WorldWideScience

Sample records for two-frequency he-ne laser

  1. HeNe-laser light scattering by human dental enamel

    NARCIS (Netherlands)

    Zijp, [No Value; tenBosch, JJ; Groenhuis, RAJ

    1995-01-01

    Knowledge of the optical properties of tooth enamel and an understanding of the origin of these properties are necessary for the development of new optical methods for caries diagnosis and the measurement of tooth color. We measured the scattering intensity functions for HeNe-laser light of 80- to

  2. A digital intensity stabilization system for HeNe laser

    Science.gov (United States)

    Wei, Zhimeng; Lu, Guangfeng; Yang, Kaiyong; Long, Xingwu; Huang, Yun

    2012-02-01

    A digital intensity stabilization system for HeNe laser is developed. Based on a switching power IC to design laser power supply and a general purpose microcontroller to realize digital PID control, the system constructs a closed loop to stabilize the laser intensity by regulating its discharge current. The laser tube is made of glass ceramics and its integrated structure is steady enough to eliminate intensity fluctuations at high frequency and attenuates all intensity fluctuations, and this makes it easy to tune the control loop. The control loop between discharge current and photodiode voltage eliminates the long-term drifts. The intensity stability of the HeNe laser with this system is 0.014% over 12 h.

  3. A transportable methane stabilized He-Ne laser

    Science.gov (United States)

    Akimoto, Yoshiaki

    1987-06-01

    The performance of a transportable methane stabilized He-Ne laser system, developed for a wavelength-optical frequency standard according to the 1983 Comite Consultatif pour la Definition du Metier, is discussed. An offset-locked laser system using a phase comparison technique is described which is used to evaluate the stabilized laser system. A frequency stability of 2.5 x 10 to the -12th tau exp -1/2, and a resettability of 1 x 10 to the -11th, are estimated for the stabilized laser system.

  4. Effects of He-Ne laser irradiation on red blood cells in vitro

    Science.gov (United States)

    Ghadage, Vijay H.; Kulkarni, Gauri R.

    2011-03-01

    Laser radiation has many applications in biomedical field, such as wound healing, tissue repairing, heating and ablation processes. Intravenous low power laser radiation is used clinically for skin and vascular disorders. Laser radiation improves microcirculation and modulates the rheological properties of blood. FTIR (Fourier Transform Infra Red Spectra) is used to see the structural changes in erythrocyte membrane. In the present work He Ne laser (λ= 632nm, power=2mW) is used to irradiate human Red blood cells. Red blood cells are separated from human whole blood using centrifugation method (time=10 min., temperature=15°C and RPM=3000) and then exposed to HeNe laser radiation. Laser exposure time is varied from 10 min. to 40min for Red blood cells. Absorption spectrum, FTIR and fluorescence spectra of RBC are compared before and after HeNe laser irradiation. The absorption spectrum of RBC after exposure to HeNe laser shows a significant decrease in absorbance. The FTIR spectrum of non irradiated RBC clearly show the peaks due to O-H (free group), C=O (amide I group), N=O (nitro group), C-O (anhydride group) and C-H (aromatic group). Laser radiation changes in transmittance in FTIR spectra related to C=O group and percentage of transmittance increases for O-H, C=C, N=O, C-O and C-H group.

  5. International Comparison of Methane-Stabilized He-Ne Lasers

    Science.gov (United States)

    Koshelyaevskii, N. B.; Oboukhov, A.; Tatarenkov, V. M.; Titov, A. N.; Chartier, J.-M.; Felder, R.

    1981-01-01

    Two portable methane-stabilized lasers designed at BIPM have been compared with a type a stationary Soviet device developed in VNIIFTRI1. This comparison is one of a series aimed at establishing the coherence of laser wavelength and frequency measurements throughout the world and took place in June 1979. The VNIIFTRI and BIPM lasers using different methods of stabilization, have different optical and mechanical designs and laser tubes. The results of previous measurements, made in VNIIFTRI, of the most important frequency shifts for Soviet lasers together with a method of reproducing their frequency which leads to a precision of 1.10-12 are also presented.

  6. Laser Interferometric Measurements of the Physical Properties for He, ne Gases and Their Mixture

    Science.gov (United States)

    Abdel-Moniem, N. M.; El-Masry, M. M.; El-Bradie, B.; El-Mekawy, F. M.

    2010-04-01

    A Mach-Zehner interferometer MZI illuminated with He-Ne Laser 632.8nm is used for measuring the refractive index for He, Ne gases and their mixture HeNe. The measurements are carried out at different pressures and temperatures. The error factors of the refractive index measurements for He, Ne and HeNe gases are equal to ±1.7×10-5, ±9.5×10-6 and ±7.25×10-5 respectively. Some calculations of the electrical properties are carried out such as the optical permittivity dielectric susceptibility and specific refractivity from the determination of the refractive index. Also, the molecular radii of the gases under investigation are computed then the transport coefficients (diffusion. viscosity and thermal conductivity) are calculated. All of these calculations are carried out at different pressures and temperatures. The experimental results of refractive index for the above mixture are compared with the results estimated using one of the mixing rules and a good agreement is achieved. Also, some physical parameters are compared with other values in another literatures.

  7. Industrial processes control with He-Ne laser devices for aligning and guiding

    International Nuclear Information System (INIS)

    Ursu, I.; Ivascu, M.; Vasiliu, V.; Ristici, M.; Gradisteanu, I.; Vilcu, G.; Pelle, V.; Botezatu, I.; Vasnea, V.; Orac, N.; Fernea, V.

    1988-03-01

    A brief presentation of the He-Ne laser devices main application fields in the national economy is given. The utilization of the devices we did in: industrial constructions, metalurgy, hydroelectric arrangements, wood industry, ship's construction, and other is presented. (authors)

  8. PENGUKURAN SIFAT POLARISASI BERBAGAI MINYAK NABATI MENGGUNAKAN LAMPU IR DAN LASER HE-NE

    Directory of Open Access Journals (Sweden)

    U Kaltsum

    2017-03-01

    Full Text Available Penelitian ini bertujuan untuk menguji sifat polarisasi berbagai minyak nabati (minyak sawit, minyak kedelai, minyak zaitun, VCO, minyak curah, dan jelantah dengan variasi keadaan baru dan kadaluwarsa, menggunakan lampu IR dan laser He-Ne. Pengujian dilakukan dengan menempatkan minyak nabati diantara polarisator dan analisator. Hasil penelitian pada kedua sumber cahaya menunjukkan pola yang hampir sama. Minyak zaitun dan VCO memiliki perubahan sudut polarisasi alami kecil, sedangkan minyak sawit, kedelai, jelantah, dan curah memiliki perubahan sudut polarisasi alami besar. Besarnya perubahan sudut polarisasi minyak kadaluwarsa lebih besar dibanding minyak baru. Perubahan sudut polarisasi sebanding dengan jumlah radikal bebas (ALB, peroksida dan molekul asimetri (asam lemak jenuh, molekul rantai panjang. Meskipun pola yang dihasilkan oleh kedua sumber cahaya sama, namun lampu IR memberikan nilai perubahan sudut polarisasi yang lebih tinggi dari laser He-Ne. Hal ini dimungkinkan karena daya lampu IR lebih besar dari He-Ne, sehingga energi yang dihasilkan lampu IR lebih tinggi dan perubahan sudut polarisasinya lebih besar. This research based on previous research that using IR lamp (250 watt and He-Ne laser (1 mW on a mixture of palm oil and animal oil. Both of light source were used again to measure polarization properties of various vegetable oils (palm oil, soybean oil, olive oil, VCO, rainfall oil and used cooking oil with a variety of new and expired. The tools used were a set polarization, IR lamp, He-Ne laser, and power supply. The experiment was done by placing vegetable oil between the polarizer and analyzers. The result showed both of light sources had similar pattern; polarization changes of olive oil and the VCO were small, while polarization changes of palm oil, soybean oil, used cooking oil, and rainfall were high. Polarization change of expired oil was higher than new oil. The value of polarization change was proportional to free

  9. He-Ne laser effects on blood microcirculation. An in vivo study through laser doppler flowmetry

    International Nuclear Information System (INIS)

    Nunez, Silvia Cristina

    2002-01-01

    Blood microcirculation performs an important function in tissue repair process, as well as in pain control, allowing for greater oxygenation of the tissues and the accelerated expulsion of metabolic products, that may be contributing to pain. Low Intensity Laser Therapy (LILT) is widely used to promote healing, and there is an assumption that it is mechanism of action may be due to an enhancement of blood supply. The purpose of this study was to evaluate, using laser Doppler flowmetry (LDF), the stated effects caused by radiation emitted by a He-Ne laser (λ=632.8 nm) on blood microcirculation during tissue repair. To this end, 15 male mice were selected and received a liquid nitrogen provoked lesion, above the dorsal region, and blood flow was measured periodically, during 21 days. Due to radiation emission by the LDF equipment, a control group was established to evaluate possible effects caused by this radiation on microcirculation. To evaluate the He-Ne laser effects, a 1.15 J/cm 2 dose was utilized, with an intensity of 6 mW/cm 2 . The results obtained demonstrate flow alterations, provoked by the lesion, and subsequent inflammatory response. There was no statistical difference between the studied groups. As per the analysis of the results there is no immediate effect due the radiation emitted by a He Ne laser on microcirculation, although a percentage increase was observed in day 7 on medium blood flow rate in irradiated specimens. New studies are necessary to validate the use of this wavelength, in order to promote beneficial alterations in blood supply in radiated areas. (author)

  10. Erythrocyte sedimentation as detected by He:Ne laser

    International Nuclear Information System (INIS)

    Abdulla, M. M.; Al-Ani, F. S.; Al-Ani, A.

    2005-01-01

    Aggregation of erythrocytes is a reversable dynamic process. The growth process of three dimensional - chain - like aggregates depends on the shape of the cell available for the attachment. A study of red blood cell aggregation and sedimentation was performed for sample of 5% and 10% red blood cells in plasma, with macromolecules and without macromolecules. The analysis was studied under dynamic conditions by applying the method of back scattering laser light. The aggregation and reorientation of red blood cells was recorded via X-Y recorder connected to a sensitive photo diode. The records decleared the phases of the process as a function of time and amplitude. The amplitude of light signal depends on the size of aggregates and concentration of sample. The time intervals of different phases of aggregation and sedimentation were measured and the contribution of macromolecule substance in the plasma was analysed. (author)

  11. Skin friction measurements using He-Ne laser

    Energy Technology Data Exchange (ETDEWEB)

    Choi, S.H. [Hankuk Aviation University Graduate School, Kyonggi-do (Korea, Republic of); Lee, Y. [Hankuk Aviation University, Kyonggi-do (Korea, Republic of)

    1997-07-01

    An experimental study of the skin friction measurement in a turbulent boundary-layer has been carried out. The skin friction measurements are made using the laser interferometer skin friction (LISF) meter, which optically detects the rate of thinning of an oil applied to the test surface. This technique produces reliable skin friction data over a wide range of flow situations up to 3-dimensional complicated flows with separation, where traditional skin friction measurement techniques are not applicable. The present measured data in a turbulent boundary-layer on a flat plate using the LISF technique shows a good comparison with the result from the previous velocity profile techniques, which proves the validity of the present technique. An extensive error analysis is carried out for the present technique yielding an uncertainty of about {+-}8%, which makes them suitable for CFD code validation purposes. Finally the measurements of the skin friction in a separated region after a surface-mounted obstacle are also presented. (author). 19 refs., 12 figs., 3 tabs.

  12. Age-dependent effects of He-Ne laser irradiation on the membrane fluidity of human erythrocytes

    Science.gov (United States)

    Kovacs, Eugenia; Savopol, Tudor; Pologea-Moraru, Roxana; Makropoulou, Mersini I.; Serafetinides, Alexander A.

    1997-12-01

    The low power He-Ne laser radiation has been extensively used in past decades as medical device to relieve pain, accelerate wound healing as well as aiming beam in invisible laser beam in invisible laser beam applications. It is not known however if there are any secondary, undesirable effects of He-Ne laser radiation on the irradiated tissue. In this paper we investigate the changes induced in membrane fluidity of human erythrocyte during/upon the interaction with the He-Ne laser beam having the parameters currently used for target aiming in laser surgery.

  13. Effects of He-Ne laser beam on mechanical, heat, chemical and superficial wounds

    International Nuclear Information System (INIS)

    Kakai, S.F.K.; Albarwari, S.E.; Alsenawi, T.A.

    1988-02-01

    This study summarizes the effects of low-doses of He-Ne laser radiation (λ = 6328 A), on healing of four types of wounds, including mechanical, heat, chemical and superficial wounds. The results revealed that variations between complete wound-closure in irradiated samples and that of control groups were statistically significant. Moreover, the results suggest that the stimulative action of laser is an accumulative phenomenon, that affects factors involved in the course of wound healing. The results also indicate that the skin epithelium is a highly responsive tissue towards this sort of radiation, which suggests that the stimulative action of He-Ne laser could be assayed easily by using such tissues as a test target. (author). 11 refs, 2 tabs

  14. Frequency stabilization of a He-Ne gas laser by controlling refractive index of laser plasma

    International Nuclear Information System (INIS)

    Xie Yi; Wu Yizun

    1991-01-01

    A new way to stabilize the frequency of a Zeeman He-Ne gas laser is described. The laser frequency is stabilized by controlling the refractive index of the laser plasma. It does not need a gas laser tube with a piezoelectric ceramic (PZT) made by special technology. As the phase-locking technology is used in the laser servo system, the self-beat frequency is a constant and the frequency stability is better than 2.2 x 10 -11 (averaging time = 10 sec.). The long term frequency fluctuation never exceeded 2 x 10 -8 during two months. The frequency of the locked point can be adjusted continuously in the range of over 200 MHz

  15. He-Ne Laser Irradiation Encourages reparative Processes After cartilage loss in New Zealand rabbits

    International Nuclear Information System (INIS)

    Ali, I.K.

    2008-01-01

    Many therapeutic methods used to encourage reparative processes of cartilage and accelerate their healing such as drugs, magneto-laser and so on.Twenty four adult New Zealand rabbits used in this study.They were divided in to two groups; control and treaded with He-Ne laser.A square skin flap done on the medial aspect of both auricles followed by pealing a square piece of cartilage from the auricle then the flaps sutured.The site of the operation in the rabbits of the treatedgroup were irradiated with He-Ne laser 5mw power for seven days began after the operation directly.3 rabbits from each group used for collection of specimens for histopathological examination at the 1, 2, 4 & 6 weeks post the operation.Significantly well developed cartilage growth, chondroblasts and chondrocytes invade the area of the operation.High increase in the thickness of connective tissue in the same area contain mainly collagen fibers and lesser amount of elastic fibers.He-Ne laser irradiation raised the mitotic activity of the cartilage cells, activated the reproduction processes in addition to the intra and extra regenerative repair

  16. Measurements on the He-Ne laser lines near 633 nm

    Science.gov (United States)

    Steinhaus, David W.

    1983-09-01

    The red line from an inexpensive He-Ne laser is made up of several closely spaced lines. To separate these lines very high spectral resolution is required. This apparatus requirement can be met by a simple modification of a student Fabry-Perot interferometer. Laboratory measurements can then be made to verify the expected number, spacing, and polarization of these lines during a single afternoon laboratory session.

  17. The second-order interference of two independent single-mode He-Ne lasers

    Science.gov (United States)

    Liu, Jianbin; Le, Mingnan; Bai, Bin; Wang, Wentao; Chen, Hui; Zhou, Yu; Li, Fu-li; Xu, Zhuo

    2015-09-01

    The second-order spatial and temporal interference patterns with two independent single-mode continuous-wave He-Ne lasers are observed when these two lasers are incident to two adjacent input ports of a 1:1 non-polarizing beam splitter, respectively. Two-photon interference based on the superposition principle in Feynman's path integral theory is employed to interpret the experimental results. The conditions to observe the second-order interference pattern with two independent single-mode continuous-wave lasers are discussed. It is concluded that frequency stability is important to observe the second-order interference pattern with two independent light beams.

  18. In vivo and in vitro HeNe laser effects on phagocyte functions

    Energy Technology Data Exchange (ETDEWEB)

    Ricevuti, G.; Mazzone, A.; Monaia, C.; Fratino, P.; Degiulio, R.; Dell' Acqua, R.; Leonardi, G.; Jucci, A.; Sacchi, S. (Univ. of Pavia (Italy))

    1989-10-01

    The goal of this work was to evaluate the effect of helium-neon (HeNe) laser irradiation on immunocompetent cells. We used the in vivo skin window method and in vitro granulocyte function tests. The study of cellular migration showed a marked decrease in vitro and in vivo in a dose-independent manner. Superoxide release was not modified by laser irradiation. The granulocyte's aggregation, when using PHA and PMA, presented a reduction that was statistically very significant, not as a subordinate dose. An increase of the release of ATP was demonstrated only at 4 joules and precedes granulocyte aggregation. When using Ca2+ ionophore A23187 as stimulus, laser irradiation at 1, 2 or 4J did not show any modification of granulocyte aggregation. The monoclonal antibody 60.1, which identifies a membrane antigen fundamental for aggregation and chemotaxis, is expressed in normal amounts on granulocyte membranes both before and after irradiation with a HeNe laser. In fact, laser irradiation preferentially attacks the area of the cellular centrosome that determines a modification of cellular morphology. The electron microscope and immunofluorescence study with a monoclonal antibody have pointed out a disorganization of the microtubules. The alteration of some of the granulocyte functions is correlated to the damage in the centrioles. The granulocyte mitochondrial system and surface membrane remain intact, and this explains the normal production and release of free radicals. Further experiments are necessary to evaluate the clinical application of lasers in various diseases with immunophagocytic pathogenesis.

