirped-pulse amplification system. The disks are edge-pumped, thus allowing for reduced doping of host material with laser ions, which translates to lower lasing threshold and lower heat dissipation in the Yb:YAG material. The latter makes it possible to amplify a near diffraction-limited seed without significant thermo-optical distortions. This work presents results of testing the laser amplifier with relay optics configured for energy extraction with up to 40 passes through the disks. Applications for the ultrashort pulse laser amplifier include producing laser-induced plasma channel, laser material ablation, and laser acceleration of atomic particles.

  20. High-gain multipassed Yb:YAG amplifier for ultrashort pulse laser

    Vetrovec, John; Copeland, Drew A.; Litt, Amardeep S.; Du, Detao


    We report on a Yb:YAG laser amplifier for ultrashort pulse applications at kW-class average power. The laser uses two large-aperture, disk-type gain elements fabricated from composite ceramic YAG material, and a multi-pass extraction architecture to obtain high gain in a chirped-pulse amplification system. The disks are edge-pumped, thus allowing for reduced doping of the host material with laser ions, which translates to lower lasing threshold and lower heat dissipation in the Yb:YAG material. The latter makes it possible to amplify a near diffraction-limited seed without significant thermo-optical distortions. This work presents results of testing the laser amplifier with relay optics and passive polarization switching configured for energy extraction with up to 40 passes through the disks. Applications for the ultrashort pulse laser amplifier include producing a laser-induced plasma channel, laser material ablation, and laser acceleration of atomic particles.

  1. Suppression of nonlinear phonon relaxation in Yb:YAG thin disk via zero phonon line pumping.

    Smrž, Martin; Miura, Taisuke; Chyla, Michal; Nagisetty, Siva; Novák, Ondřej; Endo, Akira; Mocek, Tomáš


    A quantitative comparison of conventional absorption line (940 nm) pumping and zero phonon line (ZPL) (969 nm) pumping of a Yb:YAG thin disk laser is reported. Characteristics of an output beam profile, surface temperature, and deformation of a thin disk under the different pump wavelengths are evaluated. We found that a nonlinear phonon relaxation (NPR) of the excited state in Yb:YAG, which induces nonlinear temperature rise and large aspheric deformation, did not appear in the case of a ZPL pumped Yb:YAG thin disk. This means that the advantage of ZPL pumping is not only the reduction of quantum defect but also the suppression of NPR. The latter effect is more important for high power lasers.

  2. In vitro application of optical transmission systems in erbium:YAG laser temporomandibular joint surgery

    Nuebler-Moritz, Michael; Hering, Peter; Niederdellmann, Herbert; Deuerling, Christian; Dammer, Ralf


    The experimental setup of this study is focused on the changes in temporomandibular joint tissue after irradiation with an Erbium:YAG laser. Initially, the free-running beam from the laser was focused onto freshly excised porcine tissue samples, indicating an optimum average energy density and pulse duration for the purpose of temporomandibular joint surgery of about 15 - 60 J/cm2 and 120 microsecond(s) - 240 microsecond(s) , respectively. Consecutively, an attempt was made to couple the Erbium:YAG laser beam on the one hand to optical fibers made of infrared-transmitting glasses (fluoride- and chalcogenide-based), on the other hand to a recently developed sapphire and liquid core fiber, respectively. From the preliminary observations of this investigation it appears that both the liquid core and the sapphire fiber are the most promising candidates for delivery of Erbium-YAG laser radiation in arthroscopic surgery of the craniomandibular articulation.

  3. Resistance of YAG:Nd sup 3+ laser frequency converters to ionizing radiation

    Zakharkin, B. I.; Kulevskiy, L. A.; Nikolayev, V. N.; Toropkin, G. N.


    This study presents a review of published work on the radiation resistance of YAG:Nd sup 3+ laser frequency converters, and describes the results of experiments on the influence of gamma-irradiation of nonlinear crystals on the output characteristics of YAG:Nd sup 3+ lasers with second-harmonic generation inside or outside the cavity. The influence of radiation on the optical properties of nonlinear crystals is investigated. It is found that radiation degrades the generation of optical harmonics in YAG:ND sup 3+ lasers employing nonlinear elements made of SDA, DSDA, LiIO3 and DKDR crystals, starting at doses of 10 to the 5th power - 10 to the 6th power rad. Deuterized nonlinear crystals are found to be more resistant to ionizing radiation.

  4. Effects of Er:YAG Laser on Mineral Content of Sound Dentin in Primary Teeth


    The aim of the present study was to evaluate the mineral content of sound dentin in primary teeth prepared using an Er:YAG laser at two different power settings. Thirty-six primary second molars were used in this study. Three dentin slabs were obtained from each tooth, and the slabs were randomly divided into three groups: Group A, control; Group B, Er:YAG laser at 3.5 W, 175 mJ, and 20 Hz, short pulse mode; and Group C, Er:YAG laser at 4 W, 200 mJ, and 20 Hz, medium-short pulse mode. One den...

  5. Boiling effect in liquid nitrogen directly cooled Yb³⁺:YAG laser.

    Sakurai, Toshimitsu; Chosrowjan, Haik; Furuse, Hiroaki; Taniguchi, Seiji; Kitamura, Toshiyuki; Fujita, Masayuki; Ishii, Shinya; Izawa, Yasukazu


    Liquid nitrogen (LN2) behavior on the surface of excited Yb(3+):YAG is investigated using fluorometry. From the time-resolved temperature variations and integrated fluorescence spectra intensity on this directly cooled Yb(3+):YAG surface, we observe a phase transition of LN2 from nucleate boiling to film boiling. As a result of this pool boiling, good beam quality should occur when the temperature and heat flux at an excited surface of Yb(3+):YAG are below 95 K and 15.8  W/cm2, respectively. That is, the LN2 should remain in a steady state of nucleate boiling to produce good beam quality using pool boiling.

  6. TEM00 mode Nd:YAG solar laser by side-pumping a grooved rod

    Vistas, Cláudia R.; Liang, Dawei; Almeida, Joana; Guillot, Emmanuel


    A simple TEM00 mode solar laser system with a grooved Nd:YAG rod pumped through a heliostat-parabolic mirror system is reported here. The radiation coupling capacity of a fused silica tube lens was combined with the multipass pumping ability of a 2 V-shaped cavity to provide efficient side-pumping along a 4.0 mm diameter grooved Nd:YAG single-crystal rod. TEM00 mode solar laser power of 3.4 W was measured by adopting an asymmetric large-mode laser resonant cavity. Record TEM00 mode solar laser collection efficiency of 3.4 W/m2and slope efficiency of 1.9% was achieved, which corresponds to 1.8 and 2.4 times more than the previous TEM00 mode Nd:YAG solar laser using the PROMES-CNRS heliostat-parabolic mirror system, respectively.

  7. Towards high-quality optical ceramic YAG fibers for high-energy laser (HEL) applications

    Lee, HeeDong; Keller, Kristin; Sirn, Brian


    There is a critical demand for high quality, transparent ceramic YAG fibers for high powered fiber lasers. The production of laser quality ceramic fibers hinges on advanced ceramic processing technology, along with the availability of highly sinterable powder with high phase and chemical purity. These two fundamental technologies have been successfully developed at UES. Nd (1.1 a/o) and Yb (1.0 a/o)-doped yttrium aluminum garnet (YAG) fibers with high optical quality were produced by combining UES's tailored powders with advanced consolidation processes including fiber extrusion and vacuum sintering. The as-sintered and as-annealed fibers, approximately 30 microns in diameter, appeared transparent and successfully transmitted laser beams; further development will allow for the production of doped ceramic YAG fiber lasers for advanced high power and high energy fiber laser systems.

  8. Nd:YAG laser removal of pupillary membranes developed after ECCE with PC-IOL implantation.

    Kozobolis, V P; Pallikaris, I G; Tsambarlakis, I G; Vlachonikolis, I G


    To define the frequency of development of pupillary membranes after ECCE with PC-IOL implantation, and to remove the pupillary membranes using the Nd:YAG laser. From 400 patients who had undergone ECCE and were free from local or systemic illness affecting the blood-ocular barrier, 20 eyes developed pupillary membranes Nd:YAG laser was used to remove these pupillary membranes. The frequency of pupillary membranes was found to be 5% (9.8% in pex eyes and 3.3% to the non-pex eyes). Visual acuity improved in 17 eyes by 2 to 5 Snellen lines. No serious complications were observed, endothelium inclusive. Pseudoexfoliation might play a significant role in the development of postoperative pupillary membranes which could be successfully treated with the use of Nd:YAG laser. The safety of the procedure has to be evaluated in relation to the corneal endothelium damage in long-term.

  9. Sol-gel preparation and electrical behaviour of Ln: YAG (Ln = Ce, Nd, Ho, Er



    Full Text Available A sol-gel method has been developed to prepare pure yttrium aluminum garnet, Y3Al5O12 (YAG, and rare-earth substituted (Ce-Y3Al5O12, Nd-Y3Al5O12, Ho-Y3Al5O12, and Er-Y3Al5O12 samples. The XRD patterns of the polycrystalline powders sintered at 1000ºC showed the formation of monophasic garnet materials. The micro-structural features in the polycristalline samples were studied by scanning electron microscopy. A homogeneous distribution of rare-earth dopants in the YAG lattice was achieved in all of the cases. Electrical conductivity measurements were also performed on the compacts of sol-gel derived Ln-YAG samples. In contrast to the expected dielectric behaviour, the conducting properties of the examined specimens indicate metallic behaviour with the resistivity increasing gradually with increasing temperature.

  10. Láser Er:YAG en Periodoncia: Revisión bibliográfica

    A Herrero Sánchez


    Full Text Available Diferentes láseres, como el CO2, Nd:YAG y ArF se han propuesto en la terapéutica periodontal. La mayor parte de ellos no han alcanzado relevancia clínica, debido a los resultados insatisfactorios obtenidos en las superficies radiculares tratadas, la generación de efectos colaterales o la ausencia de terminales de aplicación adecuados. Sin embargo, el nuevo láser Er:YAG se muestra como una prometedora alternativa en la remoción de placa bacteriana y cálculo de las superficies radiculares afectas, gracias a su mecanismo de ablación termomecánica y a la ausencia de efectos térmicos secundarios. El propósito de este artículo es revisar las actuales aplicaciones del láser Er:YAG en la práctica periodontal.Different lasers, such as CO2, the Nd:YAG and the ArF have been proposed for use in periodontal therapy. Most systems have not reached clinical significance because of the unsattisfactory results of laser treated root surfaces, emergence of severe side effects, or the lack of suitable delivery systems. However, the recently introduced Er:YAG laser radiation appears to be a promising alternative means of removing microbial plaque and calculus from diseased tooth root surfaces, due to its thermo-mechanical ablation properties and the lack of thermal side effects. The purpose of this article is to review current applications of laser Er:YAG to periodontal practice.

  11. Composite resin's adhesive resistance to dentin: influence of Er:YAG laser focal distance variation.

    Corona, Silmara Aparecida Milori; Atoui, Juliana Abdallah; Chimello, Daniela Thomazatti; Borsatto, Maria Cristina; Pecora, Jesus Djalma; Dibb, Regina Guenka Palma


    The aim of this study was to analyze in vitro the influence of Er:YAG laser focal distance variation on tensile bond strength of a composite resin to dentin. Although there are several studies using the Er:YAG laser for dentin treatment, there is a lack of available literature related to the Er:YAG laser focal distance variation. Sixty vestibular and lingual dentin surfaces from extracted human third molars, kept in a 0.4% azide sodium solution, were ground and assigned to six groups. The control group was conditioned with 35% phosphoric acid (CA). In the lased groups, the dentin surface treatment was performed by irradiation with Er:YAG laser (80 mJ/2 Hz), varying the focal distance (11, 12, 14, 16, and 17 mm), followed by acid etching. The Single Bond/Filtek Z250 (3M) resinous system was used for the specimen manufacture. The tensile bond strength tests were performed in a Universal Testing Machine with 50 kgf load cell and 0.5 mm/min cross head speed. The averages in MPa were: CA: 18.03 (+/-2.09); 11 mm; 9.92 (+/-3.34); 12 mm: 9.49 (+/-2.29); 14 mm: 10.99 (+/-3.45); 16 mm: 10.56 (+/-1.93); and 17 mm: 17.05 (+/-2.31). It was concluded that the application of Er:YAG laser in a defocused mode (17 mm) associated with acid etching was similar to the treatment of acid solely. Er:YAG laser irradiation in a focused (12 mm) and a defocused (11, 14, and 16 mm) mode coupled with acid conditioning produced the lowest values of adhesion.

  12. Wound healing after irradiation of bone tissues by Er:YAG laser

    Watanabe, Hisashi; Yoshino, Toshiaki; Aoki, Akira; Ishikawa, Isao


    Clinical applications of Er:YAG laser are now developing in periodontics and restorative dentistry. To date, there have been few studies indicating safety criteria for intraoral usage of the Er:YAG laser. The present study examined the effects of the Er:YAG laser on bone tissues, supposing mis- irradiation in the oral cavity during dental application, especially periodontal surgery. The experiments were performed using the newly-developed Er:YAG laser apparatus equipped with a contact probe. In experiment 1, 10 pulses of laser irradiation were administered to the parietal bone of a rat at 50, 150 and 300 mJ/pulse with and without water irrigation, changing the irradiation distance to 0, 5, 10 and 20 mm, respectively. As a control, electric knife was employed. Macroscopic and SEM observations of the wound surface were performed. In experiment 2, laser irradiation in a straight line was performed at 150 mJ/pulse, 1- pps and 0,5, 10 mm irradiation distance without water irrigation. Wound healing was observed histologically at 0, 3, 7, 14 and 28 days after laser irradiation and compared with that of the control. Non-contact irradiation by Er:YAG laser did not cause severe damage to the parietal bone tissue under water irrigation. Contact irradiation induced a limited wound, however, new bone formation was observed 28 days after laser irradiation, while osseous defect with thermal degenerative tissue remained at the control site. In conclusion, irradiation with an Er:YAG laser would not cause severe damage to surrounding bone tissues in the oral cavity when used within the usual power settings for dental treatment. Furthermore, this laser may be applicable for osseous surgery because of its high ablation efficiency and good wound healing after irradiation.

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

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


    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.

  14. Shear bond strength after Er:YAG laser radiation conditioning of enamel and dentin

    Dostalova, Tatjana; Jelinkova, Helena; Dolezalova, Libuse; Kubelka, Jiri; Prochazka, Stanislav; Hamal, Karel; Krejsa, Otakar


    This study compares bond shear strength between hard dental tissues and composite resin filling material after a classical acid etching treatment procedure and Er:YAG laser surface conditioning. The retention of composite resin was evaluated for three cases: (1) the flat dental substrate without any conditioning, (2) the classical drilling machine prepared surface with acid etching and (3) the Er:YAG laser conditioning of enamel and dentin. None significant differences between bond shear strength of the classical drilling machine prepared surface with acid etching in comparison with the laser radiation conditioning were found.

  15. Mode size and time duration fluctuations in a picosecond Nd:YAG laser

    Cutolo, A.; Zeni, L.; Berardi, V.; Bruzzese, R.; Solimeno, S.; Spinelli, N.


    A new technique is successfully used to analyze in real time the pulse-to-pulse fluctuations of mode size and time duration in a picosecond Nd:YAG laser. In particular we show that the pulse length (30 psec) of our active--passive mode-locked Nd:YAG laser is stable to within 10% when the cavity is perfectly tuned and the saturable absorber is fresh. This technique is experimentally shown to be effective and reliable for real-time analysis of the stability of ultrashort laser pulses under a broad range of experimental conditions.

  16. Ruby and Sm:YAG fluorescence pressure gauges up to 120 GPa and 700 K

    Wei, Qingguo; Dubrovinskaia, Natalia; Dubrovinsky, Leonid


    Diamond anvil cell (DAC) technique relies on pressure determination based on use of pressure gauges. Fluorescence-based gauges, such as ruby and Sm doped yttrium aluminum garnet (Sm:YAG), are frequently used in the high pressure research. Here we present the results of DAC experiments which allowed extending calibration curves of the fluorescence frequency versus pressure up to 120 GPa at high temperatures up to 700 K for both for ruby and Sm:YAG. Cubic boron nitride was used as the reference gauge.

  17. Treatment of Vascular Lesions of the Tongue with Nd:YAG Laser

    Joana Dias Coelho


    Full Text Available The treatment of vascular lesions of the tongue is a very challenging procedure since the maintenance of the lingual tissue is of critical importance. Numerous treatment options have been described in literature but the Nd:YAG Laser appears to be one of the safest therapeutic options. We described a successful treatment of vascular lesions of the tongue with an excellent clinical result after only one treatment session with the Nd:YAG laser, with conservation of the lingual tissue and its functionality.

  18. Acquisition of a Nd-Yag Pumped MOPO (Master Oscillator/Power Oscillator) Optical Parametric Oscillator


    SEP 1997 2. REPORT TYPE 3. DATES COVERED 00-00-1997 to 00-00-1997 4. TITLE AND SUBTITLE Acquisition of a Nd-Yag Pumped MOPO (Master Oscillator...unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 ACQUISITION OF A ND-YAG PUMPED MOPO (MASTER OSCILLATOR / POWER OSCILLATOR) OPTICAL...instrument is configured in a master oscillator/power oscillator configuration, hence the designation MOPO . The MOPO will be used in conjunction

  19. Comparison of Nd:YAG Ceramic Laser Pumped at 885 nm and 808 nm

    ZONG Nan; ZHANG Xiao-Fu; MA Qing-Lei; WANG Bao-Shan; CUI Da-Fu; PENG Qin-Jun; XU Zu-Yan; PAN Yu-Bai; FENG Xi-Qi


    Laser performance of 1064 nm domestic Nd: YA G ceramic lasers for 885 nm direct pumping and 808 nm traditional pumping are compared. Higher slope efficiency of 34% and maximum output power of 16.5 W are obtained for the 885nm pump with a 6ram length 1 at% Nd:YAG ceramic. The advantages for 885nm direct pumping are discussed in detail. This pumping scheme for highly doping a Nd:YAG ceramic laser is considered as an available way to generate high power and good beam quality simultaneously.

  20. Marginal microleakage in vitro study on class V cavities prepared with Er:YAG laser and etched with acid or etched with Er:YAG laser and acid; Estudo in vitro da microinfiltracao marginal em cavidades classe V preparadas com laser de Er:YAG e condicionadas com acido ou com laser de Er:YAG e acido

    Tavares, Henrique Dutra Simoes


    Microleakage at the interface between the teeth and the restorative materials remains a problem with composite resin restorations. Microleakage at the gingival margins of class V cavities restorations still challenge as they are usually placed in dentin and/or cementum. Previous studies have shown that the cavity preparation with Er:YAG laser is possible. It has been reported that Er:YAG laser has ability to create irregular surface providing micromechanical retention for adhesive dental restorative materials and to improve marginal sealing. The purpose of this in vitro study was to evaluate the marginal microleakage on class V cavities prepared with Er:YAG laser and etched with acid or with Er:YAG laser and acid, in compared to those prepared and etched conventionally. Thirty human molars were divided into three groups, namely: group I - prepared with Er:YAG laser (KaVo KEY Laser II - Germany) and etched with 37% phosphoric acid; group II - prepared with Er:YAG laser and etched with Er:YAG laser and 37% phosphoric acid; group III (control group) - prepared with high speed drill and etched with 37% phosphoric acid. All cavities were treated with same adhesive system (Single Bond - 3M) and restored with the composite resin (Z100 - 3M), according to the manufacturer's instructions. The specimens were stored at 37 deg C in water for 24 hours, polished with Sof-Lex discs (3M), thermally stressed, sealed with a nail polish coating except for the area of the restoration and 1 mm around it, and immersed in a 50% aqueous solution of silver nitrate for 24 hours. After that, the specimens were rinsed in water, soaked in a photodeveloping solution and exposed to a fluorescent light for 8 hours. The teeth were embedded in an autopolymerizing resin and sectioned longitudinally using a diamond saw microtome under running water. The sections were photographed. The microleakage at the occlusal cavity and at the gingival margins of each specimen was evaluated with scores (0

  1. Optimization Of Output Q-Switched Nd:YAG Laser Based On Switching Time

    Tamuri, Abd Rahman; Daud, Yaacob Mat; Bidin, Noriah


    This paper reports the optimization of output Q-switch Nd:YAG. A free running Nd:YAG laser was employed as source of light. KD*P crystal was utilized as a Pockels cell. Avalanche transistor pulser was designed to switch a high voltage power supply. The switching time was conducted via a control unit based PIC16F84A microcontroller. The pulser was able to switch the voltage within 3 ns. The optimum switching time of Q-switching is obtained at 182.34 μs. The corresponding laser output is 40 mJ with pulse duration of 25 ns.

  2. Composite fillings microleakage after TEM00 Er: YAG laser texturing of human tooth enamel surface

    Belikov, A. V.; Shatilova, K. V.; Skrypnik, A. V.; Fedotov, D. Y.


    The results of comparative investigation of methylene-blue microleakage between tooth enamel surface and light-cure composites various fluidity are presented. An enamel surface was treated by traditional methods or laser method (laser texturing). The role of adhesive systems is investigated at enamel texturing by the TEM00 Er: YAG radiation. It is shown, that microleakage was not observed when enamel was textured by the TEM00 Er: YAG laser radiation and covered with flowable composite "Revolution" (Kerr) without adhesive system. It is established, that for laser textured surfaces methylene-blue microleakage depends on distance between microcraters.

  3. Treatment of Special Renal Colic with Ureteroscope and Holmium YAG Laser

    沈明顺; 刘军


    Objective To investigate the method of emergent relief of special renal colicand treatment of ureter diseases causing renal colic. Methods By analyzing 63 cases of special re-nal colic treated with ureteroscope and Holmium YAG laser. Results 61 cases of renal colic were re-lieved in a short period of time and the ariginal ureter diseases causing renal colic were cured. Conclu-sion Special renal colic could be treated with ureteroscope and Holmium YAG laser in a quick and ef-fective manner.

  4. Láser Er:YAG en Periodoncia: Revisión bibliográfica


    Diferentes láseres, como el CO2, Nd:YAG y ArF se han propuesto en la terapéutica periodontal. La mayor parte de ellos no han alcanzado relevancia clínica, debido a los resultados insatisfactorios obtenidos en las superficies radiculares tratadas, la generación de efectos colaterales o la ausencia de terminales de aplicación adecuados. Sin embargo, el nuevo láser Er:YAG se muestra como una prometedora alternativa en la remoción de placa bacteriana y cálculo de las superficies radiculares afect...

  5. Novel technique to treat melasma in Chinese: The combination of 2940-nm fractional Er:YAG and 1064-nm Q-switched Nd:YAG laser.

    Tian, Wei Cheng Brian Anthony


    Melasma is one of the most common pigmented lesions in Chinese women. Although topical therapies are the mainstay treatment, lasers are being used increasingly to treat pigmented lesions. Laser treatment of melasma is however still controversial. This is because lasers have not been able to produce complete clearance of melasma and recurrence rates are high. Laser treatments also cause complications such as hypopigmentation and post-inflammatory hyperpigmentation. In this article, we report on a novel technique using a combination of fractional 2940-nm Er:YAG and 1064-nm Q-switched Nd:YAG lasers. We achieved a rapid improvement in two cases of melasma in Chinese type III skin. The improvement was seen rapidly within a month of treatment. Follow-up at 6 months showed sustained results with no complications. This novel technique is able to safely confer excellent and sustained clearance within a short treatment time.

  6. 1.8kW laser diode pumped YAG laser; Shutsuryoku 1.8kW no handotai laser reiki YAG laser



    Toshiba Corporation, as a participant in Ministry of International Trade and Industry`s `photon measurement and processing technology project` since August, 1997, is engaged in the development of an energy-efficient LD (laser diode) pumped semiconductor YAG (yttrium-aluminum-garnet) laser device to be used for welding and cutting. It is a 5-year project and the goal is a mean output of 10kW and efficiency of 20%. In this article, a simulation program is developed which carries out calculation about element technology items such as the tracking of the beam from the pumping LD and the excitation distribution, temperature distribution, thermal stress distribution, etc., in the YAG rod. An oscillator is constructed, based on the results of the simulation, and it exhibits a world-high class continuous laser performance of a 1.8kW output and 13% efficiency. The record of 13% efficiency is five times higher than that achieved by the conventional lamp-driven YAG laser device. (translated by NEDO)

  7. Evaluation of phase stresses of Al sub 2 O sub 3 /YAG binary MGC by synchrotron radiation. Residual stress states and stress behavior of YAG phase

    Suzuki, H; Akita, K; Yoshioka, Y; Waku, Y


    Melt Growth Composite material (MGC) consists of multiple single crystal with fine entangled in three dimensional network structures. The MGCs are thermally stable and have higher creep resistance. Furthermore, the flexural strength at room temperature can be maintained almost up to the melting point. In this study, in order to discuss the generation mechanism of residual stress in an Al sub 2 O sub 3 /Y sub 3 Al sub 5 O sub 1 sub 2 (YAG) binary MGC, the residual stresses of YAG phase were measured by X-rays from synchrotron radiation source. We used a method for stress determination of single crystal by using a position sensitive proportional counter (PSPC) system and a specimen-oscillating device. Lattice strains of left brace 4 6 10 right brace in the YAG phase were measured. The residual stresses were from 40 to 120 MPa in tension in the longitudinal direction which corresponds to the solidification direction, 80MPa in compression in the thickness direction, and 70MPa in tension in the width direction. Si...

  8. Influence of Nd:YAG or Er:YAG laser surface treatment on microtensile bond strength of indirect resin composites to resin cement. Lasers surface treatment of indirect resin composites.

    Caneppele, T M F; de Souza, A C Oliveira; Batista, G R; Borges, A B; Torres, C R G


    This study evaluated the influence of the surface pretreatment of indirect resin composite (Signum, Admira Lab and Sinfony) on the microtensile bond strength of a resin cement. Sixty samples made of each brand were divided into 6 groups, according to surface treatment: (1) control; (2) controlled-air abrasion with Al2O3; (3) Er:YAG Laser 200 mJ, 10 Hz, for 10s; (4) Er: YAG Laser 300 mJ, 10 Hz, for 10 s; (5) Nd:YAG 80 mJ, S15Hz for 1 min; (6) Nd:YAG 120mJ, 15 Hz for 1 min. After treatments, all the groups received an application of 37% phosphoric acid and adhesive. The pair of blocks of the same brand were cemented to each other with dual resin cement. The blocks were sectioned to obtain resin-resin sticks (1 x1 mm) and analyzed by microtensile bond testing. The bond strength values were statistically different, irrespective of the surface treatment performed, with highest values for Sinfony (43.81 MPa) and lowest values for Signum (32.33 MPA). The groups treated with the Nd:YAG laser showed the lowest bond strength values and power did not interfere in the results, both for Nd:YAG laser and Er:YAG. Controlled-air abrasion with Al203 is an efficient surface treatment method and the use of the Nd:YAG and Er:YAG lasers reduced bond strength, irrespective of the intensity of energy used.

  9. Emission spectra of YAG:Er3+ under pulse laser-thermal excitation

    Marchenko, V. M.; Shakir, Yu. A.


    Spectra and kinetics of emission of YAG:0.5% Er3+ monocrystal in visible and NIR ranges were investigated under laser-thermal excitation by the pulses of CO2 laser of 100 ns duration at wavelength λ = 10,6 μμm. Kinetics of integral emission was interpreted.

  10. Fabrication, optical and scintillation properties of transparent YAG:Ce ceramics

    Osipov, V. V.; Ishchenko, A. V.; Shitov, V. A.; Maksimov, R. N.; Lukyashin, K. E.; Platonov, V. V.; Orlov, A. N.; Osipov, S. N.; Yagodin, V. V.; Viktorov, L. V.; Shulgin, B. V.


    Highly transparent YAG:Ce ceramics (transmission of 72-82% for 2-mm-thick samples in 550-900 nm wavelength range) were fabricated by solid-state reactive sintering using a mixture of Ce2xY2-2xO3 (x = 0.001, 0.01, 0.03, and 0.05) and Al2O3 nanopowders synthesized by laser ablation with an additional round of pre-calcining before compaction. The synthesized YAG:Ce ceramic materials showed intense luminescence with a maximum at 525-545 nm. The measured absolute light yields of the synthesized YAG:Ce ceramics were 18-21 photon/MeV for 1-5 at.% Ce and 5 photon/MeV for 0.1 at.% Ce. The energy resolutions of the fabricated thin ceramic samples (2 mm) under 662 keV gamma ray were measured to be 10-15%. The decay curves of scintillations consisted of two components with the decay times depending on the Ce3+ concentration. The sample doped with 5 at.% of Ce exhibited the main fast component with 26 ns decay time. The measured data was compared to that of YAG:Ce and well-known CsI:Tl single crystal scintillators. The influence of dopant concentration on the optical, luminescence and scintillation properties was discussed.

  11. 407 W End-pumped Multi-segmented Nd:YAG Laser.

    Kracht, Dietmar; Wilhelm, Ralf; Frede, Maik; Dupré, Klaus; Ackermann, Lothar


    A composite crystalline Nd:YAG rod consisting of 5 segments with different dopant concentrations for high power diode end-pumping is presented. A maximum laser output power of 407 W with an optical-to-optical efficiency of 54 % was achieved by longitudinal pumping with a high power laser diode stack.

  12. Nd:YAG solid-state ring laser pumped by a light-emitting diode

    Belozerov, S.A.; Kornienko, L.S.; Kravtsov, N.V.; Kuratev, I.I.; Rusakov, S.I.; Stel' makh, M.F.; Shelaev, A.A.; Shelaev, A.I.


    This letter reports lasing in an Nd:YAG solid-state laser (lambda = 1.06 pumped either in pulses or continuously by a light-emitting diode. We report the first experimental results on this laser.(AIP)

  13. Neodymium:YAG treatment of interlenticular opacification in a secondary piggyback case.

    Gayton, J L; Van der Karr, M; Sanders, V


    Interlenticular opacification (ILO) developed 7 months after secondary acrylic piggyback lens implantation in which the anterior lens was placed in the bag. This resulted in glare and a hyperopic shift. Treating the ILO with the neodymium:YAG laser successfully reduced the glare and corrected the hyperopic shift.

  14. Ureteropyeloscopy and homium: YAG laser lithotripsy for treatment of ureteral calculi (report of 356 cases)

    Wu, Zhong; Din, Qiang; Jiang, Hao-wen; Zen, Jing-cun; Yu, Jiang; Zhang, Yuanfang


    Objective: To evaluate the efficacy and safety of holmium YAG laser lithotripsy for the treatment of ureteral calculi. Methods: A total of 356 patients underwent ureteropyeloscopic lithotripsy using holmium YAG laser with a semirigid uretesopyeloscope, 93 upper, 135 middle, and 128 lower ureteral stones were treated. Results: The overall successful fragmentation rate for all ureteral stones in a single session achieved 98% (349/356). The successful fragmentation rate stratified by stone location was 95% 88/93 in the upper ureter, 99% (134/135) in the mid ureter , and 99%(127/128) in the distal ureter. 12 cases with bilateral ureteral stones which caused acute renal failure and anuria were treated rapidly and effectively by the holmium YAG laser lithotripsy. No complications such as perforation and severe trauma were encountered during the operations. 2 weeks 17months (with an average of 6.8 month ) follow up postoperatively revealed that the overall stone-free rate was 98%(343/349) and no ureteral stenosis was found. Conclusions Holmium YAG laser lithotripsy is a highly effective, minimally invasive and safe therapy for ureteral calculi. It is indicated as a first choice of treatment for patients with ureteral calculi, especially for the ones with mid- lower levels of ureteral calculi.

  15. Enamel surface roughness and dental pulp response to coaxial carbon dioxide-neodymium: YAG laser irradiation.

    Arcoria, C J; Steele, R E; Wagner, M J; Judy, M M; Matthews, J L; Hults, D F


    The purpose of this study was to evaluate the effect of a coaxial carbon dioxide/neodymium:yttrium aluminium garnet laser beam on enamel surface roughness and the dental pulps of mongrel dogs. In four dogs, four maxillary left posterior teeth were irradiated at 16 cm source-tooth distances. Two teeth were irradiated with 16 W CO2/16 W Nd:YAG and the remaining two with 16 W CO2/40 W Nd:YAG. Two maxillary right teeth were untreated controls. In addition, mandibular premolars were irradiated at the same distance and power levels, extracted, and analysed for surface roughness. Significant differences in surface roughness were found between control samples and either power level, but not between enamel surfaces at the two power levels. Maxillary teeth were removed at 10 days postoperatively, sectioned and stained (H & E). The reaction of pulpal cells to irradiation was scored. Data analysis revealed statistically significant differences between the control and lower power Nd:YAG groups and between the control and higher power Nd:YAG groups. The difference in pulpal response between both laser groups approached significance.

  16. Er:YAG Laser: A New Technical Approach to Remove Torus Palatinus and Torus Mandibularis

    J. P. Rocca


    Full Text Available Objective. The aim of this study was to assess the ability of Er:YAG laser to remove by excision torus mandibularis and to smooth torus palatinus exostosis. Materials and Methods. Torus mandibularis (TM and torus palatinus (TP were surgically eliminated via the Er:YAG laser using the following parameters: TM: output power ranging from 500 to 1000 mJ, frequency from 20 to 30 Hz, sapphire tips (diameter 0.8 mm, air-water spray (ratio 5/5, pulse duration 150 μsec, fluence ranging from 99592 J/cm2 to 199044,586 J/cm2. TP: a peeling technique was used to eliminate TP, as excision by slicing being impossible here. Results. TM: excision was obtained after 12730 pulses. TP: smoothing technique took more time compared with excision. Once peeling was considered to be accomplished, the use of a surgical rasp was necessary to eliminate bone spicules that could delay the wound to heal in good conditions. Conclusion. Er:YAG excision (TM or Er:YAG peeling (TP are safe clinical techniques easy to practice even if the time required for excision or surface smoothing is more than the time required with bony burs and high speed instruments.

  17. Er:YAG Laser: A New Technical Approach to Remove Torus Palatinus and Torus Mandibularis

    Rocca, J. P.; Raybaud, H.; Merigo, E.; Vescovi, P.; Fornaini, C.