  19. He-Ne laser treatment improves the photosynthetic efficiency of wheat exposed to enhanced UV-B radiation

    International Nuclear Information System (INIS)

    Chen, Huize; Han, Rong

    2014-01-01

    The level of ultraviolet-B (UV-B) radiation on the Earth’s surface has increased due to depletion of the ozone layer. Here, we explored the effects of continuous wave He-Ne laser irradiation (632 nm, 5 mW mm –2 , 2 min d –1 ) on the physiological indexes of wheat seedlings exposed to enhanced UV-B radiation (10 KJ m –2 d –1 ) at the early growth stages. Wheat seedlings were irradiated with enhanced UV-B, He-Ne laser treatment or a combination of the two. Enhanced UV-B radiation had deleterious effects on wheat photosynthesis parameters including photosystem II (chlorophyll content, Hill reaction, chlorophyll fluorescence parameters, electron transport rate (ETR), and yield), the thylakoid (optical absorption ability, cyclic photophosphorylation, Mg 2+ -ATPase, and Ca 2+ -ATPase) and some enzymes in the dark reaction (phosphoenolpyruvate carboxylase (PEPC), carbonic anhydrase (CA), malic dehydrogenase (MDH), and chlorophyllase). These parameters were improved in UV-B-exposed wheat treated with He-Ne laser irradiation; the parameters were near control levels and the enzyme activities increased, suggesting that He-Ne laser treatment partially alleviates the injury caused by enhanced UV-B irradiation. Furthermore, the use of He-Ne laser alone had a favourable effect on seedling photosynthesis compared with the control. Therefore, He-Ne laser irradiation can enhance the adaptation capacity of crops. (paper)

  20. Effects of He-Ne laser irradiation on the storage of turkey semen

    Directory of Open Access Journals (Sweden)

    S. Passarella

    2011-03-01

    Full Text Available Maintenance or improvement of sperm quality during storage could prevent the loss of fertilizing capacity associated with stored turkey semen. Therefore the optimization of stored turkey semen could be useful to breeder industry since the commercial production of this bird relies almost entirely on artificial insemination. Previous research have shown that He-Ne laser irradiation in mammalian sperm increased the motility (Stato, 1986, decreased the mortality, promoted the acrosome reaction, which have a pivotal role in assisted fecundating programmes as therapy for resolving infertility in domestic animals..........

  1. Birefringence Optical Feedback with a Folded Cavity in HeNe Laser

    International Nuclear Information System (INIS)

    Wu Yun; Tan Yi-Dong

    2013-01-01

    The birefringence optical feedback with a folded cavity in HeNe laser is investigated. A theory model based on the equivalent cavity of the Fabry—Perot interferometer is presented. The phase difference between the two intensities in birefringence feedback is twice the retardation of the wave plate. The phase difference is invariable when the length of the feedback cavity changes. With the adoption of a cube corner prism (CCP) to form a folded cavity, the fringe frequency is doubled, and the resolution of the displacement sensor based on birefringence optical feedback with a folded cavity is improved. A resistance chain of 5-fold subdivision and 4-fold logic subdivision is used as further subdivision. The resolution of λ/80 is obtained eventually; for 632.8 nm HeNe laser it is 7.91 nm. The displacement sensor based on birefringence optical feedback with a folded cavity is simple and of high resolution, large measurement range, low cost, and is of great application potential in industry

  2. Effect of HeNe laser on calcium signals in sperm cells

    Science.gov (United States)

    Lubart, Rachel; Friedmann, Harry; Cohen, Natalie; Brietbart, Haim

    1998-12-01

    Irradiation of mouse spermatozoa by 630 nm HeNe laser was found to enhance calcium transport in these cells. The change in Ca transport was investigated through two approaches, the first employing the fluorescent Ca indicator, Fluo-3 AM and a fluorescence microscopic system, and the second the radiolabeled Ca uptake. In both approaches the effect of light on Ca transport was abrogated in the absence of Ca during the irradiation time, indicating that the effect of light is Ca-dependent. The stimulatory effect of light on Ca uptake was inhibited by treatment with catalase, suggesting H2O2 to be involved in light stimulated Ca2+ uptake. The stimulatory effect of light on Ca uptake was abolished in the presence of a voltage-dependent Ca-channel inhibitor, nifedipine, indicating the involvement of a plasma membrane, voltage- dependent Ca-channel. In contrast, addition of nifedipine prior to the HeNe laser irradiation did not affect the light-induced rise in intracellular Ca levels, as measured with Fluo-3 loaded sperm cells. Therefore, it can be concluded that this Ca influx occurs via a voltage- insensitive Ca-channel. The stimulatory effect of light on Ca uptake was almost completely abolished by the mitochondrial uncoupler FCCP. These data imply that light affects the mitochondrial Ca transport mechanisms. It is well known that Ca influx from an extracellular environment is an essential component of a signaling cascade leading to fertilization.

  3. He-Ne and CW CO2 laser long-path systems for gas detection

    Science.gov (United States)

    Grant, W. B.

    1986-01-01

    This paper describes the design and testing of a laboratory prototype dual He-Ne laser system for the detection of methane leaks from underground pipelines and solid-waste landfill sites using differential absorption of radiation backscattered from topographic targets. A laboratory-prototype dual CW carbon dioxide laser system also using topographic backscatter is discussed, and measurement results for methanol are given. With both systems, it was observed that the time-varying differential absorption signal was useful in indicating the presence of a gas coming from a nearby source. Limitations to measurement sensitivity, especially the role of speckle and atmospheric turbulence, are described. The speckle results for hard targets are contrasted with those from atmospheric aerosols. The appendix gives appropriate laser lines and values of absorption coefficients for the hydrazine fuel gases.

  4. Effect of He-Ne laser irradiation on hydrogen production by Enterobacter aerogenes

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Wenyu; Wen, Jianping; Jia, Xiaoqiang; Sun, Bing; Chen, Yu.; Liu, Minhui [Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China)

    2008-01-15

    Enterobacter aerogenes W-23 bacteria exhibiting hydrogen production (HP) ability were exposed to He-Ne laser irradiation (632.8 nm) to improve the HP ability. Upon the optimum irradiation dosage (18 mW for 22.2 min), a stable positive mutant strain E. aerogenes HB-5M was obtained. The maximum specific rate of HP of the mutant strain was 0.042h{sup -1}, which was about twice that of the wild strain. It was suggested that the higher HP ability of the mutant strain might be presumably attributed to the enhancement of hydrogenase activity. In addition, the kinetic parameters of cell growth, substrate consumption and HP of the wild strain and its mutant strain were regressed to simulate the fermentation process of E. aerogenes. The simulated results agreed well with the experimental data. (author)

  5. Diagnostics of ETL TPE-1 plasmas by using a He--Ne laser

    Energy Technology Data Exchange (ETDEWEB)

    Maejima, Y; Sugimoto, H; Tamaru, T [Electrotechnical Lab., Tanashi, Tokyo (Japan). Tanashi Branch

    1975-08-01

    The electron density in the plasma of toroidal screw pinch device TPE-1 of the Electrotechnical Laboratory has been measured with a conventional optical interferometer of He-Ne gas laser, 6,328 A in wavelength. The minimum phase shift detectable is about 1/300 lambda, equivalent to ..integral..nsub(e)dl=1x10/sup 15/cm/sup -2/. Some problems on this measuring system are presented. As the system uses conventional components, it is easy to construct and handle and is useful for determining plasma parameters in confinement experiments. The confinement time of charged particles is measured. As a result it has been found that the particles escape from the plasma mostly in conformity with the classical diffusion.

  6. Third-order nonlinear optical studies of anthraquinone dyes using a CW He-Ne laser

    Science.gov (United States)

    Pramodini, S.; Poornesh, P.

    2014-05-01

    We present investigations on the third-order optical nonlinearity and optical power limiting of anthraquinone dyes. Z-scan measurements were performed using a continuous wave He-Ne laser at 633 nm wavelength as an excitation source. The nonlinear refraction studies exhibited self-defocusing behavior of the dyes. The nonlinear absorption in the dyes was dominated by a reverse saturable absorption process. Self-diffraction ring patterns were observed due to the change in refractive index and thermal lensing. Increase of the electron donating ability of the substituents resulted in enhanced values of the nonlinear optical parameters, establishing the structure-property relationship. The optical limiting study revealed that the dyes possess a lower limiting threshold and clamping level which is very important for eye and sensor protection. Hence, the dyes investigated here emerge as promising candidates for future opto-electronic and photonic device applications such as optical power limiters.

  7. Quantitative description of the saturated absorption signal in iodine stabilized He-Ne lasers

    International Nuclear Information System (INIS)

    Brillet, A.; Cerez, P.

    1977-01-01

    He-Ne lasers stabilized by saturated absorption 127 I 2 have been studied in many laboratories and are now widely used as optical frequency standards. But, although their frequency stability and reproducibility have been extensively measured and reported, the size and the width of the saturated absorption signals used for the stabilization are not yet well understood. Particularly, the extrapolation of the linewidth to zero pressure results in an apparent discrepancy with the lifetime of the upper level of the transition. By measuring or evaluating all the important parameters which affect the operation of these lasers we are now able to describe with a good accuracy the properties of the saturated absorption signal and their variations with the iodine pressure, using Greenstein's theory of a laser with an internal absorption cell. At low iodine pressures (typically below 100 m Torr), we observe a divergence between experimental and theoretical results, which is interpreted as an effect of the laser beam geometry, when the saturation parameter becomes much larger than 1. (orig.) [de

  8. Effect of He-Ne laser beam on the ommatidia in Schistocerca Gregaria

    International Nuclear Information System (INIS)

    Abd El-Meguid, A.

    1996-01-01

    Exposing compound eye of Schistocerca Gregaria to He-Ne laser beam affected the micro-environment of the eye. The results indicated that the ionic content (Na, K and Ca) decreased and showed measurable percentage changes about 21.3, 45.9 and 14.9% (very high significant, VHS) in the right (R); and about 32.1, 71.4 and 9.4% (VHS) in the left (L) left (L) eyes. Respectively. As compared with control (Unexposed) eyes. Also protein content showed increase in concentrations about 70.2% (VHS) and 60.0% (Hs) in both right (R) and left (L) eyes. Respectively. While albumin content showed significant (S) decrease in concentrations about 34.6 and 26.3% in both right (R) and left (L) eyes. Respectively, as compared with the control ones. Histological sections as well as scanning electron micrographs showed that exposure of eyes to laser beam affected the structure of the eyes. 4 figs., 2 tabs

  9. Aquaporin-1-Mediated Effects of Low Level He-Ne Laser Irradiation on Human Erythrocytes

    Directory of Open Access Journals (Sweden)

    Gang-Yue Luo

    2012-01-01

    Full Text Available The role of membrane aquaporin-1 (APQ-1 in the photobiomodulation (PBM on erythrocyte deformability will be studied in this paper with human dehydrated erythrocytes as echinocytic shape alterations lead to decreased cellular deformability. Human dehydrated erythrocytes were irradiated with low intensity He-Ne laser irradiation (LHNL at 0.9, 1.8, 2.7, and 4.4 mW/cm2 for 5, 15, and 30 min, respectively, and APQ-1 inhibitor, 0.2 μmol/L HgCl2, was used to study the role of APQ-1 in mediating PBM with LHNL at 4.4 mW/cm2 for 5 min. Comprehensive morphological parameters of an intact cell such as contact area, perimeter, roundness and erythrocyte elongation index (EEI were measured to characterize erythrocyte deformability with fast micro multi-channel spectrophotometer. It was observed that the dosage of LHNL improvement of the morphological parameters of dehydrated erythrocytes was morphological-parameter-dependent, but the Bunsen-Roscoe rule did not hold for roundness. The LHNL at 4.4 mW/cm2 for 5 min significantly improved the contact area (P<0.05 and EEI (P<0.05 of the dehydrated erythrocytes, but the improvement was significantly inhibited by 0.2 μmol/L HgCl2 (P<0.05. It was concluded that AQP-1 might mediate the effects of LHNL on erythrocyte deformability, which supports the membranotropic mechanism of PBM.

  10. He-Ne laser irradiation affects proliferation of cultured rat Schwann cells in a dose-dependent manner

    International Nuclear Information System (INIS)

    Breugel, H.H.F.I. van; Bar, P.R.

    1993-01-01

    Schwann cell proliferation is considered an essential part of Wallerian degeneration after nerve damage. Laminin, an important component of the extracellular matrix and produced by Schwann cells, provides a preferred substrate for outgrowing axons. To study whether low energy (He-Ne) laser irradiation may exert a positive effect on nerve regeneration through an effect on Schwann cells, its effect was evaluated in vitro. Schwann cells were isolated from sciatic nerves of 4-5-day old Wistar rats and cultures on 96-multiwell plates. The cells were irradiated by a He-Ne laser beam. At three consecutive days, starting either at day 5 or day 8, cells were irradiated each day for 0.5, 1, 2, 5 or 10 min. Both cell number and laminin production were determined for each irradiation condition within one experiment. Schwann cells that were irradiated from day 8 on were hardly affected by laser irradiation. However, the proliferation of cells that were irradiated starting on day 5 was significantly increased after 1, 2 and 5 min of daily irradiation, compared to non-irradiated control cultures. The lamin production per cell of these Schwann cells was not significantly altered. From these results we conclude that He-Ne laser irradiation can modulate proliferation of rat Schwann cells in vitro in a dose-dependent manner. (Author)

  11. Changes in the ionic and protein contents of adult Schistocerca Gregaria compound eyes due to He-Ne laser exposure

    International Nuclear Information System (INIS)

    El-Gindi, A.M.; Osiris, W.G.; El-kes, N.; Abd El-Meguid, A.

    1996-01-01

    The induced change in the concentration of the ionic content such as Na, K, and Ca in the compound eyes of Schistocerca Gregaria was carried out before and after exposure for different periodic times to He-Ne ;laser beam. Total protein and albumin contents in the compound eyes were also determined. The Data indicated that the ionic contents (Na, K and Ca) showed acceptable and significant changes in both the right (R) and left (L) eyes after exposure to different periodic times up to 60 minutes in comparison with the control ones. Moreover, very high significant increase in the total protein content (about 70.2%) as well as significant decrease in the albumin content (about 39.1%) in the right (R) eyes after exposure to He-Ne laser beam for 30 minutes in comparison with the control (unexposed) eyes, were detected. 2 tabs

  12. Markers Of Apoptosis In HEP-2 Cells In Vitro Damaged By PHOTOFRIN And He:Ne Laser

    International Nuclear Information System (INIS)

    KORRAA, S.; ELMAGHRABY, T.K.; HELMY, H.M.

    2009-01-01

    Photodynamic therapy (PDT), which is a treatment for cancer and certain non-cancerous conditions, requires exposure of cells or tissue to a photosensitizing drug followed by irradiation with visible light of the appropriate wavelength. Although PDT can produce apoptosis or necrosis or a combination of the two mechanisms, PDT is a highly efficient if it induces apoptosis. The aim of the present study is to investigate the effect of combination between photofrin and He:Ne laser on killing Hep-2 cells in vitro, 2 and 24 hours post-laser irradiation. Also, to determine the markers of apoptosis in terms of levels of Bcl-2 protein and Bax mRNA relative expression in PDT treated cells six hours post laser irradiation. Cells viability was measured by trypan blue exclusion test (by light microscope). The results showed that photofrin in combination with He:Ne laser was efficient in decreasing the number of viable cells. It caused 81.47± 2.0 % cell death 2 hours post laser irradiation then reached 52.37± 2.24 % 24 hours post laser irradiation. PDT induced an increase in Bax mRNA relative expression and a decrease in Bcl-2 protein as measured 6 hours post laser irradiation.

  13. Recent Experiments Leading to the Characterization of the Performance of Portable (He-Ne)/CH4 Lasers: Part II: Results of the 1986 LPTF Absolute Frequency Measurements

    Science.gov (United States)

    Clairon, A.; Dahmani, B.; Acef, O.; Granveaud, M.; Domnin, Yu S.; Pouchkine, S. B.; Tatarenkov, V. M.; Felder, R.

    1988-01-01

    Comparison of the VNIIFTRI and LPTF frequency multiplication chains has been carried out through the measurement of the frequency of a portable VNIIFTRI (He-Ne)/CH4 laser. Agreement is within 100 Hz (1.1 parts in 1012) and is secured by the very good medium-term frequency repeatability of the (He-Ne)/CH4 VNIIFTRI portable laser (a few parts in 1013). On the same occasion a measurement of the frequency of the BIPM (He-Ne)/CH4 reference laser (B.3) has been performed at LPTF. Other experiments carried out on the BIPM laser show that the reproducibility of the (He-Ne)/CH4 system could be improved by a systematic study and then by a better control of the various perturbing factors which influence the shape of the methane-saturated absorption peak.

  14. Investigation of an He-Ne laser generating a beam with a ring-shaped intensity distribution

    Energy Technology Data Exchange (ETDEWEB)

    Sukhanov, I I; Troitskii, IU V; Iakushkin, S V

    1987-02-01

    The paper examines an He-Ne laser regime with the simultaneous generation of TEM(01) and TEM(10) modes, forming a beam with a ring-shaped intensity distribution with total suppression of the TEM(00) mode. The ratio of the intensity at the ring crest to the intensity at the axis reached a value of 200 and was limited by scattering in the optical components of the resonator. A regime of mutual frequency locking of the TEM(01) and TEM(10) modes was achieved with total spatial coherence of the ring-shaped beam. 14 references.

  15. Phase control of a Zeeman-split He-Ne gas laser by variation of the gaseous discharge voltage.

    Science.gov (United States)

    Shelton, W N; Hunt, R H

    1992-07-20

    Zeeman-split lasers are useful for precise positioning or motion control. In applications that employ such a laser to control closely the position of a moving system, phase noise in the Zeeman frequency is a serious problem. Control of low-frequency phase noise can be obtained through variation of the external magnetic field by way of a solenoid wound around the laser tube. It is the finding in this work that control of the residual higher-frequency noise of a He-Ne laser can be obtained through small variations of the high voltage that is used to effect the gaseous discharge in the laser tube. The application of the present system is to the control of the path difference in a Fourier-transform interferometric spectrometer.

  16. Study of He-Ne Laser Beam Propagation Through Air and Pure, Salt (Still and Turbulence Water

    Directory of Open Access Journals (Sweden)

    Safa AL. Barmany

    2018-01-01

    Full Text Available  This papers ,study  properties of the laser beam in the  different condition,  By using optical system consist of the (He- Ne laser ((λ =632.8nm , p=1.04mw, the parameter beam laser(spot, shape, intensity were study and also study the attenuation and turbulence for the laser mentioned above and with following environmental condition.(1 in the air (2 in the pure ,slate (seawaterwater with concentration 10-5Ml (still, turbulence  at different distance. Measurement were obtained by using a CCD camera and silicon detector type(Silicon PIN in fast response (.0.4-0.7A/W, absorption coefficient value of all cases  was calculated.

  17. Optical power calibrator based on a stabilized green He-Ne laser and a cryogenic absolute radiometer

    International Nuclear Information System (INIS)

    Varpula, T.; Seppa, H.; Saari, J.M.

    1989-01-01

    This paper describes an optical power calibrator whose overall calibration uncertainty is less than 10 -4 for an optical power of 0.13 mW. The laser light source of the system operates at a wavelength of 543.5 nm, being close to the wavelength at which the candela is defined, 555 nm. A stable optical power is achieved by stabilizing the intensity and the frequency of a green He-Ne laser. The optical power is detected by a cryogenic absolute radiometer based on the principle of electrical substitution radiometry. It can be employed to measure optical power up to 0.5 mW in the visible and near infrared region

  18. Effect of He-Ne laser irradiation of Bombyx mori L. breed in egg stage on thereproductive characters

    International Nuclear Information System (INIS)

    Ovesenska, L.; Vasileva, J.

    1984-01-01

    Two eggs of B. mori breeds were treated with laser rays at various rates. The effects of irradiation on the quantitative characters with alterating phenotypic performance characterizing the reproductive capability of the progeny was investigated. The characters were compared between parents and progeny as well as with control groups in the progeny. Data were processed by mono-factional analysis of variance of polugenic quantative characters with alternating phenotypic performance. Characterization of the characters was made by mean arithmetic value' analysis of the phenotype variance with the coeficient of genetic diversity in the investigated groups. A simulating effect of He-Ne laser irradiation on the reproductive characters of B. mori was found both in the parents and in their progeny. The effect was higher in breeds of lower reproductive capacity after treatment at lower rates (5, 10 and 15 mW), and the eggs treated were in a more advanced embrional stage

  19. A combination of He-Ne laser irradiation and exogenous NO application efficiently protect wheat seedling from oxidative stress caused by elevated UV-B stress.

    Science.gov (United States)

    Li, Yongfeng; Gao, Limei; Han, Rong

    2016-12-01

    The elevated ultraviolet-B (UV-B) stress induces the accumulation of a variety of intracellular reactive oxygen species (ROS), which seems to cause oxidative stress for plants. To date, very little work has been done to evaluate the biological effects of a combined treatment with He-Ne laser irradiation and exogenous nitric oxide (NO) application on oxidative stress resulting from UV-B radiation. Thus, our study investigated the effects of a combination with He-Ne laser irradiation and exogenous NO treatment on oxidative damages in wheat seedlings under elevated UV-B stress. Our data showed that the reductions in ROS levels, membrane damage parameters, while the increments in antioxidant contents and antioxidant enzyme activity caused by a combination with He-Ne laser and exogenous NO treatment were greater than those of each individual treatment. Furthermore, these treatments had a similar effect on transcriptional activities of plant antioxidant enzymes. This implied that the protective effects of a combination with He-Ne laser irradiation and exogenous NO treatment on oxidative stress resulting from UV-B radiation was more efficient than each individual treatment with He-Ne laser or NO molecule. Our findings might provide beneficial theoretical references for identifying some effective new pathways for plant UV-B protection.

  20. Gap In A Laser Frequency He-Ne at 632.8 nm | Aissani | Journal of ...

    African Journals Online (AJOL)

    The aim of this work is to show that the emitted signals of a double-output laser cavity exhibit distinctive features, manifesting themselves through typical dissymmetry in the corresponding spectral line shapes. Usually, such a dissymmetry in an inhomogeneously broadened gas laser appears with a clear but unpredictable ...

  1. Determination of total polyphenolic content in red wines by means of the combined He-Ne laser optothermal window and Folin-Ciocalteu colorimetric assay

    NARCIS (Netherlands)

    Doka, O.; Bicanic, D.

    2002-01-01

    The He-Ne laser (632.8 nm) and the concept of optothermal window (OW), a variant of the open photoacoustic cell, were combined with the Folin-Ciocalteu colorimetry assay to quantitate phenolics in four red wines. The total polyphenolic content in selected red wines varied between 786 and 1630 mg/L

  2. Recent Experiments Leading to the Characterization of the Performance of Portable (He-Ne)/CH4 Lasers: Part I: Results of the 1985 International Comparison BIPM-VNIIFTRI

    Science.gov (United States)

    Felder, R.; Chartier, J.-M.; Domnin, Yu S.; Oboukhov, A. S.; Tatarenkov, V. M.

    1988-01-01

    We analyse the results of beat-frequency measurements made on four (He - Ne)/CH4 lasers. It is found that the lack of reproducibility of the frequency of such standards is linked to the existence of various parameters whose relative influences lead to unpredicted experimental results.

  3. Research on optical properties of dental enamel for early caries diagnostics using a He-Ne laser

    Science.gov (United States)

    Tang, Jing; Liu, Li; Li, Song-zhan

    2008-12-01

    A new and non-invasive method adapted for optical diagnosis of early caries is proposed by researching on the interaction mechanism of laser with dental tissue and relations of remitted light with optical properties of the tissue. This method is based on simultaneous analyses of the following parameters: probing radiation, backscattering and auto-fluorescence. Investigation was performed on 104 dental samples in vitro by using He-Ne laser (λ=632.8nm, 2.0+/-0.1mW) as the probing. Spectrums of all samples were obtained. Characteristic spectrums of dental caries in various stages (intact, initial, moderate and deep) were given. Using the back-reflected light to normalize the intensity of back-scattering and fluorescence, a quantitative diagnosis standard for different stages of caries is proposed. In order to verify the test, comparison research was conducted among artificial caries, morphological damaged enamel, dental calculus and intact tooth. Results show that variations in backscattering characteristic changes in bio-tissue morphological and the quantity of auto-fluorescence is correlated with concentration of anaerobic microflora in hearth of caries lesion. This method poses a high potential of diagnosing various stages of dental caries, and is more reliability to detect early caries, surface damage of health enamel and dental calculus.

  4. He-Ne laser treatment for 16 cases of nonspecific edema

    Science.gov (United States)

    Xia, Wenlou; Liu, Sixian; Cao, Guangyi; Chen, Zhifu; Zhang, Haishui; Wei, Wei; Xia, Xinshe; Sia, Guangyu

    1993-03-01

    Nonspecific edema is a syndrome which is caused by a metabolism disorder of sodium and water. The people who suffer with this are mostly women about 25 - 50 years old. When it happens periodic edema, abdominal distension acratia, and obesity accompany the disease. Through several means of examination, no organic disease was found in the heart, liver, or kidney. Now 16 edema cases have been irradiated with laser and the result is satisfactory. The results are reported in this paper.

  5. Bullet Design and Fabrication of Dual Mode Pyroelectric Sensor: High Sensitive Energymeter for Nd: YAG Laser and Detector for Chopped He-Ne Laser

    Directory of Open Access Journals (Sweden)

    S. SATAPATHY

    2008-05-01

    Full Text Available Pyroelectric sensor using TGS has been designed and fabricated which can be operated in laser energy meter mode as well as pyroelectric detector mode. The amplifying circuit configuration has very good signal to noise ratio, very high input impedance and low drift. The pyroelectric sensor has been tested using Q-switched Nd: YAG laser and chopped He-Ne laser. The sensitivity of pyroelectric sensor in energymeter mode is 421.7V/J and the voltage responsivity of the pyroelectric sensor is 3.27 V/W in detector mode.

  6. Investigation of the Effect of He-Ne Laser on the Optical Properties through Etched CN-85 and CR-39 Containing Alpha Tracks

    International Nuclear Information System (INIS)

    Zaki, M.F.; Hegazy, T.M.; Taha, D.H.

    2013-01-01

    The effects of He-Ne laser on the optical characteristics of Cellulose nitrate, CN-85, and Poly allyl diglycole carbonate, CR-39, nuclear track detectors have been studied by using photoluminescence (PL) and UV-visible spectroscopic techniques. The polymers irradiated with alpha particles with close contact to 241 Am and then exposed to He-Ne laser with different doses. The laser energy intensities ranged between 0 and 217 J/cm 2 . The change in the PL spectra may be explained by chain conformational disorders as well as chain scission. From the UV-visible spectra, it is found that a shift in the absorption edge towards a longer wavelength with increasing laser doses can be readily observed. The absorption peak with increasing dose is seen to change into a broad one. The optical band gaps determined from the UV-visible spectra were found to decrease with the increase of energy intensities of He-Ne laser. These results have been explained on the basis of scission of the polymers due to laser irradiation. The UV absorption tail formation in both polymers was related to the diminution of optical band gap. Results show good correlation with the applied doses.

  7. Experimental and theoretical basis of agricultural plant immunostimulation with regard to pathogenic fungi by magnetic field and He-Ne laser irradiation

    Science.gov (United States)

    Belski, Alexey I.; Chivanov, Vadym D.

    1996-09-01

    Spring barley, winter wheat and maize seeds were subjected to the action of He-Ne laser irradiation having a low intensity in the visible region of the spectrum (628-640 nm) in conjunction with magnetic fields. The following results were obtained: laser irradiation with magnetic fields induced activation of the natural plant defence/immune systems gave the harvest crop level increased to about 50- 300 percent; a correlation was established between the rate of the fungal pathogens growth and the stimulation of plant immunity after the seeds had been treated with laser irradiation and magnetic field.

  8. He-Ne laser protection barrier by means of poly (Tetrafluoroethylene-Perfluoro vinyl Ether) grafted by acrylic acid complexed with Cu(II)

    International Nuclear Information System (INIS)

    El-Ahdal, M.A.; Fayek, S.A.; El-Sawy, N.M.

    2006-01-01

    Appropriate eye and skin protection is a prerequisite for the safe operation of He-Ne laser in industrial and laboratory environments. In the present paper, measurement of the optical parameters of poly (tetrafluoroethylene-perfluorovinyl ether) grafted by acrylic acid and complexed with Cu(II) are reported. He-Ne laser beam radiation on wavelength of 632.8 nm and power 12.5mW was used. Transmittance and reflectance spectra and refractive index dispersion are presented. The study showed that the material has a protective level 4. Environmental conditions like thermal and fading processes were tested. This suggested that the material preserves its protective features as a protective eye and skin barriers of protective level 4. This was applied for occupational working time up to 8 h, temperature up to 50 degree C and for a time equal 74 days after laser irradiation. Radiation protection from laser sources has attracted a great deal of attention for long time because of their importance for human body. Intensive progress in lasers, optical communications, and data storage has challenged scientists to achieve perfection in optical components. These challenges have resulted in an active development of a wide variety of unconventional optical elements (Hariharan, 1996 and Efimov et al., 2002). Alexandrite solid state lasers with a wavelength of about 755 nm are frequently used in the field of medicine (Schirmarcher and Sutter, 2001). For removing tattoos, the Q-switched versions with impulse widths of several ten nanoseconds are an ideal instrument to keep the thermal stress of the patient's skin at low level. He-Ne laser is one of the most commonly used visible light lasers

  9. Histological study on the effect of He-Ne laser on the compound eyes of the locust Schistocerca Gregaria Forsk (Orthoptera-Acridiidae)

    International Nuclear Information System (INIS)

    Abd El-Meguid, A.; El-Gundi, A.M.; Osiris, W.G.; El-Kes, N.

    1996-01-01

    In the present study, the effect of the He-Ne laser beam at different exposure periods (10,30 and 60 minutes) on the histological structure of the compound eyes of Schistocerca Gregaria Forsk is investigated. This study shows that various remarkable changes occurred in the histological structure of the right exposed eye (R) as in the left eye (L) (unexposed eye of the same insect), which may be due to a change in the micro-environment of the compound eyes, affected by the laser beam, furthermore, damage in the photoreceptors of the compound eyes of the insect was observed. 23 figs

  10. Analysis of the collagen birefringence and the relative attenuation coefficient of health and burned skin irradiated with linearly polarized He-Ne laser

    International Nuclear Information System (INIS)

    Silva, Daniela de Fatima Teixeira da

    2002-01-01

    Low-intensity laser therapy is characterized by its ability to induce athermic effects and nondestructive photobiological processes. Although it has been in use for more than 40 years, this phototherapy is still not an established therapeutic modality. The objectives of this study were: to quantify the collagen fibers organization by polarized light microscopy in normal and burned skin samples at day 17 post-injury considering preferential axis as the animal's spinal column and aligning the linear laser polarization in two directions of polarization, parallel or perpendicular to this axis; to determine the relative attenuation coefficient for the intensity light by the technique of imaging the light distribution in normal and burned skin during wound healing process taking only parallel direction of polarization. To reach the objectives, burns about 6 mm in diameter were created with liquid N 2 on the back of the rats and the lesions were irradiated on days 3, 7, 10 and 14 post-wounding, D= 1 J/cm 2 , to investigate the effects of low-intensity linearly polarized He-Ne laser beam on skin wounds healing. Control lesions were not irradiated. The results have demonstrated that: the skin samples irradiated with linearly parallel polarized He-Ne laser beam showed collagen fibers more organized; burned skin samples presents a higher attenuation coefficient than normal skin samples. These results are important to optimize low intensity laser therapy dosimetry on acceleration wound healing. (author)

  11. Application of the EPR technique to examine free radical qualities reducing infection of spring wheat grain with pathogenic fungi by He-Ne laser irradiation

    International Nuclear Information System (INIS)

    Gagoś, M.; Koper, R.; Sujak, A.; Misiak, L.E.; Kowalczuk, E.