    Objective. The aim of this study was to assess the ability of Er:YAG laser to remove by excision torus mandibularis and to smooth torus palatinus exostosis. Materials and Methods. Torus mandibularis (TM) and torus palatinus (TP) were surgically eliminated via the Er:YAG laser using the following parameters: TM: output power ranging from 500 to 1000 mJ, frequency from 20 to 30 Hz, sapphire tips (diameter 0.8 mm), air-water spray (ratio 5/5), pulse duration 150 μsec, fluence ranging from 99592 J/cm2 to 199044,586 J/cm2. TP: a peeling technique was used to eliminate TP, as excision by slicing being impossible here. Results. TM: excision was obtained after 12730 pulses. TP: smoothing technique took more time compared with excision. Once peeling was considered to be accomplished, the use of a surgical rasp was necessary to eliminate bone spicules that could delay the wound to heal in good conditions. Conclusion. Er:YAG excision (TM) or Er:YAG peeling (TP) are safe clinical techniques easy to practice even if the time required for excision or surface smoothing is more than the time required with bony burs and high speed instruments. PMID:22792500

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

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


    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...

  19. Using transurethral Ho:YAG-laser resection to treat urethral stricture and bladder neck contracture

    Bo, Juanjie; Dai, Shengguo; Huang, Xuyuan; Zhu, Jing; Zhang, Huiguo; Shi, Hongmin


    Objective: Ho:YAG laser had been used to treat the common diseases of urinary system such as bladder cancer and benign prostatic hyperplasia in our hospital. This study is to assess the efficacy and safety of transurethral Ho:YAG-laser resection to treat the urethral stricture and bladder neck contracture. Methods: From May 1997 to August 2004, 26 cases of urethral stricture and 33 cases of bladder neck contracture were treated by transurethral Ho:YAG-laser resection. These patients were followed up at regular intervals after operation. The uroflow rate of these patients was detected before and one-month after operation. The blood loss and the energy consumption of holmium-laser during the operation as well as the complications and curative effect after operation were observed. Results: The therapeutic effects were considered successful, with less bleeding and no severe complications. The Qmax of one month postoperation increased obviously than that of preoperation. Of the 59 cases, restenosis appeared in 11 cases (19%) with the symptoms of dysuria and weak urinary stream in 3-24 months respectively. Conclusions: The Ho:YAG-laser demonstrated good effect to treat the obstructive diseases of lower urinary tract such as urethral stricture and bladder neck contracture. It was safe, minimal invasive and easy to operate.

  20. Features of gallstone and kidney stone fragmentation by IR pulsed YAG:Nd laser radiation

    Batishche, Sergei A.


    It is shown that infra-red ((lambda) equals 1064 nm) long pulse (approximately 100 microsecond(s) ) radiation of YAG:Nd laser, operating in free generation regime, effectively fragments gallstones, urinary calculus and kidney stones. The features of the mechanism of this process are investigated.

  1. Investigation of two-frequency Nd{sup 3+} : YAG laser

    Arapov, Yu D; Ivanov, A F; Kas' yanov, I V; Magda, L E [E.I. Zababakhin All-Russian Scientific-Research Institute of Technical Physics, Russian Federal Nuclear Centre, Snezhinsk, Chelyabinsk region (Russian Federation)


    A repetitively pulsed two-frequency laser is developed. Pulsed operation of a laser based on a Nd{sup 3+} : YAG crystal with simultaneous amplification of radiation at two wavelengths in a single-pass amplifier is studied. (laser optics 2012)

  2. High-efficiency diode-pumped femtosecond Yb:YAG ceramic laser

    Zhou, Binbin; Wei, Z.Y.; Zou, Y.W.


    A highly efficient diode-end-pumped femtosecond Yb:yttrium aluminum garnet (YAG) ceramic laser was demonstrated. Pumped by a 968 nm fiber-coupled diode laser, 1.9 W mode-locked output power at a repetition rate of 64.27 MHz was obtained with 3.5 W absorbed pump power, corresponding to a slope...

  3. Parametric Optimization of Nd:YAG Laser Beam Machining Process Using Artificial Bee Colony Algorithm

    Rajarshi Mukherjee


    Full Text Available Nd:YAG laser beam machining (LBM process has a great potential to manufacture intricate shaped microproducts with its unique characteristics. In practical applications, such as drilling, grooving, cutting, or scribing, the optimal combination of Nd:YAG LBM process parameters needs to be sought out to provide the desired machining performance. Several mathematical techniques, like Taguchi method, desirability function, grey relational analysis, and genetic algorithm, have already been applied for parametric optimization of Nd:YAG LBM processes, but in most of the cases, suboptimal or near optimal solutions have been reached. This paper focuses on the application of artificial bee colony (ABC algorithm to determine the optimal Nd:YAG LBM process parameters while considering both single and multiobjective optimization of the responses. A comparative study with other population-based algorithms, like genetic algorithm, particle swarm optimization, and ant colony optimization algorithm, proves the global applicability and acceptability of ABC algorithm for parametric optimization. In this algorithm, exchange of information amongst the onlooker bees minimizes the search iteration for the global optimal and avoids generation of suboptimal solutions. The results of two sample paired t-tests also demonstrate its superiority over the other optimization algorithms.

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

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


    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 given

  5. Effects of Nd:YAG laser pulpotomy on human primary molars.

    Liu, Jeng-fen


    The purpose of this study was to compare the effects of Nd:YAG laser pulpotomy to formocresol pulpotomy on human primary teeth. Patients with a primary tooth that required pulpotomy because of pulpal exposure to caries, were selected for this study. After removal of coronal pulpal tissue, Nd:YAG laser at 2 W, 20 Hz, 100 mJ or a 1:5 dilution of formocresol was introduced into the canal orifice for complete hemostasis. IRM paste was then placed over the pulp stump, and the tooth was restored either with composite resin or stainless steel crown. Sixty-eight teeth were treated with Nd:YAG laser and followed up for 6 to 64 months. Clinical success was achieved in 66 out of the 68 teeth (97 %), and 94.1 % were radiographically successful. In the control group, 69 primary molars were treated with formocresol and followed up for 9 to 66 months; 85.5 and 78.3% achieved clinical and radiographic success, respectively. The success rate of Nd:YAG laser pulpotomy was significantly higher than that of formocresol pulpotomy. The permanent successors of the laser-treated teeth erupted without any complications.

  6. The Construction of a Nd:YAG Laser and Observation of the Output.


    Osternik, L. M., Thermal Effects in a Nd:YAG Laser, J. Appl. Phys. 41,-6-1 . 18. Koechner, W., p. 353. 19. Svelto , 0., Principles of Lasers, p. 152...Plenum Press, New York and London, 1982. 20. Svelto , 0., p. 154. A;6 -9 ;:..: .-,-. .- - - .- . • - -- . . . . . . . . . .. .. . . . . . .. . 9.’’, a

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

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


    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

  8. Cutting and coagulation during intraoral soft tissue surgery using Er: YAG laser.

    Onisor, I; Pecie, R; Chaskelis, I; Krejci, I


    To find the optimal techniques and parameters that enables Er:YAG laser to be used successfully for small intraoral soft tissue interventions, in respect to its cutting and coagulation abilities. In vitro pre-tests: 4 different Er:YAG laser units and one CO2 unit as the control were used for incision and coagulation on porcine lower jaws and optimal parameters were established for each type of intervention and each laser unit: energy, frequency, type, pulse duration and distance. 3 different types of intervention using Er:YAG units are presented: crown lengthening, gingivoplasty and maxillary labial frenectomy with parameters found in the in vitro pre-tests. The results showed a great decrease of the EMG activity of masseter and anterior temporalis muscles. Moreover, the height and width of the chewing cycles in the frontal plane increased after therapy. Er:YAG is able to provide good cutting and coagulation effects on soft tissues. Specific parameters have to be defined for each laser unit in order to obtain the desired effect. Reduced or absent water spray, defocused light beam, local anaesthesia and the most effective use of long pulses are methods to obtain optimal coagulation and bleeding control.

  9. 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

    Verlangieri, Eleonora Jaeger


    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)

  10. Comparison of preparation speed of Er:YAG laser and conventional drilling machine

    Jelinkova, Helena; Dostalova, Tatjana; Dolezalova, Libuse; Krejsa, Otakar; Hamal, Karel; Kubelka, Jiri; Prochazka, Stanislav


    Clinical tests of the caries treatment with a Er:YAG laser system have been very promising. The problem of the Er:YAG laser drilling machine is the speed of preparation. It is not possible to increase the laser energy and repetition rate because this process is directly connected with temperature elevation. Therefore attention has been paid to define the differences between the classical and the laser drilling effect with a safe but effective laser energy and repetition rate. For the experiment, an Er:YAG laser drilling machine with an articulated arm was designed. Thirty samples of extracted human teeth were cut by both this system and classical drilling machine. The circumference, area and structure of surface sections were observed and analyzed. From the comparison of the measured time of preparation significant differences followed from the time of preparation. The time of preparation related to 1 mm2 of the cut surface was 5.42 sec for the Er:YAG laser machine and 0.66 sec for the classical method. From this comparison it follows that the laser system is 8 times slower than the classical preparation technique. In both cases the roughness of the surface analyzed by SCAN was found similar. Also, there were no differences between the distribution of the elements, especially calcium and phosphorus.

  11. Stable mode-locking in an Yb:YAG laser with a fast SESAM

    Guifang Ju(居桂方); Lu Chai(柴路); Qingyue Wang(王清月); Zhigang Zhang(张志刚); Yonggang Wang(王勇刚); Xiaoyu Ma(马骁宇)


    Stable mode-locking in a diode-pumped Yb:YAG laser was obtained with a very fast semiconductor saturable absorber mirror (SESAM). The pulse width was measured to be 4 ps at the central wavelength of 1047 nm. The average power was 200 mW and the repetition rate was 200 MHz.

  12. Study on 660-nm quasi-continuous-wave intracavity frequency-doubled Nd:YAG laser

    Tao Wang(王涛); Jianquan Yao(姚建铨); Baigang Zhang(张百钢); Guiyan Zang(臧贵艳); Peng Wang(王鹏); Yizhong Yu(于意仲)


    A quasi-continuous-wave intracavity frequency-doubled Nd:YAG laser which operates at 660 nm is studied.By using a flat-flat laser cavity, 2 Kr-lamps, KTP crystal and an acousto-optically Q-switch, 2-W outputpower at 660 nm is obtained. The relationship between laser cavity length and output power is analyzed.

  13. Study on CW Nd:YAG infrared laser at 1319 nm

    Tao Wang (王涛); Jianquan Yao (姚建铨); Guojun Yu (禹国俊); Peng Wang (王鹏); Xifu Li (李喜福); Yizhong Yu (于意仲)


    A continuous wave (CW) Nd:YAG infrared laser at 1319 nm is reported in this paper. The energy level of 1319-nm wave was analyzed. The repression of 1064-nm lasing and enhancement of 1319-nm output power were discussed. Mirror coating and cavity structure were studied and a maximum CW output power of 43W at 1319 nm was achieved in experiments.

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

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


    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

  15. Local structure of the Ce3+ ion the yellow emitting phosphor YAG:Ce

    Ghigna, P.; Pin, S.; Ronda, C.; Speghini, A.; Piccinelli, F.; Bettinelli, M.


    The local structure of the Ce3+ ion in the yellow emitting YAG:Ce phosphor has been studied by Extended X-ray Absorption Fine Structurespectroscopy in the 300−20 K temperature range. It has evidenced that the dopant Ce3+ replaces Y3+ in the garnet structure, giving rise to a significant expan

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

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


    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 given

  17. Nd:YAG laser treatment of herpes and aphthous ulcers: a preliminary study

    Parkins, Frederick M.; O'Toole, Thomas J.; Yancey, John M.


    Previously herpes labialis and recurrent aphthous ulcers have not been successfully treated. A preliminary study with a pulsed Nd:YAG laser evaluated the results with a protocol of four minute non-contact exposures for both types of lesions. Most patients experienced relief of symptoms. The progress of herpes lesion was halted and aphthous lesions became desensitized.

  18. Preparation, characterization and photoluminescent studies of Cr and Nd co-doped Ce:YAG compounds

    Naik, S.R. [Department of Chemistry, Goa University, Goa 403206 (India); Shripathi, T. [UGC-DAE Consortium for Scientific Research, Khandwa Road, Indore 452017 (India); Salker, A.V., E-mail: [Department of Chemistry, Goa University, Goa 403206 (India)


    Sol–gel autocombustion as an efficient method in the preparation of monophasic Cr and Nd co-doped Ce:YAG compounds has been demonstrated. A reduction in the formation temperature to 1000 °C as compared to the classical ceramic method has been effectively shown. Monophasic formation of the compounds has been confirmed from the X-ray diffraction study which is equally supported by the Raman spectroscopy. The TEM analysis confirms the formation of submicron sized particles (around 100 nm) which are equally supported by SEM micrographs revealing the granular morphology for the compounds. Photoluminescence (excitation) studies carried out for the compounds at 468, 341 and 685 nm display excellent emission intensity for the compounds with similar emission pattern pointing towards a common emission centre in all the three cases. Decrease in Ce{sup 3+} emission intensity for the Cr and Nd co-doped Ce:YAG is observed. Energy transfer mechanism is suggested for the lowering of emission intensity confirming the activity of Ce{sup 3+} as a sensitizer. - Highlights: • Nd and Cr co-doped Ce:YAG are prepared by the sol–gel autocombustion. • Monophasic preparation proves the method to be efficient. • Formation of particles around 100 nm is confirmed from TEM. • Singly doped Ce:YAG exhibits maximum emission intensity. • Energy transfer between ions in excited state is in co-doped samples.

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

    van Nimwegen, S.A.


    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 vitro

  20. Er:YAG laser ablation: 5-11 years prospective study

    Dostalova, Tatjana; Jelinkova, Helena; Nemec, Michal; Sulc, Jan; Miyagi, Mitsunobu


    The Er:YAG laser at 2940 nm has been proposed for use in dental cavity preparation and removal of carious enamel and dentin. The purpose of the present study was to determine the effect of the Er:YAG laser ablation in treating dental caries after a period from 5 to 11 years. For this study, 133 cavities were chosen, and for their reparation of it the three restorative materials were used. Baseline examination was made in the following intervals: one week, 1 year, and from 5 to 11 years after cavity preparation and placement of filling material. Clinical assessments were carried out in accordance with the US Public Health Service System. The follow-up included: the marginal ridge, marginal adaptation, anatomic form, caries, color match, cavo surface margin discoloration, surface smoothness, and postoperative sensitivity. Er:YAG laser ablation is an excellent method for treating frontal teeth, i.e., incisors, canines, premolars, and initial occlusal caries of molars. However, visual control of non-contact therapy is necessary. Er:YAG laser ablation is safe, and it strongly reduces pain. The laser treatment markedly decreases the unpleasant sound and vibration.


    Galia G. Zhegova


    Full Text Available The aim of this study was to evaluate adolescents’ acceptance and pain perception of Er-YAG laser preparation in comparison to conventional mechanical preparation. Material and methods: Forty four adolescents between the age of 16 and 18 years with bilateral matched pairs of carious permanent molars participated in this study. In each patient one of the 2 cavities was prepared conventionally, the other with the Er-YAG laser. All cavities were restored with light-cured composite resin following the application of acid etch and a bonding agent. The patients were instructed to rate pain (sensitivity during treatment according to visual analogue scale and to decide which method they would prefer for their future caries treatment. Results: The patients rated lower pain perception during laser treatment. It was found that 86.36 % of the adolescents indicated that they would prefer the Er:YAG laser preparation for further caries treatment. Conclusion: The application of the Er-YAG laser for carious tissue removal, compared to conventional mechanical preparation, is perceived as more comfortable and the adolescents prefer it for a future treatment.

  2. In vitro effects of Nd:YAG laser radiation on blood: a quantitative and morphologic analysis

    Borrero, E.; Rosenthal, D.; Otis, J.B.


    Use of the Neodymium: yttrium -aluminum -garnet (Nd:YAG) laser to recanalize stenosed arteries may require delivery of the beam through blood. To assess the degree of hemolysis and debris formation, 54 samples of citrated whole blood were exposed to Nd:YAG laser radiation of varying powers (10, 20 and 30 watts) and duration (1, 2.5 and 5 seconds). Compared to control samples which were not subjected to laser light, there was no significant decrease in hematocrit (41 to 40.5 +/- 5%), hemoglobin concentration (13.8 to 13.8 +/- .06 g/1OO ml), or increase in free hemoglobin concentration. Debris weight (from .45 +/- .002 to .45 +/- .002 mg), as well as the white blood cell count, was also not significantly changed (from 5,400 to 5,200 +/- 240 WBC/cm). Light microscopy examination of debris from samples of whole blood, washed erythrocytes, and platelet-rich plasma subjected to the laser at 30 watts for five seconds failed to demonstrate the presence of membrane denaturation of blood elements, as compared with the morphologic changes observed in whole blood samples exposed to a hot tip rather than Nd:YAG laser radiation. Nd:YAG laser can be used intravascularly without fear of hemolysis or debris micro-embolization up to a power of 30 watts for five seconds.

  3. Synthesis of highly porous Al2O3-YAG composite ceramics

    Egelja Adela


    Full Text Available Al2O3-YAG composite was obtained by sintering of porous Al2O3 preforms infiltrated with water solution of aluminium nitrate nonahydrate, Al(NO33•9H2O and yttrium nitrate hexahydrate, Y(NO33•6H2O. Al2O3 preforms with porosity varying from 26 to 50% were obtained after sintering at temperature ranging from 1100 to 1500°C. Sintering of the infiltrated Al2O3 preforms led to formation of YAG particles due to reaction between Y2O3 and Al2O3 at high temperature. It was found that variation of porosity of alumina preforms and sintering temperature is an effective way to fabricate Al2O3-YAG composite with an unusual combination of properties. Open porosity was in the range 15-35%, specific surface was 0.6-6.1 m2/g, pore size was 150-900 nm whereas compressive strength was from 50 to 250 MPa. The effect of sintering temperature on YAG formation and phase composition were investigated using X-ray diffractometry whereas microstructure of the composite was analysed by scanning electron microscopy. [Projekat Ministartsva nauke Republike Srbije, br. 45012

  4. Controlled emission and coupling of small-size YAG:Ce3+ nanocrystals to gold nanowire

    Birowosuto, M D; Donega, C de Mello; Meijerink, A


    We report a controlled emission of Ce3+ ions inside single Yttrium Aluminum Gar- net Y3Al5O12 (YAG:Ce3+) nanocrystals with a diameter of 22 +- 10 nm as a result of a coupling of a surface plasmon mode propagating along single gold nanowire (NW). From the PL images, the intensity for single YAG:Ce3+ nanocrystals in the proximity of the single gold NW increases by a factor of two in comparison with that without the NW. Also, we observe a maximum of 3.8-fold emission rate en- hancements for the single nanocrystal close to the single gold NW. The emission rate enhancements of YAG:Ce3+ nanocrystals are two folds the enhancements of 100-nm fluorescent nanospheres. This value is in agreement with the calculation of a combi- nation from the analytical scattering model and boundary element method (BEM). We also confirm that the small size light sources are more efficient for the emission rate enhancements. Thus, the controlled emission of small YAG:Ce3+ nanocrystals with the perfect photostabilities will pave the way ...

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

    van Nimwegen, S.A.


    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

  6. Citrate sol-gel combustion preparation and photoluminescence properties of YAG:Ce phosphors

    ZHANG Le; LU Zhou; ZHU Jinzhen; YANG Hao; HAN Pengde; CHEN Yan; ZHANG Qitu


    Yellow-emitting YAG:Ce3+ nanocrystalline phosphors were prepared by citrate sol-gel combustion method using citric acid as the fuel and chelating agent.The influence of mole ratio of citric acid to metallic ions (MRCM),pH value of the solution,calcination temperature and Ce-doped concentration on the structures and properties of as-prepared powders were investigated in detail.Higher crystallinity and better luminescence performance powders were obtained at MRCM=2,pH=3 and the calcination temperature of 1200 ℃.The phosphors exhibited the characteristic broadband visible luminescence of YAG:Ce.The optimum concentration of Ce3+ was 1.0 mol.%,and the concentration quenching was derived from the reciprocity between electric dipole and electric quadrupole (d-q).Especially,the pH value of the solution was a key factor to obtain a stable sol-gel system and then obtain pure and homogeneous rare earth ions doped YAG phosphors at a lower temperature.The Y3Al5O12:Ce0.03 phosphor with optimized synthesis-condition and composition had a similar luminescence intensity with the commercial phosphor YAG:Ce.

  7. The effect of a pulsed Nd:YAG laser in non-surgical periodontal therapy

    Slot, D.E.; Kranendonk, A.A.; Paraskevas, S.; van der Weijden, F.


    Background: Laser treatment may serve as an alternative or adjunctive treatment to conventional mechanical therapy in periodontics. The neodymium-doped:yttrium, aluminum, and garnet (Nd:YAG) laser has been used in periodontics. Systematic reviews aid in clinical decision-making. The aim of this stud

  8. Implant Surface Temperature Changes during Er:YAG Laser Irradiation with Different Cooling Systems.

    Abbas Monzavi


    Full Text Available Peri-implantitis is one of the most common reasons for implant failure. Decontamination of infected implant surfaces can be achieved effectively by laser irradiation; although the associated thermal rise may cause irreversible bone damage and lead to implant loss. Temperature increments of over 10ºC during laser application may suffice for irreversible bone damage.The purpose of this study was to evaluate the temperature increment of implant surface during Er:YAG laser irradiation with different cooling systems.Three implants were placed in a resected block of sheep mandible and irradiated with Er:YAG laser with 3 different cooling systems namely water and air spray, air spray alone and no water or air spray. Temperature changes of the implant surface were monitored during laser irradiation with a K-type thermocouple at the apical area of the fixture.In all 3 groups, the maximum temperature rise was lower than 10°C. Temperature changes were significantly different with different cooling systems used (P<0.001.Based on the results, no thermal damage was observed during implant surface decontamination by Er:YAG laser with and without refrigeration. Thus, Er:YAG laser irradiation can be a safe method for treatment of periimplantitis.

  9. Selective removal of carious lesion with Er:YAG laser followed by dentin biomodification with chitosan.

    Curylofo-Zotti, Fabiana A; Tanta, Gabriela Solano; Zucoloto, Miriane Lucindo; Souza-Gabriel, Aline E; Corona, Silmara A M


    The aim of this study was to evaluate the effect of Er:YAG laser for selective removal of carious lesion, followed by biomodification with chitosan gel where the subsurface microhardness, chemical composition, and morphological changes of the residual caries-affected dentin were examined. Artificial dentinal lesions were created by pH-cycling method (14 days) in 104 bovine specimens (5 × 5 mm). Specimens were randomly divided according to the carious removal method: bur (low-speed handpiece) or Er:YAG laser (250 mJ/4 Hz). Specimens were treated with 35% phosphoric acid and were subdivided into two groups according to dentin biomodification: without chitosan (control) and 2.5% chitosan. Forty specimens were restored with an adhesive system and composite resin. Subsurface microhardness tests were performed in sound dentin, caries-affected dentin, residual caries-affected dentin, and after the restoration. The other 64 specimens were subjected to SEM-EDS atomic analysis. Data were statistically analyzed (p carious lesions with Er:YAG laser (p  0.05). SEM analysis showed morphological changes on residual caries-affected dentin (p > 0.05). The selective removal of carious dentin with Er:YAG laser increased microhardness of residual caries-affected dentin, changing its surface morphology and chemical composition. The biomodification with chitosan did not influence the structural and chemical composition of residual caries-affected dentin.

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

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


    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.

  11. Taladrado de pizarra mediante láser de Nd:Yag

    Larosi, M. S.


    Full Text Available A serie of experiments to investigate the feasibility of using a Nd: YAG laser to process slate tiles and the influence of the processing parameters have been undertaken. The objective of this work is to investigate the capabilities of a Nd:YAG pulsed laser to drill tiny holes in slate tiles, in order to produce a better quality drilled slate tile in a reduced time. Part of the results obtained in a systematic study about the influence of the processing parameters, such as average power, pulse width, frequency, pressure and type of assisting gas is presented.

    Se ha desarrollado una serie de experimentos para investigar la viabilidad del uso de un láser de Nd: YAG para el procesamiento de piezas de pizarra, así como los parámetros que más afectan al proceso. El objetivo concreto de este trabajo es investigar la capacidad de un láser de Nd:YAG pulsado para taladrar orificios de pequeño diámetro en láminas de pizarra, con el fin de obtener mejor calidad de taladrado en un tiempo reducido. Se presenta parte de los resultados obtenidos en un estudio sistemático de la influencia de los parámetros de procesamiento en la forma del orificio, tales como, potencia, duración de pulso, frecuencia, presión y tipo de gas de aportación.

  12. Dacriocistorrinostomia transnasal vídeo-endoscópica com Nd: YAG laser e diodo laser Endonasal dacriocystorhinosthomy with Nd: YAG laser and diodo laser

    Eurípedes da Mota Moura


    Full Text Available OBJETIVO: Avaliar a técnica de dacriocistorrinostomia para o tratamento das obstruções do ducto lacrimo-nasal, pela vídeo-endoscopia transnasal com ND:YAG "laser" e Diodo "laser". MÉTODOS: Cinqüenta e uma cirurgias de dacriocistorrinostomia transnasal vídeo-endoscópica com Nd:YAG "laser" e Diodo "laser" foram realizadas em 42 pacientes, 36 do sexo feminino e 6 do masculino com idade variando de 3 a 92 anos; idade média 52,3 anos, no período de abril 1997 a fevereiro 2003. RESULTADO: O índice de sucesso na remissão dos sintomas foi de 92,15%. Em todos os pacientes era feita entubação bicanalicular com silicone e mantida por seis a oito semanas. CONCLUSÕES: A técnica empregada mostrou-se eficaz no tratamento das obstruções do ducto lacrimo-nasal. Não se observou diferença de resultados quando se utilizou Nd:YAG e Diodo "laser". O pós-operatório em todos os casos foi confortável e sem hemorragias.PURPOSE: To evaluate the technique of dacryocysthorrinosthomy for the treatment of nasolacrimal duct obstruction, by transnasal endoscopic video-assisted approach with Nd:YAG laser and diode laser. METHODS: Fifty one surgeries dacryocysthorrinostomy transnasal endoscopic video assisted were performed in 42 patients, 36 females, 6 males, aged between 3 and 92 years, mean age 52.3 years, in the period of April 1997 to February 2003. RESULT: The surgery successfully relieved lacrimal duct obstruction in 92.15% of the patients. CONCLUSION: The technique was efficient for the treatment of nasolacrimal obstruction. In all patients bicanalicular silicone stents were inserted at the time of surgery and removed after six to eight weeks. There is no difference in the results between Nd:YAG and diode laser. The postoperative period in all cases was comfortable and there was no hemorrhage.

  13. 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

    Oliveira, Rodrigo Guerra de


    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

  14. Pulsed dye laser versus Nd:YAG laser in the treatment of plantar warts: a comparative study.

    El-Mohamady, Abd El-Shakor; Mearag, Ibrahim; El-Khalawany, Mohamed; Elshahed, Ahmed; Shokeir, Hisham; Mahmoud, Anas


    Plantar warts are common viral infection that are usually challenging in treatment. Conventional treatment methods are usually invasive, have low efficacy, and need long recovery periods. In this study, we compared pulsed dye laser (PDL) and neodymium yttrium aluminum garnet (Nd:YAG) lasers in the treatment of recalcitrant plantar warts. The study included 46 patients with multiple plantar warts. In each patient, lesions were divided into two groups: one treated with Nd:YAG (spot size, 7 mm; energy, 100 J/cm(2); and pulse duration, 20 ms) and the other with PDL (spot size, 7 mm; energy, 8 J/cm(2); and pulse duration, 0.5 ms). Laser sessions were applied every 2 weeks with maximum of six sessions. The study included 63% males and 37% females with a mean age of 29.6 ± 7.34 years. The cure rate was 73.9% with PDL with no significant difference (p = 0.87) from Nd:YAG (78.3%). The number of sessions required was more in PDL (mean, 5.05 ± 0.2) compared with Nd:YAG (mean, 4.65 ± 0.5) but without significant difference. Complications were significantly higher with Nd:YAG (43.5%) compared with PDL (8.7%). Hematoma was the most common complication recorded by Nd:YAG (28.3 %), and it was significantly higher (p = 0.002) than PDL (2.2%). Relapse was recorded in 8.7% with Nd:YAG compared with 13% in PDL with no significant difference (p = 0.74). Our results suggested that PDL and Nd:YAG lasers are effective in the treatment of resistant plantar warts. PDL is safer and less painful but needs more sessions, while Nd:YAG is more painful and shows more complications.

  15. A comparative SEM study between hand instrument and Er:YAG laser scaling and root planing.

    Moghare Abed, A; Tawakkoli, M; Dehchenari, M A; Gutknecht, N; Mir, M


    Scaling and root planing are one of the most commonly used procedures for the treatment of periodontal diseases. Removal of calculus using conventional hand instruments is incomplete and rather time-consuming. In search for more efficient and less difficult instrumentation, investigators have proposed lasers as alternatives or adjuncts for scaling and root planing. The aim of the present study was to compare the effectiveness of subgingival scaling and root planing with erbium: yttrium, aluminium, garnet (Er:YAG) laser and hand instrumentation in vitro. The mesial and distal surfaces of 15 periodontal loosed extracted teeth were treated randomly either by hand instrumentation or by Er:YAG laser irradiation. After choosing the "very long pulse mode" (pulse duration of about 700 micros), the output energy of 160 mJ with 920-microm beam diameter (RO7 Perio tip, Fidelis, Fotona, Slovenia) and frequency of 12 Hz were selected, both according to the best results of past studies. In addition, air water spray was used during the procedures. The morphology of the root surface was evaluated by three observers with a scanning electron microscopy in magnifications of 50x and 400x. The result of this setting showed that the rate of remained roughness on treated root surfaces in two groups of hand instruments and Er:YAG laser had a meaningful difference: The surface roughness in Er:YAG laser group was more than in hand instruments group. The present study could demonstrate the in vitro capability of the Er:YAG laser for scaling and root planing in periodontitis, although the effectiveness of this setting did not reach that achieved by hand instrumentation. It could be concluded that lower frequency and long pulse duration maybe more suitable for the micro-morphology of root surface after treatment. This theory is going to be tested with the same laser instrument in the next study.

  16. 2940-nm Er:YAG fractional laser enhanced the effect of topical drug for psoriasis.

    Li, Ruilian; Zhou, Jun; Su, Hui; Wang, Mei; Wang, Yongxian; Xiao, Shengxiang; Ma, Huiqun


    We observed the promoting effects of the 2940-nm erbium:YAG (Er:YAG) fractional laser in topical drug delivery for psoriasis. A total of five (four males and one female) recalcitrant psoriasis patients were given laser treatment eight times at 1-week intervals with the following parameters: 5-11% spot density and 100-μm energy depth. The psoriatic skin lesions on the left knee and the corresponding lesions at the right ones of each psoriasis patient were randomly divided into two groups: laser + topical drug group (L) and drug alone group (D). The psoriatic lesions in both groups were treated with the same topical treatment (calcipotriol ointment). The corresponding psoriatic lesions in the L group received extra 2940-nm Er:YAG laser irradiation before topical treatment. The photos of psoriatic lesions were taken before each treatment. The final photos were obtained from the patients at the seventh day after the final treatment. Drug alone or in combination with laser Er:YAG both reduced psoriatic lesions. However, with the increase in the number of treatments, increasing differences were observed between the treatment and the control sides. The therapeutic outcomes in the L groups were better than those in the D groups. Psoriasis area and severity index (PASI) scores for five cases of both groups were decreased. However, the scores in the L groups were lower than those in the D groups. The use of 2940 nm Er:YAG promoted the absorption of topical drugs for psoriasis, improving the therapeutic effect.

  17. [Retinal photocoagulation with a pulsed, frequency-doubled Nd:YAG laser (532 nm)].

    Roider, J; Schiller, M; el Hifnawi, E S; Birngruber, R


    The small difference in wavelength between an argon laser (514 nm) and a frequency-doubled Nd:YAG laser (532 nm), together with the advantage of the solid-state technology, makes the Nd:YAG laser likely to play a major role in retinal photocoagulation in the near future. For technical reasons all frequency-doubled Nd:YAG lasers work in a quasi-continuous mode, emitting a burst of highly repetitive short laser pulses during the exposure time desired. We investigated the side effects due to high peak irradiances of those short laser pulse trains (Crystal Focus Nd:YAG laser, Emerald; pulse duration 1-10 microseconds, repetition rate 13 KHz) in rabbits in comparison with a standard argon laser system (Zeiss, Visulas, Argon II). The energy necessary for blanching the retina was similar in both cases. As opposed to the argon laser system, subretinal bubbles were regularly visible ophthalmoscopically with the Nd:YAG system, when average powers as high as 200 mW were used. The ED50 power for bubble formation is about 2-3 times above the ED50 power for blanching. Thermal calculations show that this bubble formation effect is likely to be related to the peak power of the short pulses. The hemorrhage threshold is similar in both systems. However, light microscopically there is no difference between the two laser systems. Panretinal photocoagulation (300-500 microns, 100-200 ms) in patients with proliferative diabetic retinopathy produced such bubbles about once per 1000 lesions.

  18. Effects of Nd:YAG laser irradiation on the hybrid layer of different adhesive systems.

    Ferreira, Leila S; Ferreira, Lisiane Soares; Francci, Carlos; Navarro, Ricardo Scarparo; Calheiros, Fernanda Calabró; Eduardo, Carlos de Paula


    The aim of this in vitro study was to evaluate the microtensile bond strength (microTBS) and hybrid layer morphology of different adhesive systems, either followed by treatment with Nd:YAG laser irradiation or not. Previous studies have shown the effects of Nd:YAG laser irradiation on the dentin surface at restoration margins, but there are few reports about the significance of the irradiation on the hybrid layer. The flattened coronal and root dentin samples of 24 bovine teeth were randomly divided into 8 groups, according to the adhesive system used -- Scotchbond Multi Purpose (SBMP) or Clearfil SE Bond (CSEB) -- and were either irradiated with Nd:YAG or not, with different parameters: 0.8 W/10 Hz, 0.8 W/20 Hz, 1.2 W/10 Hz, 1.2 W/20 Hz. The left sides of specimens were the control groups, and right sides were irradiated. A composite crown was built over bonded surfaces and stored in water (24 h at 37 degrees C). Specimens were sectioned vertically into slabs that were subjected to microTBS testing and observed by SEM. Control groups (27.81 +/- 1.38) showed statistically higher values than lased groups (21.37 +/- 0.99), and CSEB control group values (31.26 +/- 15.71) were statistically higher than those of SBMP (24.3 +/- 10.66). There were no significant differences between CSEB (20.34 +/- 10.01) and SBMP (22.43 +/- 9.82) lased groups. Among parameters tested, 0.8 W/10 Hz showed the highest value (25.54 +/- 11.74). Nd:YAG laser irradiation caused dentin to melt under the adhesive layer of both adhesive systems tested. With the parameters used in this study, Nd:YAG laser irradiation of the hybrid layer promoted morphological changes in dentin and negatively influenced the bond strength of both adhesive systems.

  19. Effect of Er:Yag laser on dentin demineralization around restorations.

    Chinelatti, Michelle Alexandra; Rocha, Cristiane Tomaz; Colucci, Vivian; Serra, Mônica Campos; Rodrigues-Júnior, Antonio Luiz; Corona, Silmara Aparecida Milori


    The aim of this study was to evaluate the effect of cavity preparation with Er:YAG laser on dentin adjacent to restorations submitted to cariogenic challenge in situ, by subsuperficial microhardness analysis. Bovine incisors were sectioned, flattened, and polished, resulting in 40 dentin slabs. The slabs were randomly assigned to four groups (n = 10), according to the cavity preparation method: I-high-speed handpiece (control); II-Er:YAG laser (160 mJ; 3 Hz); III-Er:YAG laser (260 mJ; 3 Hz); IV-Er:YAG laser (300 mJ; 3Hz). Cavities were restored with composite resin, and the specimens were fixed in intra-oral appliances, which were worn by 10 volunteers for 14 days for simulating cariogenic challenge in situ. During the experimental period, 20% sucrose solution was dripped over each specimen 6 times a day. Samples were removed, sectioned, and examined for subsuperficial Knoop microhardness at 100, 200, and 300 μm from the restoration and at 30 μm from dentin surface. Split-plot analysis of variance showed no significant difference among the cavity preparation techniques (p = 0.1129), among distances (p = 0.9030), as well as no difference in the interaction between the main factors (p = 0.7338). It was concluded that the cavity preparation with Er:YAG laser did not influence on dentin microhardness submitted to cariogenic challenge in situ.

  20. Characterization and laser performance of a new material: 2 at. % Nd:YAG grown by the Czochralski method.

    L'huillier, Johannes A; Bitz, Gunter; Wesemann, Volker; von Loewis of Menar, Patric; Wallenstein, Richard; Borsutzky, Annette; Ackermann, Lothar; Dupré, Klaus; Rytz, Daniel; Vernay, Sophie


    We report on the optical quality and laser performance of Czochralski-grown 2-at. %-doped Nd:YAG. Using a diode pumped laser in an end pumped configuration, we compare the laser performance of this material with the performance of 1-at. %-doped Nd:YAG and 0.7-at. %-doped Nd:YVO4 crystals. Experimental results show the superior performance of 2-at. % Nd:YAG over Nd:YVO4. With a pump power of 25.7 W, a maximum output power of 12.3 W with a slope efficiency of 57% and an optical-to-optical efficiency of 48% were achieved.

  1. Evaluation of the Effectiveness of Nd: YAG Laser under Urethroscope in the Treatment of Intraurethral Condyloma Acuminata (CA) in Males

    赵冬; 曾伟宏; 翟胜


    Objective: To evaluate the therapeutic effect of Nd:YAG laser under urethroscope for the treatment of intraurethral Candyloma Acuminata (CA) in males.Method: Nd:YAG laser under urethroscope was employed to remove the warts.Result: Seventeen patients out of eighteen cases with CA were cured after the first procedure. The ure rate was 94.4%.For second treatment, the cure rate was 100% and no relapse occurred after observation for 12 - 4 months.Conclusion: Nd:YAG laser by urethroscope is a very good method for the treatment of intraurethral CA.

  2. Theoretical Analysis on the Simultaneous Operation of a Color-Center Laser and a Q-Switched Nd: YAG Laser

    WU Xing; DING Yongkui; ZHANG Rui


    The simultaneous operation for the Q- switched Nd: YAG laser at 1.06 and the tunable color-center laser over 1.12~1.26 μm has been realized by using a LiF: F2- color-center crystal both as the Q-switcher for the Nd:YAG laser and as the active medium for the color-center laser. The interaction of the two lasers has been analyzed and calculated with the rate equations. The pulse duration of YAG laser is compressed, in agreement with the experimental results.

  3. Generation of 170-fs Laser Pulses at 1053 nm by a Passively Mode-Locked Yb:YAG Laser

    ZHOU Bin-Bin; WEI Zhi-Yi; LI De-Hua; TENG Hao; Bourdet G. L


    A novel method is developed to obtain 1.05μm laser operation with a Yb:YAG laser. By using a Yb:YAG crystal with proper length and doping concentration, a femtosecond Yb: YAG laser is realized at the central wavelength of 1053nm. The measured pulse duration and spectral bandwidth (FWHM) are 17ors and 7nm; the repetition rate is 80 MHz. Under a power pump of 2 W, an average mode-locking power of 180mW is achieved.

  4. American ginseng

    ... and inflammation of the lining of the stomach (gastritis). American ginseng is also used for low iron ... Anemia. Bleeding disorders. Digestive disorders. Dizziness. Fever. Fibromyalgia. Gastritis. Hangover symptoms. Headaches. HIV/AIDS. Impotence. Insomnia. Memory ...

  5. Effect of an Indirect Composite Resin Surface Treatment with Two Types of Lasers: Nd: YAG, Er:YAG and Acid Etching on the Microshear Bond Strength of a Resin Cement


    Introduction: In order to increase the bonding strength of the composite resin cements to the indirect composites, experiments such as the creation of surface roughness with sandblasting, acid-etching, silane application, laser, etc. have been carried out. However, there is no consensus about the results. Therefore, the purpose of this study was to investigate the effect of Er: YAG and Nd: YAG lasers and acid etching on microshear bond strength of an indirect composite resin. Methods: Aft...

  6. Fine tuning of emission property of white light-emitting diodes by quantum-dot-coating on YAG:Ce nanophosphors

    Kong, Dal Sung; Kim, Min Jeong; Song, Hee Jo; Cho, In Sun; Jeong, Sohee; Shin, Hyunjung; Lee, Sangwook; Jung, Hyun Suk


    We report fine tuning of emission color of Ce-doped yttrium aluminum garnet (Y3Al5O12:Ce3+, YAG:Ce) nanophosphor-based white light-emitting diodes (WLED), by coating CdSe/CdS/ZnS quantum dots (QDs) onto the surface of the YAG:Ce nanoparticles via surface functionalization of both the QDs and the YAG:Ce. Mixture of bromo-functionalized QDs and amino-functionalized YAG:Ce nanoparticles results in conformal coating of the QDs onto the YAG:Ce nanoparticles (QD@YAG:Ce). By varying the QD to YAG:Ce weight ratios, the luminescence spectra of the QD@YAG:Ce are tuned. A high-quality warm-white-light emission is achieved by appropriate combination of the yellow and red emissions from the QD@YAG:Ce, and the blue emission from InGaN LED chip. However, without surface functionalization, irregular mixtures of YAG:Ce and QDs are formed, which consequently make it hard to control the emission spectra. This study demonstrates a promising way to prepare uniformly QD-coated nanophosphors and an approach to control the emission spectra the nanophosphors.

  7. Treatment of peri-implantitis around TiUnite-surface implants using Er:YAG laser microexplosions.

    Yamamoto, Atsuhikp; Tanabe, Toshiichiro


    Implant therapy can lead to peri-implantitis, and none of the methods used to treat this inflammatory response have been predictably effective. It is nearly impossible to treat infected surfaces such as TiUnite (a titanium oxide layer) that promote osteoinduction, but finding an effective way to do so is essential. Experiments were conducted to determine the optimum irradiation power for stripping away the contaminated titanium oxide layer with Er:YAG laser irradiation, the degree of implant heating as a result of Er:YAG laser irradiation, and whether osseointegration was possible after Er:YAG laser microexplosions were used to strip a layer from the surface of implants placed in beagle dogs. The Er:YAG laser was effective at removing an even layer of titanium oxide, and the use of water spray limited heating of the irradiated implant, thus protecting the surrounding bone tissue from heat damage.

  8. Role of surface tension and roughness on the wettability of Er:YAG laser irradiated dentin: In vitro study


    Introduction: The aim of this “in vitro” study was to evaluate the role of surface tension and surface roughness in the wettability, considered essential for a good adhesion, comparing Er:YAG laser - to bur-prepared dentin.

  9. Direct laser writing of near-IR step-index buried channel waveguides in rare earth doped YAG.

    Rodenas, A; Benayas, A; Macdonald, J R; Zhang, J; Tang, D Y; Jaque, D; Kar, A K


    A new (to our knowledge) ultrashort laser pulse irradiation regime that allows us to directly modify and increase the refractive index of rare earth doped YAG polycrystalline ceramics has been identified. Single-mode buried channel waveguides in both Ho:YAG and Er:YAG ceramics at the near-IR wavelengths of 1.55 μm and 1.95 μm are demonstrated by fabricating positive square step-index cores. Minimum propagation losses of 1.5 dB cm(-1) at a 1.51 μm wavelength have been preliminarily obtained. Confocal microluminescence mapping reveals that the increased refractive index regions retain the near-IR spectral properties of Er3+ ions in the YAG crystalline matrix.

  10. Diode-Pumped, 2-Micron, Q-Switched Thulium: Y3Al5O12 (Tm:Yag) Microchip Laser


    as predicted by Shaw et al. [16]. ................ 13 Figure 11: Photograph of bulk Tm:YAG crystal grown by Czochralski method [23]. ..... 14...requiring a custom growth run. 2.4 Production Tm:YAG is conventionally produced by the Czochralski method , which involves both the host and dopant...then pulled into a large crystal boule and allowed to cool. The Czochralski method allows for crystals to be grown which are free from or low in

  11. Effect of Fluoride Varnish Combined with Er:YAG Laser on the Permeability of Eroded Dentin: An In Situ Study.

    Nemezio, Mariana Alencar; Carvalho, Sandra Chiga; Scatolin, Renata Siqueira; Colucci, Vivian; Galo, Rodrigo; Corona, Silmara Aparecida Milori


    This study evaluated the combined effect of fluoride varnish and Er:YAG laser on the permeability of eroded bovine root dentin. After initial erosive challenge followed by a remineralization period, the specimens were divided in two groups according to the treatment - fluoride varnish and non-fluoride varnish - and were subdivided according to the irradiation protocol: Er:YAG laser (100 mJ, 3 Hz, 12.8 J/cm2per pulse, non-contact and defocus mode) and non-irradiated. After a lead-in period, 7 volunteers wore a palatal device containing 4 specimens that were subjected to erosive challenges. At the first experimental phase, 4 volunteers used specimens treated with fluoride varnish and fluoride varnish+Er:YAG laser and 3 volunteers used specimens treated with non-fluoride varnish and non-fluoride varnish+Er:YAG laser. After a washout period, volunteers were crossed to treatments, characterizing a 2x2 crossover experiment. At the end of the experimental phase, the quantitative response variable was obtained by permeability analysis and the qualitative response by scanning electron microscopy (SEM). Two-way ANOVA and Tukey-Kramer's test revealed that specimens treated with fluoride varnish+Er:YAG laser showed the lowest permeability and a significant difference was found between this group and the others. When varnish (fluoride/non-fluoride) was applied in the absence of Er:YAG laser, higher permeability was found when compared to the laser-treated groups. SEM evaluations showed partially or completely obliterated dentinal tubules when specimens were treated with fluoride varnish+Er:YAG laser. It may be concluded that Er:YAG laser was able to control the permeability of eroded root dentin and the combination with fluoride varnish increased laser action.

  12. American Connections

    Petersen, Anne Ring


    The Danish artist Thomas Bang spent his early years in the USA. The works he created in this formative period were thus profoundly shaped by the contemporary movements in American art of the 1960s and 1970s when sculpture, or to be more precise, three-dimensional work became a hotbed of expansive...... experiments. This article traces how Bang made a radical move from painting to sculpture, which was characteristic of that time, and how he developed his artistic idiom by taking an active part in some of the seminal new departures in American art, in particular process art and post-minimalism. By leaping...... to the lasting impact of Bang's American period, which remains the key to understanding his works....

  13. Improvement of light collection efficiency of lens-coupled YAG screen TV system for a high-voltage electron microscope.

    Yamamoto, K; Tanji, T; Hibino, M; Schauer, P; Autrata, R


    A new lens coupling television (TV) system using a YAG (Yttrium Aluminum Garnet: Y(3)Al(5)O(12) : Ce(3+)) single crystal screen has been developed for a high-voltage electron microscope (HVEM), and its performance is examined. The system, using a combination of YAG and lenses, is less damaged by high-energy electron irradiation and reduces the influence of X-rays on the image. YAG screens have not been used for lens-coupling systems, because the high refractive index (n = 1.84) of YAG results in a low light collection efficiency for emitted light. This disadvantage is overcome by combining a thin YAG disk screen (thickness; 100 microm) with a glass hemisphere whose refractive index is 1.81. We found that the light intensity is almost the same as that obtained with a conventional P22 powder screen and lenses system. The resolution is about 55 microm on the YAG screen, and this value is 1.3 times higher than that measured by the conventional system. Shading and distortion do not affect TV observation. Detection quantum efficiency, obtained after correction of the channel mixing effect, is about 0.1.

  14. Crystallization and fluorescence properties of Ce:YAG glass-ceramics with low SiO{sub 2} content

    Wang, Lili [Department of Materials Science and Engineering, University of Science and Technology Beijing 100083 (China); Mei, Lin; He, Gang; Liu, Guanghua [Technical Institute of Physics and Chemistry, Key Laboratory of Functional Crystals and Laser Technology, Chinese Academy of Sciences, Beijing 100190 (China); Li, Jiangtao, E-mail: [Technical Institute of Physics and Chemistry, Key Laboratory of Functional Crystals and Laser Technology, Chinese Academy of Sciences, Beijing 100190 (China); Xu, Lihua [Department of Materials Science and Engineering, University of Science and Technology Beijing 100083 (China)


    Ce{sup 3+} doped YAG (Ce:YAG) glass-ceramics with 20 mol% SiO{sub 2} were fabricated by the method of amorphous sintering followed by controlled crystallization (ASCC). An investigation on the crystallization process of as-sintered glasses revealed that surface crystallization occurred first and YAlO{sub 3} (YAP) was precipitated as the main crystalline phase; then bulk crystallization continued inside these glasses and YAP phase transited to YAG. The phase transition from YAP to YAG could be promoted by an inert atmosphere instead of reductive one and by the increase of the crystallization temperature and holding time. By combining the Ce:YAG glass-ceramics with a blue-emitting InGaN chip, white LEDs with a relatively high color rendering index of 80.3 and low color temperature of 5098 K were produced. Their luminous efficacy decreased with the increasing annealing temperatures, which was probably caused by the degradation of transparency. -- Highlights: ► Translucent SiO{sub 2}-low Ce:YAG glass-ceramics were successfully obtained. ► A white LED (CIR, 80.3 and CT, 5098 K) was equipped with the obtained glass-ceramic. ► Controlled surface and bulk crystallizations of the glass were observed. ► Three Ce{sup 3+} emission centers were possibly involved during the luminescence decay. ► Luminous efficacy decreased with elevated annealing temperatures.

  15. Short-pulse Er:YAG laser increases bond strength of composite resin to sound and eroded dentin

    Cersosimo, Maria Cecília Pereira; Matos, Adriana Bona; Couto, Roberta Souza D.'Almeida; Marques, Márcia Martins; de Freitas, Patricia Moreira


    This study evaluated the influence of the irradiation with a short-pulse Er:YAG laser on the adhesion of composite resin to sound and eroded dentin (SD and ED). Forty-six samples of occlusal dentine, obtained from human molars, had half of their surface protected, while the other half was submitted to erosive cycles. Afterward, 23 samples were irradiated with Er:YAG laser, resulting in four experimental groups: SD, sound irradiated dentine (SID-Er:YAG, 50 μs, 2 Hz, 80 mJ, and 12.6 J/cm2), ED, and eroded irradiated dentin (EID-erosion + Er:YAG laser). A self-etching adhesive system was used, and then cylinders of composite resin were prepared. A microshear bond strength test was performed after 24 h storage (n=20). The morphology of SD and ED, with or without Er:YAG laser irradiation, was evaluated under scanning electron microscopy (n=3). Bond strength values (MPa) were subjected to analysis of variance followed by Tukey's test. Statistically significant differences were found among the experimental groups: SD (9.76±3.39 B), SID (12.77±5.09 A), ED (5.12±1.72 D), and EID (7.62±3.39 C). Even though erosion reduces the adhesion to dentin, the surface irradiation with a short-pulse Er:YAG laser increases adhesion to both ED and SD.

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

    Radmanesh, Mohammed; Radmanesh, Ramin


    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.

  17. American Dream in Early American Literatuer

    屈彩娥; 李小玺


    American dream has often been closely rehted to American literature.Many say that the American literary history can be seen as the history of American dreams.In most periods in history,writers,whose dreams have been infused in a variety of characters create the American literature.While in Early American literature,American dream had been presented in a dif-ferent way.

  18. Evaluation of tissue tightening by the subdermal Nd: Yag laser-assisted liposuction versus liposuction alone

    Alberto Goldman


    Full Text Available Background: Skin tightening is a desirable outcome for skin flaccidity. Objective: We evaluated the applicability, safety, capacity and intensity of skin tightening with the subdermal 1,064 nm Nd: YAG laser application to the upper arms, and compared the results with liposuction. Materials and Methods: Patients with lipodystrophy and mild-to-severe skin laxity of the arms were included (n=28. In half of patients, a single treatment with a subcutaneous laser and liposuction was performed, while the other 14 had a regular liposuction. Treatment parameters, adverse effects and photographic documentation were recorded. Results: Aesthetic improvement and skin retraction was superior by laser lipolysis. The procedure was well tolerated without significant complications. Conclusions: The subdermal laser-assisted liposuction using a 1,064 nm Nd: YAG laser achieves improved skin tightening.

  19. Directly diode-pumped high-energy Ho:YAG oscillator.

    Lamrini, Samir; Koopmann, Philipp; Schäfer, Michael; Scholle, Karsten; Fuhrberg, Peter


    We report on the high-energy laser operation of an Ho:YAG oscillator resonantly pumped by a GaSb-based laser diode stack at 1.9 μm. The output energy was extracted from a compact plano-concave acousto-optically Q-switched resonator optimized for low repetition rates. Operating at 100 Hz, pulse energies exceeding 30 mJ at a wavelength of 2.09 μm were obtained. The corresponding pulse duration at the highest pump power was 100 ns, leading to a maximum peak power above 300 kW. Different pulse repetition rates and output coupling transmissions of the Ho:YAG resonator were studied. In addition, intracavity laser-induced damage threshold measurements are discussed.

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

    Vernon, S A; Cheng, H


    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.

  1. High-Efficiency High-Power Nd:YAG Laser under 885 nm Laser Diode Pumping

    LI Fang-Qin; ZHANG Xiao-Fu; ZONG Nan; YANG Jing; PENG Qin-Jun; CUI Da-Fu; XU Zu-Yan


    A high-efficiency high-power Nd:YAG laser under 885 nm laser diode (LD) pumping is demonstrated. The laser crystal is carefully designed, and the overlapping between the pump modes and the laser modes is optimized. The maximum output power at 1064 nm is 87 W under the absorbed pump power 127.7 W, corresponding to a slope efficiency of 72.4% and an optical-optical efficiency of 68.1%. The optical-optical efficiency is 58.4% for the pump power emitted directly from the LD. To our best knowledge, this is the maximal optical-optical conversion efficiency obtained for the LD end-pumped Nd:YAG lasers so far.

  2. Potential acuity meter for predicting visual acuity after Nd:YAG posterior capsulotomy

    Smiddy, W.E.; Radulovic, D.; Yeo, J.H.; Stark, W.J.; Maumenee, A.E.


    We studied 30 patients with opacifications of the posterior capsule to determine if the potential acuity meter (PAM) could accurately predict final visual outcome after Nd:YAG discussion. The final visual acuity was within one line of the PAM prediction in 22 of 30 patients (73%), better by two or more lines in seven patients (23%), and worse in one patient (4%) by two lines. Although in thicker capsules the final acuity was occasionally better than the PAM prediction, the rates of false negative and false positive predictions were very low. Mild cystoid macular edema (3 patients), age-related macular degeneration (3 patients), intraocular lens status, and level of initial acuity did not diminish PAM accuracy. The PAM effectively predicts final visual acuity after YAG posterior capsulotomy, when used in a patient, unhurried manner.

  3. Results of Endoscopic Treatment for Early Gastric Cancer by Nd-YAG Laser

    M. Tani


    Full Text Available We have introduced two endoscopic treatments for early gastric cancer: endoscopic mucosal resection using a cap-fitted panendoscope (EMRC, and endoscopic laser therapy using a Nd-YAG laser. Thirty-two patients (34 lesions with gastric cancer were treated by Nd-YAG laser; including 23 initial-therapy cases (25 lesions and 9 second-therapy cases representing failures of endoscopic mucosal resection or endoscopic ethanol injection. Endoscopic laser therapy was performed safely without complication in all patients. Three patients had residual cancer, and 2 of these required surgery. Six patients died from other disease. Endoscopic laser therapy can remove early gastric cancer even when the lesion has ulceration or submucosal invasion, and has a powerful hemostatic effect. It is a safe and effective treatment for early gastric cancer.

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

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


    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.

  5. High-power, 1-ps, all-Yb:YAG thin-disk regenerative amplifier.

    Fattahi, Hanieh; Alismail, Ayman; Wang, Haochuan; Brons, Jonathan; Pronin, Oleg; Buberl, Theresa; Vámos, Lénárd; Arisholm, Gunnar; Azzeer, Abdallah M; Krausz, Ferenc


    We report a 100 W, 20 mJ, 1-ps, all-Yb:YAG thin-disk regenerative amplifier seeded by a microjoule-level Yb:YAG thin-disk Kerr-lens mode-locked oscillator. The regenerative amplifier is implemented in a chirped pulse amplification system and operates at an ambient temperature in air, delivering ultrastable output pulses at a 5 kHz repetition rate and with a root mean square power noise value of less than 0.5%. Second harmonic generation of the amplifier's output in a 1.5 mm-thick BBO crystal results in more than 70 W at 515 nm, making the system an attractive source for pumping optical parametric chirped pulse amplifiers in the visible and near-infrared spectral ranges.

  6. Healing of bone in the rat following surgery with the erbium-YAG laser

    Dickinson, Mark R.; Devlin, Hugh; El Montaser, Monsour A.; Sloan, Philip


    Background and objectives: the aim of this study was to examine the pattern of healing in rat calvarial defects prepared with the erbium-YAG laser, using the 'guided tissue regeneration' technique. Materials and method: PTFE membranes were placed over lased skull defects, and the skin wounds sutured. Rats were killed humanely at intervals after surgery, and the skulls processed for paraffin wax histology. A further group of mature rats were also killed humanely and the calvariae removed. Slots were prepared using the erbium-YAG laser and immediately examined under the environmental scanning electron microscope (ESEM) in hydrated conditions, which avoided drying artifacts. Results: An amorphous, mineral-rich carbon layer surrounds the lased bone defect, which in the in vivo experiments was seen as a basophilic zone which was resistant to resorption.

  7. The Overlapped Triple Circle Pulse Technique with Nd:YAG Laser for Refractory Hand Warts.

    Bingol, Ugur Anil; Cömert, Asuman; Cinar, Can


    Inadvertent superficial treatment of hand warts causes recurrence, whereas aggressive treatment can lead to tissue defects resulting in hand dysfunction. This study aimed to determine the effectiveness of a novel laser treatment modality for recalcitrant hand warts. The study included 51 patients who were treated for 146 recalcitrant hand warts using 1064 nm long-pulsed Nd:YAG laser between 2011 and 2014. The laser treatment method is novel because each treated wart was aligned at the intersection point of the circles of 3 laser pulses per session. Among the 146 hand warts, 88.35% were successfully treated with one session and 100% of those that required a second treatment session were treated successfully, based on the 12 month follow-up examination. Long-pulsed Nd:YAG laser treatment was observed to be a safe, rapid, and effective method for treating recalcitrant hand warts.

  8. Beam quality investigation in Nd:YAG crystal fiber amplifier pumped at >110w

    Rodin, Aleksej M.; Aleknavicius, Aidas; Michailovas, Andrejus; Dementjev, Aleksandr S.


    We present results of beam quality investigation in Nd:YAG crystal fiber amplifier seeded by ns, sub-ns and ps laser pulses counter-propagating to continuous pump of refractive index at zero stresses and zero strains is found for YAG type cubic crystals. Using plane strain approximation the analytical expression for thermal radial and tangential changes of refractive index is found, and the relation between different expressions for so-called photoelastic constants Cr,θ is established. The methods of numerical calculation of rays and Gaussian beam propagation in a graded-index medium of active element are developed. The error in widely used formula for M2 of Gaussian beam with quartic phase aberration is corrected. It is shown that beam quality degradation can be explained by active thermal lens in power amplifier when changes of transverse beam shape or beam width during amplification are taken into account.

  9. Dual-rod Yb: YAG laser for high-power and high-brightness applications

    Honea, E C; Beach, R; Mitchell, S C; Skidmore, J A; Emanuel, M A; Sutton, S B; Payne, S A; Avizonis, P V; Monroe, R S; Harris, D G


    The authors describe a diode-pumped Yb:YAG laser producing 1,080 W cw with 27.5% optical-optical efficiency and 532 W Q-switched with M{sup 2} = 2.2 and 17% optical-optical efficiency. The laser uses two composite Yb:YAG rods separated by a 90 degree quartz rotator for bifocusing compensation. A microlensed diode array end-pumps each rod using a hollow lens duct for pump delivery. By changing resonator parameters, they can adjust the fundamental mode size and the output beam quality. Using a flattened gaussian intensity profile to calculate the mode fill efficiency and clipping losses, the authors compare experimental data to modeled output power vs beam quality.

  10. Yb:YAG ceramic-based laser driver for Inertial Fusion Energy (IFE)

    Vetrovec, John; Copeland, Drew A.; Litt, Amardeep S.


    We report on a new class of laser amplifiers for inertial confinement fusion (ICF) drivers based on a Yb:YAG ceramic disk in an edge-pumped configuration and cooled by a high-velocity gas flow. The Yb lasant offers very high efficiency and low waste heat. The ceramic host material has a thermal conductivity nearly 15-times higher than the traditionally used glass and it is producible in sizes suitable for a typical 10- to 20-kJ driver beam line. The combination of high lasant efficiency, low waste heat, edge-pumping, and excellent thermal conductivity of the host, enable operation at 10 to 20 Hz at over 20% wall plug efficiency while being comparably smaller and less costly than recently considered face-pumped alternative drivers using Nd:glass, Yb:S-FAP, and cryogenic Yb:YAG. Scalability of the laser driver over a broad range of sizes is presented.

  11. Synthesis of alumina/YAG 20 vol% composite by co-precipitation

    Radosław Lach


    Full Text Available Co-precipitation of alumina/YAG precursor from aluminum and yttrium nitrate solution with ammonium carbonate results in dawsonite. Its crystallographic parameters differ from the compound precipitated with no yttrium additive. It suggests that yttrium ions become incorporated into the dawsonite structure. The DSC/TG and X-ray diffraction measurements show decomposition of dawsonite at elevated temperatures resulting in γ-Al2O3 and then δ- and θ-alumina modifications. Full transformation to α-Al2O3 and YAG occurs at temperatures higher than 1230°C. Starting powder for the sintering experiments was prepared using the coprecipitated precursor calcined at 600°C. Seeding of such powder with 5 wt.% α-Al2O3 results in material of 98% density at 1500°C. Much lower densification show compacts of unseeded powder.

  12. Synthesis of Polycrystalline Nd∶YAG Nanopowders Used for Sintering Transparent Ceramics via Gel Combustion


    Polycrystalline nano-sized neodymium doped yttrium aluminum garnet (Nd∶Y3Al5O12, Nd∶YAG) powders were synthesized via a gel combustion method using nitrates and citric acid as starting materials. The evolution of phase composition and micro-structure of the powders were characterized by X-ray powder diffraction, thermogravimetry/differential thermal analysis and scanning electron microscopy. Well-crystallized Nd∶YAG nano-sized powders could be obtained at 950 ℃ for 2 h. The resultant powders are well dispersed, have a relatively narrow size distribution with an average particle size of approximately 50 nm, and show excellent sinterability. These powders can be densified to 99.2% of the theoretical density by HP sintering at 1700 ℃ for 3 h under 20 MPa nitrogen pressure.

  13. Treatment of nevus of OTA by Q-switched, frequency doubled, ND: Yag laser

    National Skin and Hair Care Centre


    Full Text Available Nevus of Ota is a dermal melanocytic nevus for which hitherto no effective therapy was available. Lasers have been successfully tried for ablation. But there is no Indian experience till date. Q- Switched, Frequency Doubled, Nd: YAG Laser was installed at our centre an year ago. The first operated case, which has shown near complete pigment dilution, is being presented. The patient underwent three treatments with a minimum of 2 months between sessions. Pre and post therapy photographs were taken and side effects documented. The patient has shown near complete pigment dilution after 3 treatments. Q-Switched, Frequency Doubled, Nd: YAG Laser is effective in treating Nevus of Ota in the Indian skin types. There are no complications noticed till date in our experience.

  14. Concentration and crystallite size dependence of the photoluminescence in YAG:Ce3+ nanophosphor

    Ovalle, Raquel; Arredondo, Alejandro; Diaz-Torres, Luis A.; Salas, Pedro; Angeles, Carlos; Rodriguez, Ruben A.; Meneses, Marco A.; De la Rosa, Elder


    Nanocrystalline yttrium aluminum garnet doped with Cerium (YAG:Ce3+), was synthesized by means of a modified sol-gel method that consists of a mixture of salts in an aqueous media. Structure and morphology were characterized by X-ray diffraction and Transmission Electron Microscopy. Single crystalline phase were obtained and the crystallite size range from 26 nm to 96 nm depending on the annealing temperature (from 800 to 1150 °C, respectively). The photoluminescence dependence on the crystallite size and ion concentration was performed. The experimental results show that the best ion concentration where the highest luminescence was obtained correspond to 0.1 mol% and that increases as the crystallite size increases. The feasibility of the modified sol-gel method for the preparation of nanocrystalline YAG is discussed.

  15. Development of a YAG laser system for the edge Thomson scattering system in ITER.

    Hatae, T; Yatsuka, E; Hayashi, T; Yoshida, H; Ono, T; Kusama, Y


    A prototype YAG laser system for the edge Thomson scattering system in ITER has been newly developed. Performance of the laser amplifier was improved by using flow tubes made of samarium-doped glass; the small signal gain reached 20 at its maximum. As a result, an output energy of 7.66 J at 100 Hz was successfully achieved, and the performance exceeded the target performance (5 J, 100 Hz).

  16. Partially end-pumped Nd:YAG slab laser with a hybrid resonator.

    Du, K; Wu, N; Xu, J; Giesekus, J; Loosen, P; Poprawe, R


    A Nd:YAG slab is partially end pumped by a diode laser stack with three diode laser bars. The pumped volume has a rectangular cross section. A hybrid resonator, which is stable in the plane of small dimension and is off-axis unstable in the plane of large dimension of the gain cross section, was used to yield highly efficient laser operation at diffraction-limited beam quality. The laser design and experimental results are reported.

  17. 1.32 μm Nd3+∶YAG Pulse Laser

    WANG Zhaoying; WU Xing


    Using specially coated mirrors, an output energy of 0.97 J at 1.32 μm from a Nd3+∶YAG pulse laser is obtained with pumping energy of 66 J. The repetition rate is 1 pulse/sec and the slope efficiency is 1.7%. The repetition rate can be changed from 1 pulse/sec to 10 pulses/sec.

  18. Measurement of pulse lengthening with pulse energy increase in picosecond Nd:YAG laser pulses

    Cutolo, A.; Zeni, L.; Berardi, V.; Bruzzese, R.; Solimeno, S.; Spinelli, N.


    Taking advantage of a new technique, we have monitored the relative variations of time duration and mode size as a function of the pulse energy for 30-ps-long Nd:YAG laser pulses. In particular, by carrying out a statistical analysis, we have observed that the pulse time duration is an increasing function of the pulse energy, according to the theoretical modeling of passively mode-locked lasers. The measurements can be easily extended to the femtosecond regime.

  19. Features of gallstone and kidney stone fragmentation by IR-pulsed Nd:YAG laser radiation

    Batishche, Sergei A.


    It is shown that infra-red ((lambda) equals 1064 nm) long pulse (approximately 100 microsecond(s) ) radiation of YAG:Nd laser, operating in free generation regime, effectively fragments gallstones, urinary calculus and kidney stones. The features of the mechanism of this process are investigated. Laser lithotripsy is nowadays a method widely used for fragmentation of gallstones, urinary calculus and kidney stones. Flashlamp pumped dye lasers of microsecond duration are most often used for such purposes. Nevertheless, there are some reports on lithotripsies with nanosecond duration laser pulses (for example, Q-switched YAG:Nd laser). The mechanism of the laser fragmentation of such stones was supposed to be the next. The laser powerful radiation, delivered through the optical fiber, is absorbed by the material of the stone. As a result of such highly localized energy absorption, dense plasma is formed, which expands. Such plasma and vapor, liquid confined, forms a cavitation bubble. This bubble grows, reaches its most dimension and then collapses on itself in some hundreds of micro seconds. Shock waves generated during the growth and the collapse of these bubbles are the origin of fragmentation of the stone. It is necessary to say that there are rather confined data on the hundreds microsecond laser pulse fragmentation especially what concerns the usage of infra-red (IR) YAG:Nd lasers with long laser pulses. Clearing this problem would result in better understanding of the fragmentation mechanism and it could favor development of simple and more reliable laser systems for lithotripsy. In this work we report about investigation of features of an effective fragmentation of gallstones, urinary calculus and kidney stones under exposure of IR ((lambda) equals 1064 nm) radiation of repetitive YAG:Nd laser working in free generation regime.

  20. High repetition rate femtosecond dye amplifier using a laser diode pumped neodymium:YAG laser

    Zysset, B.; LaGasse, M.J.; Fujimoto, J.G.; Kafka, J.D.


    A high repetition rate femtosecond dye amplifier is demonstrated using a laser diode pumped Q-switched Nd:YAG laser. Amplification of wavelength tunable 300 fs pulses from a synchronously mode-locked rhodamine dye laser is achieved with a saturated gain of 70 and a small gain of 200 at a repetition rate of 800 Hz. Maximum pulse energies of 40 nJ are obtained, and pulse compression to as short as 30 fs is demonstrated.

  1. High repetition rate femtosecond dye amplifier using a laser diode pumped neodymium:YAG laser

    Zysset, B.; LaGasse, M. J.; Fujimoto, J. G.; Kafka, J. D.


    A high repetition rate femtosecond dye amplifier is demonstrated using a laser diode pumped Q-switched Nd:YAG laser. Amplification of wavelength tunable 300 fs pulses from a synchronously mode-locked rhodamine dye laser is achieved with a saturated gain of 70 and a small gain of 200 at a repetition rate of 800 Hz. Maximum pulse energies of 40 nJ are obtained, and pulse compression to as short as 30 fs is demonstrated.