    2000-01-01

    Samples of spring wheat grain, Jasna cv., infected with pathogenic fungi (Aspergillus niger, Penicillium sp., Fusarium, Mucor) were examined using an EPR technique. Considering the quantity of generated free radicals the fungi belonged to most toxine generating. Their toxicity was connected with the number of free radicals generated in examined grain. Grain was irradiated with He-Ne laser at known wavelength, power density and time of exposure what gave the mycostatic effect appearing in decrease of free radicals in grain samples. However, this process was not stable as the increase of free radicals was observed again with the regrowth of fungi after some days

  12. A efetividade do laser de HeNe 632,8 nm no reestabelecimento da integridade dos tecidos cutâneos em animais experimentais: revisão sistemática Effectiveness of HeNe 632.8 nm laser on skin tissue integrity repair in experimental animals: a systematic review

    Directory of Open Access Journals (Sweden)

    Clarissa Tôrres Leal

    2012-09-01

    Full Text Available O objetivo desta revisão sistemática foi analisar o efeito do laser de HeNe na cicatrização de feridas em ratos. Foram selecionados estudos experimentais que adotaram o laser HeNe para o tratamento de feridas agudas em ratos adultos saudáveis, com lesões induzidas por bisturi, nas bases de dados PubMed/MEDLINE, LILACS e SciELO. Foram utilizados os seguintes descritores: cicatrização de feridas e colágeno, de acordo com o MeSH e o DeCS, além dos unitermos laser HeNe e reparação da pele e seus equivalentes em inglês e espanhol. Três estudos foram incluídos na revisão sistemática, não sendo possível a realização de metanálise, devido à impossibilidade de comparação entre as metodologias dos estudos selecionados. Todos os estudos realizaram análise por meio de cortes histológicos das cicatrizes. A presença de falhas metodológicas nos três artigos dificultou a interpretação fidedigna dos dados encontrados. Os estudos destacaram uma redução na intensidade da resposta inflamatória e uma melhor organização das fibras colágenas no grupo irradiado. A terapia com laser HeNe mostrou boa resposta no reparo tecidual. No entanto, tais resultados devem ser analisados de modo criterioso, uma vez que há presença de heterogeneidade, principalmente em relação aos parâmetros adotados.The aim of this systematic review was to analyze the effect of HeNe laser on wound healing in rats. Experimental studies that adopted HeNe laser as a treatment of acute lesions in healthy adult rats were selected, with scalpel-induced lesions, at PubMed/MEDLINE, LILACS, and SciELO databases. The following keywords were used: wound healing and collagen, according to MeSH and DeCS, besides the terms HeNe laser and skin repair, and their equivalent in Portuguese and Spanish. Three studies were included in this systematic review, but it was not possible to perform a metanalysis, due to impossibility to compare methods of the selected studies. All

  13. Responses of He-Ne laser on agronomic traits and the crosstalk between UVR8 signaling and phytochrome B signaling pathway in Arabidopsis thaliana subjected to supplementary ultraviolet-B (UV-B) stress.

    Science.gov (United States)

    Gao, Limei; Li, Yongfeng; Shen, Zhihua; Han, Rong

    2018-05-01

    UV-B acclimation effects and UV-B damage repair induced by a 632.8-nm He-Ne laser were investigated in Arabidopsis thaliana plants in response to supplementary UV-B stress. There was an increasing trend in growth parameters in the combination-treated plants with He-Ne laser and UV-B light compared to those stressed with enhanced UV-B light alone during different developmental stages of plants. The photosynthetic efficiency (Pn) and survival rates of seedlings were significantly higher in the combination treatments than UV-B stress alone. The expression of UVR8, phytochrome B (PhyB), and their mediated signal responsive genes such as COP1, HY5, and CHS were also significantly upregulated in plants with the laser irradiation compared with other groups without the laser. Levels of flavonol accumulation in leaves and capsule yield of He-Ne laser-treated plants were increased. The phyB-9 mutants were more sensitive to enhanced UV-B stress and had no obvious improvements in plant phenotypic development and physiological damage caused by enhanced UV-B stress after He-Ne laser irradiation. Our results suggested that UVR8 and its mediated signaling pathway via interaction with COP1 can be induced by He-Ne laser, and these processes were dependent on cytoplasmic PhyB levels in plant cells, which might be one of the most important mechanisms of He-Ne laser on UV-B protection and UV-B damage repair. These current data have also elucidated that the biostimulatory effects of He-Ne laser on Arabidopsis thaliana plants would happen not only during the early growth stage but also during the entire late developmental stage.

  14. Measurements of line-averaged electron density of pulsed plasmas using a He-Ne laser interferometer in a magnetized coaxial plasma gun device

    Science.gov (United States)

    Iwamoto, D.; Sakuma, I.; Kitagawa, Y.; Kikuchi, Y.; Fukumoto, N.; Nagata, M.

    2012-10-01

    In next step of fusion devices such as ITER, lifetime of plasma-facing materials (PFMs) is strongly affected by transient heat and particle loads during type I edge localized modes (ELMs) and disruption. To clarify damage characteristics of the PFMs, transient heat and particle loads have been simulated by using a plasma gun device. We have performed simulation experiments by using a magnetized coaxial plasma gun (MCPG) device at University of Hyogo. The line-averaged electron density measured by a He-Ne interferometer is 2x10^21 m-3 in a drift tube. The plasma velocity measured by a time of flight technique and ion Doppler spectrometer was 70 km/s, corresponding to the ion energy of 100 eV for helium. Thus, the ion flux density is 1.4x10^26 m-2s-1. On the other hand, the MCPG is connected to a target chamber for material irradiation experiments. It is important to measure plasma parameters in front of target materials in the target chamber. In particular, a vapor cloud layer in front of the target material produced by the pulsed plasma irradiation has to be characterized in order to understand surface damage of PFMs under ELM-like plasma bombardment. In the conference, preliminary results of application of the He-Ne laser interferometer for the above experiment will be shown.

  15. Measurement of the electron density of a plasma by interferometry with a He - Ne laser ({lambda} = 3.39 {mu}); Mesure de la densite electronique d'un plasma par interferometrie avec un laser He - Ne ({lambda} = 3.39 {mu})

    Energy Technology Data Exchange (ETDEWEB)

    Belland, P [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1968-07-01

    The characteristics of the He-Ne gas laser used in a simple interferometric technique have been studied. After passing through the plasma, the beam is reflected back into the laser cavity, and the intensity of the laser itself, modulated by this optical feedback, is used to observe the fringes. Furthermore, owing to the coupling of the two laser transitions 0.63{mu} (red) and 3.39{mu} (infra red), interferences in the infra red can be detected by a simple photomultiplier monitoring the red line. This method has been applied to two plasma machines (E.P.P.E. and SABLIER) for spatial and temporal measurements of the mean electron density. (author) [French] Nous avons etudie les caracteristiques d'un laser a gaz He-Ne utilise dans une technique simple d'interferometrie. La lumiere qui traverse le plasma est reinjectee dans le laser, et l'intensite propre de celui-ci, modulee par cette reinjection, sert a observer les franges. De plus, a cause du couplage des deux transitions laser: 0.63{mu} (rouge) et 3.39{mu} (infrarouge), les interferences dans l'infrarouge peuvent etre detectees par un simple photomultiplicateur sensible au rouge. Nous avons applique cette methode a deux machines a plasma (E.P.P.E. et SABLIER) pour la mesure de la densite electronique moyenne en fonction du temps et de l'espace. (auteur)

  16. Determination of total polyphenolic content in red wines by means of the combined He-Ne laser optothermal window and Folin-Ciocalteu colorimetry assay.

    Science.gov (United States)

    Dóka, Ottó; Bicanic, Dane

    2002-05-01

    The He-Ne laser (632.8 nm) and the concept of optothermal window (OW), a variant of the open photoacoustic cell, were combined with the Folin-Ciocalteu colorimetry assay to quantitate phenolics in four red wines. The total polyphenolic content in selected red wines varied between 786 and 1630 mg/L gallic acid equivalent (GAE) as determined by OW-Folin-Ciocalteu colorimetry, which compares well to 778 and 1614 mg/L GAE obtained for the same wines by means of classical spectrophotometry. The originality and merit of OW colorimetry used here is that, unlike what is encountered in conventional spectrometry, no intermediate dilution step is required when total polyhenolics are determined in red wine. The precision, defined as the closeness to each other of 256 replicate readings of the OW signal, is generally better than 2%.

  17. Analysis of the collagen birefringence and the relative attenuation coefficient of health and burned skin irradiated with linearly polarized He-Ne laser; Analise da birrefringencia do colageno e do coeficiente de atenuacao de amostras de pele sadia e queimada irradiadas pelo laser de He-Ne linearmente polarizado

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Daniela de Fatima Teixeira da

    2002-07-01

    Low-intensity laser therapy is characterized by its ability to induce athermic effects and nondestructive photobiological processes. Although it has been in use for more than 40 years, this phototherapy is still not an established therapeutic modality. The objectives of this study were: to quantify the collagen fibers organization by polarized light microscopy in normal and burned skin samples at day 17 post-injury considering preferential axis as the animal's spinal column and aligning the linear laser polarization in two directions of polarization, parallel or perpendicular to this axis; to determine the relative attenuation coefficient for the intensity light by the technique of imaging the light distribution in normal and burned skin during wound healing process taking only parallel direction of polarization. To reach the objectives, burns about 6 mm in diameter were created with liquid N{sub 2} on the back of the rats and the lesions were irradiated on days 3, 7, 10 and 14 post-wounding, D= 1 J/cm{sup 2}, to investigate the effects of low-intensity linearly polarized He-Ne laser beam on skin wounds healing. Control lesions were not irradiated. The results have demonstrated that: the skin samples irradiated with linearly parallel polarized He-Ne laser beam showed collagen fibers more organized; burned skin samples presents a higher attenuation coefficient than normal skin samples. These results are important to optimize low intensity laser therapy dosimetry on acceleration wound healing. (author)

  18. He-Ne laser effects on blood microcirculation. An in vivo study through laser doppler flowmetry; Efeito do laser de helio neonio sobre a microcirculacao sanguinea durante a reparacao tecidual. Estudo in vivo por meio de fluxometria laser doppler

    Energy Technology Data Exchange (ETDEWEB)

    Nunez, Silvia Cristina

    2002-07-01

    Blood microcirculation performs an important function in tissue repair process, as well as in pain control, allowing for greater oxygenation of the tissues and the accelerated expulsion of metabolic products, that may be contributing to pain. Low Intensity Laser Therapy (LILT) is widely used to promote healing, and there is an assumption that it is mechanism of action may be due to an enhancement of blood supply. The purpose of this study was to evaluate, using laser Doppler flowmetry (LDF), the stated effects caused by radiation emitted by a He-Ne laser ({lambda}=632.8 nm) on blood microcirculation during tissue repair. To this end, 15 male mice were selected and received a liquid nitrogen provoked lesion, above the dorsal region, and blood flow was measured periodically, during 21 days. Due to radiation emission by the LDF equipment, a control group was established to evaluate possible effects caused by this radiation on microcirculation. To evaluate the He-Ne laser effects, a 1.15 J/cm{sup 2} dose was utilized, with an intensity of 6 mW/cm{sup 2}. The results obtained demonstrate flow alterations, provoked by the lesion, and subsequent inflammatory response. There was no statistical difference between the studied groups. As per the analysis of the results there is no immediate effect due the radiation emitted by a He Ne laser on microcirculation, although a percentage increase was observed in day 7 on medium blood flow rate in irradiated specimens. New studies are necessary to validate the use of this wavelength, in order to promote beneficial alterations in blood supply in radiated areas. (author)

  19. Analysis of the influence of low-power HeNe laser on the healing of skin wounds in diabetic and non-diabetic rats

    Directory of Open Access Journals (Sweden)

    Carvalho Paulo de Tarso Camillo de

    2006-01-01

    Full Text Available PURPOSE: To study the influence of HeNe laser irradiation on the collagen percentage in surgically-induced skin wounds in rats with and without alloxan-induced diabetes, by morphometric analysis of collagen fibers. METHODS: 48 male Wistar rats were used, divided into groups: laser-treated diabetic (group 1; untreated diabetic (group 2; treated non-diabetic (group 3; and untreated non-diabetic (group 4. For groups 1 and 2, diabetes was induced by intravenous injection of alloxan (2,4,5,6-tetraoxypyrimidine; 5,6-dioxyuracil; Sigma, into the dorsal vein of the penis, at a rate of 0.1 ml of solution per 100 g of body weight. A wound was made on the back of all the animals. Groups 1 and 3 were treated with HeNe laser (4 J/cm² for 60 s. One animal from each group was sacrificed on the 3rd, 7th and 14th days after wounding. Samples were taken, embedded in paraffin, stained with hematoxylin-eosin and Masson's trichrome, and morphometrically analyzed using the Imagelab software. The percentages of collagen fibers were determined from the samples from the euthanasia animals. The data were treated statistically using analysis of variance (ANOVA and the Student t and Kruskal-Wallis tests. The significance level was set at 0.05 or 5%. RESULTS: The results obtained from the samples taken on the third, seventh and fourteenth days after wounding demonstrated that the laser-treated group presented a statistically significant (p<0.05 greater mean quantity of collagen fibers than in the non-treated group, both for diabetic rats (p = 0.0104 and for non-diabetic rats (p = 0.039. CONCLUSION: The low-power laser (632.8 nm was shown to be capable of influencing the collagen percentage in skin wounds by increasing the mean quantity of collagen fibers, both for the diabetic and for the non-diabetic group.

  20. Frequency stabilized HeNe gas laser with 3.5 mW from a single mode

    NARCIS (Netherlands)

    Ellis, J.D.; Voigt, D.; Spronck, J.W.; Verlaan, A.L.; Munnig Schmidt, R.H.

    2012-01-01

    This paper describes an optical frequency stabilization technique using a three-mode Helium Neon laser at 632.8 nm. Using this configuration, a maximum frequency stability relative to an iodine stabilized laser of 6×10 -12 (71 s integration time) was achieved. Two long term measurements of 62 h and

  1. 632 nm氦-氖激光治疗智齿冠周炎的研究%Study on 632 nm He-Ne laser therapy on pericoronitis

    Institute of Scientific and Technical Information of China (English)

    韦界飞; 邹群

    2013-01-01

    目的 通过临床试验,验证632 nm氦-氖红色激光对智齿冠周炎的镇痛效果和临床疗效.方法 选择下颌第3磨牙冠周炎患者75例,随机分为实验组和对照组.2组均采用局部常规治疗后,实验组用氦-氖激光局部照射15 min/d;对照组不再采取其他治疗.治疗后3、7d采用疼痛3度记分法记录消炎镇痛情况,并对2种治疗方法的效果进行综合评价.结果 治疗后3d,实验组78.9%患者疼痛消失,对照组51.4%患者疼痛消失;治疗后7d,实验组97.4%的患者疼痛消失,对照组91.9%的患者疼痛消失.治疗后3、7d,2组间疗效对比差异有统计学意义(P<0.05).结论 氦-氖激光在治疗智齿冠周炎上具有明显的消炎镇痛效果.%Objective To investigate the effects of He-Ne laser on the treatment of pericoronitis.Methods 75 clinical patients with pericoronitis were randomly divided into the experimental group and control group.Local conventional therapy was given to the two groups.The experimental group was given routine treatment with He-Ne laser local exposure for 15 minutes every day,while the control group took no other treatment.3 days and 7 days later,pain and inflammation degree were recorded by three-degree pain scoring method.Total treatment effects were evaluated under a comprehensive clinical treatment standard.Results After 3 days' treatment,78.9% patients in the experimental group and 51.4% patients in control group felt their pain disappeared.After 7 days' treatment,97.4% patients in experimental group and 91.9% patients in control group felt their pain disappeared.Treatment comprehensive evaluation showed that there were statistical significance differences between two groups (P<0.05).Conclusion He-Ne laser treatment of pericoronitis has significant anti-inflammatory analgesic effect.

  2. Influence of the He-Ne laser in different irradiation regimes on the cornea cells after ionizing irradiation

    International Nuclear Information System (INIS)

    Bulyakova, N.V.

    1984-01-01

    A study was made on epithelium cells of the eye cornea in mices entering the first postradiation mitosis. The influence of laser rays acting in the course of each exposure during one and the same period of time, or continuously, or by pulses was compared. The effect of laser radiation was evaluated from the frequency of occurrence of cells with chromosomal aberrations, mitotic index, coefficient of mitosis phases. It has been established that pulse radiation of a helium-neon laser in a certain operation regime produces a sanitating effect on cells of eye cornea epithelium in white mice damaged by ionizing radiation. Cells being killed in the interphase were not revealed in epithelium of the eye cornea. It enables to conclude that the amount of aberrant mitoses decreases as a result of postradiation repair of cells damaged by ionizing radiation, but not as a result of their elimination

  3. Effect of conjugation length on nonlinear optical parameters of anthraquinone dyes investigated using He-Ne laser operating in CW mode

    Science.gov (United States)

    Pramodini, S.; Poornesh, P.

    2014-10-01

    We report the studies on third-order optical nonlinearity and optical limiting of anthraquinone dyes. Z-scan technique was employed to evaluate the nonlinear parameters such as nonlinear absorption coefficient βeff and nonlinear index of refraction n2. Continuous wave He-Ne laser was used as the source of excitation. The estimated values of βeff, n2 and χ(3) are of the order of 10-3 cm/W, 10-5 esu and 10-7 esu respectively. The presence of donor and acceptor groups in the structure results in increase in conjugation length. This resulted in the enhancement of nonlinear optical parameters values of the dye. Multiple diffraction rings were observed when the samples were exposed to laser beam due to thermal lensing. Dyes exhibited good optical limiting behavior under the experimental conditions. The results indicate that the dyes investigated here are materialise as candidates for photonics device applications such as optical power limiters.