  2. Clinical, radiographic, and histopathologic evaluation of Nd:YAG laser pulpotomy on human primary teeth.

    Odabaş, Mesut Enes; Bodur, Haluk; Bariş, Emre; Demir, Cem


    The purpose of this study was to compare clinical, radiographic, and histopathologic effects of Nd:YAG laser pulpotomy to formocresol pulpotomy on human primary teeth. Patients with at least two vital primary molar teeth that required pulpotomy, because of pulpal exposure to caries, were selected for this study. After hemorrhage control, complete hemostasis into the canal orifice was achieved by exposure to Nd:YAG laser (1064 nm) and an He-Ne laser (the aiming beam of the Nd:YAG laser) in noncontact mode at 2 W, 20 Hz, 100 mJ, or was achieved by applying 1:5 dilution of formocresol. Forty-two teeth in two groups were to be followed up clinically and radiographic at 1, 3, 6, 9, and 12 months. Eighteen teeth planned for serial extractions were selected for histopathologic study. The teeth were extracted at 7 and 60 days. The teeth in the laser group had a clinical success rate of 85.71% and a radiographic success rate 71.42% at 12 months. The teeth in the formocresol group had a clinical and radiographic success rate of 90.47% at 12 months. There were no statistically significant differences between laser and formocresol group with regard to both clinical and radiographic success rates. There was a statistically significant difference between 7- and 60-day laser groups with regard to inflammatory cell response criteria. Dentin bridge was absent in all samples. No stained bacteria were observed in any of these samples. In conclusion, Nd:YAG laser may be considered as an alternative to formocresol for pulpotomies in primary teeth.

  3. Electro-optical cavity-dumped Ce:Nd:YAG laser for aesthetic medicine

    Lv, Yuandong; Liu, Jiaqi; Hao, Lijun


    An electro-optical cavity-dumped 20 Hz Ce:Nd:YAG laser with an optimized thermal-insensitive concavo-convex cavity for aesthetic medicine was demonstrated. The pulse width remained constant at 6.0 ns. The maximum output energy and peak power were 120 mJ and 20 MW, respectively. The average output energy was very stable. The fluctuations of average output energy within 6 cycles and 10 min were 0.89% and 7.9%, respectively.

  4. Frequency-stabilized diode-pumped Nd:YAG laser of high power

    Taccheo, S.; Laporta, P.; Longhi, S. [CNR, Milano (Italy). Centro di Elettronica Quantistica e Strumentazione Elettronica]|[Politecnico di Milano (Italy). Dipt. di Fisica; Svelto, C. [Politecnico di Milano (Italy). Dipt. di Elettronica e Informazione


    The authors describe a frequency-stabilized diode-pumped Nd:YAG laser of high power whose single-mode operation is obtained by suppressing the spatial hole burning through the twisted-mode technique. Active frequency stabilization is achieved by fringe side locking the laser beam to a reference Fabry-Perot cavity. Output power up to 800 mW in single-transverse and -longitudinal mode operation with a linewidth of less than 20 kHz is obtained.


    Brigita Drnovšek-Olup


    Full Text Available Background. In this study, a new type of Er:YAG laser, emitting irradiation with variable pulse duration, has been used for blepharoplasty and skin resurfacing in periocular region.More than 40 patients have been treated with second generation Er:YAG laser (Fotona Fidelis for blepharoplasty and skin resurfacing. A focused laser beam (diameter 0.4 mm with very short pulse width (100 µs, that is significantly below the thermal relaxation time of skin, leads to a precise cut with no observable thermal effect on surrounding tissue. The depth of the cut is approximately 1–2 mm, precision comparable to a surgical scalpel. The high repetition rate of consecutive laser pulses (50 Hz at 120 mJ energy accounts for accumulation of thermal load in tissue, and thus leads to complete hemostasis of the cut tissue. Due to improved cutting abilities of the Er:YAG laser, excision of orbital fat is also performed with one pass of the laser beam. By changing the laser parameters to short pulses (300 µs, energy 500 mJ, spot diameter 5 mm and repetition rate 12–15 Hz, skin resurfacing was performed. No special pretreatment therapy was used. Anesthesia: 2% Xylocain inj. subcutaneously. Non adhesive dressing for 24 hours was applied after surgery.Epithelisation was complete after ten days. Redness persists up to 5 weeks. Discomfort of patients was mild. Cosmetic results are satisfying.Conclusions. New generation of Er:YAG laser offers a possibility to cut and coagulate the tissue simultaneously, and by changing the parameters to ablate the tissue with heating influence on skin collagen.

  6. Polarization Self-Modulation Phenomenon in a Free Oscillated Nd: YAG Laser

    YANG Qian-Suo; LUO Geng-Xing; ZOU Nian-Yu; YANG Guo-Wei; ZHU Nai-Yi


    @@ Polarization self-modulation effect in a free oscillated Nd:YAG laser is investigated after a quarter wave plate is introduced independently in the two positions of the cavity. As described in the previous experiments, the intensity components in the orthogonal directions are modulated with a period of the round-trip time or twice.Different pulse shapes reveal that the seed field from the spontaneous emission is not uniform and seems to be stochastic for each pulse.

  7. Physical and optical limitations using ArF-excimer and Er:YAG lasers for PRK

    Semchishen, Vladimir A.; Mrochen, Michael; Seiler, Theo


    The Erbium:YAG laser emitting at a wavelength of 2,94 micrometer have been promised as an alternative laser for the ArF-excimer laser (193 nm) in photorefractive keratectomy (PRK). This report discusses the limitations of laser parameters such as wavelength, energy density and pulse duration for the ablation of the cornea. In addition, the melting process during ablation on the corneal surface roughness may play a role.

  8. Dynamics of two coupled chaotic multimode Nd:YAG lasers with intracavity frequency doubling crystal

    Thomas Kuruvilla; V M Nandakumaran


    The effect of coupling two chaotic Nd:YAG lasers with intracavity KTP crystal for frequency doubling is numerically studied for the case of the laser operating in three longitudinal modes. It is seen that the system goes from chaotic to periodic and then to steady state as the coupling constant is increased. The intensity time series and phase diagrams are drawn and the Lyapunov characteristic exponent is calculated to characterize the chaotic and periodic regions.

  9. Nd:YAG laser bloodless tonsillectomy by fiber optic doppler coupled handpiece beam delivery

    Palmieri, Beniamino; Rottigni, Valentina


    Laser ablation of palatine tonsils is a relatively new technique recently performed in head and neck surgery departments, in order to treat recurrent tonsillar infections or obstructions from enlarged tonsils. In our study, we have investigated a new procedure using the fiber optic laser beam Nd:YAG to remove up to the 89% of tonsillar tissue, and leaving in place the capsule avoiding any hemorrhagic complication and limiting the pain.

  10. Diode-pumped Solid-state Cr4+∶Nd∶YAG/KTP Green Laser

    YU Ting; CUI Junwen; LU Yutian; HU Qiquan


    A diode-pumped solid-state Cr4+∶Nd∶YAG/KTP green laser with intracavity second harmonic generation is reported. Stable quasi-cw output of 1.03 W in average power, 100 kHz of repetition rate and about 25 ns of pulse width were obtained. Repetition rate and pulse width were studied experimentally and analyzed under different conditions.

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

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


    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.

  12. Bleb failure and intraocular pressure rise following Nd: Yag laser capsulotomy.

    Diagourtas, Andreas; Petrou, Petros; Georgalas, Ilias; Oikonomakis, Kostantinos; Giannakouras, Panagiotis; Vergados, Athanasios; Papaconstantinou, Dimitrios


    To report the negative effect of Nd: Yag (Neodymium-doped: Yttrium Aluminium Garnet) laser capsulotomy on the intraocular pressure (IOP) and the trabeculectomy bleb integrity, in a small series of eyes, both trabeculectomised and pseudophakic, following the laser application for the management of posterior capsular opacification (PCO). This is a retrospective, non-comparative interventional case series study, in which 20 trabeculectomised and pseudophakic eyes from 15 patients, with otherwise well functioning blebs, were presented with uncontrolled IOP, in a variable distance of time following the application of YAG laser capsulotomy. Student paired t-test confirmed a statistically significant difference (P nd the respective one, 2 to 6 months after Nd: Yag capsulotomy (34.5 ± 11 mmHg). All of the cases failed to respond to conservative treatment and were successfully managed with the implantation of Ahmed drainage devices. All patients showed flat filtering bleb and uncontrolled IOP (34.5 ± 11 mmHg), under maximum topical treatment, in a period of 2 to 6 months following Nd: YAG laser caspulotomy. The implantation of Ahmed valve proved to be effective treatment for these patients (IOP nd usually is done without second thought, in this series of eyes, it is postulated that it may be responsible for the deregulation of the filtering bleb and subsequent loss of IOP control. We consider that laser capsulotomy should be performed with caution, especially in eyes with previous trabeculectomy. Also close monitoring of the intraocular pressure and assessment of eventual bleb morphology variations in the follow-up period is mandatory. Further studies are needed in order to confirm our findings.

  13. A Case Report of Telangiectatic Rosacea Treated with Long Pulsed Nd-YAG Laser

    Can Ergin


    Full Text Available Rosacea is a chronic enflammatory skin disease characterized by facial erythema, telangiectasia, papules and pustules. A variety of topical and systemic medications are used in the treatment of the disease. Recently, erythema and telangiectasia in rosacea patients have been frequently treated with laser applications. Herein, we present a case of rosacea whose telangiectasia were successfully treated with Nd-YAG laser treatment. 

  14. Processing and Characterization of Polycrystalline Yag (Yttrium Aluminum Garnet) Core-Clad Fibers - Postprint


    In this study, green and binder-removed fibers were investigated for cladding studies using dip coating . The processing steps used to make the...fibers were dip coated in this slurry multiple times to form the YAG cladding . After each dip coating , the coated fiber was dried at 120°C. Organics...the slurry and further dip coating was not possible. As a result the achievable cladding thickness was limited. Nevertheless, dip coating the binder

  15. Optodynamic analysis of pulsed-laser processing with a Nd:YAG laser

    Strgar, Simon; Možina, Janez


    Laser drilling and laser marking of metals with a pulsed Nd:YAG laser are discussed. Some characteristics of pulsed-laser processing and the possibilities of process optodynamic analysis are presented for the laser-drilling of aluminium. The optodynamic analysis is based on observation of generated shock waves, which propagate in the material as well as in the surrounding air during laser processing. For the detection of laser-induced shock waves in the air and for measurements of their chara...

  16. American Houses



    American houses usually have private kitchens,a living room and sometimes separate areas for eating and watching television,A house usually has its own mailbox,a yard with plants or perhaps a lawn,and a place to store garbage out of sight.

  17. Layered Yb:YAG ceramics produced by two different methods: processing, characterization, and comparison

    Hostaša, Jan; Biasini, Valentina; Piancastelli, Andreana; Vannini, Matteo; Toci, Guido


    Yb:YAG ceramic solid-state laser gain media have been of growing interest for high-repetition rate and high-power lasers during the last few years. A great advantage of ceramic technology compared with that of single crystals is the flexibility of shaping methods allowing the production of near-net-shape components with a well-defined internal structure. A favorable dopant distribution can enhance laser efficiency by mitigating thermal effects. The presented work reports on Yb:YAG transparent ceramics composed of layers with different Yb doping produced by two different shaping methods: dry pressing of spray-dried powders and tape casting, all sintered under high vacuum. The selected geometry of materials was based on numerical simulations. Optical quality of produced ceramics was characterized and discussed in connection with the microstructure and laser emission results. Output power of nearly 7 W and slope efficiency of 58.1% were obtained in quasi-continuous wave regime from bilayered 0% to 10% Yb:YAG. In the case of multilayered materials, higher scattering losses were observed. The comparison of the two processing methods highlighted that the tape-cast materials provided higher optical uniformity and the diffusion zone between the single layers with different dopant content was about 150 μm compared to about 250 μm in samples produced by pressing of powders.

  18. Morphological changes produced by acid dissolution in Er:YAG laser irradiated dental enamel.

    Manuela Díaz-Monroy, Jennifer; Contreras-Bulnes, Rosalía; Fernando Olea-Mejía, Oscar; Emma Rodríguez-Vilchis, Laura; Sanchez-Flores, Ignacio


    Several scientific reports have shown the effects of Er:YAG laser irradiation on enamel morphology. However, there is lack of information regarding the morphological alterations produced by the acid attack on the irradiated surfaces. The aim of this study was to evaluate the morphological changes produced by acid dissolution in Er:YAG laser irradiated dental enamel. Forty-eight enamel samples were divided into four groups (n = 12). GI (control); Groups II, III, and IV were irradiated with Er:YAG at 100 mJ (12.7 J/cm(2) ), 200 mJ (25.5 J/cm(2) ), and 300 mJ (38.2 J/cm(2) ), respectively, at 10 Hz without water irrigation. Enamel morphology was evaluated before-irradiation, after-irradiation, and after-acid dissolution, by scanning electron microscopy (SEM). Sample coating was avoided and SEM analysis was performed in a low-vacuum mode. To facilitate the location of the assessment area, a reference point was marked. Morphological changes produced by acid dissolution of irradiated enamel were observed, specifically on laser-induced undesired effects. These morphological changes were from mild to severe, depending on the presence of after-irradiation undesired effects.

  19. Study of diode-pumped Yb:YAG disk lasers at low temperature

    Jianlei Wang; Zhenhua Zhang; Xiaojin Cheng; Lei Li; Xiangchun Shi; Xiaolei Zhu; Weibiao Chen


    A Yb:YAG disk laser with V-shaped stable resonator and active-mirror configuration, end-pumped by a 940-nm InGaAs laser diode array, is demonstrated. Performances and optimization of the disk laser at low temperature over a range of 130-200 K are investigated theoretically and experimentally. Laser output energy of 1.46 J/pulse operating at 10-Hz repetition rate is obtained with the optimum output coupler transmission of 30%, and the corresponding optical-to-optical efficiency is 48.7%.%Yb:YAG[1-4],by virtue of its high quantum efficiency (>90%),long life time,no concentration quenching,no excite-state absorption,and no upconversion effect,has recently been considered as a suitable candidate for lasers with high average power and high efficiency[5-7].Due to their wide absorption band centered at 941 nm,Yb:YAG lasers are more acceptable for variation of pump laser diode (LD) wavelength.

  20. Temperature-related performance of Yb3+:YAG disc lasers and optimum design for diamond cooling

    Cao Ding-Xiang; Yu Hai-Wu; Zheng Wan-Guo; He Shao-Bo; Wang Xiao-Feng


    In this paper the temperature-related performances of the Yb3+:YAG disc laser has been investigated based on quasi-three level rate equation model. A compact diamond window cooling scheme also has been demonstrated. In this cooling scheme, laser disc is placed between two thin discs of single crystal synthetic diamond, the heat transfer from Yb3+:YAG to the diamond, in the direction of the optical axis, and then rapidly conducted radically outward through the diamond to the cooling water at the circumference of the diamond/Yb3+ :YAG assembly. Simulation results show that increasing the thickness of the diamond and the overlap-length (between diamond and water) decreases the disc temperature. Therefore a 0.3-0.5 mm thick diamond window with the overlap-length of 1.5-2.0 mm will provide acceptable cost effective cooling, e.g., with a pump intensity of 15 kW/cm2 and repetitive rate of 10 Hz, to keep the maximum temperature of the lasing disc below a reasonable value (310K), the heat exchange coefficient of water should be about 3000 W/m2K.

  1. Effects of Nd:YAG laser radiation in cultured porcine vertebral disc tissue

    Thal, Dietmar R.; Werkmann, Klaus; Leheta, Fouad; Schober, Ralf; Ulrich, Peter


    Nd:Yag laser radiation is used for the treatment of protrusion of intervertebral discs. It is known that laser radiation leads to coagulation, vaporization and carbonization of the disk. Little is known about the early changes in vertebral discs after laser radiation. Therefore, we exposed cadaveric porcine vertebral discs by Nd:YAG laser radiation immediately after death. The discs were quartered and either formalin fixed after laser radiation or kept in culture for 1, 4 and 7 days and then formalin fixed. Immunohistochemistry was performed with antibodies directed against vimentin and amyloid precursor protein (APP). Results showed a jerky leak of notochordial remnant cells and mucopolysaccharides at the distal end of the application needle during laser radiation, which was interpreted as a bursting extrusion of damaged but not vaporized tissue. Histology and immunohistochemistry revealed an incomplete loss of nucleus pulposus and a large, almost complete necrosis of the notochordial remnant cells. In surviving notochordial remnant cells after laser radiation a slight increase of vimentin and APP could be seen without any other cellular reactions. The annulus fibrosus showed no significant changes except a defect with a small necrosis zone at the site of the application needle. Therefore, it can be concluded that Nd:YAG laser radiation leads to an increased volume reduction by the leak of nucleus pulposus and to a slight cellular reaction of surviving notochordal remnant cells detectable by vimentin and APP increase.

  2. Soft-tissue applications of the holmium:YAG laser in urology

    Denstedt, John D.; Razvi, Hassan A.; Chun, Samuel S.; Sales, Jack L.


    The ideal surgical laser for the treatment of soft tissue pathology should possess both ablative and hemostatic abilities. As well, for use in urologic conditions the laser must also be suitable for endoscopic use. The Holmium:YAG laser possesses these qualities and in preliminary clinical use has demonstrated a variety of potential urologic applications. In this study we review our initial experience with the Holmium:YAG laser over a 18 month period. A total of 51 patients underwent 53 procedures for a variety of soft tissue conditions including: bladder tumor ablation (25), incision of ureteral stricture (15), incision of urethral stricture (6), treatment of ureteropelvic junction obstruction (3), incision of bladder neck contracture (2), and ablation of a ureteral tumor (2). Satisfactory hemostasis was achieved in all cases. Procedures were considered successful (no further intervention being required to treat the condition) in 81% of the cases. Two patients with dense bladder neck contractures required electroincision under the same anesthetic for completion of the procedure. A single complication, that of urinary extravasation following incision of a urethral stricture resolved with conservative management. In summary, the Holmium:YAG laser has demonstrated safety and proficiency in the treatment of a variety of urologic soft tissue conditions.

  3. [Use of airway stent subsequent to endoscopic Nd-YAG laser treatment in central airway obstruction].

    Akaogi, E; Yuasa, H; Ishibashi, O; Inage, Y; Dai, Y; Sato, Y; Ishikawa, S; Morita, R; Onizuka, M; Mitsui, K


    Ten cases of central airway obstruction mainly caused by extrinsic compression due to the growth of extratracheal malignant tumors or longitudinal extension of tracheal adenoid cystic carcinomas, underwent palliative intubation subsequent to endoscopic Nd-YAG laser treatment. Mean length of the severe stenosis in these cases was 4.4 cm (3-7 cm). Sole application of endoscopic Nd-YAG laser to the stenosis failed relief of the symptom and an immediate palliative intubation was recommended. Mean time of the temporary intubation was 7 days (4-11 days). Airway was maintained by this intubation and also retained enough after extubation. Therefore, it seemed that, in a palliative treatment of the central airway severe stenosis, usefulness of the combination management of Nd-YAG laser with following temporary intubation was revealed. However, in order to maintain the airway for recurrence of the obstruction, use of indwelling airway stents seemed a better application. The longest period of follow-up in the cases treated by indwelling airway stents was 6 months and one of the cases is a now in comfortable state.

  4. Selective removal of dental composite with a diode-pumped Er:YAG laser

    Fried, William A.; Chan, Kenneth H.; Darling, Cynthia L.; Fried, Daniel


    Selective removal of dental composite with high precision is best accomplished using lasers operating at high pulse repetition rates focused to a small spot size. Conventional flash-lamp pumped Er:YAG lasers are poorly suited for this purpose, but new diode-pumped Er:YAG lasers have become available operating at high pulse repetition rates. The purpose of this study was to compare the ablation rates and selectivity of enamel and composite for a 30 W diode-pumped Er:YAG laser operating with a pulse duration of 30-50-μs and evaluate it's suitability for the selective removal of composite from tooth surfaces. The depth of ablation and changes in surface morphology were assessed using digital microscopy. The fluence range of 30-50 J/cm2 appeared optimal for the removal of composite, and damage to sound enamel was limited to less than 100-μm after the removal of composite as thick as 700-800-μm. Future studies will focus on the use of methods of feedback to further increase selectivity.

  5. Novel pressure sensor by diode-pumped birefringent Nd:YAG dual-frequency laser

    Huang, Chunning; Li, Yan; Zhang, Shulian; Guo, Hui


    The prototype of a novel sensor based on laser frequency splitting technology is presented in this paper and the results of a series of experiments are reported. A scheme of the novel pressure sensor by diode-pumped birefringent Nd:YAG dual-frequency laser is brought forward. As a result of the stress birefringence the laser's longitudinal mode is split to two with frequency difference. Both the theoretical analysis and the experiments indicate that there is a direct ratio relation between the frequency difference and the pressure imposed on the Nd:YAG crystal. Therefore when the external pressure is sensed by the Nd:YAG dual-frequency laser and the beat frequency is measured by the frequency counter, the pressure value can be obtained from the magnitude of the beat frequency. The laser can operate under single mode or complex modes with little error to the experiment results. Some research work under different pumping ways is finished and it indicates that the beat frequency has little relation with pumping ways. The experiment has a good linearity (R greater than 0.999) with satisfied precision, sensitivity (5.27 MHz/kPa) and stability, which provides a good academic and experimental foundation for further research.

  6. Response of feline intradental nerve fibers to tooth cutting by Er:YAG laser.

    Chaiyavej, S; Yamamoto, H; Takeda, A; Suda, H


    The aim of this study was to investigate the response of intradental A- and C-fibers during tooth cutting by Er:YAG laser. Bipolar electrical stimulation was applied to the cat's canine to identify functional single nerve fibers of the inferior alveolar nerve. The tip of the canine tooth was cut in 0.5-mm steps until the pulp was exposed. Teeth were alternately cut by using Er:YAG laser (50 mJ, 5 pps) and micromotor under water cooling. The nerve response recorded from the single nerve fibers during laser cutting was compared with that during micromotor cutting. All 26 A-fibers responded to laser cutting with high frequency of nerve firings. The nerve firing rate was significantly higher during laser cutting compared with that during micromotor cutting of superficial dentin (Chi(2) test, P or = 0. 05). Nine of 11 C-fibers responded to laser cutting when the deep dentin was cut. Among those nine nerve fibers, three also showed a low frequency response to laser cutting of the superficial dentin. During the tooth cutting, Er:YAG laser was more effective in activating intradental A-fibers compared with micromotor and also caused the activation of intradental C-fibers. Copyright 2000 Wiley-Liss, Inc.

  7. Simulation of medical Q-switch flash-pumped Er:YAG laser

    Wang Yanlin; Huang Chuyun; Yao Yucheng; Zou Xiaolin, E-mail:, E-mail:, E-mail:, E-mail: [Physics school, Hubei University of Technology, Wuhan, China 430068 (China)


    Er: YAG laser, the wavelength is 2940nm, can be absorbed strongly by water. The absorption coefficient is as high as 13000 cm{sup -1}. As the water strong absorption, Erbium laser can bring shallow penetration depth and smaller surrounding tissue injury in most soft tissue and hard tissue. At the same time, the interaction between 2940nm radiation and biological tissue saturated with water is equivalent to instantaneous heating within limited volume, thus resulting in the phenomenon of micro-explosion to removal organization. Different parameters can be set up to cut enamel, dentin, caries and soft tissue. For the development and optimization of laser system, it is a practical choice to use laser modeling to predict the influence of various parameters for laser performance. Aim at the status of low Erbium laser output power, flash-pumped Er: YAG laser performance was simulated to obtain optical output in theory. the rate equation model was obtained and used to predict the change of population densities in various manifolds and use the technology of Q-switch the simulate laser output for different design parameters and results showed that Er: YAG laser output energy can achieve the maximum average output power of 9.8W under the given parameters. The model can be used to find the potential laser systems that meet application requirements.

  8. Role of Nd:YAG laser for prevention of neuroma formation: an in vivo experimental study.

    Elwakil, Tarek F; Elkharbotly, Ahmad


    Nerve transection is commonly followed by the development of neuroma at the proximal stump. It can be very painful especially at exposed sites. It may arise spontaneously or after mechanical irritation. Neuroma and its high recurrence rate might be resisting problems to treat. Various treatment modalities for neuroma and its recurrence have been proposed, but none has provided satisfactory results. The present study was conducted to evaluate the neodymium:yttrium aluminum garnet (Nd:YAG) laser (1,064 nm) nerve transection technique for prevention of neuroma formation. There were 48 facial nerves out of 24 Rex rabbits divided into two equal groups. The 24 left-sided facial nerves at group A were subjected to Nd:YAG laser for nerve transection, while the 24 right-sided facial nerves at group B were subjected to scalpel nerve transection. The results were grossly and histopathologically evaluated. Grossly, laser-transected nerves showed an infrequent incidence of neuroma formation. Histopathologically, laser-transected nerves showed photothermal degenerative changes of the axons and myelin sheaths with intact perineurium and endoneurium. No Schwann cell hyperactivity could also be elicited among laser-transected nerves. Nd:YAG laser was found to be an effective tool that could be applied, whenever it is possible, for division of major nerves to prevent the formation of the subsequent stump neuroma. Moreover, this technique should be considered during treatment of well-established neuroma to prevent the challenging reported high incidence of recurrence.

  9. Growth and characterization of air annealing Mn-doped YAG:Ce single crystal for LED

    Xiang, Weidong, E-mail: [College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, Zhejiang 325035 (China); College of Materials Science and Engineering, Tongji University, Shanghai 201804 (China); Zhong, Jiasong [College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, Zhejiang 325035 (China); College of Materials Science and Engineering, Tongji University, Shanghai 201804 (China); Zhao, Yinsheng [Pan Asia Technical Automotive Center Co. Ltd., Shanghai 201201 (China); Zhao, Binyu [College of Materials Science and Engineering, Tongji University, Shanghai 201804 (China); Liang, Xiaojuan [College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, Zhejiang 325035 (China); Dong, Yongjun [Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Science, Shanghai 201800 (China); Zhang, Zhimin; Chen, Zhaoping; Liu, Bingfeng [College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, Zhejiang 325035 (China)


    Highlights: Black-Right-Pointing-Pointer The YAG:Ce,Mn single crystal was well synthesized by the Czochralski (CZ) method. Black-Right-Pointing-Pointer The emission intensity of the sample has been influenced after annealing. Black-Right-Pointing-Pointer Annealed in the air at 1200 Degree-Sign C was the most optimal annealing condition. Black-Right-Pointing-Pointer The single crystal could be used in the white light LED which emitted by blue light. - Abstract: The growth of Mn-doped YAG:Ce (yttrium aluminum garnet doped cerium) single crystal by the Czochralski (CZ) method and the characterization of its spectroscopy and color-electric parameters are presented. The absorption spectra indicate that the crystal absorbed highly in the 300-500 nm wavelength range. The emission spectrum of the crystal consists of a peak around 538 nm when excited by 460 nm blue light, which prove the YAG:Ce,Mn single crystal could be used in the white light emitting doides (LED). The different charges of Mn ions have different luminescence properties, and the air annealing process for the single crystal would change the concentration of Mn ions with different charges, which could influence the emission intensity of the single crystal.

  10. Surface nanomorphology of human dental enamel irradiated with an Er:YAG laser

    Ţălu, Ş.; Contreras–Bulnes, R.; Morozov, I. A.; Rodríguez-Vilchis, L. E.; Montoya-Ayala, G.


    To determine the effects of Er:YAG laser irradiation on the surface nanomorphology of human dental enamel. Materials and methods: five samples of human dental enamel were divided into five groups: (a) I and II were irradiated with Er:YAG & water irrigation (12.7 J cm-2 and 25.5 J cm-2, respectively); (b) III and IV were Er:YAG laser irradiated & no water irrigation (12.7 J cm-2 and 25.5 J cm-2, respectively); (c) V or control (no laser irradiation). Nanomorphological changes were observed on 1 μm  ×  1 μm areas by AFM (contact mode and air). The partition functions and multifractal spectra were calculated. The graphical results showed that the larger the spectrum width Δα (Δα  =  α max  -  α min) of the multifractal spectra f(α) the more non-uniform the surface nanomorphology. One way analysis of variance (ANOVA) was performed (P  roughness parameters, and multifractal analysis provided useful information about the surface nanomorphology and optimal surface characteristics. This approach could be extended to other enamel surfaces in order to characterize its structural 3D microrelief.

  11. Effects of Er:YAG laser on mineral content of sound dentin in primary teeth.

    Guler, Cigdem; Malkoc, Meral Arslan; Gorgen, Veli Alper; Dilber, Erhan; Bulbul, Mehmet


    The aim of the present study was to evaluate the mineral content of sound dentin in primary teeth prepared using an Er:YAG laser at two different power settings. Thirty-six primary second molars were used in this study. Three dentin slabs were obtained from each tooth, and the slabs were randomly divided into three groups: Group A, control; Group B, Er:YAG laser at 3.5 W, 175 mJ, and 20 Hz, short pulse mode; and Group C, Er:YAG laser at 4 W, 200 mJ, and 20 Hz, medium-short pulse mode. One dentin slab per group was used to evaluate the dentinal morphology and surface roughness values using SEM and profilometer, respectively. Mineral content in the dentin slabs were calculated by inductively coupled plasma-atomic emission spectrometry (ICP-AES). The data were analyzed by one-way analysis of variance and Tukey's HSD tests. No significant differences in Ca, K, Mg, Na, and P levels or Ca/P ratio were found among the groups (P > 0.05). SEM micrographs showed that surface irregularities increased with a higher power setting. The surface roughness after laser treatment in Group B and Group C was found to be similar, unlike Group A.

  12. Effectiveness of an Er:YAG laser in etching the enamel surface for orthodontic bracket retention.

    Kim, Jung-Ho; Kwon, Oh-Won; Kim, Hyung-Il; Kwon, Yong Hoon


    The purpose of this study was to test the effectiveness of an Er:YAG laser in etching the enamel surface for orthodontic treatment. Bovine incisors were either acid-etched or laser-treated. An orthodontic bracket was attached on each treated surface using one-step dentin adhesive and self-curing resin. Tensile bond strength was then evaluated. In addition, the surface morphology of specimens treated with phosphoric acid/laser and self-etching primer, as well as the cross-section of enamel-primer-resin interfaces, were observed. One-Up Bond F-treated specimens after Er:YAG laser ablation showed statistically similar tensile bond strength (9.9 +/- 1.3 MPa) to that of phosphoric acid-etched specimens (11.8 +/- 1.7 MPa). Surface roughness and thickness of the enamel-primer-resin interfaces did not much affect the tensile bond strength of the tested specimens. In conclusion, Er:YAG laser ablation achieved clinically acceptable level of tensile bond strength when used with One-Up Bond F.

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

    Torchia, G.A. [Grupo de Optica, Departamento de Fisica Aplicada, Universidad de Salamanca, Plaza de la Merced s/n, 37008 Salamanca (Spain); Centro de Investigaciones Opticas (CIOp), CIC-Conicet, CC 124 La Plata (1900) (Argentina)], E-mail:; Mendez, C.; Roso, L. [Grupo de Optica, Departamento de Fisica Aplicada, Universidad de Salamanca, Plaza de la Merced s/n, 37008 Salamanca (Spain); Tocho, J.O. [Centro de Investigaciones Opticas (CIOp), CIC-Conicet, CC 124 La Plata (1900) (Argentina)


    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{sup -3} which allows TE propagation. By pumping with a CW solid-state laser at 532 nm reaching the {sup 2}G{sub 9/2} and {sup 4}G{sub 7/2} manifolds of Nd{sup 3+} ions, we have explored the emission band corresponding to {sup 4}F{sub 3/2}{yields}{sup 4}I{sub 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 {sup 4}F{sub 3/2} metaestable level was determined to be 240 {mu}s 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.

  14. Synthesis and Modeling of Temperature Distribution For Nanoparticles Produced Using Nd:YAG Lasers

    Mu’ataz S. Hassan


    Full Text Available Nanosecond pulses of Nd:YAG laser were employed to produce silver and silicon nanoparticles by laser ablation process in liquid. Two Nd:YAG laser systems of 6 and 10 nanoseconds pulse duration with variable laser energy in the range 700–760 mJ were employed. Morphological investigation using AFM and TEM reveals the formation of silver and silicon nanoparticles with uniform size distribution. It is found that mean nanoparticles sizes of 50 and 70 nm for silver and silicon, respectively, are produced under similar laser parameters. Moreover, theoretical model was used to estimate the temperature distributions for both silver and silicon nanoparticles. It is also found that the maximum temperature of about 50 k K° and 70 k K° for silver and silicon nanoparticles, respectively, is generated when Nd:YAG of 10 ns is used to prepare nanoparticles. Zeta potential measurements reveal that silver nanoparticles are more stable than those of silicon prepared by similar conditions.

  15. Nd:YAG laser-induced hyperthermia treatment of spontaneously occurring veterinary head and neck tumors.

    Panjehpour, M; Overholt, B F; Frazier, D L; Klebanow, E R


    Conventional hyperthermia treatment of superficial tumors in the oral cavity is troublesome due to difficulty in accessing the lesion. A new hyperthermia technique employing near-infrared radiation delivered through a flexible silica optical fiber is described. The system consisted of an Nd:YAG laser for tissue heating, a He-Ne laser for aiming beam, a computer-controlled optical shutter, an interstitial thermometer, computer, and a printer. A 3-m-long 600-microns silica fiber delivered laser energy to the tumor via surface illumination. Using the aiming beam, the spot size was adjusted to include 5 mm of surrounding normal tissue. A thermocouple implanted in the tumor base provided temperature feedback to maintain desired hyperthermic temperature within the lesion. Three spontaneously occurring canine (two squamous cell carcinomas on the gum, one pigmented melanoma on the hard palate) and one feline tumor (squamous cell carcinoma on the nose) have been treated with Nd:YAG laser hyperthermia. Hyperthermia was delivered at 43.5 degrees C for 1 h. All animals received standard radiation treatment prior to hyperthermia. Nd:YAG laser hyperthermia allowed effective and efficient delivery of heat to veterinary nasal and oral lesions otherwise not treatable with conventional heating techniques.