  4. Determination of lactose in raw milks by means of the combined He-Ne laser optothermal window

    NARCIS (Netherlands)

    Bakos, P.; Doka, O.; Ajtony, Z.; Bicanic, D.; Szucs, D.

    2002-01-01

    The concept of OW (with 632.8 nm He–Ne laser), combined with colorimetry based on a reaction of anthrone-sulphuric acid, was proposed as a new tool for determination of lactose in raw milk. Data obtained from various milk samples by OW colorimetry were compared to those acquired from the MilkoScan

  5. Information content in spectral dependencies of optical unit volume parameters under action of He-Ne laser on blood

    Science.gov (United States)

    Khairullina, Alphiya Y.; Oleinik, Tatiana V.

    1995-01-01

    Our previous works concerned with the development of methods for studying blood and action of low-intensity laser radiation on blood and erythrocyte suspensions had shown the light- scattering methods gave a large body of information on a medium studied due to the methodological relationship between irradiation processes and techniques for investigations. Detail analysis of spectral diffuse reflectivities and transmissivities of optically thick blood layers, spectral absorptivities calculated on this basis over 600 - 900 nm, by using different approximations, for a pathological state owing to hypoxia testifies to the optical significance of not only hemoglobin derivatives but also products of hemoglobin decomposition. Laser action on blood is specific and related to an initial state of blood absorption due to different composition of chromoproteids. This work gives the interpretation of spectral observations. Analysis of spectral dependencies of the exinction coefficient e, mean cosine m of phase function, and parameter Q equals (epsilon) (1-(mu) )H/(lambda) (H - hematocrit) testifies to decreasing the relative index of refraction of erythrocytes and to morphological changes during laser action under pathology owing to hypoxia. The possibility to obtain physical and chemical information on the state of blood under laser action in vivo is shown to be based on the method proposed by us for calculating multilayered structures modeling human organs and on the technical implementation of this method.

  6. Efeitos da aplicação do L.A.S.E.R. HeNe e do ultravioleta B no vitiligo

    Directory of Open Access Journals (Sweden)

    Ana Carolina Brandt de Macedo

    Full Text Available INTRODUÇÃO: O vitiligo é uma doença crônica despigmentante da pele, ocasionada pela perda funcional dos melanócitos da epiderme. Este estudo teve como objetivo comparar os efeitos da aplicação do L.A.S.E.R. HeNe e do ultravioleta B em pacientes com vitiligo. MÉTODO: Foram selecionados 22 pacientes (11 mulheres e 11 homens, com idade entre 12 e 60 anos (31,68 ± 16,29. Os pacientes foram distribuídos aleatoriamente, de acordo com a ordem de comparecimento no serviço e foram divididos randomicamente em dois grupos: o grupo A (n = 12, submetido à aplicação do L.A.S.E.R. HeNe, para o qual a técnica utilizada foi a pontual com aproximadamente 3 cm de distância entre cada ponto, perpendicularmente à pele, e o grupo B (n = 10, exposto ao Ultravioleta B, aplicado de forma perpendicular com 10 cm de afastamento da pele do paciente. Para mensuração da área tratada, utilizou-se o programa AUTOCAD 2002, no qual foi delimitada a borda da mácula em fotos tiradas no início e no fim do tratamento. RESULTADOS: Inicialmente, no grupo A, a área era de 4,87 cm² ± 3,70 e, após a aplicação, foi de 4,15 cm² ± 2,89, com diferença média de 0,72 cm² (1,89. No grupo B, verificou-se que antes da aplicação a média era de 5,36 cm² ± 6,36 e, a após a aplicação, foi de 4,43 cm² ± 5,17, com diferença média de 0,92 cm² ± 1,29. CONCLUSÃO: Ambos os aparelhos obtiveram resultados significativos na redução da mácula, com maior redução no grupo da ultravioleta.

  7. Influence of He-Ne laser irradiation of soybean seeds on seed mycoflora, growth, nodulation, and resistance to Fusarium solani

    International Nuclear Information System (INIS)

    Ouf, S.A.; Abdel-Hady, N.F.

    1999-01-01

    Laser irradiation of soybean seeds for 3 min caused a clear reduction in the number of seed-borne fungi which became more pronounced as the irradiation time was extended. Pretreatment of the seeds with methylene blue, methyl red and carmine enhanced the effect of laser. Rhizoctonia solani, Alternaria tenuissima, Cercospora kikuchii and Colletotrichum truncatum were completely eliminated when the seeds were pretreated with a dye and irradiated for 10 min. Seed germination was stimulated on exposure of the seed to 1-min irradiation. Chlorophyll a, chlorophyll b and carotenoid content of developed plants differed, depending on the irradiation dose and dye treatment of the seeds. The number and dry mass of nodules were mostly greater (as compared to the corresponding control), when the seeds irradiated for 1 or 3 min were pretreated with methyl red, chlorophenol red, crystal violet and methylene blue. Irradiation of pre-sowing seeds greatly protected soybean stands against F. solani

  8. Treatment of relapse in herpes simplex on labial and facial areas and of primary herpes simplex on genital areas and "area pudenda" with low-power He-Ne laser or Acyclovir administered orally

    Science.gov (United States)

    Velez-Gonzalez, Mariano; Urrea-Arbelaez, Alejandro; Nicolas, M.; Serra-Baldrich, E.; Perez, J. L.; Pavesi, M.; Camarasa, J. M.; Trelles, Mario A.

    1996-01-01

    Sixty patients (greater than 16 yrs old) suffering primary or relapse genital herpes simplex viruses (HSV) and relapse labial HSV were appointed for this study. Three or more relapses were experienced per year. Patients (under treatment) were divided into two groups (distribution areas), corresponding to either labial herpes or genital herpes. These groups were sub-divided into 3 groups. The total number of labial or facial HSV patients was 36 (10 in group 1, 12 in group 2, 14 in group 3) and 24 for genital, buttocks, or 'area pudenda' HSV patients (6 in group 1, 8 in group 2, 10 in group 3). The design was a randomized, double- blind study. The setting was hospital and outpatient. The patients diagnosed as having the HVS disease were sent to the dermatology department and were assigned to a group at random. Treatment was begun as follows: During the treatment signs and symptoms were assessed and after the treatment, the relapses were also assessed (biochemical and hematological tests before and after the treatment) and the diagnosis of the HSV type I and II. The statistical evaluation of the results was performed and carried out with the SPSS and BMDP program. The relapses of the herpes infection in the lips and the face were significantly reduced (p less than 0.026) in patients treated with laser He-Ne and laser He-Ne plus Acyclovir. The interim between the relapses also increased significantly (p less than 0.005) in relation with the group treated with Acyclovir. The duration of the herpetic eruptions was clearly reduced in all locations in patients treated with laser He-Ne plus Acyclovir. No differences were noted between patients treated with laser He-Ne only or Acyclovir only. Therefore it is probable that therapeutic synergism took place. In relation with this, laser He-Ne shows the same therapeutic efficacy as Acyclovir taken orally. The association of Acyclovir and laser Ne-Ne could be an alternative method for the treatment of HSV in the face. The number

  9. Study on the Therapeutic Effect of Dispersive He-Ne Laser on Radiation Proctitis%弥散型He-Ne激光治疗放射性直肠炎的临床研究

    Institute of Scientific and Technical Information of China (English)

    吴先哲; 宋奇; 邢国良

    2012-01-01

    目的 探讨弥散型He-Ne激光直肠内照射对放射性直肠炎的临床治疗作用.方法 将功率为30 mW、能量密度为3.62 J/cm2弥散型He-Ne激光导入直肠,使He-Ne激光直接照射直肠病变黏膜,观察患者直肠出血、直肠疼痛、腹泻等,比较治疗前后患者直肠黏膜病理组织学的改变.结果 He-Ne激光可以显著减少放射性直肠炎患者的直肠出血,对直肠疼痛、腹泻等症状的影响不大,能明显减轻黏膜组织的炎症反应,并能促进黏膜的修复.结论 弥散性He-Ne激光直肠腔内照射对放射性直肠炎所致的直肠出血有较好的治疗作用.%Objective To study the therapeutic effect of dispersive He-Ne laser on radiation proctitis. Methods Sent He-Ne laser to the rectum, irradiated the mucoga lesions of the rectum with He-Ne laser, observed the major therapeutic effects of He-Ne laser, including but not limited to rectal bleeding and pain, and diarrhea, and compared the histopathological changes of the rectum mncosa before and after the treatment. Results For radiation proctitis patients, He-Ne laser can significantly reduce significantly rectal bleeding .reduce the and inflammatory reaction of mucosal tissue inflammatory reaction, and as well as can facilitate mucosal tissue repair, but has little effect in relieving other symptoms, such as pain and diarrhea. Conclusions The laser irradiation in the rectal cavity with dispersive He-Ne is effective in treating the bleeding caused by radiation proctitis.

  10. 低能量He-Ne激光血管内照射治疗肿瘤疼痛的临床观察%The clinical observation of treatment with He-Ne laser of low energy cancer pain

    Institute of Scientific and Technical Information of China (English)

    王丽芬; 关兴惠

    2001-01-01

    Treatment with He-Ne laser of low energy is new method.The way was directly shining irradiate blood.Biological effects were widespread.That can enhance immunity function and controlpain of cancer.By cleanins harmful matlers in the blood and changing composition of blood.We obtained yield good results in improving immunity of body and function of oryans.The cases were gotten from 1999 to 2000 year.%低能量He-Ne激光血管内照射(ILIB)是一种新的治疗技术,是将低能量激光导入血液系统直接照射血液,产生广泛良好的生物效应。ILIB疗法具有提高机体免疫功能及控制癌性疼痛的两种特性;对清除血液内有害的中分子物质(MMS)改善血液流变学特性对癌症患者有重要的治疗作用。多样的生物学效应可纠正癌症对机体脏器功能和免疫系统功能造成的损害。我科自1999年12月将这一新技术用于治疗顽固性癌性疼痛,提高患者的免疫力,改善各脏器的功能,作为化疗的辅助治疗。收到了意想不到的效果,报告如下。

  11. Two-frequency operation of a hybrid TEA CO2 laser and its application to two-frequency pulse injection locking

    International Nuclear Information System (INIS)

    Sasaki, Koichi; Ohno, Hirotaka; Fujii, Takaharu; Tsukishima, Takashige.

    1990-10-01

    Simultaneous two-frequency oscillation of a hybrid TEA CO 2 laser is exhibited when the cw section is operated in a 'below threshold' state. The output of the hybrid laser thus obtained is injected into a main TEA CO 2 laser to obtain a power-modulated, long-pulse output with a well suppressed gain-switched spike. (author)

  12. Diode-pumped two-frequency lasers based on c-cut vanadate crystals

    International Nuclear Information System (INIS)

    Sirotkin, A A; Garnov, Sergei V; Zagumennyi, A I; Zavartsev, Yu D; Kutovoi, S A; Vlasov, V I; Shcherbakov, Ivan A

    2009-01-01

    The luminescent and lasing properties of the neo-dymium ion at the 4 F 3/2 - 4 I 11/2 transition in c-cut vanadate crystals (Nd:YVO 4 , Nd:GdVO 4 , and Nd:Gd 1-x Y x VO 4 ) are studied. Tuning of the laser radiation wavelength (Δλ = 5.4 nm) is demonstrated. Two-frequency laser schemes with the use of a Lyot filter, a Fabry-Perot etalon, and a Brewster prism as spectral selection elements are proposed and experimentally realised. Stable two-frequency lasing of a laser based on the c-cut Nd:GdVO 4 crystal was obtained in the cw, Q-switched (nanosecond pulses), and active acousto-optic mode-locked (picosecond pulses) regimes. (lasers)

  13. International comparisons of He-Ne lasers stabilized with (sup. 127) I (sub 2) at [lambda] approximately equals 633 nm (July 1993 to September 1995). Part IV: Comparison of Western European lasers at [lambda] approximately equals 633 nm

    NARCIS (Netherlands)

    Darnedde, H.; Rowley, W.R.C.; Bertinetto, F.; Millerioux, Y.; Haitjema, H.; Wetzels, S.F.C.L.; Piree, H.; Prieto, E.; Perez, M.Mar; Vaucher, B.; Chartier, A.; Chartier, J.M.

    1999-01-01

    This paper reports the fourth set of results of a series of grouped laser comparisons from national laboratories undertaken by the Bureau International des Poids et Mesures (BIPM) at the request of the Comite Consultatif pour la Definition du Metre (CCDM; now the Consultative Committee for Length,

  14. Multicascade X-Ray Free-Electron Laser with Harmonic Multiplier and Two-Frequency Undulator

    Science.gov (United States)

    Zhukovsky, K. V.

    2018-06-01

    The feasibility of generation of powerful x-ray radiation by a cascade free-electron laser (FEL) with amplification of higher harmonics using a two-frequency undulator is studied. To analyze the FEL operation, a complex phenomenological single-pass FEL model is developed and used. It describes linear and nonlinear generation of harmonics in the FEL with seed laser that takes into account initial electron beam noise and describes all main losses of each harmonic in each FEL cascade. The model is also calibrated against and approved by the experimental FEL data and available results of three-dimensional numerical simulation. The electron beam in the undulator is assumed to be matched and focused, and the dynamics of power in the singlepass FEL with cascade harmonic multipliers is investigated to obtain x-ray laser radiation in the FEL having the shortest length, beam energy, and frequency of the seed laser as low as possible. In this context, the advantages of the two-frequency undulator used for generation of harmonics are demonstrated. The evolution of harmonics in a multicascade FEL with multiplication of harmonics is investigated. The operation of the cascade FEL at the wavelength λ = 1.14 nm, generating 30 MW already on 38 m with the seed laser operating at a wavelength of 11.43 nm corresponding to the maximal reflectivity of the multilayered mirror MoRu/Be coating is investigated. In addition, the operation of the multicascade FEL with accessible seed UVlaser operating at a wavelength of 157 nm (F2 excimer UV-laser) and electron beam with energy of 0.5 GeV is investigated. X-ray radiation simulated in it at the wavelength λ 3.9 nm reaches power of 50 MW already at 27 m, which is by two orders of magnitude shorter than 3.4 km of the x-ray FEL recently put into operation in Europe.

  15. He-, Ne-, and Ar-phosgene intermolecular potential energy surfaces

    DEFF Research Database (Denmark)

    Munteanu, Cristian R.; Henriksen, Christian; Felker, Peter M.

    2013-01-01

    Using the CCSD(T) model, we evaluated the intermolecular potential energy surfaces of the He-, Ne-, and Ar-phosgene complexes. We considered a representative number of intermolecular geometries for which we calculated the corresponding interaction energies with the augmented (He complex) and doub...... of the complexes, providing valuable results for future experimental investigations. Comparing our results to those previously available for other phosgene complexes, we suggest that the results for Cl2-phosgene should be revised....

  16. Enhancing the healing processes of chemical burns with He-Ne radiation

    International Nuclear Information System (INIS)

    Kakai, S.F.K.; Albarwari, S.E.; Alsenawi, T.A.

    1988-02-01

    The process by which He-Ne laser radiation (λ = 632.8 nm) enhances the healing of cutaneous wounds, made by concentrated nitric acid on mice has been studied. The dose used was of the order of 2.7 Joule per day, till the day of complete wound closure. The wounds were irradiated at three points on its periphery so that to form a semitriangular pattern this method was adopted, because chemical burns involve the killing of both the epidermis and dermis. The influence of the laser on the healing was estimated quantitatively and statistically, with a significance of p<0.001 over the control (the unirradiated). (author). 8 refs, 2 figs, 2 tabs

  17. The clinical effects observation of He-Ne laser combined with dryness itching capsules for treating herpes zoster%氦氖激光联合润燥止痒胶囊治疗带状疱疹的临床疗效观察

    Institute of Scientific and Technical Information of China (English)

    聂丽; 单玉珍

    2015-01-01

    Objective To investigate the clinical effects of He-Ne laser combined with dryness itching capsules for treating herpes zoster.Methods 140 patients with herpes zoster based on the random lottery principle were equally divided into the treatment group of 70 patients and 70 patients in the control group.140 patients were given the acyclovir oral and helium-neon laser therapy,on the basis of these,the treatment group were added treated with oral dryness itching capsules therapy.Results The response rate was 98.6% in the treatment group and 90.0% in the control group.The response rate of the treatment group was significantly higher (P < 0.05) than that of the control group.The pain scores before treatment was not statistically significant between the two groups while the pain scores of the treatment group after treatment were significantly lower than the control group (P < 0.05).The analgesic immediately onset time,crusting time and pain began to ease time of the treatment group were significantly less than the control group (P < 0.05).Followed-up eight weeks after treatment,the recurrence rate in the treatment group was 4.3% and 20.0% in the control group,the recurrence rate in the treatment group was significantly lower than the control group (P < 0.05).Conclusions He-Ne laser combined with itching dryness capsule in the treatment of herpes zoster can effectively relieve pain,improve clinical symptoms,thus improve the overall efficacy and recurrence rate that should be widely applied.%目的 探讨氦氖激光联合润燥止痒胶囊治疗带状疱疹的临床疗效.方法 根据随机抽签原则,将带状疱疹患者140例分为治疗组70例与对照组70例,两组都选择阿昔洛韦口服与氦氖激光治疗,治疗组在此基础上加用口服润燥止痒胶囊治疗,都治疗14天.结果 治疗组的有效率为98.6%,对照组的有效率为90.0%,治疗组的有效率经明显高于对照组(P<0.05).两组治疗前的疼痛评分对比

  18. Two-wavelength HeNe laser interferometer

    International Nuclear Information System (INIS)

    Granneman, E.H.A.