  16. Effect of Heat Treatment on Crystallization of ND:YAG Ceramics

    ZHANG Huashan; HUI Han; SU Chunhui; ZHANG Hongbo


    (Nd0.01Y0.99)3Al5O12 nano-sized powders were synthesized by low temperature combustion (LCS), using Nd2O3, Y2O3, Al(NO3)3·9H2O, ammonia water and citric acid as starting materials. The powders were characterized by TG-DTA, XRD, FT-IR, ICP and TEM, respectively. The grain sizes were calculated by the Scherrer's formula using the full width at half maximum (FWHM) of YAG (420) crystal plane diffraction lines. The study focused on crystallization of ceramics at different heat treatment temperatures. The experimental results show that crystallizing temperature of YAG is 850℃ and the intermediate crystal phase YAP, appearing during heat treatment, transforms to YAG cubic crystal phase at the temperature of 1 050 ℃.The particle size of the powders synthesized by LCS is nano-sized. With the temperature increasing, the mean grain sizes raise, the stand deviations keep almost at the value of 2.0 and the lattice parameters decrease. The grains mainly grow by grain boundary diffusion. The lattice parameter expansion is caused by an increase of the repulsive dipolar interactions on surfaces of crystallites.

  17. Sub ablative Er: YAG laser irradiation on surface roughness of eroded dental enamel.

    Curylofo-Zotti, Fabiana Almeida; Lepri, Taísa Penazzo; Colucci, Vivian; Turssi, Cecília Pedroso; Corona, Silmara Aparecida Milori


    This study evaluated the effects of Er:YAG laser irradiation applied at varying pulse repetition rate on the surface roughness of eroded enamel. Bovine enamel slabs (n = 10) were embedded in polyester resin, ground, and polished. To erosive challenges, specimens were immersed two times per day in 20mL of concentrated orange juice (pH = 3.84) under agitation, during a two-day period. Specimens were randomly assigned to irradiation with the Er:YAG laser (focused mode, pulse energy of 60 mJ and energy density of 3.79 J/cm(2) ) operating at 1, 2, 3, or 4 Hz. The control group was left nonirradiated. Surface roughness measurements were recorded post erosion-like formation and further erosive episodes by a profilometer and observed through atomic force microscopy (AFM). Analysis of variance revealed that the control group showed the lowest surface roughness, while laser-irradiated substrates did not differ from each other following post erosion-like lesion formation. According to analysis of covariance, at further erosive episodes, the control group demonstrated lower surface roughness (P > 0.05), than any of the irradiated groups (P dental enamel eroded. The AFM images showed that the specimens irradiated by the Er:YAG laser at 1 Hz presented a less rough surface than those irradiated at 2, 3, and 4 Hz. © 2015 Wiley Periodicals, Inc.

  18. Photothermal ablation is the primary mechanism in holmium:YAG laser lithotripsy of urinary calculi

    Glickman, Randolph D.; Teichman, Joel M. H.; Corbin, Nicole S.; Vassar, George J.; Weintraub, Susan T.; Chan, Kin Foong; Welch, Ashley J.


    Because of the >= 250 microsecond(s) pulsewidth emitted by the Ho:YAG laser used in clinical lithotripsy, it is unlikely that stress confinement occurs within the irradiated stones. Experimental data supports a thermal mechanism for Ho:YAG laser stone ablation. Previous work has shown that stone fragmentation occurs soon after the onset of the laser pulse, is uncorrelated to cavitation bubble formation or collapse, and is associated with low pressures. Moreover, lithotripsy proceeds fastest with desiccated stones in air (data based on laser ablation of calcium oxalate monohydrate stones), indicating that direct absorption of the laser radiation by the stone material is required for the most efficient ablation. Lowering the initial temperature of calculi reduces the stone mass-loss following 20 J of delivered laser energy: 2.2 +/- 1.1 mg vs 5.2 +/- 1.6 mg for calcium oxalate monohydrate (COM) stones (-80 vs 23 degree(s)C), and 0.8 +/- 0.4 mg vs 2.2 +/- 1.1 mg for cystine stones (-80 vs 23 degree(s)C), p cystine; Ca2O7P2 from calcium hydrogen phosphate dihydrate, and cyanide and alloxan from uric acid. All of these observations are most consistent with a photothermal breakdown process induced by Ho:YAG laser lithotripsy.

  19. Selective removal of dental caries with a diode-pumped Er:YAG laser

    Yan, Ruth; Chan, Kenneth H.; Tom, Henry; Simon, Jacob C.; Darling, Cynthia L.; Fried, Daniel


    Selective removal of caries lesions with high precision is best accomplished using lasers operating at high pulse repetition rates utilizing small spot sizes. Conventional flash-lamp pumped Er:YAG lasers are poorly suited for this purpose, but new diode-pumped Er:YAG lasers have become available operating at high pulse repetition rates. The purpose of this study was to measure the ablation rate and selectivity of sound and demineralized enamel and dentin for a 30 W diode-pumped Er:YAG laser operating with a pulse duration of 20-30-μs and evaluate it's potential for the selective removal of natural occlusal lesions on extracted teeth. Microradiography was used to determine the mineral content of the demineralized enamel and dentin of 300-μm thick sections with natural caries lesions prior to laser ablation. The ablation rate was calculated for varying mineral content. In addition, near-IR reflectance measurements at 1500-1700- nm were used to guide the laser for the selective ablation of natural occlusal caries lesions on extracted teeth.

  20. In vitro study of the variable square pulse Er:YAG laser cutting efficacy for apicectomy.

    Grgurević, Josko; Grgurević, Lovro; Miletić, Ivana; Karlović, Zoran; Krmek, Silvana Jukić; Anić, Ivica


    Variable square pulse (VSP) Er:YAG laser should be quicker than older Er:YAG lasers. The objectives were: (1) comparison of VSP laser and mechanical handpiece efficacy for apicectomy and (2) determination of optimal pulse width/energy/frequency combination. Sixty extracted, single-rooted mature human teeth with round apical parts were instrumented, root filled, cleaned, and divided into four groups. Apical 2 mm of each root were apicectomized with mechanical handpiece and Er:YAG laser with three different settings (LaserA = 200 mJ/300 microseconds/ 8 Hz; LaserB = 200 mJ/100 microseconds/8 Hz; LaserC = 380 mJ/100 microseconds/20 Hz). Timing results were statistically compared. LaserC was the most efficient setting. Differences between groups were significant except between LaserC-Mechanical and LaserA-LaserC (P apicectomy is slower by a factor of 7-31 than mechanical handpiece, but treatment outcome is acceptable. Optimal settings for apicectomy with VSP laser are 380 mJ/100 microseconds/20 Hz. Copyright 2005 Wiley-Liss, Inc.

  1. Endoluminal Nd:YAG laser application in ex vivo biliary porcine tissue.

    Rea, Roberta; Di Matteo, Francesco Maria; Martino, Margareth; Pandolfi, Monica; Saccomandi, Paola; Rabitti, Carla; Crescenzi, Anna; Costamagna, Guido


    Adequate biliary drainage with endoscopic or percutaneous placement of self-expandable metal stents represents the goal of palliation in patients with inoperable malignant obstruction of the biliary tree. As an adjunct to stenting, various tissue ablation treatments have been proposed with conflicting results. The aim of this study was to test the effect on biliary tissue of a new ablation technique based on Nd:YAG laser light delivery. The study was conducted on ex vivo specimens of 18 healthy farm pigs, using cystic ducts that are the simplest biliary structures to isolate and cannulate ex vivo. A 22G cannula was positioned into the cystic duct and a quartz optical fibre, with a prototypal cooling system, was inserted into the cannula. Nd:YAG laser output powers of 10, 12, and 15 W were tested, with a total delivered energy of 1000 J in continuous mode in each case. After laser treatment, histological analysis was performed. At macroscopical examination, no lesions of the external wall of the cystic ducts were detected. At histopathological examination, a coagulative necrosis involving the entire mucosa up to the muscolaris propria without significant changes of periductal tissues was observed in all specimens. This study shows the possibility of using Nd:YAG laser on ex vivo porcine biliary ducts with the effect of obtaining a coagulative necrosis involving the whole mucosa.

  2. The analysis of the transient temperature distribution of double-slab Nd:YAG laser medium

    Yan Huang; Junqing Meng; Lingling Zhang; Qiquan Hu


    A novel double-slab Nd:YAG laser, which uses face-pumped slab medium cooled by liquid with different temperatures on both sides, is proposed. The thermal distortion of wavefront caused by the non-uniform temperature distribution in the laser gain media can be self-compensated. According to the method of operation, the models of the temperature distribution and stress are presented, and the analytic solutions for the model are derived. Furthermore, the numerical simulations with pulse pumping energy of 10 J and repetition frequencies of 500 and 1000 Hz are calculated respectively for Nd:YAG laser medium. The simulation results show that the temperature gradient remains the approximative linearity, and the heat stress is within the extreme range. Then the absorption coefficient is also discussed. The result indicates that the doping concentration cannot be too large for the high repetition frequency laser. It has been proved that the high repetition frequency, high laser beam quality, and high average output power of the order of kilowatt of Nd: YAG slab laser can be achieved in this structure.

  3. Long-pulse Nd:YAG 1064-nm laser treatment for onychomycosis

    ZHANG Rui-na; WANG Dong-kun; ZHUO Feng-lin; DUAN Xiao-han; ZHANG Xiao-yan; ZHAO Jun-ying


    Background Recent research shows that lasers can inhibit fungal growth and that Nd:YAG 1064-nm lasers can penetrate as deep as the lower nail plate.The aim of this study was to observe the effect of a long-pulse Nd:YAG 1064-nm laser on 154 nails of 33 patients with clinically and mycologically proven onychomycosis.Methods Thirty-three patients with 154 nails affected by onychomycosis were randomly assigned to two groups,with the 154 nails divided into three sub-groups (Ⅱ degree,Ⅲ degree,and Ⅳ degree) according to the Scoring Clinical Index of Onychomycosis.The 15 patients (78 nails) in group 1 were given eight sessions with a one-week interval,and the 18patients (76 nails) in group 2 were given four sessions with a one-week interval.Results In group 1,the effective rates at 8 weeks,16 weeks,and 24 weeks were 63%,62%,and 51%,respectively,and the effective rates in group 2 were 68%,67%,and 53% respectively.The treatment effect was not significantly different between any sub-group pair (P >0.05).Conclusions Long pulse Nd:YAG 1064-nm laser was effective for onychomycosis.It is a simple and effective method without significant complications or side effects and is expected to become an alternative or replacement therapy for onychomycosis.

  4. Composite material in the Al 2 O3 -20 vol% YAG system

    Radosław Lach


    Full Text Available Within alumina particle suspension yttria precursor was precipitated with ammonium carbonate. Drying and calcination at 600°C resulted in the mixture of alumina and yttria particles, the latter being much finer than alumina particles. This mixture was additionally homogenized by short attrition milling in aqueous suspension of pH selected on the basis of zeta (ζ potential measurements. It was found that acidic conditions (realized with HNO3 resulted in hard agglomerates. Such powder shows poor sintering ability. Much better properties showed powders homogenized under basic conditions. They give dense materials composed of YAG inclusions within alumina matrix. YAG particles resulted from the reaction of Y2O3 with Al2O3 during heat treatment. Homogenization of the system mixed at pH=8, corresponding to the heterofloculation conditions, is slightly better than observed at pH=10. YAG inclusions (20 vol% increase hardness and fracture toughness of the material in comparison with pure alumina polycrystals.

  5. Sol Freeze Dry Nd:YAG Nanopowder Synthesis and Sinterability Studies

    Rekha Mann


    Full Text Available Citrate nitrate sol freeze dry synthesis of 2 atomic % neodymium ion doped Yttrium Aluminium Oxide (Nd:YAG nanopowders was explored for the first time. Sol was prepared by dissolving nitrates of Al3+, Y3+ and Nd3+ keeping molar ratio to be 5: 2.94: 0.06. Total metal ion to citric acid ratio was optimised at 1 is to 0.25. Sol was freeze dried at -80 °C for 48 h. Dried mass thus obtained was calcined at 1000 °C for 2 h to give phase pure Nd:YAG as characterised by FTIR and XRD. Particles were in the size range of 35 nm - 50 nm with close to spherical morphology as observed by TEM. Nanopowder was compacted and sintered at 1700 °C for 5 h under 10-6 mbar followed by hot isostatic press at 1750 °C for 4 h under 200 MPa, to give 71 per cent transmission at 1064 nm indicating synthesis of well sinterable Nd:YAG nanopowders.

  6. The applications of diode and Er:YAG lasers in labial frenectomy in infant patients.

    Gontijo, Isa; Navarro, Ricardo S; Haypek, Patrícia; Ciamponi, Ana Lídia; Haddad, Ana Estela


    This paper describes a clinical case of labial frenectomy using different high power lasers: diode (810 nm) and Er:YAG (2940 nm). Considerations are made about specific indications, surgery techniques, and advantages of labial frenectomy using these laser wavelengths. The diode laser has high absorbance by pigmented tissues with hemoglobin, melanin, and collagen chromophores. For this reason, this wavelength is well indicated for surgery in soft tissue (vaporization, incision, coagulation, hemostasis). It is not properly absorbed, however, and should never be used in contact with hard tissues (bone). The Er:YAG laser has high absorbance to water and mineral apatite, making this wavelength useful and safe for the ablation of hard tissues. In the labial frenectomy clinical procedure, a combined technique is suggested: using the diode laser in soft tissues and the Er:YAG laser in periosteal bone tissues and for removal of final collagen fibers. It is important for the professional to understand the physical characteristics of the different laser wavelengths and their interaction with biological tissues to assure that they are used in a safe way, and that the benefits of this technology can be provided to infant patients.

  7. Comparison of SHR Mode IPL System with Alexandrite and Nd: YAG Lasers For Leg Hair Reduction

    Şemsettin Karaca


    Full Text Available Objective: Multiple lasers and light sources are currently available for hair removal and many studies comparing efficacy and safety exist. SHR mode IPL is a technique that gives the total energy in divided doses with fewer side effects. We compared a SHR mode IPL system with alexandrite and Nd: YAG lasers for leg hair reductionMaterial and Methods: Twenty-five female participants with skin types II–IV, underwent treatment of unwanted hair on the cruris. Three selected areas were randomly treated with the SHR mode IPL system, Alexandrite laser and Nd: YAG laser in three sessions. Hair reduction was evaluated with digital photography by a blinded assessor every 6 weeks and 6 months after the last session. Pain severity, side effects and patient satisfaction analysis were also investigated. Results: Twenty-one participants completed the trial. The mean hair reductions in 6 weeks after the last treatment were 50% for the IPL system, 53% for Alexandrite and 39% for the Nd: YAG lasers. However after 6 months; 40%, 49% and 34% hair reduction was observed, respectively. The Alexandrite laser was the least painful system. Conclusion: Although there is no obvious advantage of one laser system over the others in terms of treatment outcome, the Alexandrite laser is still the most efficient and reliable way of hair removal in fair skinned individuals.

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

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


    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.

  9. Photoluminescence enhancement of YAG:Ce3+ phosphor prepared by co-precipitation-rheological phase method

    YE Xinyu; LONG Zhen; YANG Youming; NIE Huaping; GUO Yanwei; CAI Yufa


    YAG:Ce3+ phosphor was prepared by a novel co-precipitation-rheological phase method.The resulting YAG:Ce3+ phosphor was characterized by X-ray diffraction (XRD),scanning electron microscopy (SEM) and photoluminescent emission spectra.By using acetic acid as solvent,YAG:Ce3+ powder with small particle size (≤2 μm) was obtained at a relatively lower sintering temperature of 1400 ℃.With the content of acetic acid increasing,small particles dissolved and disappeared,but larger particles grew up and changed its shape from spherical to partially rectangular.Meanwhile,the emission intensity of the sample prepared by co-precipitation-rheological phase method was about 43% higher than that of the sample prepared by co-precipitation method.It was assumed that the significant improvement of luminescence was mainly because the rheological phase presented a better diffusion environment,and therefore,a better homogeneity of activators of Ce3+.

  10. 1064 nm long-pulsed Nd:YAG laser treatment of basal cell carcinoma.

    Ortiz, Arisa E; Anderson, R Rox; Avram, Mathew M


    Standard surgical and destructive treatments for basal cell carcinoma (BCC) can result in significant morbidity and scarring, stimulating the investigation of alternative non-surgical options. The objective of this study was to determine the safety, clinical, and histological efficacy of pulsed, high-fluence 1064 nm Nd:YAG laser therapy for the treatment of BCC on the trunk and extremities. This was a prospective, non-randomized, open-label clinical trial. Ten subjects with a biopsy-proven BCC less than 1.5 cm in diameter on the trunk or extremities received one treatment with a 10 milliseconds pulsed 1064 nm Nd:YAG laser. Standard excision was performed 1 month after laser treatment to confirm histologic clearance. The laser treatment was quick and well tolerated. There was complete histologic clearance after one treatment in 92% of the BCC tumors, overall. At higher fluences, there was 100% histologic clearance after one treatment. No significant adverse events were seen, including scarring. The 1064 nm long-pulsed Nd:YAG laser may offer a safe alternative for treating BCC off the face. A larger study is highly warranted to confirm these preliminary results. Lasers Surg. Med. 47:106-110, 2015. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  11. Implant Surface Temperature Changes during Er:YAG Laser Irradiation with Different Cooling Systems.

    Monzavi, Abbas; Shahabi, Sima; Fekrazad, Reza; Behruzi, Roohollah; Chiniforush, Nasim


    Peri-implantitis is one of the most common reasons for implant failure. Decontamination of infected implant surfaces can be achieved effectively by laser irradiation; although the associated thermal rise may cause irreversible bone damage and lead to implant loss. Temperature increments of over 10ºC during laser application may suffice for irreversible bone damage. The purpose of this study was to evaluate the temperature increment of implant surface during Er:YAG laser irradiation with different cooling systems. Three implants were placed in a resected block of sheep mandible and irradiated with Er:YAG laser with 3 different cooling systems namely water and air spray, air spray alone and no water or air spray. Temperature changes of the implant surface were monitored during laser irradiation with a K-type thermocouple at the apical area of the fixture. In all 3 groups, the maximum temperature rise was lower than 10°C. Temperature changes were significantly different with different cooling systems used (Plaser with and without refrigeration. Thus, Er:YAG laser irradiation can be a safe method for treatment of periimplantitis.

  12. Pulpal Thermal Changes following Er-YAG Laser Debonding of Ceramic Brackets

    Didem Nalbantgil


    Full Text Available Lasers are effective in debonding ceramic brackets. Unfortunately, while reducing the adhesive bond strength, lasers are also reported to increase pulpal temperature. The aim of this study was to evaluate the shear bond strengths and temperature increase levels after debonding ceramic brackets using an Er-YAG laser with or without water-cooling. Sixty polycrystalline upper premolar ceramic brackets were placed on the labial surface of sixty human premolar teeth which were randomly divided into three groups of twenty. A laser pulse at 5 W for 9 seconds was delivered to each bracket in both study groups either with water-cooling (water group or without water-cooling (waterless group using an Er-YAG laser. Debonding was performed 45 seconds after laser exposure and shear bond strengths were measured. Data comparison revealed a statistically significant difference between the groups. Mean temperature increases of 2.41°C and 4.59°C were recorded for the water and waterless laser groups, respectively. The shear bond strength value for the control group was 22.76 MPa and 10.46 and 6.36 MPa for the water and waterless laser groups, respectively. The application of Er-YAG laser with water-cooling was an efficient and safe method of debonding ceramic brackets.

  13. Fine tuning of emission property of white light-emitting diodes by quantum-dot-coating on YAG:Ce nanophosphors

    Kong, Dal Sung [Department of Energy Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Kim, Min Jeong [School of Chemical & Biological Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Song, Hee Jo [Department of Materials Science and Engineering, Seoul National University, Seoul 151-742 (Korea, Republic of); Cho, In Sun [Department of Materials Science and Engineering & Energy Systems Research, Ajou University, Suwon 443-749 (Korea, Republic of); Jeong, Sohee [Nano-Mechanical Systems Research Division, Korea Institute of Machinery and Materials (KIMM), Daejeon 305-343 (Korea, Republic of); Shin, Hyunjung [Department of Energy Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Lee, Sangwook, E-mail: [School of Materials Science and Engineering, Kyungpook National University, Daegu 41566 (Korea, Republic of); Jung, Hyun Suk, E-mail: [School of Advanced Materials Science & Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)


    Highlights: • Surface-functionalization makes uniform coating of QDs on YAG nanoparticles. • Luminescence spectra of QD@YAG:Ce are finely tuned by QD contents. • Warm white LED with a high CRI of 92.82, and low CCT of 2617 K is obtained. - Abstract: We report fine tuning of emission color of Ce-doped yttrium aluminum garnet (Y{sub 3}Al{sub 5}O{sub 12}:Ce{sup 3+}, YAG:Ce) nanophosphor-based white light-emitting diodes (WLED), by coating CdSe/CdS/ZnS quantum dots (QDs) onto the surface of the YAG:Ce nanoparticles via surface functionalization of both the QDs and the YAG:Ce. Mixture of bromo-functionalized QDs and amino-functionalized YAG:Ce nanoparticles results in conformal coating of the QDs onto the YAG:Ce nanoparticles (QD@YAG:Ce). By varying the QD to YAG:Ce weight ratios, the luminescence spectra of the QD@YAG:Ce are tuned. A high-quality warm-white-light emission is achieved by appropriate combination of the yellow and red emissions from the QD@YAG:Ce, and the blue emission from InGaN LED chip. However, without surface functionalization, irregular mixtures of YAG:Ce and QDs are formed, which consequently make it hard to control the emission spectra. This study demonstrates a promising way to prepare uniformly QD-coated nanophosphors and an approach to control the emission spectra the nanophosphors.

  14. American Culture Reflected in American English



    Language is a vehicle for culture. It is also a key component of culture. It not only reflects culture but also influences culture. As a variety of British English, American English, especially American words and expressions can reflect American culture from many aspects. This paper studies some typical traits of American culture reflected in words and expressions of American Eng-lish.

  15. Marginal microleakage in vitro study of occlusal fissures sealing prepared and etched or not with Er: YAG laser; Avaliacao in vitro da microinfiltracao marginal em selamentos oclusais preparados e condicionados ou nao pelo laser de Er:YAG

    Youssef, Fernanda de Almeida


    The aim of this in vitro study was to evaluate the degree of marginal microleakage in occlusal sealing by invasive techniques, after preparation with Er:YAG laser followed or not by Er:YAG laser etching and compared to the conventional technique. Thirty human premolars were divided into three groups: A (control group) - cavities were prepared with high speed and etched with 37% orthophosphoric acid; group B - cavities were prepared with Er:YAG (350 mJ, 4 Hz and 112 J /cm{sup 2}) and etched with 37% orthophosphoric acid; group C - cavities were prepared with Er:YAG laser (350 mJ, 4 Hz and 112 J/cm{sup 2}), and etched with Er:YAG laser (80 mJ, 4 Hz and 25 m/cm{sup 2}). All cavities were treated with the same adhesive system and restored with flow composite according to manufacturer instructions. Teeth were submitted to thermal cycling procedures and immersed in 50% Silver Nitrate Solutions for 8 hours in total darkness. Teeth were sectioned longitudinally in the bucco-lingual direction, in slices of 1 mm thick. Each slice was immersed into photo developing solution under 16 hours of fluorescent light. Slices were photographed and microleakage was scored from 0 to 7 J by three standard examiners. Results showed statistically significant differences for group C (Er:YAG laser preparation and etching). We concluded that Er:YAG laser can be used for cavity preparation of occlusal sealing, like the conventional high speed method. However, this laser, used as enamel etching agent, could not promote an adequate surface for adhesive procedures. (author)

  16. Ce-doped YAG phosphors prepared via sol–gel method: Effect of some modular parameters

    Boukerika, A., E-mail: [Laser Department/Nuclear Research Centre of Algiers (CRNA), 02, Boulevard Frantz Fanon, B.P. 399, Algiers 16000 (Algeria); Laboratory of Materials Study, Faculty of Science, Department of Physics, Jijel University, B.P. 98, Ouled Aissa, Jijel 18000 (Algeria); Guerbous, L., E-mail: [Laboratory of Materials Study, Faculty of Science, Department of Physics, Jijel University, B.P. 98, Ouled Aissa, Jijel 18000 (Algeria); Brihi, N. [Laboratory of Materials Study, Faculty of Science, Department of Physics, Jijel University, B.P. 98, Ouled Aissa, Jijel 18000 (Algeria)


    Highlights: • Ce-doped YAG phosphor powders have been prepared using sol-gel method. • The influence of complexing agent and the molar ratio on some properties have been studied. • The effect of ethylene glycol and citric acid on the structural and luminescence havebeen discussed. • The specific role of molar ratio between ethylene glycol and citric acid has been studied. • The effect of pH on the pure phase and luminescence property of YAG: Ce has been discussed. - Abstract: Cerium doped yttrium aluminum garnet (YAG:Ce{sup 3+}) nanopowders have been synthesized using sol–gel method. Different synthesized parameters such as molar ratio of citric acid and ethylene glycol to the total metallic ions, complexing molar ratio and pH of the solution have been changed and their influence on structural and luminescence properties have been investigated. Thermal gravimetry and differential scanning calorimetry (TG/DSC), X-ray diffraction technique (XRD), Fourier transforms infrared spectroscopy (FTIR) and photoluminescence (PL) have been used to characterize the samples. Single cubic phase YAG was formed with pH ⩽ 4 and for pH ⩾ 6 additional impurities crystalline phase namely Y{sub 4}Al{sub 2}O{sub 9} (YAM) and YAlO{sub 3} (YAP) have been detected. All samples exhibit intense broad green–yellow emission band in the range of 460–700 nm with a maximum intensity at around 530 nm assigned to the 5d → 4f ({sup 2}F{sub 5/2}, {sup 2}F{sub 7/2}) interconfigurationnelles transitions of Ce{sup 3+} ion in YAG nanomaterial. The origin of the highest emission intensity obtained for pH = 4, citric acid to the total metallic ions of 1:1 (CA:M{sup 3+}, of 1:1) and a molar ratio of ethylene glycol:citric acid corresponding to 2:1 (EG:CA = 2:1) parameters are discussed.

  17. Comparative study of excimer and erbium:YAG lasers for ablation of structural components of the knee

    Vari, Sandor G.; Shi, Wei-Qiang; van der Veen, Maurits J.; Fishbein, Michael C.; Miller, J. M.; Papaioannou, Thanassis; Grundfest, Warren S.


    This study was designed to compare the efficiency and thermal effect of a 135 ns pulsed-stretched XeCl excimer laser (308 nm) and a free-running Erbium:YAG laser (2940 nm) with 200 microsecond(s) pulse duration for ablation of knee joint structures (hyaline and fibrous cartilage, tendon and bone). The radiant exposure used for tissue ablation ranged from 2 to 15 J/cm2 for the XeCl excimer and from 33 to 120 J/cm2 for Er:YAG. The excimer and Er:YAG lasers were operated at 4 and 5 Hz respectively. The ablative laser energy was delivered to tissue through fibers. Ablation rates of soft tissues (hyaline and fibrous cartilage, tendon) varied from 8.5 to 203 micrometers /pulse for excimer and from 8.2 to 273 micrometers /pulse for Er:YAG lasers. Ablation rates of soft tissues are linearly dependent on the radiant exposure. Within the range of parameters tested all the tissues except the bone could be rapidly ablated by both lasers. Bone ablation was much less efficient, requiring 15 J/cm2 and 110 J/cm2 radiant exposure for excimer and Er:YAG lasers to ablate 9.5 and 8.2 micrometers tissue per pulse. However, excimer laser ablation produced less thermal damage in the tissues studied compared to Er:YAG at the same laser parameters. The authors conclude that both lasers are capable of efficient knee joint tissue ablation. XeCl excimer laser requires an order of magnitude less energy than Er:YAG laser for comparable tissue ablation.

  18. Side-pumped neodymium slab lasers Q-switched by V:YAG on 1.3μm

    Jabczyński, Jan K.; Żendzian, Waldemar; Kwiatkowski, Jacek; Šulc, Jan; Němec, Michal; Jelínkova, Helena


    Nd:YAG and Nd:YAP crystals in form of triangle which makes possible to realize a slab side-pumped configuration with one total internal reflection were tested as an active media for diode-pumped laser. The resonator arrangements for Q-switched regime were prepared for the emission corresponding to Nd 3+ ion transition 4F 3/2--> 4I 13/2 referring to each crystal (λ= 1318 nm Nd:YAG and λ= 1342 nm Nd:YAP). Optical pumping was accomplished by a fast axis collimated quasi-CW diode DILAS E7Y1-808.3-600Q-H175V with peak power 600 W. Pumping radiation was focused by two plan-convex lenses into an active medium. The parameters of the pumping radiation were: wavelength 806nm, maximum pumping energy was 150mJ, pulse length 250μs, repetition rate up to 14 Hz. In free running regime the maximum reached energy was 24 mJ and 27.5 mJ for Nd:YAG and Nd:YAP, respectively. The corresponding obtained slope efficiency was 19.9 % and 23.7 % for Nd:YAG and Nd:YAP laser oscillator, respectively. Proper Q-switching for 1.3 μm was realized with saturable absorber V:YAG which initial transmission was optimized for shortest possible pulse length. For that obtained pulses were 6 ns with the energies 740 μJ and 432 μJ for Nd:YAG and Nd:YAP, respectively. This results correspond to peak power reached 125 kW (Nd:YAG), and 77 kW (Nd:YAP) in fundamental TEM 00 mode which allows this laser to be used as an efficient source for further nonlinear conversion or other applications.

  19. Radially polarized and passively Q-switched Nd:YAG laser with composite structure of gain medium

    Kegui Xia; Jianlang Li


    We report on a radially polarized and passively Q-switched Nd:YAG/Cr4+:YAG laser.The bulk Nd:YAG crystal is bonded with two undoped YAG crystal end caps to weaken the thermal lens effect and thus,enhance the extraction of stored energy in the bulk gain material.In the absence of active water cooling,the average laser power reaches 383 mW with 33% slope efficiency,and the laser pulse achieves 1.457-W peak power,18.9-ns duration,and 13.9-kHz repetition rate with 97.6% polarization purity.The radially polarized laser beam shows axial symmetry both in amplitude and polarization[1-3].The beam is applied in a variety of fields[3-8] such as particle trapping and acceleration[5],high-resolution microscopy[6],and material processing (e.g.,metal cutting or drilling).Because radially polarized light is globally of the ptype with respect to the cutting surface,the material absorption to the irradiation could be maximized,the significant effect of the cutting depth and cutting speed can be facilitated[7,8].This advantage has created a high demand for high power and radially polarized lasers.%We report on a radially polarized and passively Q-switched Nd:YAG/Cr4+:YAG laser. The bulk Nd:YAC crystal is bonded with two undoped YAG crystal end caps to weaken the thermal lens effect and thus, enhance the extraction of stored energy in the bulk gain material. In the absence of active water cooling, the average laser power reaches 383 mW with 33% slope efficiency, and the laser pulse achieves 1.457-W peak power, 18.9-ns duration, and 13.9-kHz repetition rate with 97.6% polarization purity.

  20. Histological and SEM analysis of root cementum following irradiation with Er:YAG and CO2 lasers.

    Almehdi, Aslam; Aoki, Akira; Ichinose, Shizuko; Taniguchi, Yoichi; Sasaki, Katia M; Ejiri, Kenichiro; Sawabe, Masanori; Chui, Chanthoeun; Katagiri, Sayaka; Izumi, Yuichi


    Recently, the Er:YAG and CO(2) lasers have been applied in periodontal therapy. However, the characteristics of laser-irradiated root cementum have not been fully analyzed. The aim of this study was to precisely analyze the alterations of root cementum treated with the Er:YAG and the CO(2) lasers, using non-decalcified thin histological sections. Eleven cementum plates were prepared from extracted human teeth. Pulsed Er:YAG laser contact irradiation was performed in a line at 40 mJ/pulse (14.2 J/cm(2)/pulse) and 25 Hz (1.0 W) under water spray. Continuous CO(2) laser irradiation was performed in non-contact mode at 1.0 W, and ultrasonic instrumentation was performed as a control. The treated samples were subjected to stereomicroscopy, scanning electron microscopy (SEM), light microscopy and SEM energy dispersive X-ray spectroscopy (SEM-EDS). The Er:YAG laser-treated cementum showed minimal alteration with a whitish, slightly ablated surface, whereas CO(2) laser treatment resulted in distinct carbonization. SEM analysis revealed characteristic micro-irregularities of the Er:YAG-lased surface and the melted, resolidified appearance surrounded by major and microcracks of the CO(2)-lased surface. Histological analysis revealed minimal thermal alteration and structural degradation of the Er:YAG laser-irradiated cementum with an affected layer of approximately 20-μm thickness, which partially consisted of two distinct affected layers. The CO(2)-lased cementum revealed multiple affected layers showing different structures/staining with approximately 140 μm thickness. Er:YAG laser irradiation used with water cooling resulted in minimal cementum ablation and thermal changes with a characteristic microstructure of the superficial layer. In contrast, CO(2) laser irradiation produced severely affected distinct multiple layers accompanied by melting and carbonization.

  1. Effects of Er:YAG laser irradiation on the microtensile bond strength to bleached enamel.

    Leonetti, Eduardo dos Santos; Rodrigues, José Augusto; Reis, André Figueiredo; Navarro, Ricardo Scarparo; Aranha, Ana Cecília Correa; Cassoni, Alessandra


    The objective of this study was to evaluate the influence of different Er:YAG laser (λ = 2.94  μm) energy parameters on the microtensile bond strength (μTBS) and superficial morphology of bovine enamel bleached with 16% carbamide peroxide. Laser irradiation could improve adhesion to bleached enamel surfaces. Sixty bovine enamel blocks (7 × 3 × 3  mm(3)) were randomly assigned to six groups according to enamel preparation procedures (n = 10): G1-bleaching and Er:YAG laser irradiation with 25.52  J/cm(2) (laser A, LA); G2-bleaching and Er:YAG laser irradiation with 4.42 J/cm(2) (laser B, LB); G3-bleaching; G4-Er:YAG laser irradiation with 25.52  J/cm(2); G5-Er:YAG laser irradiation with 4.42 J/cm(2); G6-control, no treatment. G1 to G3 were bleached for 6  h during 21 days. Afterwards, enamel surfaces in all groups were slightly abraded with 600-grit SiC papers and G1, G2, G4 and G5 were irradiated according to each protocol. Enamel blocks were then restored with an etch-and-rinse adhesive system and a 4-mm thick composite buildup was made in two increments (n = 9). After 24  h, restored blocks were serially sectioned with a cross-section area of ∼1  mm(2) at the bonded interface and tested in tension in a universal testing machine (1  mm/min). Failure mode was determined at a magnification of x100 using a stereomicroscope. One treated block of each group was selected for scanning electron microscopy (SEM) analysis. μTBS data were analyzed by two-way ANOVA and no statistical differences were observed among groups. Mean bond strengths (SD) in MPa were: G1-30.4(6.2); G2-27.9(8.5); G3-32.3(3.9); G4-23.7(5.8); G5-29.3(6.0); G6-29.1(6.1). A large number of adhesive failures was recorded for bleached and irradiated enamel surfaces. Bleached enamel surfaces μTBS values were not significantly different from those of unbleached enamel. Even though Er:YAG laser irradiation with both parameters had no influence on μTBS for bleached

  2. American Connections

    Petersen, Anne Ring


    The Danish artist Thomas Bang spent his early years in the USA. The works he created in this formative period were thus profoundly shaped by the contemporary movements in American art of the 1960s and 1970s when sculpture, or to be more precise, three-dimensional work became a hotbed of expansive...... experiments. This article traces how Bang made a radical move from painting to sculpture, which was characteristic of that time, and how he developed his artistic idiom by taking an active part in some of the seminal new departures in American art, in particular process art and post-minimalism. By leaping...... forward to Bang's later works produced after his return to Denmark, the article also demonstrates how the sculptural syntax and working principles developed in the early works still underlie and structure the artist's more allegorical sculptures and installations from the 2000s, thus testifying...