    1981-01-01

    This paper presents an interferometer set-up in which two wavelengths are used simultaneously. This enables one to determine separately the phase shifts caused by changes in plasma density and by mechanical vibrations of the interferometer structure

  19. Increase in the temperature of a laser plasma formed by two-frequency UV - IR irradiation of metal targets

    International Nuclear Information System (INIS)

    Antipov, A A; Grasyuk, Arkadii Z; Efimovskii, S V; Kurbasov, Sergei V; Losev, Leonid L; Soskov, V I

    1998-01-01

    An experimental investigation was made of a laser plasma formed by successive irradiation of a metal target with 30-ps UV and IR laser pulses. The UV prepulse, of 266 nm wavelength, was of relatively low intensity (∼ 10 12 W cm -2 ), whereas the intensity of an IR pulse, of 10.6 μm wavelength, was considerably higher (∼3 x 10 14 W cm -2 ) and it was delayed by 0 - 6 ns (the optimal delay was 2 ns). Such two-frequency UV - IR irradiation produced a laser plasma with an electron temperature 5 times higher than that of a plasma created by singe-frequency IR pulses of the same (∼3 x 10 14 W cm -2 ) intensity. (interaction of laser radiation with matter. laser plasma)

  20. Photodynamic effect produced by HeNe radiation in Harderian glands of Wistar rats: an experimental model for PDT studies

    Science.gov (United States)

    dos Reis, Edmyr R.; Nicola, Ester M. D.; Metze, Konradin; Nicola, Jorge H.

    2000-06-01

    In rats, the Harderian Gland secret Protoporphirin IX which is retained at acinar lumina. Since this photosensitizer is important for PDT of malignant tumors, we propose to study this gland as a model to help understanding PDT with endogenous photosensitizers. Twenty Wistar SPF adult rats were submitted to surgical exposure of both Harderian glands, revealing red fluorescence upon UV, characterizing the protoporphirin IX presence. After that, one gland of each pair (one kept as control) was irradiated with an 8 mW HeNe (6328 angstrom) for 45 minutes, delivering about 2.7 joules/mm2. After 24 hours a group of 10 animals were scarified and the glands removed for histological analysis. The remaining animals were subjected to the same procedure but the glands were removed immediately after laser treatment. Histological and fluorescence analysis immediately after laser irradiation showed cell fragmentation with loss of acinar architecture with diffusion of protoporphirin in the cytoplasm of damaged cells, as well as interstitial edema. After 24 hours these alterations were more pronounced with accentuated loss of intraluminal protoporphirin and beginning of leukocytic demarcation of necrotic areas. The innate Harderian glands of rats, exposed to HeNe laser, showed a similar behavior as tumor tissue under PDT.

  1. Theoretical and experimental study of two-frequency solid-state lasers in the GHz to THz ranges. Opto-microwave applications waves

    International Nuclear Information System (INIS)

    Lai, N.D.

    2003-07-01

    We explored some new features of single- and dual-frequency solid-state lasers oscillating in continuous-wave or pulsed regimes. First, we have developed some techniques to optimise the characteristics of pulsed lasers. A weak modulation of the pump power made it possible to obtain a stable repetition rate with a relative stability of 10 -6 . The pulse duration was continuously controlled from ten nanoseconds to a few hundreds nanoseconds by three different methods: adjustment of the laser beam diameter in the absorber, adjustment of the pump beam diameter in the active medium, and, in particular, the use of forked eigenstates in a two-axis laser. Moreover, the forked eigenstates allows to increase the pulse energy by coherent addition of the pulses. A compact two-frequency Nd:YAG-Cr:YAG laser with a beat note frequency continuously adjustable up to 2,7 GHz was demonstrated. The two-frequency pulses are ideal sources to meet various needs of applications such as the Doppler lidar-radar. Moreover, we show that two-frequency pulses at 1,55 μm can be obtained by using a new c-cut Co:ASL saturable absorber in an Er-Yb:glass laser. These pulses are perfectly adapted to free-space detection systems requiring eye safety. The coherence time of the beat note in these lasers was also studied: it is limited by the pulse duration. A new technique of modulating the pump power of a solid-state laser at frequencies close to its relaxation oscillation frequency was studied and made it possible to generate a beat note coherence from pulse to pulse. Frequency conversion techniques using the nonlinear optical effects make it possible to obtain tunable two-frequency sources in the visible spectrum. Green and red two-frequency pulses were obtained by using different conversion techniques, intra-cavity or extra-cavity. A two-frequency THz source in the red spectrum was also obtained by doubling the frequencies of a two-frequency THz Er-Yb:glass laser using a mixed fan-out PPLN crystal

  2. Repulsive wall potentials for He-(Ne,Ar,Kr,Xe) as inferred from differential cross sections

    International Nuclear Information System (INIS)

    Nitz, D.E.; Larson, J.; Swanson, K.; Wildgoose, C.

    1993-01-01

    We have obtained representations of the He-(Ne,Ar,Kr,Xe) ground state repulsive walls using model potentials optimized to fit published absolute differential cross section data for 500 and 1500 eV collisions. The HeNe potential, like the He 2 potentials can be fit using the semi-empirical HFD-B form constrained to cross zero at the proper internuclear separation. For the heavier atoms, this approach is unsuccessful and superior fits are obtained using only the purely repulsive V(r) - A EXP [-αr - βr 2 ] term of the HFD-B potential. Comparison of fitted potentials with previous results will be presented

  3. Effects of chirping on the dissociation dynamics of H2 in a two-frequency laser field

    International Nuclear Information System (INIS)

    Datta, Avijit; Bhattacharyya, S.S.; Kim, Bongsoo

    2002-01-01

    We present the effects of frequency chirping of laser pulses on (1+1)-photon resonance-enhanced dissociation dynamics of H 2 . The dissociation occurs via two closely spaced nonadiabatically coupled intermediate levels which are in one-photon resonance or near resonance with the initial level. Predissociating levels embedded into continua are considered. When the first laser field is sufficiently intense and suitably chirped, the dissociation probability is enhanced by adiabatic rapid passage through the avoided crossing arising from the frequency swept radiative interaction. The whole population of the ground level can be effectively transferred to the intermediate levels by this technique facilitating the dissociation process by the second field. We also report the effect of frequency detuning and chirp width on the dissociation probability. Widths of the two peaks of the dissociation line shape increase with an increase in chirp width, resulting in the possibility of control in the dissociation yield. When the first field is a laser pulse of low intensity and constant frequency and the second laser frequency is chirped, predissociating levels take important parts in the dissociation dynamics and we obtain a signature of the nonadiabatic effect of the first step on the second step of photodissociation dynamics. This feature is due to the presence of the predissociating levels and the nonadiabatic mixing of two intermediate levels. All these results can be explained in terms of the adiabatic dressed levels

  4. Formation and migration properties of the rare gases He, Ne, Ar, Ke, and Xe in nickel

    International Nuclear Information System (INIS)

    Melius, C.F.; Wilson, W.D.; Bisson, C.L.

    1980-01-01

    The energies of formation and migration of various rare gas-point defect complexes in an f.c.c. nickel lattice have been calculated for He, Ne, Ar, Kr, and Xe. Formation energies of rare gas atoms at interstitial sites are compared with those in substitutional sites. Binding energies are presented for self-interstitials and vacancies trapped to the various rare gas substitutionals. Migration energies and migration paths are also presented for various rare gas interstitials and substitutionals with and without trapped vacancies and self-interstitials. The migration energies are compared with the breakup energies for the corresponding complexes. It is found that divacancy-rare gas complexes are rather stable and will migrate at relatively low energies compared to other substitutional rare gas migration processes. (author)

  5. Mass spectrometer determinations of solar wind He, Ne, and Ar and radiation belt He

    International Nuclear Information System (INIS)

    Warasila, R.L.

    1976-01-01

    A unique mass spectrometer system was built and used to measure He, Ne, and Ar abundances and isotopic ratios in various samples of spacecraft that have been exposed to the space environment. The Apollo 12 mission brought back sections of the Surveyor 3 vehicle suitable for mass spectrometric studies of implanted solar wind and solar cosmic ray particles. Using the mass spectrometer, a 4 He flux of 6-8 x 10 6 ions/cm 2 --sec was measured, and in addition 4 He/ 3 He = 2700 +- 50; 4 He/ 20 Ne = 410 + 30; 20 Ne/ 22 Ne = 13.5 +- 0.2; 20 Ne/ 36 Ar = 24.5 +- 2.5; and 36 Ar/ 38 Ar = 5.41 +- 0.20 isotopic abundances were measured. An upper limit for the flux of SCR 3 He in the 10-20 MeV/nucleon range was also determined, for the thirty-one month exposure period. In the radiation belt environment, 3 He was found in the aluminum antenna housing from the recovered second stage of a pre-Apollo Saturn test flight launched January 28, 1964 and returned to earth on April 28, 1966. The amount of 3 He found was about 6 x 10 -10 cc(STP)/cm 2 with a 4 He/ 3 He ratio of 145 or less. The 3 He was shown to come from the lower radiation belt as all other sources of 3 He were orders of magnitude lower than the observed value

  6. Solar cycle variation of interstellar neutral He, Ne, O density and pick-up ions along the Earth's orbit

    OpenAIRE

    Sokół, Justyna M.; Bzowski, Maciej; Kubiak, Marzena A.; Möbius, Eberhard

    2016-01-01

    We simulated the modulation of the interstellar neutral (ISN) He, Ne, and O density and pick-up ion (PUI) production rate and count rate along the Earth's orbit over the solar cycle from 2002 to 2013 to verify if solar cycle-related effects may modify the inferred ecliptic longitude of the ISN inflow direction. We adopted the classical PUI model with isotropic distribution function and adiabatic cooling, modified by time- and heliolatitude-dependent ionization rates and non-zero injection spe...

  7. Transition from hydrodynamic to fast sound in a He-Ne mixture a neutron Brillouin scattering experiment

    CERN Document Server

    Bafile, U; Barocchi, F; Sampoli, M

    2002-01-01

    The presence of a fast-sound mode in the microscopic dynamics of the rare-gas mixture He-Ne, predicted by theoretical studies and molecular-dynamics simulations, was demonstrated by an inelastic neutron scattering experiment. In order to study the transition between the fast and the normal acoustic modes in the hydrodynamic regime, k values lower by about one order of magnitude than in the usual experiments have to be probed. We describe here the results of the first neutron Brillouin scattering experiment performed with this purpose on the same system already investigated at larger k. The results of both experiments, together with those of a new molecular-dynamics simulation, provide a complete and consistent description, still missing so far, of the onset of fast-sound propagation in a binary mixture. (orig.)

  8. Oscillatory behaviour of Rydberg state total cross sections in the collisions Ne+-He and He+-Ne

    International Nuclear Information System (INIS)

    Andresen, B.; Jensen, K.; Veje, E.

    1976-01-01

    The Ne + -He and He + -Ne collisions have been studied by means of optical spectrometry in the projectile energy range 10-150 keV. Very similar and regular oscillations in the Rydberg state total cross sections are found for HeI in both collisions and for singlet as well as triplet excitation. These oscillations are well described by the Rosenthal model. The HeI 4d sup(1,3)D states display two superimposed oscillations for center-of-mass collision energies above 6.4 keV. This is interpreted as the opening of a third exit channel, believed to be the HeI 4f sup(1,3)F. No, or very little structure is found in the Rydberg state total cross sections for HeII, NeI, NeII and NeIII levels. (Auth.)

  9. Plasma density evolution in plasma opening switch obtained by a time-resolved sensitive He-Ne interferometer

    Science.gov (United States)

    Chen, Lin; Ren, Jing; Guo, Fan; Zhou, LiangJi; Li, Ye; He, An; Jiang, Wei

    2014-03-01

    To understand the formation process of vacuum gap in coaxial microsecond conduction time plasma opening switch (POS), we have made measurements of the line-integrated plasma density during switch operation using a time-resolved sensitive He-Ne interferometer. The conduction current and conduction time in experiments are about 120 kA and 1 μs, respectively. As a result, more than 85% of conduction current has been transferred to an inductive load with rise time of 130 ns. The radial dependence of the density is measured by changing the radial location of the line-of-sight for shots with the same nominal POS parameters. During the conduction phase, the line-integrated plasma density in POS increases at all radial locations over the gun-only case by further ionization of material injected from the guns. The current conduction is observed to cause a radial redistribution of the switch plasma. A vacuum gap forms rapidly in the plasma at 5.5 mm from the center conductor, which is consistent with the location where magnetic pressure is the largest, allowing current to be transferred from the POS to the load.

  10. Product state resolved excitation spectroscopy of He-, Ne-, and Ar-Br2 linear isomers: experiment and theory.

    Science.gov (United States)

    Pio, Jordan M; van der Veer, Wytze E; Bieler, Craig R; Janda, Kenneth C

    2008-04-07

    Valence excitation spectra for the linear isomers of He-, Ne-, and Ar-Br2 are reported and compared to a two-dimensional simulation using the currently available potential energy surfaces. Excitation spectra from the ground electronic state to the region of the inner turning point of the Rg-Br2 (B,nu') stretching coordinate are recorded while probing the asymptotic Br2 (B,nu') state. Each spectrum is a broad continuum extending over hundreds of wavenumbers, becoming broader and more blueshifted as the rare gas atom is changed from He to Ne to Ar. In the case of Ne-Br2, the threshold for producing the asymptotic product state reveals the X-state linear isomer bond energy to be 71+/-3 cm(-1). The qualitative agreement between experiment and theory shows that the spectra can be correctly regarded as revealing the one-atom solvent shifts and also provides new insight into the one-atom cage effect on the halogen vibrational relaxation. The measured spectra provide data to test future ab initio potential energy surfaces in the interaction of rare gas atoms with the halogen valence excited state.

  11. Production of He-, Ne-, Ar-, Kr-, and Xe-isotopes by proton-induced reactions on lead

    International Nuclear Information System (INIS)

    Leya, I.; Michel, R.

    2003-01-01

    We measured integral thin target cross sections for the proton-induced production of He-, Ne-, Ar-, Kr-, and Xe-isotopes from lead from the respective reaction thresholds up to 2.6 GeV. The production of noble gas isotopes in lead by proton-induced reactions is of special importance for design studies of accelerator driven systems and energy amplifiers. In order to minimise the influences of secondary particles on the production of residual nuclides a new Mini-Stack approach was used instead of the well-known stacked-foil techniques for all experiments with proton energies above 200 MeV. With some exceptions our database for the proton-induced production of noble gas isotopes from lead is consistent and nearly complete. In contradistinction to the production of He from Al and Fe, where the cross sections obtained by thin-target irradiation experiments are up to a factor of 2 higher than the NESSI data, both datasets agree for the He production from lead. (orig.)

  12. Solar cycle variation of interstellar neutral He, Ne, O density and pick-up ions along the Earth's orbit

    Science.gov (United States)

    Sokół, Justyna M.; Bzowski, Maciej; Kubiak, Marzena A.; Möbius, Eberhard

    2016-06-01

    We simulated the modulation of the interstellar neutral (ISN) He, Ne, and O density and pick-up ion (PUI) production rate and count rate along the Earth's orbit over the solar cycle (SC) from 2002 to 2013 to verify if SC-related effects may modify the inferred ecliptic longitude of the ISN inflow direction. We adopted the classical PUI model with isotropic distribution function and adiabatic cooling, modified by time- and heliolatitude-dependent ionization rates and non-zero injection speed of PUIs. We found that the ionization losses have a noticeable effect on the derivation of the ISN inflow longitude based on the Gaussian fit to the crescent and cone peak locations. We conclude that the non-zero radial velocity of the ISN flow and the energy range of the PUI distribution function that is accumulated are of importance for a precise reproduction of the PUI count rate along the Earth orbit. However, the temporal and latitudinal variations of the ionization in the heliosphere, and particularly their variation on the SC time-scale, may significantly modify the shape of PUI cone and crescent and also their peak positions from year to year and thus bias by a few degrees the derived longitude of the ISN gas inflow direction.

  13. Excitation processes in slow K+--He, Ne, Ar, H2, N2 and Na+--He collisions

    International Nuclear Information System (INIS)

    Kikiani, B.I.; Gochitashvili, M.R.; Kvizhinadze, R.V.; Ankudinov, V.A.

    1984-01-01

    Quasimolecular features of excitation processes in K + --He, Ne, Ar, H 2 , N 2 and Na + --He collisions were investigated by measuring the cross sections for the emission of the resonance lines of potassium (lambda = 766.5 and 769.9 nm), sodium (lambda = 589 and 589.6 nm), and helium (lambda = 584 nm) atoms at ion energies in the range 0.5--10 keV. In Na + --He collisions, the resonance-line excitation functions obtained for sodium and helium atoms exhibit oscillations that are in antiphase and are due to phase interference between the quasimolecular states of the system of colliding particles. Experimental data on K + --Ar collisions are interpreted in terms of schematic correlation diagrams for molecular orbitals. The excitation mechanisms for K + --N 2 and K + --Ar have beenfound to be similar, and this leads to the conclusion that the quasimolecular model used for the ion-atom case is also valid for the ion-molecule case. It is shown that the excitation of the 4p-state of the potassium atom in the K + --Ar case is due to a Landau-Zener type of interaction in the region of the quasicrossing of (KAr) + terms. Analysis of the excitation of this state in K + --N 2 collisions also shows that the capture of an electron into the excited 4p-state of the potassium atom is due to a nonadiabatic transition in the region of quasicrossing of energy terms of the same symmetry

  14. Discharge characteristics of He-Ne-Xe gas mixture with varying Xe contents and at varying sustain electrode gap lengths in the plasma display panel

    International Nuclear Information System (INIS)

    Kwon, Ohyung; Whang, Ki-Woong; Bae, Hyun Sook

    2009-01-01

    The discharge characteristics of He-Ne-Xe gas mixture in the plasma display panel were investigated using a two-dimensional numerical simulation to understand the effects of adding He and varying the Xe contents in the gas mixture, and also varying sustain electrode gap. With 5% Xe content and 60 μm sustain electrode gap, decreased ionization led to the improvement of the vacuum ultraviolet (vuv) efficacy at increasing He mixing ratios. However, at 20% Xe content and 60 μm sustain electrode gap, increased electron heating improved the vuv efficacy until the He mixing ratio reached 0.7, but the efficacy decreased beyond the ratio of 0.7 due to the increased ionization of Xe atoms. At 5% Xe content and 200 μm sustain electrode gap, the vuv efficacy increased as a result of increased electron heating at the gap space at increasing He mixing ratios.

  15. Coupled cluster calculations of mean excitation energies of the noble gas atoms He, Ne and Ar and of the H2 molecule

    DEFF Research Database (Denmark)

    Sauer, Stephan P. A.; Ul Haq, Inam; Sabin, John R.

    2014-01-01

    by about 1%. For the two-electron systems He and H2, our CCSD results (for a Lanczos chain length equal to the full excitation space), I0 = 42:28 eV (Helium) and I0 = 19:62 eV (H2), correspond to full conguration interaction results and are therefore the exact, non-relativistic theoretical values......Using an asymmetric-Lanczos-chain algorithm for the calculation of the coupled cluster linear response functions at the CCSD and CC2 levels of approximation, we have calculated the mean excitation energies of the noble gases He, Ne and Ar, and of the hydrogen molecule H2. Convergence with respect...... for the mean excitation energy of these two systems within the Bethe theory for the chosen basis set and, in the case of H2, at the experimental equilibrium geometry....

  16. Static electric polarizabilities and first hyperpolarizabilities of molecular ions RgH + (Rg = He, Ne, Ar, Kr, Xe): ab initio study

    Science.gov (United States)

    Cukras, Janusz; Antušek, Andrej; Holka, Filip; Sadlej, Joanna

    2009-06-01

    Extensive ab initio calculations of static electric properties of molecular ions of general formula RgH + (Rg = He, Ne, Ar, Kr, Xe) involving the finite field method and coupled cluster CCSD(T) approach have been done. The relativistic effects were taken into account by Douglas-Kroll-Hess approximation. The numerical stability and reliability of calculated values have been tested using the systematic sequence of Dunning's cc-pVXZ-DK and ANO-RCC-VQZP basis sets. The influence of ZPE and pure vibrational contribution has been discussed. The component αzz has increasing trend in RgH + while the relativistic effect on αzz leads to a small increase of this molecular parameter.

  17. Laser scanning camera inspects hazardous area

    International Nuclear Information System (INIS)

    Fryatt, A.; Miprode, C.

    1985-01-01

    Main operational characteristics of a new laser scanning camera are presented. The camera is intended primarily for low level high resolution viewing inside nuclear reactors. It uses a He-Ne laser beam raster; by detecting the reflected light by means of a phomultiplier, the subject under observation can be reconstructed in an electronic video store and reviewed on a conventional monitor screen

  18. A Simple Laser Teaching Aid for Transverse Mode Structure Demonstration

    Science.gov (United States)

    Ren, Cheng; Zhang, Shulian

    2009-01-01

    A teaching aid for demonstrating the transverse mode structure in lasers is described. A novel device called "multi-dimension adjustable combined cat-eye reflector" has been constructed from easily available materials to form a He-Ne laser resonator. By finely adjusting the cat-eye, the boundary conditions of the laser cavity can be altered, which…

  19. Two frequency ICRF operation on TFTR

    International Nuclear Information System (INIS)

    Rogers, J.H.; Majeski, R.; Wilson, J.R.; Hosea, J.C.; Schilling, G.; Stevens, J.; Phillips, C.K.

    1993-01-01

    Modifications have been made recently to allow two of the ICRF antennas (bays L and M) on TFTR to operate at either of two frequencies, 43 MHz or 64 MHz. This was accomplished by lengthening the resonant loops (2Λ at 43 MHz, 3Λ at 64 MHz) and replacing the conventional quarter wave impedance transformers with a tapered impedance design. The other two antennas (bays K and N) will operate at a fixed frequency, 43 MHz. The two frequency operation will allow a combination of 3 He-minority and H-minority heating at near full field on TFTR. The higher frequency, 64 MHz, may also be useful in direct electron heating and current drive experiments at lower toroidal fields. Models of the antenna, resonant loops and impedance matching system are presented

  20. Numerical simulation for nuclear pumped laser

    Energy Technology Data Exchange (ETDEWEB)

    Sakasai, Kaoru [Japan Atomic Energy Research Inst., Tokyo (Japan)

    1998-07-01

    To apply nuclear pumped laser of {sup 3}He-Ne-Ar gas to detect neutron, the optimum gas mixture was investigated by numerical simulation. When {sup 3}He-Ne-Ar mixture gas are irradiated by neutron, proton and triton with high velocity are produced by {sup 3}He(np)T and two charge particles ionized {sup 3}He, Ne and Ar which reacted each other and attained to 3p`(1/2){sub 0}-3S`(1/2). The calculation method is constructed by defining the rate equations of each ion and exited atom and the electron energy balance equation and by time integrating the simultaneous differential equations of the above two equations and the law of conservation of charge. Penning ionization and energy transport by elastic collision of neutral atom were considered in the transport process of electron energy direct ionization by secondary charge particle. Calculation time was 1 msec. The optimum component was shown 3 atm He, 24 Torr He and 8 Torr Ar by simulation. Laser oscilation was generated under the conditions 3.3 x 10{sup 14} (N/cm{sup 2}/5) thermal neutron flux at 50 cm laser cell length and 99% coefficient of reflection of mirror. After laser oscilation, laser output was proportional to neutron flux. These results showed nuclear pumped laser of {sup 3}He-Ne-Ar was able to detect optically neutron. (S.Y)

  1. Gas discharge laser and method of manufacturing same

    International Nuclear Information System (INIS)

    Haans, P.F.A.

    1975-01-01

    On a thick-walled capillary tube rounded edges are pressed at either end. Double-conical surfaces are ground on the rounded edges so that a fitting edge which is very obtuse in cross-section is obtained for laser mirrors of a He-Ne laser of an economic construction

  2. The ATF two-frequency correlation reflectometer

    International Nuclear Information System (INIS)

    Hanson, G.R.; Wilgen, J.B.; Anabitarte, E.; Bell, J.D.; Harris, J.H.; Dunlap, J.L.; Thomas, C.E.

    1990-01-01

    The Advanced Toroidal Facility (ATF) density fluctuation reflectometer system consists of two individual reflectometers operating in the 30- to 40-GHz band. Each reflectometer consists of a tunable microwave source and a quadrature phase detector connected to the same antenna system. This arrangement allows two-frequency operation along the same radial chord for radial coherence measurements. The technique used in making radial coherence measurements is discussed and the results of such experiments are given. Initial experiments have shown high coherence when the frequencies of the two reflectometers are tuned close together and a clear loss of coherence as the radial separation of the cutoff layers is increased by increasing the frequency separation of the two reflectometers. Recent results have shown that local measurements of density fluctuations in plasmas with electron cyclotron heating (ECH) are possible and that detailed structure can be seen in the fluctuation spectra. In addition, radial correlation lengths have been found to be from 0.5 to 1.0 cm in ECH plasmas, with some frequency structures having correlation lengths up to 3 cm. In plasmas with neutral beam injection (NBI), the radial correlation lengths in the edge region have been found to be approximately 0.1--0.2 cm. 4 figs

  3. Scanning Color Laser Microscope

    Science.gov (United States)

    Awamura, D.; Ode, T.; Yonezawa, M.

    1988-01-01

    A confocal color laser microscope which utilizes a three color laser light source (Red: He-Ne, Green: Ar, Blue: Ar) has been developed and is finding useful applications in the semiconductor field. The color laser microscope, when compared to a conventional microscope, offers superior color separation, higher resolution, and sharper contrast. Recently some new functions including a Focus Scan Memory, a Surface Profile Measurement System, a Critical Dimension Measurement system (CD) and an Optical Beam Induced Current Function (OBIC) have been developed for the color laser microscope. This paper will discuss these new features.

  4. Laser Photochemistry.

    Science.gov (United States)

    1981-07-01

    inverted by the first, i.e., at the moment of time t = T, such that i = (2n+)lT, where 0 is the Rabi frequency (Oraevski et al., 1976). . classical... anisotropic molecule present. CW HeNe, Ar+ and Kr+ lasers are used, and the filter method is necessary because of time-scales lo8 - 10ll Hz. Some general...e.g., truncated harmonic oscillator, square well, spherically symmetric Morse or Lennard-Jones, anisotropic (angle-dependent) Morse or Lennard-Jones

  5. Pulsating instabilities and chaos in lasers

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, R G; Biswas, D J

    1985-01-01

    A detailed state of the art survey of deterministic chaos in laser systems is presented. The mechanism of single mode instability is discussed, including spontaneous and induced mode splitting and the threshold for laser instabilities. Single mode homogeneously broadened systems are addressed, including optically pumped far infrared lasers and near-resonantly pumped midinfrared systems. Single mode inhomogeneously broadened systems are considered, including the He-Xe laser and the He-Ne laser at 3.39 microns. Single mode lasers with external control parameter are discussed, as is the multimode laser. 297 references.

  6. The effect of green helium-neon laser on the healing of extraction wounds: histological study in rats

    International Nuclear Information System (INIS)

    Nicolli Filho, Walter Domingos; Picon, Luciana Christofolini; Okamoto, Tetuo; Cardenuto, Ney

    1993-01-01

    A histological study on healing of extraction wounds following laser irradiation, using a green He-Ne laser, was carried out in rats. The results suggest that this kind of treatment has no significant beneficial effect on bony wound healing. Proliferation of fibroblasts and formation of trabecular osteoid were found to be not more pro eminent within the irradiated group. (author)

  7. Laser Ablation of Biological Tissue Using Pulsed CO2 Laser

    International Nuclear Information System (INIS)

    Hashishin, Yuichi; Sano, Shu; Nakayama, Takeyoshi

    2010-01-01

    Laser scalpels are currently used as a form of laser treatment. However, their ablation mechanism has not been clarified because laser excision of biological tissue occurs over a short time scale. Biological tissue ablation generates sound (laser-induced sound). This study seeks to clarify the ablation mechanism. The state of the gelatin ablation was determined using a high-speed video camera and the power reduction of a He-Ne laser beam. The aim of this study was to clarify the laser ablation mechanism by observing laser excision using the high-speed video camera and monitoring the power reduction of the He-Ne laser beam. We simulated laser excision of a biological tissue by irradiating gelatin (10 wt%) with radiation from a pulsed CO 2 laser (wavelength: 10.6 μm; pulse width: 80 ns). In addition, a microphone was used to measure the laser-induced sound. The first pulse caused ablation particles to be emitted in all directions; these particles were subsequently damped so that they formed a mushroom cloud. Furthermore, water was initially evaporated by laser irradiation and then tissue was ejected.

  8. Effect of laser on human blood

    International Nuclear Information System (INIS)

    Abdalsamad, Amuna Nagash Mohammed

    2016-03-01

    In this work, the effect of He-Ne (632.8 nm), N2 (337.1 nm), LED (450 nm) on the human blood, and blood component was studied by using CBC machine ( complete blood count) and UV -visible spectroscopy. Blood samples platoon A+ were collected and irradiated for different periods of time (10 minute, 20 minute, and 30 minute), to varied types of light source ( He- Ne laser and LED). Blood parameters of samples were measured by using complete Blood Count Machine (CBC). The absorption spectrum of blood samples were examined by using UV-visible spectrometer. The obtained results have shown different values of Complete Blood Counts and absorption spectrum due to different laser types and periods of time. We conclude that the laser light has clear effect on blood samples. (Author)

  9. Application of nuclear pumped laser to an optical self-powered neutron detector

    Science.gov (United States)

    Yamanaka, N.; Takahashi, H.; Iguchi, T.; Nakazawa, M.; Kakuta, T.; Yamagishi, H.; Katagiri, M.

    1996-05-01

    A Nuclear Pumped Laser (NPL) using 3He/Ne/Ar gas mixture is investigated for a purpose of applying to an optical self-powered neutron detector. Reactor experiments and simulations on lasing mechanism have been made to estimate the best gas pressure and mixture ratios on the threshold input power density (or thermal neutron flux) in 3He/Ne/Ar mixture. Calculational results show that the best mixture pressure is 3He/Ne/Ar=2280/60/100 Torr and thermal neutron flux threshold 5×1012 n/cm2 sec, while the reactor experiments made in the research reactor ``YAYOI'' of the University of Tokyo and ``JRR-4'' of JAERI also demonstrate that excitational efficiency is maximized in a similar gas mixture predicted by the calculation.

  10. Low-level laser therapy with helium-neon laser improved viability of osteoporotic bone marrow-derived mesenchymal stem cells from ovariectomy-induced osteoporotic rats

    Science.gov (United States)

    Fallahnezhad, Somaye; Piryaei, Abbas; Tabeie, Faraj; Nazarian, Hamid; Darbandi, Hasan; Amini, Abdoldllah; Mostafavinia, Ataroalsadat; Ghorishi, Seyed Kamran; Jalalifirouzkouhi, Ali; Bayat, Mohammad

    2016-09-01

    The purpose of this study was to evaluate the influences of helium-neon (He-Ne) and infrared (IR) lasers on the viability and proliferation rate of healthy and ovariectomy-induced osteoporotic (OVX) bone marrow mesenchymal stem cells (BMMSCs) in vitro. MSCs harvested from the BM of healthy and OVX rats were culture expanded. He-Ne and IR lasers were applied three times at energy densities of 0.6, 1.2, and 2.4 J/cm2 for BMMSCs. BMMSCs viability and proliferation rate were evaluated by MTT assay on days 2, 4, 6, 14, and 21. The results showed that healthy BMMSCs responded optimally to 0.6 J/cm2 using an IR laser after three times of laser radiation. Moreover, it was found that OVX-BMMSCs responded optimally to 0.6 J/cm2 with He-Ne laser and one-time laser radiation. It is concluded that the low-level laser therapy (LLLT) effect depends on the physiological state of the BMMSCs, type of the laser, wavelength, and number of laser sessions. The biostimulation efficiency of LLLT also depends on the delivered energy density. LLLT can enhance the viability and proliferation rate of healthy and especially osteoporotic autologous BMMSCs, which could be very useful in regenerative medicine.

  11. Low power laser irradiation does not affect the generation of signals in a sensory receptor

    Energy Technology Data Exchange (ETDEWEB)

    Lundeberg, T.; Zhou, J.

    1989-01-01

    The effect of low power Helium-Neon (He-Ne) and Gallium-Arsenide (Ga-As) laser on the slowly adapting crustacean stretch receptor was studied. The results showed that low power laser irradiation did not affect the membrane potential of the stretch receptor. These results are discussed in relation to the use of low power laser irradiation on the skin overlaying acupuncture points in treatment of pain syndrome.