  3. Longitudinal Effect of Surface Treatments Modified by NaOCl-Induced Deproteinization and Nd:YAG Laser on Dentin Permeability.

    Esteves, Stella Renata Machado Silva; Huhtala, Maria Filomena Rocha Lima; Gomes, Ana Paula Martins; Ye, Qiang; Spencer, Paulette; De Paiva Gonçalves, Sérgio Eduardo


    The purpose of this study was to evaluate dentin permeability after dentin hypersensitivity treatments: fluoride, adhesive system, and collagen deproteinization with and without Nd:YAG laser exposure, and after erosive and abrasive challenges. Dentin permeability was assessed by measuring dentinal fluid flow using a permeability device. Eighty bovine dentin specimens (6 mm diameter/1 mm thickness) had permeability measured in the presence of the smear layer and after removal of the smear layer by ethylenediaminetetraacetic acid (EDTA). They were then divided into eight groups according to treatment (n = 10): Group C, control; Group L, Nd:YAG laser; Group F, fluoride; Group FL, fluoride plus Nd:YAG laser; Group A, adhesive; Group AL, adhesive plus Nd:YAG laser; Group D, 10% NaOCl plus adhesive; and group DL, NaOCl plus adhesive plus Nd:YAG laser. Nd:YAG laser was irradiated at 60 mJ/pulse/10 Hz/47.7 J/cm2/1 W and applied freehanded without contact for 60 sec. Permeability was measured 24 h after the treatments. The specimens were exposed to erosive and abrasive challenges for 5 days. Erosive challenge was done by immersion in Coca-Cola, four times a day/90 sec each. After the first and last erosive challenge of the day, the abrasive challenge was conducted by brushing the specimens (24,000 cycles/3.8 cm range/200 g weight), and permeability was measured again. Results were analyzed statistically using two factor ANOVA and Tukey tests (α = 0.05). With the exception of groups FL and A, all treatments reduced permeability. A significant reduction in permeability was seen when the treatments were combined with laser exposure. The association of adhesive and Nd:YAG laser led to the lowest rate of permeability after 24 h. NaOCl-induced deproteinization associated with Nd:YAG laser showed the lowest permeability rate after erosive/abrasive challenges. Dentin hypersensitivity treatments reduced dentin permeability when associated with Nd:YAG

  4. Er:YAG and alexandrite laser radiation propagation in the root canal and its effect on bacteria

    Jelinkova, Helena; Dostalova, Tatjana; Duskova, Jana; Miyagi, Mitsunobu; Shoji, Shigeru; Sulc, Jan; Nemec, Michal


    The goal of the study was to verify differences between the alexandrite and Er:YAG laser energy distribution in the root canal and in the surrounding dentin and bone tissues. For the experiment, two lasers were prepared: the Er:YAG laser (λ=2.94 μm) with a delivery system fluorocarbon polymer-coated silver hollow glass waveguide ended by a special sapphire tip and the alexandrite laser (λ=0.75 μm) with a silicon fiber. The Er:YAG laser was operated in a free-running mode, the length of the generated pulses was 250 μsec and the output energy ranged from 100 to 350 mJ. The pulse length of the free- running alexandrite laser was 70 μsec and the output energy was ranged from 80 up to 200 mJ. For the experiment prepared root canals of molars were used. It was ascertained that the radiation of the alexandrite laser passes through the root canal and hits the surrounding tissue. Nocardia asteroids, Filaments, Micrococcus albus, Lactobacillus sp and Streptococcus sanguis colonies were treated by the Er:YAG or alexandrite laser radiation. The surface was checked by scanning electron microscopy. From the result it follows that the Er:YAG laser destroyed microbial colonies but the differences is in the depth of the affected area.

  5. Luminescence properties of YAG:Nd3+ nano-sized ceramic powders via co-microemulsion and microwave heating

    He Jun; Pang Qi; Li Xia; Liang Chun Jie


    Nano-sized ceramic powders with weaker aggregation of Nd3+-doped yttrium aluminum garnet (YAG:Nd3+) were synthesized via co-microemulsion and microwave heating. This method provides a limited small space in a micelle for the formation of nano-sized precursors. It also requires a very short heating time, thus reducing energy consumption in comparison with conventional solid-state sintering processes. As a result, small-sized particles with narrow size distribution, weaker aggregation and high purity were obtained. Powder X-ray diffraction results revealed that the structure of pure YAG:Nd3+ nanoparticles was cubic garnet. Transmission electron microscopy results indicated that the synthesized particles were almost spherical with average diameters of 40 and 80 nm. The luminescent properties of YAG:Nd3+ were investigated through PL. Under excitation at 488 nm, YAG:Nd3+ nanosized ceramic powders showed main emission bands of 1045–1080 nm because of ${}^{4}F_{3/2} \\rightarrow 4I_{11/2}$ transitions that are identical to those observed for a single YAG:Nd3+ crystal.

  6. Enamel pretreatment with Er:YAG laser: effects on the microleakage of fissure sealant in fluorosed teeth

    Mahtab Memarpour,


    Full Text Available Objectives The purpose of this in vitro study was to evaluate the microleakage and penetration of fissure sealant in permanent molar teeth with fluorosis after pretreatment of the occlusal surface. Materials and Methods A total of 120 third molars with mild dental fluorosis were randomly divided into 6 groups (n = 20. The tooth surfaces were sealed with an unfilled resin fissure sealant (FS material. The experimental groups included: 1 phosphoric acid etching (AE + FS (control; 2 AE + One-Step Plus (OS, Bisco + FS; 3 bur + AE + FS; 4 bur + AE + OS + FS; 5 Er:YAG laser + AE + FS; and 6 Er:YAG laser + AE + OS + FS. After thermocycling, the teeth were immersed in 0.5% fuchsin and sectioned. Proportions of mircoleakage (PM and unfilled area (PUA were measured by digital microscope. Results Overall, there were significant differences among all groups in the PM (p = 0.00. Group 3 showed the greatest PM, and was significantly different from groups 2 to 6 (p < 0.05. Group 6 showed the lowest PM. Pretreatment with Er:YAG with or without adhesive led to less PM than bur pretreatment. There were no significant differences among groups in PUA. Conclusions Conventional acid etching provided a similar degree of occlusal seal in teeth with fluorosis compared to those pretreated with a bur or Er:YAG laser. Pretreatment of pits and fissures with Er:YAG in teeth with fluorosis may be an alternative method before fissure sealant application.

  7. Preparation and properties of Pr$_{3+}$/Ce$_{3+}$:YAG phosphors using triethanolamine as dispersant and pH regulator



    Pr$_{3+}$/Ce$_{3+}$:YAG precursors were co-precipitated using triethanolamine as dispersant and pH regulator. The different dosages of triethanolamine (D) vs. the properties of Pr$_{3+}$/Ce$_{3+}$:YAG phosphors were discussed. When $D = 0.5$ vol%, the pH of titration process was controlled in the range of $\\sim$7.94–8.16 to guarantee the uniform distribution of Al, Y, Ce and Pr in the precursors. The relatively higher pH could decrease the loss of Ce and Pr in the precursors and increase the particle size of the obtained powders, which was beneficial to the enhancement of luminescent intensity. Therefore, the precursors directly converted to pure-phase YAG at 900$^{\\circ}$C, and the phosphors calcined at 1000$^{\\circ}$C showed the best dispersity due to the dispersion effect of triethanolamine and the most excellent luminescent property. When $D ≥ 2$ vol%, although pure-phase YAG was detected, the emission intensity of the phosphors decreased due to the decrease of dispersity and purity. Moreover, the co-doped Pr$^{3+}$ enhanced the red emission of Pr$^{3+}$/Ce$^{3+}$:YAG phosphors.

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

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


    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.

  9. Assessing microleakage of composite restorations in class V cavities prepared by Er:YAG laser irradiation or diamond bur

    Sakineh Arami


    Full Text Available Introduction: The aim of this study was to make a comparison between microleakage of conventionally restored class V cavities using bur and acid etchant and, the ones prepared and conditioned by Er:YAG laser. Materials and Methods: 30 recently extracted intact caries and filling free human permanent molars were used for this study. Then, Cold cure acrylic resin was used to seal the apices. The samples were randomly assigned to 5 groups of six each. Class V cavities were prepared one on buccal and one on lingual surface of each sample. Group 1: cavity preparation by diamond bur and turbine + acid etch, Group 2: cavity preparation by Er:YAG laser + acid etch, Group 3: cavity preparation by Er:YAG laser + Laser etching, Group 4: cavity preparation by diamond bur and turbine + laser etching, Group 5: cavity preparation by Er:YAG laser with no conditioning procedure. The cavities restored with restorative composite resin. Samples were then immersed in 2% methylene blue solution for 24 hours. The data were then analyzed using Wilcoxon signed ranks test and Kruskal-Wallis statistical tests. Results: The Kruskal Wallis test showed a significant difference (P < 0.05 between enamel and cementum margin microleakage, while the higher microleakage was related to the cementum margin of restorations. Conclusion: There was no significant difference in evaluating microleakeage degree of cavities prepared by Er:YAG laser and diamond bur.

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

    Ashish Sharma


    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.

  11. Comparison of Nd: YAG capsulotomy rate between 1-piece and 3-piece acrylic intraocular lenses: A STROBE-compliant article.

    Kim, Sun Young; Chung, Young Kwon; Shin, Hye Young; Lee, Mee Yon; Lee, Young-Chun; Kim, Su-Young


    The aim of the study is to compare Nd:YAG capsulotomy rate between acrylic 1- and 3-piece intraocular lenses. Among 924 eyes of 762 patients who received cataract surgery, we selected the 303 patients (404 eyes) implanted with an SN60WF 1-piece intraocular lens (Alcon, Fort Worth, TX) or a YA-60BBR 3-piece intraocular lens (Hoya Co., Tokyo, Japan). For intraindividual comparison, we enrolled the 17 patients implanted with an SN60WF in 1 eye and a YA-60BBR in the contralateral eye. We compared Nd:YAG capsulotomy rate between acrylic 1- and 3-piece intraocular lenses 24 months after the operation. Of the 404 eyes in this study, Nd:YAG capsulotomy was performed in 20 of 268 eyes (7.5%) in the SN60WF 1-piece intraocular lens group and 24 of 136 eyes (17.6%) in the YA-60BBR 3-piece intraocular lens group; the difference was statistically significant (P = .002). Among the 17 patients (34 eyes) who were implanted with 2 different inraocular lenses, Nd:YAG capsulotomy was performed in only 2 eyes (12%) in the SN60WF group and 9 eyes (53%) in the YA-60BBR group; the difference was statistically significant (P = .020).The authors found a significantly greater incidence of Nd:YAG capsulotomy in eyes who received 3-piece lenses compared with those who received 1-piece lenses.

  12. Carbon dioxide laser versus erbium:YAG laser in treatment of epidermal verrucous nevus: a comparative randomized clinical study.

    Osman, Mai Abdel Raouf; Kassab, Ahmed Nazmi


    A verrucous epidermal nevus (VEN) is a skin disorder that has been treated using different treatment modalities with varying results. Ablative lasers such as carbon dioxide laser (CO2) and erbium:yttrium-aluminum-garnet (Er:YAG) laser have been considered as the gold standard for the treatment of epidermal nevi. To evaluate and compare the efficacy, postoperative wound healing and side effects of pulsed CO2 laser and Er:YAG laser for the treatment of verrucous epidermal nevi. Twenty patients with localized VEN were randomly divided into two groups. Group 1 was administered CO2 laser and group 2 underwent Er:YAG laser treatment. A blinded physician evaluated the photographs and dermoscopic photomicrographs for the efficacy and possible side effects. All patients received one treatment session and were followed up over a 6-month period. Both lasers induced noticeable clinical improvement, but there were no significant differences between two lasers in treatment response, patient satisfaction, duration of erythema and side effects. The average time to re-epithelialization was 13.5 days with CO2 and 7.9 days with Er:YAG laser (p< .0005). No scarring was observed in Er:YAG laser group and no lesional recurrence was detected in CO2 laser group since treatment. Apart from re-epithelialization, both lasers showed equivalent outcomes with respect to treatment response, patient satisfaction, side effects and complications.

  13. Síntese e caracterização do compósito Al2O3 -YAG e do Al2O3-YAG e Al2O3 aditivados com Nb2O5 Synthesis and characterization of Al2O3 -YAG composite and Al2O3-YAG and Al2O3 with Nb2O5 additives

    R. F. Cabral


    Full Text Available O compósito Al2O3-YAG possui alta resistência à corrosão e à fluência em ambientes agressivos, o que permite vislumbrar aplicações bastante atrativas, tais como aletas de motores a jato e de turbinas a gás. Este compósito também apresenta elevada dureza e alta resistência à abrasão possibilitando o seu emprego em blindagens balísticas. Nesse estudo os pós precursores de Al2O3, Y2O3 e Nb2O5 foram homogeneizados em moinho de bolas planetário por 4 h, secados em estufa a 120 ºC por 48 h, desaglomerados e peneirados. O compósito Al2O3-YAG foi produzido a partir das misturas de Al2O3-Y2O3 a 1300 ºC por 2 h. Foram produzidas amostras de Al2O3-YAG, Al2O3-YAG com Nb2O5 e Al2O3 com Nb2O5. Posteriormente os pós foram prensados uniaxialmente a 70 MPa. A sinterização foi feita a 1400 e 1450 ºC. Os pós como recebidos e os processados foram caracterizados quanto à área de superfície específica e ao tamanho médio de partícula. Os materiais sinterizados foram caracterizados por densidade e porosidade aparente pelo método de Arquimedes e avaliados quanto à retração e à perda de massa. Os resultados mostraram que são necessários ainda ajustes nas condições de sinterização da composição Al2O3-YAG com Nb2O5 para melhorar a densificação e a retração, que foram baixas, da ordem de 60 e 3%, respectivamente. O Al2O3 aditivado com Nb2O5, por sua vez, apresentou uma densificação satisfatória, de 96% e uma retração em torno de 15%.The Al2O3-YAG composite exhibits high corrosion and creep resistance in aggressive environments, which provides quite glimpse attractive applications such as jet engine vanes and as gas turbines. This composite also shows high hardness and wear resistance allowing its use in ballistic armor. In this study, precursor powders of Al2O3, Y2O3 and Nb2O5 were homogeneously mixed in a planetary ball mill for 4 h, dried in an oven at 120 ºC for 48 h, sieved and deagglomerated. The Al2O3-YAG composite

  14. Tratamiento de la estenosis traqueal isquémica con Nd-YAG láser Treatment of ischemic tracheal stenosis with Nd-YAG laser

    ILsa García Estrada


    Full Text Available Introducción: la estenosis traqueal corresponde a una complicación común, secundaria a la intubación o a la traqueotomía. Existen varias modalidades en cuanto a su tratamiento, por eso nos propusimos evaluar los resultados del tratamiento de la estenosis traqueal isquémica mediante fotorresección con Nd-YAG láser. Métodos: se realizó un estudio prospectivo descriptivo en 160 pacientes, con estenosis traqueal isquémica operados en el Servicio de Otorrinolaringología del Centro de Investigaciones Médico-Quirúrgicas, en el período comprendido de enero de 1987 hasta diciembre del 2010. Se clasificó a las estenosis traqueales postintubación, en 5 grupos, según Luis Rocabado y otros. El método diagnóstico empleado fue la broncoscopia. Los pacientes admitidos en el estudio tenían traqueotomía y fueron clasificados en grupo I y II. Como proceder quirúrgico se realizó fotorresección con Nd-YAG láser y colocación de cánula en T de Montgomery. Los enfermos se valoraron clínica y endoscópicamente al alta y posteriormente en consulta externa durante un período de 1 año. Resultados: el mayor porciento de los pacientes corresponde al sexo femenino. El rango de edad fue entre los 30 y 49 años con una desviación estándar de 36,7 ± 5,0 años. Se clasificaron 93 (58,1 % pacientes en el grupo I y 67 (41,9 % en el grupo II. La causa más frecuente de intubación endotraqueal prolongada, fue el politrauma. Se complicaron 13 pacientes, con una mortalidad de 2,5 %. El resultado final se evaluó como bueno en 94 pacientes (58,7 %, satisfactorio en 53 (33,2 % y malo en 9 (5,6 %. Conclusiones: el tratamiento inicial para las estenosis traqueales isquémicas clasificadas como grado I y II debe ser por vía endoscópica con Nd-YAG láser.Introduction: Tracheal stenosis is a common complication secondary to intubation or to tracheostomy. There are several treatment modalities to face this problem, hence we suggested that the results of the

  15. Combined application of Er:YAG and Nd:YAG Laser in Oral Homogeneous Leukoplakia%Er:YAG激光和Nd:YAG激光联合应用治疗口腔均质型白斑

    蒋红柳; 王文梅; 段宁; 白杨; 王翔


    目的:探讨Er:YAG激光和Nd:YAG激光联合应用治疗口腔均质型白斑的临床疗效。方法:应用Er:YAG激光和Nd:YAG激光联合治疗均质型白斑31例,根据病损面积、患者的疼痛状况调整激光参数。治疗间隔时间1个月。结果:本组31例白斑治愈14例,显效14例,有效3例,治愈率45.1%,有效率90.3%。结论:Er:YAG激光和Nd:YAG激光联合应用治疗口腔均质型白斑临床疗效好,不良反应小,是治疗口腔均质型白斑的有效方法之一。%Objective:To evaluate the effect of combined application of Er:YAG and Nd:YAG laser in oral homoge-neous leukoplakia. Method:Er:YAG and Nd:YAG laser were conducted in 31 patients with oral homogeneous leukoplakia , adjusting the parameters according to the lesional area,depth and pain extent of the patients. The Interval of therapy was 1 month. Result:Of the 31 patients with oral homogeneous leukoplakia,14 experienced more than 95% subsidence,14 achieved 60%~94%subsidence,3 got 30%~59%subsidence. The cure rate and effective rate were 45.1 %and 90.3%, respectively. Conclusion:The combined application of Er:YAG and Nd:YAG laser is an effective treatment on oral homoge-neous leukoplakia with fast effects and few side reactions.

  16. Preoperative Nd:YAG laser anterior capsulotomy in white intumescent cataracts: report of 11 cases Capsulotomia anterior pré-operatória com Nd:YAG laser em cataratas brancas intumescentes: relato de 11 casos

    Roberto Pinto Coelho


    Full Text Available Creating a continuous curvilinear capsulorhexis in eyes with white intumescent cataracts is a challenge due to the high risk of extension of capsular tears to the lens periphery. Several approaches have been described to avoid this complication and preoperative Nd:YAG laser anterior capsulotomy has been little reported as an optional technique. Eleven patients with white intumescent cataracts were submitted to preoperative Nd:YAG laser anterior capsulotomy. All patients had some degree of cortex falling in anterior chamber after laser application. No patient developed later complications. Thus, preoperative Nd:YAG laser anterior capsulotomy represents a safe and easy option for white intumescent cataracts.A realização da capsulorrexis curvilínea contínua em olhos com catarata branca intumescente é ainda considerada um desafio pelo alto risco de extensão da capsulotomia para a periferia do cristalino. Apesar da descrição de diversas técnicas cirúrgicas voltadas para a prevenção de tal complicação, o uso de Nd:YAG laser no pré-operatório tem raros relatos na literatura internacional. Onze pacientes com cataratas brancas intumescentes foram submetidos a capsulotomia pré-operatória com Nd:YAG laser. Todos os pacientes apresentaram, após a aplicação do laser, a saída de córtex liquefeito para a câmara anterior. Nenhum paciente apresentou complicações cirúrgicas com o procedimento. Desta forma, a capsulotomia anterior com Nd:YAG laser representa uma opção técnica fácil e segura no manejo de cataratas brancas intumescentes.

  17. [Gingival depigmentation for aesthetic purposes using erbium:YAG laser: rationale and technique].

    Tal, H; Oelgiessr, D; Tal, M


    Melanin, carotene and hemoglobin are the most common natural pigments contributing to the normal color of the gums. Although physiologic and ethnic melanin pigmentation is not a medical problem, complains about "black gums" are common. Gingival depigmentation has been carried out using surgical, chemical, electrosurgical and cryosurgical procedures. Recently, Laser Ablation has been recognized as one of the most effective, pleasant and reliable techniques. Effective depigmentation of the gingival requires removal of all or most of the melanocytes from the basal layer of the gingival epithelium. Using non-specific radiation means ablation of all the epithelial cell layers, as well as connective tissue rete pegs, leaving behind only remnants of the epithelial rete ridges. CO2, Nd:YAG and Erbium:YAG lasers, meeting most of these requirements and being available in the dental office, seems to be the lasers of choice for this procedure. Five patients (3 F; 2 M) who were referred to the TAUSDM for cosmetic therapy of "black gums" were treated using Erbium-YAG laser. The laser beam was set up at 850 mj/10 pulses per second producing peak power of 2.13 kwand peak power density of 30.43 kw/sq/cm. The beam was defocused to produce a 3 mm diameter circle, thus reducing the beam penetration while increasing the treated surface. Using the "brush" technique, 800-2,000 pulses were required per patient, with an average of 500-1,100 pulses per 1, depending on the thickness of the epithelium and the intensity of the pigmentation. Treatment required only topical anesthesia. Healing was uneventful and required no supportive therapy. Three months follow up has shown no repigmentation in any of the patients. Patients' evaluation analysis showed that the results were pleasing; no pain was experienced during lasing as well as during healing. Two patients were interupted by the lasing burning smell, which may be reduced or eliminated by operating a power suction during the procedure.

  18. Comparison of Dentin Permeability After Tooth Cavity Preparation with Diamond Bur and Er:YAG Laser

    Masoumeh Hasani Tabatabaei


    Full Text Available Objectives: The aim of this study was to compare the permeability of dentin after using diamond bur and Er:YAG laser.Materials and Methods: Seventy-two recently extracted, intact, and restoration-free human permanent molars were used in this study. The samples were randomly divided into three groups of 24 each and class I cavities were prepared as follows. Group 1: High speed diamond bur with air and water spray. Group 2: Er:YAG laser. Group 3: Er:YAG laser followed by additional sub-ablative laser treatment. Each group consisted of two subgroups with different cavity depths of 2mm and 4mm.  The entire cavity floor was in dentin. Two samples from each subgroup were observed under scanning electron microscope (SEM. The external surfaces of other samples were covered with nail varnish (except the prepared cavity and immersed in 0.5% methylene blue solution for 48 hours.  After irrigation of samples with water, they were sectioned in bucco-lingual direction. Then, the samples were evaluated under a stereomicroscope at ×160 magnification. The data were analyzed using two-way ANOVA and Tukey’s HSD test.Results: Two-way ANOVA showed significant difference in permeability between groups 2 and 3 (laser groups with and without further treatment and group 1 (bur group. The highest permeability was seen in the group 1. There was no significant difference in dentin permeability between groups 2 and 3 and no significant difference was observed between different depths (2mm and 4mm.Conclusion: Cavities prepared by laser have less dentin permeability than cavities prepared by diamond bur.

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

    D K Gupta


    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.


    王立清; 胡盛涛; 李澎; 谢峰; 吴清玉; 郭加强


    Objective. To study the mechanism and effects of blood perfusion to the acute ischemic region of myecardium through Ho-YAG laser channels with myocardial contrast echocardiography Methods. To produce the model of acute myocardial ischemia, we partially ligated the left anterior decending (IAD)coromry artery of canine hearts between 1st. and 2nd. diagonal branches and then performed transmyocardial revasmgafizafion in this region with Ho- YAG laser. Myocardial contrast echecardingmphy was made with a new gen-eration of ultrasound contrast agent and second harmonic imaging of this region before,after ischemia and after laser revascalarizafion. Pictures were taken with “R” wave trigger skill. Results. Acoustic demity derterming in the ischemia region (anterior wall)with MCE(myocardial contrast e-checardiography) was obviously decreased(5.40 ± 1.81) after the LAD was ligated,as compared with before( 11.69± 1.61, P 0.05). There were no dif-ferences in acoustic density in the lateral wall(as control)among these comprehensive three periods (P > 0.05). Con-trast in the laser region developed one cardiac cycle ahead of that in the non-iscbemic normal region. Conclusion. Acute ischemic myecardium can be perfused by oxygenated blood from the left ventricle through Ho-YAG laser channels. Evidenee of blood perfusion through laser channels during systolic phase was detected,and my-ocardial cormast ultrasonngtaphy using intravenous perfluorocarbon-exposed sonicated dextrose albumin may be regard-ed as a reliable method in the study of tranmlyecardial revasculariztion.

  1. Photoluminescence characterization of porous YAG: Yb{sup 3+}–Er{sup 3+} nanoparticles

    Desirena, H., E-mail: [Centro de Investigaciones en Óptica, A. P. 1-948, León 37150, Guanajuato (Mexico); Diaz-Torres, L.A. [Centro de Investigaciones en Óptica, A. P. 1-948, León 37150, Guanajuato (Mexico); Rodríguez, R.A. [Centro Universitario de Los Lagos, Universidad de Guadalajara, Lagos de Moreno, Jalisco (Mexico); Meza, O. [Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apartado Postal J-48, Centro Historico 72570, Puebla (Mexico); Salas, P. [Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, Apartado Postal 1-1010, Querétaro 76000, Querétaro México (Mexico); Angeles-Chávez, C. [Instituto Mexicano del Petróleo, Ciudad México, D.F. 07730, México (Mexico); Tobar, E.H.; Castañeda-Contreras, J. [Centro Universitario de Los Lagos, Universidad de Guadalajara, Lagos de Moreno, Jalisco (Mexico); De la Rosa, E., E-mail: [Centro de Investigaciones en Óptica, A. P. 1-948, León 37150, Guanajuato (Mexico)


    Yb{sup 3+}/Er{sup 3+} codoped yttrium aluminium garnet (YAG) porous nanocrystals were prepared by glycolate method assisted with poly-vinyl alcohol (PVA) and urea. The typical cubic structure for YAG was confirmed from XRD with crystallite average size of ∼40 nm, calculated from Scherrer formula and corroborated by TEM. Strong green and red upconversion emissions are observed readily with the naked eyes, and the color coordinates were obtained from emission spectra. A theoretical model to calculate CIE coordinate as a function of donor (Yb{sup 3+}) and acceptors (Er{sup 3+}) concentration is proposed. The eye-safe near infrared emitted signal and fluorescence lifetime were also measured and results show lifetime as large as 8.5 ms. The maximum energy transfer efficiency from Yb{sup 3+} to Er{sup 3+} was 72% for 20 mol% of Yb{sub 2}O{sub 3}. The proposed mechanisms for signal emitted are explained in terms of direct and energy back transfer processes, and cross relaxation. - Highlights: • Strong upconversion emission were observed in YAG:Er{sup 3+}–Yb{sup 3+} samples. • Color emission can be tuned from green to red by choosing properly the Yb{sup 3+} concentration. • The experimental colour coordinates match very well with the proposed theoretical model. • Cross relaxation and energy back transfer are mainly responsible for the red emission. • Fluorescence lifetime of {sup 4}I{sub 13/2} level increase with the Yb{sup 3+} concentration.

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

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


    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.

  3. Nd:YAG Laser to obtain Irregularities on the Inner Surface of Porcelain.

    Porto, Thiago Soares; Porto, Betina Grehs; de Campos, Edson Alves; Porto-Neto, Sizenando de Toledo; da Silva, Monica Barros; Bhandi, Shilpa H; Tonetto, Mateus Rodrigues; Dinelli, Welingtom; Bandeca, Matheus Coelho


    The aim of this study was to evaluate the inner surface of two ceramic systems: IPS Empress II (Ivoclar Vivadent, Germany) and In-Ceram Alumina (Vita Zahnfabrick, Germany) submitted to surface treatments, especially by Nd:YAG laser. Fifty samples were prepared in pellet form for each ceramic system according to manufacturers' specifications. The samples were stored at room temperature and then be subjected to surface treatment: without treatment (T0) (control), hydrofluoric acid-etched (T1), hydrofluoric acid-etched associated with the airborne particle-abraded (T2); CoJet system (T3), Nd:YAG laser (T4). The data were performed the statistical analysis by ANOVA and Tukey's test (p treatment with hydrofluoric acid (T1), associated with hydrofluoric acid and airborne particle-abraded (T2) and Nd:YAG laser (T4), had no statistically significant difference, whereas for the IPS Empress System II treatment with hydrofluoric acid (T1) and hydrofluoric acid associated with airborne particle-abraded (T2), had no statistically significant difference between the system and also CoJet (T3) and hydrofluoric acid associated with the airborne particle-abraded (T2). Photomicrographs of scanning electron microscopy showed different characteristics to the treatments for each ceramic system. The IPS Empress II had the appearance of favoring the retention when treated with hydrofluoric acid, as well as its association with the airborne particle-abraded. Uncertainty in Alumina, treatment with hydrofluoric acid associated with the airborne particle-abraded and CoJet system and provided a surface with irregularities. With respect to the laser further studies should be performed for parameters that are ideal for your application. The ceramic restorations are attractive due of their excellent esthetics and the ability to stay for long periods. However, the retention of ceramic requires further study.

  4. Effects of Er:YAG laser treatments on surface roughness of base metal alloys.

    Kunt, Göknil Ergün; Güler, Ahmet Umut; Ceylan, Gözlem; Duran, Ibrahim; Ozkan, Pelin; Kirtiloğlu, Tuğrul


    We investigated the effects of different Er:YAG laser treatments on the surface roughness of base metal alloys. A total of 36 specimens were prepared of two base metal alloys (Wiron 99, Bellabond plus). The surfaces of the specimens were standardized by gradual wet grinding with 320-, 600-, 800- and 1,000-grit silicon carbide paper for 10 s each on a grinding machine at 300 rpm. Specimens of each alloy were randomly divided into six groups (n = 6) comprising a control group (group C), a group sandblasted with Al(2)O(3) powder at 60 psi for 10 s through a nozzle at a distance of 10 mm (group S), and four Er:YAG laser (Fotona AT) treatment groups. The laser treatment groups were as follows: 500 mJ, 10 Hz, 100 μs (group 500MSP); 500 mJ, 10 Hz, 300 μs (group 500SP); 400 mJ, 10 Hz, 100 μs (group 400MSP); and 400 mJ, 10 Hz, 300 μs (group 400SP). Surface roughness measurements (Ra) were performed using a profilometer. The data were analysed by two-way ANOVA, and mean values were compared using Tukey's HSD test (α = 0.05). According to the two-way ANOVA results, the base metal alloys and interaction between base metal alloy and surface treatment were not statistically significant different (p > 0.05), the surface treatments were significantly different (p Er:YAG laser treatment at 400 and 500 mJ/10 Hz is not an alternative method for surface roughening of base metal alloys.

  5. Cellulite: a new treatment approach combining subdermal Nd: YAG laser lipolysis and autologous fat transplantation.

    Goldman, Alberto; Gotkin, Robert H; Sarnoff, Deborah S; Prati, Clarissa; Rossato, Flávia


    Cellulite is an alteration of the topography of the skin that occurs in body areas where fat deposition seems to be under the influence of estrogen: mainly the hips, buttocks, thighs, and abdomen. The presence of cellulite is a significant source of patient dissatisfaction. There is currently no cure or consistently effective treatment for cellulite. The authors sought to show that the subdermal application of the neodymium-doped yttrium aluminium garnet (Nd:YAG) laser combined with autologous fat transplantation is a safe and effective treatment for cellulite. From January 2003 to December 2006, 52 female patients with Curri grade III to IV cellulite were treated with subdermal 1064-nm Nd:YAG laser lipolysis combined with autologous fat transplantation. Patient assessment was collected for data analysis. After the treatment, tissue samples were obtained in some subjects in order to ascertain the histologic effects of the laser treatment. This treatment resulted in significant clinical improvement in cellulite. The adverse effects were mild and temporary, and the postoperative period was well tolerated. A majority of patients (84.6%) rated the results of treatment as either good or excellent. The treatment of severe cases of cellulite (Curri grades III and IV) by a combination of 1064-nm Nd:YAG laser lipolysis and autologous fat transplantation proved to be both safe and effective. In addition, subdermal laser lipolysis has the advantage of inducing neocollagenesis and stimulating postoperative skin tightening. This represents a new treatment option for the ubiquitous cellulite disorder. Although this treatment has shown promising results in this pilot study, further studies are necessary in order to draw final conclusions.

  6. Treatment of Axillary Osmidrosis Using a Subcutaneous Pulsed Nd-YAG Laser

    Daejin Kim


    Full Text Available Background Axillary osmidrosis is characterized by an unpleasant odor, profuse sweating, andin some instances, staining of clothes that may socially and psychologically impair affectedindividuals. Various types of surgical procedures have been developed for the treatment ofaxillary osmidrosis. This study was undertaken to evaluate the effectiveness of subcutaneouspulsed neodymium: yttrium-aluminum-garnet (Nd-YAG laser treatment for the treatment ofaxillary osmidrosis.Methods Twenty-nine patients with axillary osmidrosis were included in this study. Patientswere categorized according to the results of an axillary malodor grading system, and asubcutaneous pulsed Nd-YAG laser was applied to all patients. The treatment area for theappropriate distribution of laser energy was determined using the iodine starch test (Minor’stest against a grid pattern composed of 2×2 cm squares. The endpoint of exposure was300 to 500 J for each grid, depending on the preoperative evaluation results. The resultswere evaluated by measurement of axillary malodor both pre- and postoperatively using thegrading system and iodine starch test.Results The average follow-up period was 12.8 months. Nineteen patients had a fair-togoodresult and ten patients had poor results. The postoperative Minor’s test demonstratedthat there were remarkable improvements for patients with mild to moderate symptoms.Complications including superficial second degree burns (n=3 were treated in a conservativemanner. A deep second degree burn (n=1 was treated by a surgical procedure.Conclusions Subcutaneous pulsed Nd-YAG laser has many advantages and is an effectivenoninvasive treatment for mild to moderate axillary osmidrosis.

  7. Do Parameters Of Irradiation Influences The Apical Sealing Of Er:YAG Laser Apicetomies?

    Marques, Aparecida Maria Cordeiro; dos Santos, Jean Nunes; Pinheiro, Antonio Luiz Barbosa


    Failures on the sealing of the tooth apex are responsible for many failures of apical surgeries. The Er:YAG laser has been proposed as an alternative for the use of rotator instruments on surgical endodontics. 12 human extracted canines had root endodontic treatment being the apical limit was set at 1mm before the apical foramen and were distributed into 2 groups. On group I, apicectomy was performed with the Er:YAG laser (250 mJ/15 Hz). Apical cut was performed of perpendicular mode with 3mm from the apical foramen. On Group II, the same procedures and the same sequence as above was used, varying only the parameters of the Er:YAG laser (400 mJ/6 Hz). The specimens were divided into groups and fixed, by the cervical third, on wax. Impermeabilization of the residual root apical third was performed following the same procedures used in the cervical third but the residual apex was left free from the impermeabilization. After that, the roots were immersed in a 2% methylene blue solution and placed in a bacteriological oven for 48 h. The segments were visually observed and the one showing greatest level of dye leakage was selected and kept in individual container and coded accordingly. Apical staining was measured using a stereoscopic magnifying glass; a compass; and caliper. The results showed that Group I showed significantly different higher mean level of dye leakage (5.67±4.9, papicectomies carried out with 400 mJ/6 Hz showed the smallest infiltration value.

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

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


    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.

  9. Odontoblast response to cavity preparation with Er:YAG laser in rat molars: an immunohistochemical study.

    Shigetani, Yoshimi; Suzuki, Hironobu; Ohshima, Hayato; Yoshiba, Kunihiko; Yoshiba, Nagako; Okiji, Takashi


    This study aimed to examine the dynamics of odontoblast-lineage cells following cavity preparation with erbium:yttrium-aluminum-garnet (Er:YAG) laser in rat molars. Cavity preparation was made with Er:YAG laser in the mesial surface of the maxillary left first molar of 8-week-old Wistar rats. Contralateral first molar served as unirradiated control. Immediately, 6 and 12 h and 1, 2, 3, 5 and 7 days after the lasing (n = 5, each), specimens were collected and processed for immunohistochemistry for heat-shock protein (HSP)-25 and nestin as markers for odontoblast-lineage cells. Cell proliferation assay using bromodeoxyuridine (BrdU) labeling was also performed. Unirradiated teeth showed HSP-25- and nestin-immunoreactivity in odontoblasts. At 6-12 h after irradiation, the odontoblastic layer was disorganized and some of odontoblasts lost the immunoreactivity to HSP-25 and nestin. At 1-2 days, however, HSP-25- and nestin-immunoreactivities in the odontoblast layer showed a noticeable recovery, resulting in the rearrangement of odontoblast-like cells intensely immunoreactive to HSP-25 and nestin at 3-7 days. BrdU-positive cells showed a significant increase at 2 days (P cavity preparation with Er:YAG laser induced mild and reversible damage to odontoblasts. The reparative process was characterized by the rearrangement of HSP-25- and nestin-immunoreactive odontoblast-like cells, which took place subsequent to the odontoblastic layer disorganization with partial loss of these immunoreactivities.

  10. Impact of pulse duration on Ho:YAG laser lithotripsy: fragmentation and dusting performance.

    Bader, Markus J; Pongratz, Thomas; Khoder, Wael; Stief, Christian G; Herrmann, Thomas; Nagele, Udo; Sroka, Ronald


    In vitro investigations of Ho:YAG laser-induced stone fragmentation were performed to identify potential impacts of different pulse durations on stone fragmentation characteristics. A Ho:YAG laser system (Swiss LaserClast, EMS S.A., Nyon, Switzerland) with selectable long or short pulse mode was tested with regard to its fragmentation and laser hardware compatibility properties. The pulse duration is depending on the specific laser parameters. Fragmentation tests (hand-held, hands-free, single-pulse-induced crater) on artificial BEGO stones were performed under reproducible experimental conditions (fibre sizes: 365 and 200 µm; laser settings: 10 W through combinations of 0.5, 1, 2 J/pulse and 20, 10, 5 Hz, respectively). Differences in fragmentation rates between the two pulse duration regimes were detected with statistical significance for defined settings. Hand-held and motivated Ho:YAG laser-assisted fragmentation of BEGO stones showed no significant difference between short pulse mode and long pulse mode, neither in fragmentation rates nor in number of fragments and fragment sizes. Similarly, the results of the hands-free fragmentation tests (with and without anti-repulsion device) showed no statistical differences between long pulse and short pulse modes. The study showed that fragmentation rates for long and short pulse durations at identical power settings remain at a comparable level. Longer holmium laser pulse duration reduces stone pushback. Therefore, longer laser pulses may result in better clinical outcome of laser lithotripsy and more convenient handling during clinical use without compromising fragmentation effectiveness.

  11. Morphological change study on root surfaces treated with curettes, sonic instruments or Er:YAG laser; Estudo in vitro da alteracao morfologica em superficie radicular tratada com curetas, aparelho ultrasonico ou com laser de Er:YAG

    Guimaraes Filho, Arlindo Lopes


    Periodontal disease is caused by dental plaque and dental calculus on roots surfaces, specially on cervical areas. As dental plaque is the main cause and dental calculus a secondary one, it is practically impossible to separate one factor to the other one. In order to get periodontal tissue health it is necessary to eliminate dental plaque and calculus from root surfaces. In this sense, Er:YAG laser comes in as an excellent way to control periodontal disease, not only, by removing calculus and dental plaque but also for its bacteria reduction. The aim of this study is to compare, by S.E.M., root surfaces changing when they are treated with curettes and ultrasonic scaling or Er:YAG laser irradiation with two different energy levels of 60 mJ/pulse and 100 mJ/pulse and repetition tax of 10 Hz (in the display). It is also objective of this study to check a possible thermic damage to pulp tissue when the roots surfaces are irradiated with Er:YAG laser. We used for this study, five human dental roots, each one of them were cut into four samples, giving us a total of twenty samples, which were divided in five groups of four samples each one. The control group, we did not indicated any kind of treatment. The first group, the roots samples were scaled and planned with Gracey curettes 5/6 and 7/8. The second group, the roots samples were treated with ultrasonic instruments. The third group was irradiated with Er:YAG laser using 60 mJ/pulse , 10 Hz and energy density of 4 J/cm{sup 2} (approximated). The fourth group was irradiated with Er:YAG laser using 100 mJ/pulse, 10 Hz and energy density of 7 J/cm{sup 2} (approximated). The results analysis showed that roots scaling either with Gracey curettes or with ultrasonic instruments created smear layer covering roots surfaces; roots surfaces irradiated with Er:YAG laser showed few roughness in the third group; roots surfaces irradiated with Er:YAG laser showed no smear layer and the Er:YAG laser irradiation did not bring any

  12. Avaliação morfológica da união entre adesivo/resina composta e dentina irradiada com laser Er:YAG e laser Nd:YAG: estudo comparativo por microscopia de varredura Morphological evaluation of the bonding between adhesive/composite resin and dentin irradiated with Er:YAG and Nd:YAG lasers: comparative study using scanning microscopy

    Margareth ODA


    Full Text Available Desde a introdução de sistemas adesivos nos procedimentos restauradores com materiais estéticos, tem-se estudado de forma abrangente o tipo de tratamento na superfície dentinária para se consagrar uma técnica ideal. A utilização do ácido fosfórico a 37% sobre a dentina é atualmente ainda o método que mais se domina em termos de adesividade. Porém, métodos de tratamento alternativos, na dentina, têm sido discutidos na literatura, entre eles a aplicação de alguns tipos de irradiação a laser. O objetivo desta pesquisa foi avaliar morfologicamente a união adesivo/resina composta e dentina irradiada com laser Er:YAG e laser Nd:YAG num estudo comparativo por microscopia de varredura, utilizados em substituição ao condicionamento ácido ou associados ao mesmo. Foram utilizados dentes bovinos recém-extraídos, que receberam um preparo de cavidade de classe V, e restauração com sistema adesivo e resina composta fotoativada. Como variantes alguns deles receberam o tratamento prévio de irradiação com laser Er:YAG e outros de irradiação com laser Nd:YAG, à aplicação do agente adesivo e da resina composta. As amostras foram seccionadas, preparadas para microscopia de varredura e submetidas a uma análise morfológica, e foram feitos os registros por meio de fotomicrografias. Com base nessas observações microscópicas, concluímos que somente no tratamento da superfície da dentina com laser Er:YAG e condicionamento ácido houve penetração da resina na dentina. Nos tratamentos com laser Nd:YAG, houve apenas aparente superposição da resina na superfície dentinária, sugerindo que houve oclusão dos túbulos com características de fusão na dentina superficial.Since bonding systems were introduced in the restorative procedures carried out with esthetic materials, the treatment of dentin surfaces has been widely studied in order to establish the ideal technique. The application of 37% phosphoric acid on dentin is still

  13. Hereditary haemorrhagic telangiectasia treated by pulsed neodymium:yttrium-aluminium-garnet (Nd:YAG) laser (1,064 nm).

    Werner, A; Bäumler, W; Zietz, S; Kühnel, T; Hohenleutner, U; Landthaler, M


    Hereditary haemorrhagic telangiectasia (HHT) is a familial, autosomal, dominant, multi-system, vascular, dysplasia. Besides repetitive epistaxis, cutaneous eruptive macules and nodules lead to recurring bleeding and cosmetic problems. We report on a pilot study of four cases of HHT in which cutaneous lesions were treated with a pulsed neodymium:yttrium-aluminum-garnet (Nd:YAG) laser (1,064 nm). Pulsed Nd:YAG laser treatment, without anaesthesia, was performed several times on eruptive angiomas on palmar and facial skin. Lesions on fingers and face mostly showed very good, or even complete, clearing after the first laser treatment. Several macules required multiple treatment; only a few lesions showed no effect. Pulsed Nd:YAG laser therapy (1,064 nm) appears to be an effective and safe treatment option for hereditary haemorrhagic telangiectasia on the skin of face and extremities.

  14. Evaluation of Er:YAG laser radiation cavity preparation under transmitted and polarized light and by electron microanalyser

    Dostalova, Tatjana; Krejsa, Otakar; Rokytova, Kveta; Jelinkova, Helena; Hamal, Karel


    The results of evaluation of Er:YAG radiation cavity preparation under transmitted and polarized light and by the electron microanalyzer are presented. We examined the longitudinal sections of intact teeth, teeth with early dental caries, teeth with laser preparation in enamel and teeth with Er:YAG laser preparation in enamel and dentine class I and V. We examined intact teeth and laser prepared teeth for the variation of mineralization. Phosphorus and calcium were regularly distributed. The margins of cavities had no necrosis zones. The defects of mineralization in caries depend on demineralization of hard tissues. In the structures was irregular loss of calcium and phosphorus. Thus, Er:YAG laser irradiation with water cooling has been found to be a non-invasive preparation technique.

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

    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:; Meng Yao; Huang Lan [Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041 (China)


    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.

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

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


    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. Analysis of therapeutical effects of Er:YAG and CO2 laser post treatments of small hemangiomas

    Remlová, E.; Vránová, J.; Rosina, J.; Navrátil, L.


    The main goal of our study was the evaluation of treatment efficiency of two types of ablative laser-CO2 and Er:YAG (or ERB) treatment. 183 patients (Er:YAG—105 patients, CO2—78 patients) were analyzed to compare the curative effects and adverse events, such as loss of pigment and appearance of scars caused by these two lasers. The results of the study showed the slightly better effectiveness of Er:YAG laser radiation in comparison with CO2 laser in the case of treatment of small hemangiomas up to 3 mm in diameter. In the Er:YAG laser application the curative effect was in 99%, hypo-pigmentation occurred in 18%, and scars in 70% of all treatments. In the CO2 laser application the curative effect was in 97%, hypo-pigmentation in 52%, and scars in 77% from all treatments.

  18. Effect of cobalt oxide on the sintering and grain growth of Al2O3-YAG composite nanopowder

    Hassanzadeh-Tabrizi S.A.


    Full Text Available In the present study, the effect of cobalt oxide on the densification of Al2O3-YAG composite nanopowder was investigated. An amorphous nanopowder was synthesized and crystallized to Al2O3-YAG after heat-treatment via a solid-state reaction. The average particle size of heat-treated powder at 800°C was about 80 nm. Cobalt oxide improved the sintering rate of Al2O3-YAG composite nanopowders and promoted grain boundary mobility. Cobalt oxide doping increased the ratio of densification/grain growth rate. The activation energy for grain growth decreased from 590 to 485 kJ/mol by adding cobalt oxide to the composite nanopowder.

  19. Adapting American Policymaking to Overcome American Exceptionalism


    missions, and of military operations spanning administrations. In conclusion, an apologist posture to defend American foreign policies is not called...military operations spanning administrations. In conclusion, an apologist posture to defend American foreign policies is not called for. However, a deep...and brings to light the tension between American ideals and American practices and policies. V/ hen exposed, this tension opens the door for American

  20. Effective shortening of picosecond pulses emitted by a YAG:Nd/sup 3 +/ laser

    Dianov, E.M.; Karasik, A.Y.; Mamyshev, P.V.; Onishchukov, G.I.; Prokhorov, A.M.; Stel' makh, M.F.; Fomichev, A.A.


    A 15-fold reduction in the duration of YAG:Nd/sup 3 +/ laser pulses was achieved under conditions of active mode locking and Q switching at a pulse repetition frequency approx.1 kHz. Phase self-modulation in a single-mode quartz fiber waveguide of length 10 m resulted in broadening of the laser emission spectrum right up to approx.10 cm/sup -1/ at the waveguide exit. The pulses were then shortened in a system with a diffraction grating. The pulse duration was measured by a correlation system in which the second harmonic was generated.

  1. Spectroscopic characterization of dynamical processes for Tm,Ho:YAG lasers

    Armagan, G.; Buoncristiani, A. M.; Edwards, W. C.; Inge, A. T.; Dibartolo, B.


    The energy transfer processes in Tm,Ho:YAG lasers were investigated in spectral studies and measurements of the temporal response to pulsed excitation. These processes include the population of the 3H4 pump band of Tm, cross-relaxation in Tm, the transfer of energy from Tm to Ho, and various loss mechanisms. It was found that the Tm cross-relaxation is due to a dipole-dipole interaction between Tm ions and that the rate of this process is a function of temperature and ion concentration.

  2. Continuous-wave theory of Yb:YAG end-pumped thin-disk lasers.

    Jafari, Ahmad Khayat; Aas, Mehdi


    The fundamental principles of the operation of a thin-disk laser are presented. We derived equations from a set of coupled rate equations that predict that the characteristics of a laser are affected by the Boltzmann occupation factors of the pump and the laser states simultaneously. The model is used to investigate the influence of the effective parameters on the operational efficiency of an end-pumped Yb:YAG disk laser. Based on our results, we examined laser output power as a function of output coupler reflectivity, crystal thickness or doping concentration, number of the pump beam passes, and temperature.

  3. A 12.1-W SESAM mode-locked Yb:YAG thin disk laser

    Yingnan, Peng; Zhaohua, Wang; Dehua, Li; Jiangfeng, Zhu; Zhiyi, Wei


    Pumped by a 940 nm fiber-coupled diode laser, a passively mode-locked Yb:YAG thin disk oscillator was demonstrated with a semiconductor saturable absorber mirror (SESAM). 12.1 W mode-locked pulses were obtained with pulse duration of 698 fs at the repetition rate of 57.43 MHz. Measurement showed that the beam quality was close to the diffraction limit. Project supported by the National Key Basic Research Program of China (Grant No. 2013CB922402), the National Major Instrument Program of China (Grant No. 2012YQ120047), and the National Natural Science Foundation of China (Grant No. 61210017).

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

    Deam, R T; Harris, J


    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

  5. Vapor emissions resulting from Nd:YAG laser interaction with tooth structure.

    Gelskey, S C; White, J M; Gelskey, D E; Kremers, W


    The Neodymium:yttrium aluminum garnet (Nd:YAG) dental laser has been cleared by the United States Food and Drug Administration (FDA) for marketing in intraoral soft tissue treatment. The efficacy and safety of the Nd:YAG laser in the treatment of hard dental tissue as well as the effects of dental irradiation on the pulp and periodontium have been investigated. Odors resulting from laser irradiation have been reported, but the nature and toxicity of associated decomposition vapors is unknown and the health consequences of their inhalation have not yet been studied. The purpose of this in vitro study was to identify vapors emitted during interaction of the Nd:YAG laser with carious human enamel and dentin and sound enamel and dentin coated with organic ink. Vapor emissions were collected from prepared sections of extracted human teeth receiving laser irradiation of 100 mJ and 10 Hz for a duration of 1, 10, or 60 s. Emissions were collected by means of charcoal absorption tubes, and subsequently analyzed using a Gas Chromatograph equipped with Mass Selective (GC/MS) and Flame Ionization Detectors to identify the chemical constituents of the vapors. No compounds were identified in Nd:YAG laser-treated caries, enamel and dentin. No volatile vapors were identified from samples of tooth materials exposed to the laser for 1 or 10 s. Camphor was positively identified in the test sample which consisted of India ink-coated dentin and the reference sample of India ink-coated glass beads, both exposed to the laser for 60 s. 2,5-norbornadiene was tentatively identified in these samples. The Threshold Limit Value (TLV) of camphor is 2 ppm with a Lethal Dose Level (LDLo) of 50 mg/kg (human oral), while the TLV and LDLo of 2,5-norbornadiene is unknown. Occupational and public health safety measures are discussed in this article. Further research is needed to quantify the compounds produced and to determine their toxicity to patients and to dental care providers.

  6. Preliminary report on use of the neodymium-YAG laser in plastic surgery.

    Apfelberg, D B; Smith, T; Lash, H; White, D N; Maser, M R


    Thirty-four patients with 57 cutaneous lesions have been treated with the Nd:YAG laser under an experimental protocol over a year of study. The majority of treatments were done on an outpatient basis under local anesthesia. Capillary/cavernous hemangiomas of the oral cavity responded well, but hemangiomas of infancy responded poorly. Hypertrophic scars and keloids responded well only in conjunction with steroid treatment. Epistaxis in patients with hereditary hemorrhagic telangiectasia responded well for 4-5 months and then recurred. Areas with thin skin or mucosa have the potential for full-thickness injury with complications of scar, bony exposure, or septal perforation.

  7. Tunable Sum Frequency Mixing of a Ti∶sapphire Laser and a Nd∶YAG Laser

    DING Xin; YAO Jianquan; YU Yizhong; YU Xuanyi; XU Jingjun; ZHANG Guangyin


    In this paper the theoretical and experimental results of sum-frequency mixing of a Ti∶sapphire laser and a 1.064 μm Nd∶YAG laser are presented. By using two KTP crystals cut at θ=76° and 85° (φ=90° in both crystals), respectively, the sum-frequency mixing tuning range from 459.3 to 509.6 nm in one Ti∶sapphire laser setup is experimentally achieved. The maximum output energy was 14.6 mJ and the energy conversion efficiency was up to 15.2%.

  8. Effect of Er:YAG laser on debonding strength of laminate veneers

    Iseri, Ufuk; Oztoprak, Mehmet Oguz; Ozkurt, Zeynep; Kazazoglu, Ender; Arun, Tulin


    Objective: The purpose of this study was to evaluate the debonding strength of laminate veneers after using erbium-doped: yttrium aluminium garnet (Er:YAG) laser. Materials and Methods: A total of 60 bovine mandibular incisor teeth were divided into two groups (n = 30). Cylindrical specimens (0.7 mm × 5 mm) were fabricated from Empress II ceramic. Then, they were cemented to incisors using dual-cured resin cement (Variolink II). In the first group, no laser application was performed. The Er:Y...

  9. Effects of root surface debridement using Er:YAG laser versus ultrasonic scaling - a SEM study.

    Miremadi, S R; Cosyn, J; Schaubroeck, D; Lang, N P; De Moor, R J G; De Bruyn, H


    Despite promising results of Er:YAG laser in periodontal debridement, to date there is no consensus about the ideal settings for clinical use. This experimental clinical trial aimed to determine the effects of debridement using Er:YAG laser and to compare with ultrasonic treatment. Sixty-four teeth were divided into two in vivo and in vitro subgroups. Each tooth received ultrasonic treatment on one side and Er:YAG laser debridement at either 60, 100, 160 or 250 mJ pulse(-1) and at 10 Hz on the other side on a random basis. All samples were morphologically analyzed afterwards under scanning electron microscope for surface changes and dentinal tubules exposure. Treatment duration (d) was also recorded. Laser debridement produced an irregular, rough and flaky surface free of carbonization or meltdown while ultrasound produced a relatively smoother surface. The number of exposed dentinal tubules (n) followed an energy-dependent trend. The number of exposed tubules among the in vivo laser groups was n 60 mJ = n 100 mJ lasers led to significantly more dentinal exposure than ultrasound under in vivo condition. Within the in vitro laser groups, dentinal tubules exposure was n 60 mJ laser treatments at 100, 160 and 250 mJ led to significantly more dentinal denudation than ultrasound. Treatment duration (d) for the in vivo groups was d 60 mJ > d 100 mJ > d Ultrasound = d 160 mJ > d 250 mJ (P ≤ 0.046), while for the in vitro groups it was d 60 mJ > d 100 mJ = d Ultrasound = d 160 mJ >d 250 mJ (P ≤ 0.046). Due to excessive treatment duration and surface damage, Er:YAG laser debridement at 60 and 250 mJ pulse(-1), respectively, is not appropriate for clinical use. Although laser debridement at 100 and 160 mJ pulse(-1) seems more suitable for clinical application, compared to ultrasound the former is more time-consuming and the latter is more aggressive. Using a feedback device or lower pulse energies are recommended when using laser in closed field. © 2014 John Wiley

  10. DUVEX: An X-ray counting system based on YAG:Ce scintillator

    Andre, J.-M., E-mail: [Laboratoire de Chimie Physique - Matiere et Rayonnement, UPMC, CNRS UMR 7614, 11 rue Pierre et Marie Curie, F-75231 Paris Cedex 05 (France); Le Guen, K.; Jonnard, P. [Laboratoire de Chimie Physique - Matiere et Rayonnement, UPMC, CNRS UMR 7614, 11 rue Pierre et Marie Curie, F-75231 Paris Cedex 05 (France); Menesguen, Y. [CEA, LIST, Laboratoire National Henri Becquerel, F-91191 Gif-sur-Yvette (France)


    A detector system, called DUVEX, has been developed for the soft-x-ray and extreme ultraviolet domain. It consists of a YAG:Ce scintillator coupled to a photomultiplier module working under vacuum in counting mode. The design and the performances of this detector in terms of yield, absolute efficiency, response and noise are reported. Spectra in the soft x-ray range of different elements (W, Ag, Al, Mg, Cu, N, C and B) obtained in WDS mode using this detector are presented. DUVEX appears as a competitive detection tool in terms of cost and easiness of implementation.

  11. [Moist ablation of the corneal surface with the Er:YAG laser. Results of optimizing ablation].

    Bende, T; Jean, B; Matallana, M; Seiler, T; Steiner, R


    The Er:YAG laser, emitting light at 2.94 microns, may be an alternative to the 193 nm excimer laser for photorefractive keratectomy. Compared to the excimer laser, the ablation rate is very high. Surface roughness is also more pronounced than for the excimer laser. Using a precorneal liquid film, these two factors can be reduced, as shown in ablation experiments performed on porcine corneas. Thermal damage of the remaining corneal tissue is another side effect. There is no significant decrease in the amount of thermal damage with this new technique,--not even when the pulse length is reduced.

  12. Spherical YAG:Ce3+ Phosphor Particles Prepared by Spray Pyrolysis

    Qi Faxin; Wang Haibo; Zhu Xianzhong


    Spherical YAG:Ce3+ phosphor particles with narrow size distribution were prepared by spray pyrolysis. The effects of the concentration of solution, the flow rate of carrier gas and the annealing temperature on the phosphor morphology were studied. The productivity of precursor particles shows a trend of drop after rising with the increase of concentration. Raising the flow rate of nitrogen can improve the productivity of the precursor particles. Phosphor prepared by spray pyrolysis has obviously higher emission intensity than that synthesized by solid state reaction, spray pyrolysis makes Ce3+ ions well distributed in the crystal lattice as the luminescent centers, and phosphor particles have regular sphericity and narrow size distribution.

  13. Nd:YAG Ceramic ThinZag (registered trademark) High-Power Laser Development


    CHAPTER 9 Nd:YAG Ceramic ThinZag® High-Power Laser Development Daniel E. Klimek Principal Research Scientist, Textron Defense Systems, Wilmington...ThinZag High-Power Laser Development 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER...Power Laser Development N d : Y A G C e r a m i c T h i n Z a g ® H i g h - P o w e r L a s e r D e v e l o p m e n t 209 over the years at

  14. Impulse transfer to the surface of aluminum and copper from a pulsed Nd: YAG laser

    Xu, Bingzhang; Wang, Qingpu; Zhang, Xingyu; Zhao, Shenzi; Xia, Yueyuan; Mei, Liangmo; Wang, Xiangtai; Wang, Gongtong


    Impulse coupling coefficients in air from 1.06 μm, 10 ns, Nd: YAG pulsed-laser radiation to aluminum and copper targets are measured using the ballistic pendulum method in the laser power-density range from 2.0×108 W/cm2 to 4.0×109 W/cm2. A modified laser-supported detonation (LSD) wave and cylindrical blast wave theory incorporating the vaporization model is proposed to calculate the impulse coupling coefficients. It is found that the theoretical results obtained with the modified model agree well with the experimental data.

  15. Regenerative amplification and bifurcations in a burst-mode Nd:YAG laser.

    Mance, Jason G; Slipchenko, Mikhail N; Roy, Sukesh


    An Nd:YAG-based burst-mode regenerative amplifier laser was developed that offers high extraction efficiency at high repetition rates with low seed energies. The regenerative amplification technique, combined with the burst-mode laser technology, shows promise as an efficient method for amplification of femtojoule-nanojoule pulses up to millijoule energies at repetition rates exceeding 100 kHz. Output energies at repetition rates near the inverse upper state lifetime are limited by bifurcations in the pulse energies of the burst. A model is developed and advantages and limitations are discussed.

  16. Nd:YAG laser induced E' centers probed by in situ absorption measurements

    Cannas, M.; Messina, F.


    We investigated various types of commercial silica irradiated with a pulsed Nd:YAG laser radiation (4.66 eV), with exposure time ranging up to 10000 s. Transient E' centers were probed in situ by measuring the amplitude of the optical absorption band at 5.8 eV (due to E' centers) both during and after irradiation. The laser-induced absorption is observed only in natural samples, whereas the synthetic materials exhibit high toughness to radiation effect. The reported results evidence that the ...

  17. UV and visible upconversion luminescence in Er3+:YAG under red laser excitation

    Yang Hai-Gui; Dai Zhen-Wen; Zu Ning-Ning


    This paper reports that the ultraviolet and visible upconversion luminescence from the 4S3/2, 2G9/2 and 2Ps/2 levels have been observed in Er3+:YAG following 647.2 nm excitation of the 4F9/2 multiple. Upconversion luminescence intensity dependence on pump power was recorded. The measured decay profiles were theoretically fitted by kinetics theory and the basically good agreements were achieved. The results indicate that some energy transfer processes proposed to explain the observed upconversion phenomena are reasonable.

  18. Effects of output waveforms on penetration for Nd: YAG laser welding


    By using a Nd: YAG laser welding system devised for transmitting continuous, rectangular and pulsed waveforms, comprehensive and deep investigation is focused on the effects of several parameters of rectangular waveform and pulsed output wave superimposed on a rectangular waveform on the penetration depth of weld. Research results indicate that the average power, duty cycle, frequency and peak power of rectangular wave affect the weld penetration depth to different extent. Results of experiments and analysis also indicate that the pulse delay time, pulse width and the power ratio of pulse to rectangular waveform seriously influence the penetration when the pulsed wave is superimposed on a rectangular waveform.

  19. Posterior capsule opacification and neovascularization treated with intravitreal bevacizumab and Nd:YAG capsulotomy

    Sánchez-Castro, Grimelda Yuriana; Hitos-Fájer, Alejandra; Mendoza-Schuster, Erick; Velez-Montoya, Raul; Velasco-Barona, Cecilio Francisco


    We reported a 75-year-old diabetic man, who developed opacification and neovascularization of the posterior capsule after extracapsular cataract extraction and posterior chamber intraocular lens implantation. The patient was treated with two injections of 2.5 mg of intravitreal bevacizumab. The treatment produced an important regression of the posterior capsular new vessels, allowing us to perform a successful Nd:YAG capsulotomy, clearing the visual axis and improving the visualization of the posterior pole. Even though, best corrected visual acuity was 20/200 due to diabetic macular edema. PMID:19668770

  20. Polarization properties of laser-diode-pumped micro-grained Nd:YAG ceramic lasers

    Otsuka, Kenju


    Detailed polarization properties have been examined in laser-diode-pumped (LD-pumped) micro-grained ceramic Nd:YAG lasers in different microchip cavity configurations. Stable linearly-polarized single-frequency oscillations, whose polarization direction coincides with that of an LD pump light, were observed in an external cavity scheme. While, in the case of a thin-slice laser scheme with coated reflective ends, elliptically-polarized single-frequency operations took place in the low pump-power regime and dynamic instabilities appeared, featuring self-induced antiphase modulations among counter-rotating circularly-polarized components belonging to the same longitudinal mode, with increasing the pump power

  1. Yagé una posible experiencia de transformación

    Vergara Carulla, Ignacio


    Cuando en nuestra cultura vamos a hacer una reflexión sobre una planta sagrada como el Yagé , muy posiblemente hablaremos de ella clasificándola como una "droga", una "sustancia química", un "principio activo" que va a producir en nuestro sistema nervioso o en nuestro organismo, un efecto determinado el cual puede ser medido, cualificado, repetido en situaciones experimentales diferentes y convalidado dentro de una manera determinada de percibir la realidad, la cual está encuadrada dentro de ...

  2. Application of YAG laser technique in the treatment of anal fistula

    Liu, Jian-xun; Zhang, Xinrong


    The method of treating anal fistula with YAG laser technique is described in this essay. One-hundred-twenty patients have been treated successfully with this method and no recurrence was found in our series. Anal fistula is a common disorder in the anus and rectum. The tunnel of fistula zigzags around the external or internal sphincters. If the drainage is poor, and the skin around the external opening grows rapidly, false healing may occur and cause recurrent abscess. In this case, a fistula can not be cured except by operation.

  3. Diffractive optics for reduction of hot cracking in pulsed mode Nd:YAG laser welding

    Bagger, Claus; Olesen, Søren; Roos, Sven-Olov


    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...... of systematic tests, the applicability of this system is tested on an industrial 1 kW Nd:YAG laser. Three separate series of tests are conducted, one with the diffractive optical system at 500 W and two without the diffractive system at 400 W and 500 W, respectively. In principle the diffractive, optical system...

  4. Characterization of spectral hole depth in Tm3+ :YAG within the cryogenic temperature range

    Chen Lei; Ma Xiu-Rong; Wang Wei; Zhang Shuang-Gen; Mu Kuan-Lin; Wang Xia-Yang; Zhang Shi-Yu


    In this paper,spectral hole depth dependence on temperature below 10 K in Tm3+∶YAG crystal is investigated in detail.A novel model is proposed to analyze the temperature dependence on the spectral hole.By using the proposed model,we theoretically deduce the temperature dependence of spectral hole depth.The results are compared with experimental results and they are in good agreement.According to the theoretic results,the optimum temperature in experiment can be found.

  5. Electronic structure calculations of rare-earth intermetallic compound YAg using ab initio methods

    (S).U(g)ur; G.U(g)ur; F.Soyalp; R.Ellialtio(g)lu


    The structural,elastic and electronic properties of YAg-B2(CsC1) were investigated using the first-principles calculations.The energy band structure and the density of states were studied in detail,including partial density of states (PDOS),in order to identify the character of each band.The structural parameters (lattice constant,bulk modulus,pressure derivative of bulk modulus) and elastic constants were also obtained.The results were consistent with the experimental data available in the literature,as well as other theoretical results.

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

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


    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.

  7. Er:YAG pre-treatment for bonding of orthodontic bracket: 1 year of in vitro treatment

    de Jesus Tavarez, Rudys Rodolfo; Lima Bezerra, Gisele; de Souza Penha, Karla Janilee; Torres, Carlos Rocha Gomes; Firoozmand, Leily Macedo


    Objective The aim of this study was to evaluate in vitro bond strength of metal brackets bonded with: total etch, total etch with erbium: yttrium aluminum garnet laser (Er:YAG) and self-etching adhesive systems, submitted to thermal-mechanical cycling, simulating 1 year of orthodontic treatment. Materials and methods For the study, 80 bovine incisors were randomly divided into 3 experimental groups (n=16 each): XT- acid etching + Transbond XT, XT/Er:YAG- Transbond XT associated with Er:YAG laser irradiation (λ=2.94 μm, 60 mJ, 10 Hz) and SEP- Transbond Plus Self Etching Primer. Samples were submitted to thermal-mechanical cycling, simulating 1 year of orthodontic treatment. Afterward, the shear bond strength test was performed in a universal test machine at a speed of 0.5mm/min. Samples were evaluated under a stereomicroscope and by scanning electron microscopy for analysis of enamel surface and adhesive remnant index. Data were analyzed using Kruskal–Wallis and Mann–Whitney (with Bonferroni correction) statistical tests. Results Statistically significant difference was observed between the groups studied (p<0.05). Groups XT and SEP showed the highest bond strength values, without statistical difference between them, while group XT/Er:YAG showed reduction in bond strength values. Higher frequency of adhesive failures between enamel and adhesive system was verified for groups XT and XT/Er:YAG. Conclusion The conventional (XT) and self-etching (SEP) adhesive systems showed mean bond strength values, similar between them, whereas the previous application of Er:YAG laser promoted the lowest bond strength values.

  8. Thermoluminescence investigations of sol–gel derived and γ-irradiated rare earth (Eu and Nd) doped YAG nanophosphors

    Kurrey, M.S. [Department of Applied Physics, Government Engineering College, Bilaspur 495006 (India); Tiwari, Ashish, E-mail: [Department of Chemistry, Government Lahiri College, Chirimiri 497449 (India); Khokhar, M.S.K. [Department of Rural Technology, Guru Ghasidas Vishwavidyalaya, Bilaspur 495006 (India); Kher, R.S. [Department of Physics, Government E.R.R. PG Science College, Bilaspur 495006 (India); Dhoble, S.J. [Department of Physics, RTM Nagpur University, Nagpur 440033 (India)


    Nanocrystalline YAG doped with Eu{sup 3+} and Nd{sup 3+} has been synthesized by a sol–gel technique. The prepared nanophosphors were calcined and characterized by XRD, SEM. The XRD analysis revealed well-defined cubic phase. Electron microscopy showed spherical morphologies with an average size of 15–20 nm. The thermoluminescence (TL) properties of as prepared nanophosphors were investigated after γ-irradiation using {sup 60}Co source at room temperature. It has been found that there is a prominent TL glow peak at 290–295 °C for the as prepared doped samples. The TL glow curve showed variation in TL peak intensity as the concentration of dopant is changed. Kinetic data and trap depth for the synthesized samples were calculated by a peak shape method. It has been found that TL response is nonlinear in the range 0.29–1.16 kGy. This paper discusses about the optimal doping concentration of Eu and Nd in YAG nanophosphors. - Highlights: • TL properties of YAG:Eu{sup 3+}/Nd{sup 3+} nanoparticles were investigated after γ-irradiation. • TL peak intensity and glow curve structure varies with concentration of dopant. • Optimal TL intensity was obtained for YAG:Eu{sub 3.0}. and YAG:Nd{sub 3.0}. • Blue-shift in the TL peaks was observed as the gamma dose is increased for YAG:Eu{sub 5.0}. • TL response was found to be nonlinear in the range 0.29–1.16 kGy.

  9. Effects of Er:YAG laser on bond strength of self-etching adhesives to caries-affected dentin.

    Koyuturk, Alp Erdin; Ozmen, Bilal; Cortcu, Murat; Tokay, Ugur; Tosun, Gul; Erhan Sari, Mustafa


    The erbium:yttrium-aluminum-garnet (Er:YAG) laser may be effective the bond strength of adhesive systems on dentine surfaces, the chemical composition and aggressiveness of adhesive systems in clinical practice. The purpose of this study was to evaluate the effects of the Er:YAG laser system with the bonding ability of two different self-etching adhesives to caries-affected dentine in primary molars. Ninety mid-coronal flat dentine surfaces obtained from sound and caries-affected human primary dentine were treated with an Er:YAG laser or a bur. The prepared surfaces were restored with an adhesive system (Xeno V; Clearfil S³) and a compomer (Dyract Extra). The restored teeth were sectioned with a low-speed saw and 162 samples were obtained. The bond strength of the adhesive systems was tested using the micro-tensile test method. The data were statistically analyzed. A restored tooth in each group was processed for scanning electron microscopy evaluation. The values of the highest bond strength were obtained from the Clearfil S³-Er:YAG laser-sound dentine group in all groups. (24.57 ± 7.27 MPa) (P > 0.05). The values of the lowest bond strength were obtained from the Xeno V-Er:YAG laser-sound dentine group in all groups (11.01 ± 3.89 MPa). It was determined that the Clearfil S³ increased the bond strength on the surface applied with Er:YAG laser according to the Xeno V. Copyright © 2014 Wiley Periodicals, Inc.

  10. Short-pulse Er:YAG laser increases bond strength of composite resin to sound and eroded dentin.

    Cersosimo, Maria Cecília Pereira; Matos, Adriana Bona; Couto, Roberta Souza D'Almeida; Marques, Márcia Martins; de Freitas, Patricia Moreira


    This study evaluated the influence of the irradiation with a short-pulse Er:YAG laser on the adhesion of composite resin to sound and eroded dentin (SD and ED). Forty-six samples of occlusal dentine, obtained from human molars, had half of their surface protected, while the other half was submitted to erosive cycles. Afterward, 23 samples were irradiated with Er:YAG laser, resulting in four experimental groups: SD, sound irradiated dentine (SID—Er:YAG, 50  μs 50  μs , 2 Hz, 80 mJ, and 12.6  J/cm 2 12.6  J/cm2 ), ED, and eroded irradiated dentin (EID—erosion + Er:YAG laser). A self-etching adhesive system was used, and then cylinders of composite resin were prepared. A microshear bond strength test was performed after 24 h storage (n=20 n=20 ). The morphology of SD and ED, with or without Er:YAG laser irradiation, was evaluated under scanning electron microscopy (n=3 n=3 ). Bond strength values (MPa) were subjected to analysis of variance followed by Tukey’s test. Statistically significant differences were found among the experimental groups: SD (9.76±3.39  B 9.76±3.39  B ), SID (12.77±5.09 A 12.77±5.09 A ), ED (5.12±1.72 D 5.12±1.72 D ), and EID (7.62±3.39 C 7.62±3.39 C ). Even though erosion reduces the adhesion to dentin, the surface irradiation with a short-pulse Er:YAG laser increases adhesion to both ED and SD.

  11. Synthesis of cubic yttrium aluminum garnet (YAG) powders by co-precipitation and two-step calcinations

    Girish, H. N.; Zhu, C.; Ma, F. F.; Shao, G. Q.


    YAG powders were synthesized by co-precipitation and two-step moderate calcinations at 600/800 °C or 600/900 °C in air, respectively. Two kinds of the synthesized powders both possess pure cubic YAG phases without any secondary phases such as YAH, YAP and YAM, etc.. The former has low agglomeration with nano-sized primary particles and large active energy, and the latter has homogeneously dispersed and well-crystallized particles, with a narrow particle size distribution of 8 - 13 µm.

  12. The effect of Er:YAG laser irradiation on the surface microstructure and roughness of hydroxyapatite-coated implant


    Purpose The present study was performed to evaluate the effect of erbium:yttrium-aluminium-garnet (Er:YAG) laser irradiation on the change of hydroxyapatite (HA)-coated implant surface microstructure according to the laser energy and the application time. Methods The implant surface was irradiated by Er:YAG laser under combination condition using the laser energy of 100 mJ/pulse, 140 mJ/pulse and 180 mJ/pulse and application time of 1 minute, 1.5 minutes and 2 minutes. The specimens were exam...

  13. Effect of Fluoride Varnish Combined with Er:YAG Laser on the Permeability of Eroded Dentin: An In Situ Study

    Nemezio,Mariana Alencar; Carvalho,Sandra Chiga; Scatolin, Renata Siqueira; Colucci,Vivian; Galo, Rodrigo; Corona, Silmara Aparecida Milori


    This study evaluated the combined effect of fluoride varnish and Er:YAG laser on the permeability of eroded bovine root dentin. After initial erosive challenge followed by a remineralization period, the specimens were divided in two groups according to the treatment - fluoride varnish and non-fluoride varnish - and were subdivided according to the irradiation protocol: Er:YAG laser (100 mJ, 3 Hz, 12.8 J/cm2per pulse, non-contact and defocus mode) and non-irradiated. After a lead-in period, 7 ...

  14. Computer modelling and numerical simulation of the solid state diode pumped Nd:YAG laser with intracavity saturable absorber

    Yashkir, Yuriy


    Stimulated emission in the Nd:YAG laser with a saturable absorber Cr:YAG is modelled as a superposition of interacting optical modes which are stable in a given optical cavity. The interaction of the active laser crystal and a passive Q-switch with diode pump and optical cavity modes is modelled with account of transversal two-dimentional variation of the pump field and of all participating optical modes. Each elementary volume of an active laser crystal and the Q-switching crystal in...

  15. Stable single-mode operation of injection-seeded Q-switched Nd:YAG laser by sine voltage modulation

    Yongfei Gao; Junxuan Zhang; Huaguo Zang; Xiaolei Zhu; Yingjie Yu; Weibiao Chen


    Based on the modified ramp and fire technique,a novel injection seeding approach with real-time resonance tracking is successfully demonstrated in a single-frequency Nd:YAG pulsed laser.Appling a high-frequency sinusoidal modulation voltage to one piezo actuator and an adjustable DC voltage to another piezo actuator for active feedback,single-mode laser output with high-frequency stability is obtained,and the effect of the piezo hysteresis on the frequency stability can be eliminated for a laser diode pumped Q-switched Nd:YAG laser at a repetition rate of 400 Hz.

  16. Dependence of calculus retropulsion dynamics on fiber size and radiant exposure during Ho:YAG lithotripsy.

    Lee, Ho; Ryan, Robert T; Kim, Jeehyun; Choi, Bernard; Arakeri, Navanit V; Teichman, Joel M H; Welch, A J


    During pulsed laser lithotripsy, the calculus is subject to a strong recoil momentum which moves the calculus away from laser delivery and prolongs the operation. This study was designed to quantify the recoil momentum during Ho:YAG laser lithotripsy. The correlation among crater shape, debris trajectory, laser-induced bubble and recoil momentum was investigated. Calculus phantoms made from plaster of Paris were ablated with free running Ho:YAG lasers. The dynamics of recoil action of a calculus phantom was monitored by a high-speed video camera and the laser ablation craters were examined with Optical Coherent Tomography (OCT). Higher radiant exposure resulted in larger ablation volume (mass) which increased the recoil momentum. Smaller fibers produced narrow craters with a steep contoured geometry and decreased recoil momentum compared to larger fibers. In the presence of water, recoil motion of the phantom deviated from that of phantom in air. Under certain conditions, we observed the phantom rocking towards the fiber after the laser pulse. The shape of the crater is one of the major contributing factors to the diminished recoil momentum of smaller fibers. The re-entrance flow of water induced by the bubble collapse is considered to be the cause of the rocking of the phantom.

  17. Er:YAG laser ablation: evaluation after a two-year clinical treatment

    Dostalova, Tatjana; Jelinkova, Helena; Kucerova, Hana; Krejsa, Otakar; Hamal, Karel; Kubelka, Jiri; Prochazka, Stanislav


    The aim of the clinical study is to evaluate Er:YAG laser ablation after two year-long clinical treatment. One hundred fifty cavities were volunteered for checking. Three restorative materials were used following manufacturer's directions. For the experiment, an Er:YAG laser drilling machine was applied. The laser delivered energy from 100 to 450 mJ, repetition rate from 1 to 4 Hz. The length of the generated pulses was 200 microseconds. During our experiments cooling of the teeth was achieved by fine water mist. The number of pulses was from 16 to 489. Caries of enamel and dentin were treated. Old insufficient fillings were also removed (not amalgam or metal alloys). The experiments followed the guidelines of the Declaration of Helsinki (1964), Tokyo (1975), Venice (1983) and Hong-Kong (1989). Clinical evaluation of fillings after 6, 12, 18 and 24 months based on ADA recommendation was used. Eight criteria were applied for the restoration control. Composite resins and glassionomers could be used as filling materials.

  18. Memory effect and cathodoluminescent properties of YAG:Nd3+ nanoceramics

    Orekhova, K. N.; Trofimov, A. N.; Zamoryanskaya, M. V.; Stręk, W.


    The cathodoluminescent properties of nanoceramics based on neodymium-doped yttrium-aluminum garnet (YAG:Nd3+) are studied in a wide optical spectral range (from UV to IR). It is shown that the spectral positions of the emission bands of nanoceramics are identical to that of single crystal, but the bands of nanoceramics are broadened by no more than 15% from the half bandwidths of single crystal. The intensity of cathodoluminescence bands in nanoceramics is lower, and the lifetimes of radiative levels are shorter. It is found for the first time that electron-beam irradiation of nanoceramics increases the cathodoluminescence intensity of bands in visible and UV ranges (by two or more times). Preliminary electron beam irradiation of YAG:Nd3+ nanoceramics samples leads to the increase of cathodoluminescence efficiency. Such effect retains for a long time (a year and more) and can be compared to the memory effect. This effect is not observed in single crystal. We propose a model describing this effect in nanoceramics.

  19. Water content contribution in calculus phantom ablation during Q-switched Tm:YAG laser lithotripsy.

    Zhang, Jian J; Rajabhandharaks, Danop; Xuan, Jason Rongwei; Wang, Hui; Chia, Ray W J; Hasenberg, Tom; Kang, Hyun Wook


    Q-switched (QS) Tm:YAG laser ablation mechanisms on urinary calculi are still unclear to researchers. Here, dependence of water content in calculus phantom on calculus ablation performance was investigated. White gypsum cement was used as a calculus phantom model. The calculus phantoms were ablated by a total 3-J laser pulse exposure (20 mJ, 100 Hz, 1.5 s) and contact mode with N=15 sample size. Ablation volume was obtained on average 0.079, 0.122, and 0.391  mm3 in dry calculus in air, wet calculus in air, and wet calculus in-water groups, respectively. There were three proposed ablation mechanisms that could explain the effect of water content in calculus phantom on calculus ablation performance, including shock wave due to laser pulse injection and bubble collapse, spallation, and microexplosion. Increased absorption coefficient of wet calculus can cause stronger spallation process compared with that caused by dry calculus; as a result, higher calculus ablation was observed in both wet calculus in air and wet calculus in water. The test result also indicates that the shock waves generated by short laser pulse under the in-water condition have great impact on the ablation volume by Tm:YAG QS laser.

  20. Relationship between the chemical and morphological characteristics of human dentin after Er:YAG laser irradiation.

    Soares, Luís Eduardo Silva; Martin, Ovídio César Lavesa; Moriyama, Lilian Tan; Kurachi, Cristina; Martin, Airton Abrahão


    The effects of laser etching on dentin are studied by microenergy-dispersive x-ray fluorescence spectrometry (μ-EDXRF) and scanning electron microscopy (SEM) to establish the correlation of data obtained. Fifteen human third molars are prepared, baseline μ-EDXRF mappings are performed, and ten specimens are selected. Each specimen received four treatments: acid etching (control-CG) or erbium:yttrium-aluminum-garnet (Er:YAG) laser irradiation (I-100 mJ, II-160 mJ, and III-220 mJ), and maps are done again. The Ca and P content are significantly reduced after acid etching (pmappings illustrated that acid etching created homogeneous distribution of inorganic content over dentin. Er:YAG laser etching (220 mJ) produced irregular elemental distribution and changed the stoichiometric proportions of hydroxyapatite, as showed by an increase of mineral content. Decreases and increases of mineral content in the μ-EDXRF images are correlated to holes and mounds, respectively, as found in SEM images.

  1. Shear test of composite bonded to dentin: Er:YAG laser versus dental handpiece preparations

    Visuri, Steven R.; Gilbert, Jeremy L.; Walsh, Joseph T., Jr.; Wigdor, Harvey A.


    The erbium:YAG laser coupled with a cooling stream of water appears to be an effective means of removing dental hard tissues. However, before the procedure is deemed clinically viable, there are several important issues of safety and efficacy that need to be explored. In this study we investigated the surface that remains following laser ablation of dentin and compared the results to the use of a dental handpiece. Specifically, we studied the effect the laser radiation had on the bonding of composite to dentin. The crowns of extracted human molars were removed revealing the underlying dentin. An additional thickness of material was removed with either a dental handpiece or an Er:YAG laser by raster scanning the samples under a fixed handpiece or laser. Comparable surface roughnesses were achieved. A cylinder of composite was bonded onto the prepared surfaces following the manufacturer's directions. The dentin-composite bond was then shear stressed to failure on a universal testing apparatus and the maximum load recorded. Preliminary results indicated that laser irradiated samples had improved bond strengths. SEM photographs of the surfaces were also taken to compare the two methods of tooth preparation.

  2. Clinical assessments of the erbium:YAG laser for soft tissue surgery and scaling.

    Watanabe, H; Ishikawa, I; Suzuki, M; Hasegawa, K


    We evaluated the clinical usefulness of an erbium:YAG laser for soft tissue surgery, and scaling. Thirty-one patients with soft tissue lesions (13 males and 18 females from 24 to 71 years old), and 60 patients with calculus deposits (21 males and 39 females from 19 to 72 years old) were treated with the laser. The clinical parameters evaluated were pain, redness, swelling of the gingiva, and the subjective patient comfort parameters including uneasiness with the sound and vibration associated with laser treatment. Additionally, hemorrhage and wound healing during and after the surgery, the roughness of the root surface after scaling, and the effectiveness of scaling using the laser were examined. Laser surgery caused less hemorrhage and resulted in better wound healing when compared with conventional methods. It was easy to remove calculi from the root surface with the laser in 95% of the cases. Although the scaled site showed some irregularity, it was not clinically significant in 98% of the cases. Only a few patients complained about the unpleasant sound and vibration. There were no complications or side effects during this clinical trial. Thus, this study suggests that an Er:YAG laser is useful for soft tissue surgery and scaling.

  3. Human cornea wound healing in organ culture after Er:YAG laser ablation

    Shen, Jin-Hui; Joos, Karen M.; Robinson, Richard D.; Shetlar, Debra J.; O'Day, Denis M.


    Purpose: To study the healing process in cultured human corneas after Er:YAG laser ablation. Methods: Human cadaver corneas within 24 hours post mortem were ablated with a Q- switched Er:YAG laser at 2.94 micrometer wavelength. The radiant exposure was 500 mJ/cm2. The cornea was cultured on a tissue supporting frame immediately after the ablation. Culture media consisted of 92% minimum essential media, 8% fetal bovine serum, 0.125% HEPES buffer solution, 0.125% gentamicin, and 0.05% fungizone. The entire tissue frame and media container were kept in an incubator at 37 degrees Celsius and 5% CO2. Serial macroscopic photographs of the cultured corneas were taken during the healing process. Histology was performed after 30 days of culture. Results: A clear ablated crater into the stroma was observed immediately after the ablation. The thickness of thermal damage ranges between 1 and 25 micrometer. Haze development within the crater varies from the third day to the fourteenth day according to the depth and the roughness of the crater. Histologic sections of the cultured cornea showed complete re- epithelization of the lased area. Loose fibrous tissue is observed filling the ablated space beneath the epithelium. The endothelium appeared unaffected. Conclusions: The intensity and time of haze development appears dependent upon the depth of the ablation. Cultured human corneas may provide useful information regarding the healing process following laser ablation.

  4. Experimental removal of subgingival calculus with the Er:YAG laser

    Keller, Ulrich; Hibst, Raimund


    The purpose of this study was to evaluate the effects of the Er:YAG laser removal of subgingival calculi in periodontal treatment and to describe laser-induced cementum surface alterations. Freshly extracted human teeth with adherent plaques and mineralized calculi were laser treated using modified quartz fiber tips in direct contact to the root surface. For the fiber tip tested, the ablation threshold was 6.5 mJ. An effective removal of calculi was possible with 50 mJ resp. 150 mJ for a triple fiber. For the latter, a mass loss with a mean of about 5.1. mg/min was achieved. Histologic examinations of the cementum surface showed smoothed appearance alternately with rough depressions of the fiber tips, which can be discussed as a good precondition for periodontal tissue regeneration. Maximum temperature increase of 1.4 K was reached in the pulp, if an additional water irrigation was applied to the root surface. From these results it can be concluded that with the Er:YAG laser an effective removal of subgingival calculi can be performed without thermal risk for the pulp.

  5. Er:YAG removal of subgingival calculi: efficiency, temperature, and surface quality

    Stock, Karl; Hibst, Raimund; Keller, Ulrich


    Aim of this study was to evaluate a handpiece with a special fiber tip for Er:YAG laser removal of subgingival calculus. The morphological changes of the treated areas were observed by light microscopy and SEM. To evaluate the efficiency, the time for complete removal of the calculi was measured. The temperature development in the pulp during laser treatment was investigated by a thermocouple inserted into a root canal. After calculi ablation, only smooth ablation traces are visible. The depth of the ablation traces is about 100 micrometers . Roughness of the treated area is similar to the untreated area. The ablation efficiency depends strongly on the shape and location of the calculi and varies between 4.6 and 20 mm2/min. During non stop preparation the maximum occurred temperature in pulp was 7.8 K. The results show that the Er:YAG laser with the used fiber delivery systems and handpiece is suitable for effective and sparing removal of subgingival calculus in periodontal treatment.

  6. Nd:YAG 1.44 laser ablation of human cartilage

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


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

    Kirwan, R P


    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.

  8. [Thermographic assessment of thermal effects of Er:YAG laser in periodontal surgery].

    Zmuda, Stanisław; Ignatowicz, Elzbieta; Stankiewicz, Justyna; Marczyńiska-Stolarek, Magdalena; Dabrowski, Mirosław


    An assessment of thermal effect of Er:YAG laser (KEYII, KaVo) on oral soft tissues in select procedures. Experimental researches were carried out on Wistar rats. To measure the temperature changes the thermal imaging camera (ThermaCAM SC3000, FLIR Systems) was used. There has been a significant increase of temperature observed on the end of optical fibre: the mean temperature ranged from 270 to 360 degrees C (at laser energy of 100 mJ and repetition rate of 25 Hz) and from 230 to 290 degrees C (300 mJ, 15 Hz). On the surface of oral mucosa thermal changes at the time of laser frenulectomy was analysed along the line of incision. The temperature above 50 degrees C was recorded on the length of 2 mm (at 100 mJ) and 3 mm (at 300 mJ). The temperature maintained on this level for about 0.4 s. On the surface of tongue during lingual mucosa excision the temperature above 40 degrees C was observed on the length of 1.6 mm (80 mJ, 2 Hz) or 2.5 mm (160 mJ, 2 Hz). The rate of cooling for both cases was lower than 0.5 s. To prevent undesirable thermal side effects from an Er:YAG laser optical fibre should be moved very fluently in non-contact mode.

  9. 1.06-μm Nd:YAG laser coagulation tonsillectomy: an animal study

    Wang, Zhi; Pankratov, Michail M.; Volk, Mark S.; Perrault, Donald F., Jr.; Shapshay, Stanley M.


    Tonsillectomy is one of the most frequently performed surgeries which is not free from post- operative morbidity. We have developed a non contact photocoagulation technique using 1.06 micrometers Nd:YAG laser and tested its safety and efficacy in an animal model. Eight animals were divided into the laser coagulation group (6 animals) and the laser excision group (2 animals). Tonsils of the laser coagulation animals were irradiated with 8 - 10 W of laser power for 5 - 6 min in a slow painting-like motion over the surface of a tonsil until slight blanching of mucosa was noticed. Tonsils of the laser excision group were resected with 25 - 30 W of 1.06 micrometers Nd:YAG laser power through a contact fiber. The animals were examined endoscopically at 1.5 hrs and at 2, 5, 12, 30, and 42 days post treatment. Atrophic process was followed until total disappearance of tonsillar tissue was observed. The animals were sacrificed at various time intervals and the tonsillar specimens were collected for gross and histological examination. The thermal damage to mucosa and adjacent tissues was minimal which we attribute to a low laser power and cooling from preoperative injection of saline into subcapsular space. The potential advantages of this technique include intact mucosa with no intra- or post-operative bleeding, less pain, and avoidance of general anesthesia. These advantages may enable this surgery to become an in-the-office procedure.

  10. Ultrasound-guided interstitial Nd:YAG laser therapy of cavernous hemangiomas

    Hoffmann, Peter; Offergeld, Christian F.; Huettenbrink, Karl-Bernd; Hackert, I.; Scholz, A.


    Preoperative embolization and excision used to be standard therapy amongst a wide range of other more or less successful methods for the treatment of voluminous hemangiomas. Nowadays a combination of argon, tunable dye, copper vapor and Nd:YAG laser therapy achieves better cosmetic and functional results. Due to its limited penetration depth percutaneous laser therapy can only be utilized for superficial vascular malformations. Interstitial laser therapy, as performed with the Nd:YAG laser, allows treatment of voluminous hemangiomas in their full extent. The localization of these vascular lesions is evaluated by high resolution ultrasound with a new anular array scanner which ensures the precise intraoperative placement of the laser light fiber in the target tissue. Modified new light applicators improve the interstitial thermotherapy of hemangiomas. The tip design of the scattering-dome fiber allows diffuse circumferential irradiation with larger defined coagulation volume and minimized carbonization. Continuous intraoperative sonographic monitoring lowers the risk of damaging adjacent intact anatomical structures, helps to reach all tumor areas an to estimate the effect of the applied laser light caused by changes of sonomorphology. The postoperative outcome is evaluated by B-mode sonography and the new technique of ultrasound color angiography.

  11. Comparison of CW Nd:YAG contact transscleral cyclophotocoagulation with cyclocryopexy

    Schubert, H.D.; Federman, J.L.


    The cyclodestructive and inflammatory effects of CW Nd:YAG contact laser were compared to those of conventional cryopexy. CW Nd:YAG light transmitted by fiber optic cable and sapphire crystal was applied transsclerally to the ciliary body of pigmented and albino rabbits. Cyclocryopexy was given to a comparable second group. The intraocular pressure (IOP), flare, iritis, cells and conjunctival hyperemia were monitored clinically up to 3 weeks. The breakdown of the blood-aqueous barrier and time course of ocular inflammation was similar for both modalities and IOP was -12.2 +/- 4.2 mm Hg for laser cyclopexy and -15.1 +/- 5.4 mm Hg for cyclocryopexy at 3 weeks. Ciliary body lesions were noted in both groups. Overall, albino rabbits showed less histological damage and faster recovery of IOP. Contact cyclophotocoagulation and cyclocryopexy can be considered models of ocular injury. The similarities in ocular irritative response suggest a similar pathophysiologic mechanism underlying the pressure behavior in both thermal mode injuries.

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

    Ramazani, S.A. Ahmad, E-mail: [Polymer Group, Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Mousavi, Seyyed Abbas, E-mail: [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)


    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. Labial frenectomy with Nd:YAG laser and conventional surgery: a comparative study.

    Medeiros Júnior, Rui; Gueiros, Luiz Alcino; Silva, Igor Henrique; de Albuquerque Carvalho, Alessandra; Leão, Jair Carneiro


    Labial frenulums are sagittal fibrous folds of oral mucosa with a periosteal insertion that extend from the lips to the alveolar or gingival mucosa. Occasionally, they assume inadequate size or location and may lead to functional and esthetic limitations. The aim of the present study was to compare pre-, trans-, and postsurgical clinical parameters of labial frenectomies performed with conventional surgery and neodymium-doped yttrium aluminum garnet (Nd:YAG) laser. Forty individuals were assessed as a convenience sample and were divided into two groups according to the treatment: group 1 (G1), conventional surgery (n = 22), and G2, Nd:YAG laser surgery (n = 18). Clinical parameters such as frenulum insertion, location, bleeding, surgical time, suturing, preoperative fear, and postoperative discomfort/functional limitations were evaluated. All surgeries were performed by the same operator, and the level of fear, pain, and discomfort related to oral functions were assessed with a visual numeric scale. Most of the frenulums (90%) were classified as papillary or transpapillary insertion. Preoperative fear was similar between groups (p = 0.593). All G2 patients did not require suture (p frenectomies reduces transoperative bleeding, avoiding the need of suturing, and promotes a significant reduction of surgical time in comparison with conventional surgery. Therefore, further studies are necessary to provide a complete understanding and standardization of the technique as well as the expected clinical results.

  14. Comparative study of microstructural characteristics of electrospark and Nd:YAG laser epitaxially growing coatings

    Xie, Yu-jiang; Wang, Mao-cai; Huang, Da-wei


    As low-heat input welding processes, electrospark deposition and pulsed Nd:YAG laser cladding can be commonly used to prepare epitaxially growing coatings. However, these two processes have quite different characteristics in the energy input, the amount of materials involved, and the temperature gradient, and hence might result in dissimilar microstructural characteristics. In this paper, a comparative study has been made between microstructural characteristics in epitaxial growth coatings prepared by electrospark deposition and pulsed Nd:YAG laser cladding. Some interesting results have been achieved. Firstly, epitaxial growth coatings can be commonly achieved by these two techniques. Secondly, microstructural morphologies of these two epitaxial growth coatings are obviously different, cellular columnar structure prevails in the electrospark coating while columnar dendritic structure occupies most of the laser coating thickness, more importantly, electrospark coating remains fully columnar in the whole layer whereas laser coating tends to change from columnar to equiaxed at the top of the layer. Thirdly, electrospark coating possesses finer and more homogeneous microstructure than laser coating.

  15. Surface Profiling Of Paper Radiated With Focused Infra-Red Nd:yag Pulsed Laser

    Ahmad Hadi Ali


    Full Text Available A Nd:YAG pulsed laser with wavelength of 1.06 mm can cause a tremendous damage when interacts with material. In this study the effects of Nd:YAG laser interactions onto paper are reported. A combination lens technique was used with different focal length of lens. The target material that is a photographic paper was positioned at a focal spot of the laser beam. IR laser pulsed with peak power up to megawatt (MW is brought to focus thus interacts with the photographic paper. This high-power impact of the laser pulsed shockwave caused a tremendeous damage on the photographic paper. Measurement of the impact was base on the surface size of the damage. From the observation result it shows that the maximum damage diameter for short lens system is 0.613 mm at peak power of 21.93 MW, whereas the maximum damage diameter for long lens system is 1.224 mm at 22.25 MW peak power.

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

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


    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 <2. The single frequency 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.


    Sebastiano Cimino


    Full Text Available Background: Pneumatic lithotripsy (PL and Holmium:YAG laser lithotripsy (LL are two valid mini-invasive approaches in the treatment of urologic stones disease. The aim of this study was to compare stone free rates between these two treatment options. Material and methods: From January 2010 to January 2011, 120 consecutive patients with single and primary ureteral stones were prospectively enrolled in this prospective study. The study was single-blinded and none of the patients knew which approach for stone fragmentation would be used. Results: The ureteral stone-free rate (SFRs in the PL group was 80.7% and 86.1 % in the LL group (p=0.002. The mean operating time was 60 (± 25 minutes in the LL group and 61 (± 21 minutes in the PL group, without significant differences (p=0.68. Multivariate logistic analysis revealed that stone location was not significantly predictive of SFRs (p=0.47. None of the patients had blood transfusions and no other severe complications appeared in either group. Conclusions: In our study LL was significantly associated with a stone 80.7% in the PL group and 86.1% in the LL group (p<0.05. Also, Holmium:YAG laser lithotripsy was demonstrated to be the more efficacious endoscopic procedure for the treatment of ureteral stones, allowing stones to be successfully fragmented, with few complications.

  18. An Auto-Fluorescence guided surgical approach performed with Er:YAG laser and Nd:YAG Low Level Laser Therapy for Medication-Related Osteonecrosis of the Jaw

    Ilaria Giovannacci


    Full Text Available Medication-Related Osteonecrosis of the Jaw (MRONJ therapy remains an unresolved problem. The proposed conservative and surgical treatment regimens are associated to contradictory success rates. Surgical approach with Er:YAG laser is associated to significant better results compared to medical treatment and traditional surgical approaches. Objective: To describe a new surgical approach that couples the advantages of the Er:YAG laser and the usefulness of the AF in highlighting surgical margins. One of the difficulties encountered during surgical removal of a MRONJ is the precise individuation of necrotic bone margins. Case Report: A case of Stage III mandibular osteonecrosis treated with a new surgical approach is presented. The aim is to describe an auto-fluorescence (AF guided surgical approach performed with Er:YAG laser and Nd:YAG Low Level Laser Therapy (LLLT. After one month of follow-up, the complete mucosal healing was evident and symptoms was unobserved. Such a technique allowed a highly accurate and minimally invasive approach through the selective ablation of the non-/hypofluorescent areas. Conclusion: Taking into account the advantages of laser therapy and the possible effectiveness of the AF in highlighting surgical margins, this approach would probably achieve excellent outcomes.DOI: 10.14693/jdi.v22i2.486

  19. Root planing with Er:YAG laser X Gracey curette, a study in vitro in scanning electron microscopic study; Avaliacao em microscopia eletronica de varredura da superficie radicular, raspada e alisada com Er: YAG laser

    Mello, Fabiano Augusto Sfier de


    The Er:YAG laser has been studied as a periodontal therapies, used to remove subgingival calculus and its bactericidal effects. The proposal of this study is to evaluate the effectiveness of the Er:YAG laser in root planing in comparison to the traditional method, not surgical. Six recently extracted due to the disease periodontal, were cut longitudinally, tends like this two half of the root. These half were separate in four groups. The first group is the natural tooth (group controls negative), the second group (group controls) was accomplished to root planing with Gracey curette. And in the third to Er:YAG laser with a contact tip, using a 45 deg angle in relation to the root; in the fourth group was scraped and planned with Er:YAG laser and complemented root planing with Gracey curette. The used energy was of 100 mJ (out put) and the frequency of 10 Hz accomplished with irrigation. The obtained results were similar in the groups 2 and 3 in comparison to the amount of smear-layer. In group 4 however, better result was obtained, because the image (SEM) was much more regular and with less amount of smear-layer. The conclusion of the work is that with the association of the laser technique and Gracey curette the results are superior to the conventional treatment. (author)

  20. Marginal microleakage of cavities prepared with Er:YAG laser on primary teeth in vitro%乳牙应用 Er:YAG 激光备洞充填微渗漏效果的离体研究

    谢窈; 张笋; 葛立宏


    Objective:To investigate the marginal microleakage after cavity preparation by Er:YAG la-ser and conventional bur applying different adhesive systems , conditioning surface with acid etching or not.Methods:In the study, 50 primary teeth were divided into 5 groups.(1) Bur+etch-and-rinse sys-tem, (2) Bur+self-etching system, (3) Er:YAG laser+etch-and-rinse system, (4) Er:YAG laser+self-etching system, (5) Er:YAG laser+none-etched.The class V cavities were all filled with composite resin.The microleakage tests were performed , observed and scored under stereomicroscope .Results:Bur+etch-and-rinse group had higher microleakage than Er:YAG laser +etch-and-rinse group , and Bur+self-etching group had higher microleakage than Er:YAG laser +self-etching group ( P<0 .05 ) . There was no difference between Er:YAG laser+etch-and-rinse group and Er:YAG laser+self-etching group, while they had significantly lower microleakage than that of Er:YAG+none-etched group.Con-clusion:Composite resin restoration showed less marginal microleakage when all-in-one self-etch system was used after irradiation by Er:YAG laser on primary teeth .%目的:Er:YAG激光备洞和传统的涡轮钻针备洞,使用不同粘接系统和界面处理方式,对乳牙树脂充填的微渗漏效果进行研究。方法:50颗乳牙随机分为5组,第1组:涡轮钻针预备+全酸蚀粘接充填;第2组:涡轮钻针预备+自酸蚀粘接充填;第3组:Er:YAG激光预备+全酸蚀粘接充填;第4组:Er:YAG激光预备+自酸蚀粘接充填;第5组:Er:YAG激光预备后不酸蚀+配合全酸蚀粘接剂充填,对不同组进行微渗漏体视显微镜检查。结果:涡轮钻针+全酸蚀组和涡轮钻针+自酸蚀组的微渗漏分别高于Er:YAG激光+全酸蚀组和Er:YAG激光+自酸蚀组(P<0.05);涡轮钻针+全酸蚀组与Er:YAG激光+不酸蚀组的微渗漏差异无统计学意义。 Er:YAG激光预备的3个组中,全