  12. Application of laser therapy in treating inherited forms of psychoverbal retardation in children

    Science.gov (United States)

    Ulas, V. Y.; Voinova, V. M.; Il'in, L. B.; Troitskaya, L. A.; Dobrynina, E. V.; Kazantseva, L. Z.

    2001-04-01

    An investigation was made of applying combined laser therapy in the treatment of 619 children (422 children constituted the experimental group and 197 children composed the control group) affected by inherited forms of psychoverbal retardation. It was found that low-intensity He-Ne laser radiation with the wavelength of 632.8 nm and the output power of 2 mW made it possible to improve the children's mental development. Moreover, it effectively increased their mental activities, such as speech, communication, arbitrary behavior regulation, and locomotory functions. Laser therapy applied in treating children affected by the arrested mental development aggravated by obesity additionally decreased their body weight, increased their field of vision, and eliminated dyslipidemia. It was also found that contraindications to He-Ne laser acupuncture included phenylketonuria-related noncorrected metabolic defects, convulsive syndromes, epileptic activities, convulsive readiness, and cerebrolysine intramuscular injections.

  13. Effect Of Laser Irradiation On Biosynthesis Of Antibiotics

    International Nuclear Information System (INIS)

    SALAMA, S.M.; MAHMOUD, S.M.; EL-KABBANY, H.M.

    2010-01-01

    An investigation concerning the effect of He:Ne laser irradiation on some isolated actinomycetes was carried out. Seven isolated actinomycetes were considered as most potent producing broad spectrum antibiotics. The strains have been identified on the basis of taxonomic studies as Streptomyces nogalator (H12), Streptomyces griseoluteus (YM23), Amycolatopsis mediterranei (B40), Glycomyces harbinensis (KA16), Streptosporangium corrugatum (B67), Streptoalloteichus hindustamus (B74) and Streptomyces aurantiogriseus (S15). Seven genotypes were chosen after He:Ne laser irradiation as representative for each isolated strain. The active metabolite from most potent genotype of Streptomyces nogalator (H12) was extracted by ethyl acetate then concentrated under vacuo and the crude fraction was purified using thin layer and column chromatography. Ultra violet maximum absorption peak was recorded at 231.5 and 206 nm. The IR and NMR were consulted to confirm the chemical characteristics of the antibiotic. The biological activity and toxicity were also investigated.

  14. Investigation of two-frequency Paul traps for antihydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Leefer, Nathan; Krimmel, Kai, E-mail: kkrimmel@students.uni-mainz.de [Helmholtz-Institut Mainz (Germany); Bertsche, William [University of Manchester (United Kingdom); Budker, Dmitry [Helmholtz-Institut Mainz (Germany); Fajans, Joel [University of California at Berkeley, Department of Physics (United States); Folman, Ron [Ben-Gurion University of the Negev, Department of Physics (Israel); Häffner, Hartmut [University of California at Berkeley, Department of Physics (United States); Schmidt-Kaler, Ferdinand [Helmholtz-Institut Mainz (Germany)

    2017-11-15

    Radio-frequency (rf) Paul traps operated with multifrequency rf trapping potentials provide the ability to independently confine charged particle species with widely different charge-to-mass ratios. In particular, these traps may find use in the field of antihydrogen recombination, allowing antiproton and positron clouds to be trapped and confined in the same volume without the use of large superconducting magnets. We explore the stability regions of two-frequency Paul traps and perform numerical simulations of small samples of multispecies charged-particle mixtures of up to twelve particles that indicate the promise of these traps for antihydrogen recombination.

  15. Effects of pre-sowing laser stimulation on sowing value of lucerne seeds

    International Nuclear Information System (INIS)

    Dziwulska, A.

    2006-01-01

    Seeds of alfalfa c.v. Legend and hybrid alfalfa c.v. Radius were irradiated with divergent He-Ne laser bundle and sown on Petri dishes with four repetitions. Germination lasted for 10 days at a constant temperature 20 +- 1 deg C. Seeds germinating normally, abnormally, hard seeds and those infected with pathogenic fungi were determined. The number of seeds germinating normally increased and hard seeds decreased upon laser stimulation [pl

  16. Laser speckle velocimetry applied to Rayleigh-Benard convection

    International Nuclear Information System (INIS)

    Arroyo, M.P.; Yonte, T.; Quintanilla, M.; Saviron, J.M.

    1986-01-01

    An application of speckle velocimetry technique to Rayleigh-Benard convection is presented. A 5-mW He-Ne laser allows precise determination of the two-dimensional velocity flow field, up to several mm/sec. The digital techniques used to analyze automatically the multiexposed photographs and to generate velocity and vorticity fields are described. The obtained results are in good agreement with previously reported data. The ability of the technique to cover other experimental conditions is discussed. 14 references

  17. Bibliography of Soviet Laser Developments: January - February 1988

    Science.gov (United States)

    1989-02-21

    light in LiNbO(sub3), CsH(sub2)AsO(sub4) and Ba(sub2)NaNb(sub5)O(sub 15) crystals under synchronous pumping by a picosecond La (sub2)Be(sub2)O(sub5):Nd...Weber,T. 0 Determining the metrological characteristics of an He-Ne laser at 633 nm as a secondary standard of length (in Romanian). Metrologia

  18. Laser beam-forming by deformable mirror for laser isotope separation

    International Nuclear Information System (INIS)

    Nemoto, Koshichi; Fujii, Takashi; Goto, Naohiko

    1995-01-01

    A rectangular laser beam of uniform intensity is very suitable for laser isotope separation. In this paper, we propose a beam-forming system which consists two deformable mirrors. One of the mirrors changes the beam intensity and the other compensates for phase distortion. We developed a deformable mirror for beam-forming. Its deformed surface is similar to the ideal mirror surface for beam-forming. We reshaped a Gaussian-like He-Ne laser beam into a beam with a more uniform intensity profile by a simple deformable mirror. (author)

  19. Two-frequency, one-detector reactivity system (TFODRS)

    International Nuclear Information System (INIS)

    Sachs, R.D.; Woodall, D.M.

    1985-01-01

    A two-frequency, one-detector reactivity system (TFODRS) was experimentally verified on the University of New Mexico (UNM) AGN-201M thermal reactor. That system was used to obtain the absolute steady-state reactivity and to demonstrate the feasibility of acquiring the transient reactivity. A detailed description of TFODRS hardware and software is given in this paper. The TFODRS obtains the absolute and net reactivity by computing the frequency spectrum of the reactor neutron-detector signal. The ratio of the high-frequency to the low-frequency components about an empirical break point is used to determine the reactivity. The TFODRS was successfully used to measure a known AGN-201M steady-state reactivity, with a relative error of 18%. TFODRS transient curves as a function of reactivity were shown to be different from the steady-state curves. The transient curves appear to be a function of the rate of reactivity insertion. The authors speculate that a modified TFODRS, using state-of-the-art microprocessors, could be used for fast reactors. The TFODRS is not presently a practicable reactimeter. However, with more research and development, it is felt it could be used in near-term nuclear industry applications, such as monitoring fuel storage pools

  20. CW-laser induced microchannels in dye-polymethacrylic acid films

    OpenAIRE

    M.A. Camacho-López

    2007-01-01

    In this work we report on the formation of microchannels on dye-polymethacrylic acid films using a cw-laser. A focalized beam of a He-Ne laser (632.8 nm emission line) was used to form microchannels on the films. It was found that there exists a laser power density threshold for a pit formation that depends on the dye concentration. The dimensions of the laser-induced channels are dependent on the laser power density. Microchannel formation in the transparent polymethacrylic acid films was no...

  1. Semiconductor lasers in rheumatological treatment

    Science.gov (United States)

    Pascu, Mihail-Lucian; Suteanu, S.; Ignat, P.; Pruna, Simion; Chitu, A.

    1995-03-01

    A computer controlled equipment, containing 6 lasers (HeNe and 5 diode lasers--DL) conceived to be used in rheumatological treatment is reported. DL emit at 895 nm and for typical applications, their expanded spots are superposed within the irradiation plane, on the HeNE defocused spot used to define the surface to be irradiated. DL emit 100 nsec pulses between 0.5 KHz and 1.5 KHz repetition rate and 0.5 mW average power (measured at 1 KHz). 150 patients with rheumathologic diseases were treated: lumbar spondylosis (75), gonarthrosis (30), cervical spondylosis (21), coxarthrosis (15), Heberden and Bouchard (9). The treatment consisted of: group I, 50 patients--laser therapy, 10 min/day, 10 days; group II, 50 patients--classical antirheumatic treatment; group III, 50 patients--mixed treatment. Assessment of sympathetic skin activity made using reactometry measurements, shows that latency time was longer before irradiation, 1867 +/- 289) msec then after, (1234 +/- 321) msec. Pain rating indexes decreasing for all three groups of patients were measured. Better results for more superficial diseases were obtained and best results were observed after irradiation with 1 KHz - 1.5 KHz repetition rate IR pulses. Better results were obtained when spot irradiation in a few points combined with zone irradiations was used.

  2. Trace gas detection by laser intracavity photothermal spectroscopy

    International Nuclear Information System (INIS)

    Fung, K.H.; Lin, H.h.

    1986-01-01

    A novel laser intracavity photothermal detector is described. In this scheme, sample absorption of the pump laser power takes place within the cavity of a probe He-Ne laser causing modulation in the gain and in turn the output power. Comparison of this intracavity detector with two other photothermal techniques, namely, phase fluctuation optical heterodyne spectroscopy and thermal beam deflection, is made in terms of practicality and sensitivity. For in situ measurements, sensitivity of 0.5 x 10 -7 cm -1 for a probe length of 3 cm has been achieved

  3. Design and construction of single path Raman laser

    International Nuclear Information System (INIS)

    Mavaddat, M.; Soltanolkotabi, M.

    2007-01-01

    In this paper the stimulated Raman effect has been reported.The pumping laser in this setup is He-Ne with wavelength of 632.8 nm. The first order Stokes line has been observed, to be at 776 nm. The pressure of methane gas in this setup has been increased to 20 bar. The diagram of the effect of the intensity of first order Stokes line as a function of pressure has been plotted. Also, two different pumping laser powers have been used in these investigations. Intensity of first order Stokes line has been increased with increasing gas pressure or laser power.

  4. Momentum distributions of selected rare-gas atoms probed by intense femtosecond laser pulses

    DEFF Research Database (Denmark)

    Abu-Samha, Mahmoud; Madsen, Lars Bojer

    2011-01-01

    We provide a direct comparison between numerical and experimental (Rudenko et al 2004 J. Phys. B: At. Mol. Opt. Phys. 37 L407) photoelectron momentum distributions in strong-field ionization of selected rare-gas atoms (He, Ne and Ar), probed by femtosecond linearly polarized laser pulses. The cal......We provide a direct comparison between numerical and experimental (Rudenko et al 2004 J. Phys. B: At. Mol. Opt. Phys. 37 L407) photoelectron momentum distributions in strong-field ionization of selected rare-gas atoms (He, Ne and Ar), probed by femtosecond linearly polarized laser pulses....... The calculations are performed by solving the time-dependent Schrödinger equation within the single-active-electron approximation, and focal-volume effects are taken into account by appropriately averaging the results. The resulting momentum distributions are in quantitative agreement with the experimental...

  5. Laser experimental system as teaching aid for demonstrating basic phenomena of laser feedback

    International Nuclear Information System (INIS)

    Xu, Ling; Zhao, Shijie; Zhang, Shulian

    2015-01-01

    An experimental laser teaching system is developed to demonstrate laser feedback phenomena, which bring great harm to optical communication and benefits to precision measurement. The system consists of an orthogonally polarized He-Ne laser, a feedback mirror which reflects the laser output light into the laser cavity, and an optical attenuator which changes the intensity of the feedback light. As the feedback mirror is driven by a piezoelectric ceramic, the attenuator is adjusted and the feedback mirror is tilted, the system can demonstrate many basic laser feedback phenomena, including weak, moderate and strong optical feedback, multiple feedback and polarization flipping. Demonstrations of these phenomena can give students a better understanding about the intensity and polarization of lasers. The system is well designed and assembled, simple to operate, and provides a valuable teaching aid at an undergraduate level. (paper)

  6. Study of non-thermal effects from laser radiation on live tissues

    International Nuclear Information System (INIS)

    Cotta, M.A.

    1987-02-01

    The functional biological effects related to the irradiation of live tissues with low power lasers, called non-thermal effects were theoretical and experimentally studied. For the experimental part, a device which allows to: irradiation lesions artificially created on the back of rats by a He-Ne laser, or put a moving ground glass in front of the laser beam, by irradiation of this same laser with its coherence degree decreased. The relevance of the radiation coherence in the lesion cicatrization process was shown. The electrical field distribution and the intensity distribution on a surface with micro-roughness when irradiated by coherent light are theoretically studied. (M.C.K.) [pt

  7. Multiple Order Diffractions by laser-Injured Transient Grating in Nematic MBBA Film

    International Nuclear Information System (INIS)

    Kim, Seong Kyu; Kim, Hack Jin

    1999-01-01

    The laser-induced transient grating method is applied to study the dynamics of the nematic MBBA film. The nanosecond laser pulses of 355 nm are used to make the transient grating and the cw He-Ne laser of 633 nm is used to probe the dynamics. Strong multiple order diffractions are observed at high nematic temperatures. The reordering process induced by the phototransformed state, which is the locally melted state from the nematic sample, is attributed to the main origin of the multiple order diffractions from the nematic MBBA. The characteristics of the multiple order gratings are discussed with the grating profiles simulated from the multiple diffraction signals

  8. Monooxignase ensymic system of a liver of rats exposed to intravascular laser irradiation of blood

    International Nuclear Information System (INIS)

    Ibadova, G.A.

    1997-01-01

    Experimental study of the dynamic monooxidation of liver enzymic system was carried out on rats with experimental salmonellosis and the influence of the blood intravascular laser irradiation of blood on these enzymes was revealed. It was determined that by experimental salmonellosis oppression of the MOES activity of hepatocytes occurred. The blood intravascular irradiation by He-Ne laser promotes MOES oppression in rats suffered from salmonellosis. IVLIB as well as UV-laser show pronounced effect on the enzymes detoxication protection, mobilize their resistance to endogenic intoxication under the conditions of experimental salmonellosis. (author)

  9. Laser illuminated flat panel display

    Energy Technology Data Exchange (ETDEWEB)

    Veligdan, J.T.

    1995-12-31

    A 10 inch laser illuminated flat panel Planar Optic Display (POD) screen has been constructed and tested. This POD screen technology is an entirely new concept in display technology. Although the initial display is flat and made of glass, this technology lends itself to applications where a plastic display might be wrapped around the viewer. The display screen is comprised of hundreds of planar optical waveguides where each glass waveguide represents a vertical line of resolution. A black cladding layer, having a lower index of refraction, is placed between each waveguide layer. Since the cladding makes the screen surface black, the contrast is high. The prototype display is 9 inches wide by 5 inches high and approximately I inch thick. A 3 milliwatt HeNe laser is used as the illumination source and a vector scanning technique is employed.

  10. Gas-laser behavior in a low-gravity environment

    Science.gov (United States)

    Owen, R. B.

    1981-01-01

    In connection with several experiments proposed for flight on the Space Shuttle, which involve the use of gas lasers, the behavior of a He-Ne laser in a low-gravity environment has been studied theoretically and experimentally in a series of flight tests using a low-gravity-simulation aircraft. No fluctuation in laser output above the noise level of the meter (1 part in 1000 for 1 hr) was observed during the low-gravity portion of the flight tests. The laser output gradually increased by 1.4% during a 1.5-hr test; at no time were rapid variations observed in the laser output. A maximum laser instability of 1 part in 100 was observed during forty low-gravity parabolic maneuvers. The beam remained Gaussian throughout the tests and no lobe patterns were observed.

  11. A three-dimensional laser vibration measurement technology realized on five laser beam and its calibration

    Science.gov (United States)

    Li, Lu-Ke; Zhang, Shen-Feng

    2018-03-01

    Put forward a kind of three-dimensional vibration information technology of vibrating object by the mean of five laser beam of He-Ne laser, and with the help of three-way sensor, measure the three-dimensional laser vibration developed by above mentioned technology. The technology based on the Doppler principle of interference and signal demodulation technology, get the vibration information of the object, through the algorithm processing, extract the three-dimensional vibration information of space objects, and can achieve the function of angle calibration of five beam in the space, which avoid the effects of the mechanical installation error, greatly improve the accuracy of measurement. With the help of a & B K4527 contact three axis sensor, measure and calibrate three-dimensional laser vibrometer, which ensure the accuracy of the measurement data. Summarize the advantages and disadvantages of contact and non-contact sensor, and analysis the future development trends of the sensor industry.

  12. A laser optical method for detecting corn kernel defects

    Energy Technology Data Exchange (ETDEWEB)

    Gunasekaran, S.; Paulsen, M. R.; Shove, G. C.

    1984-01-01

    An opto-electronic instrument was developed to examine individual corn kernels and detect various kernel defects according to reflectance differences. A low power helium-neon (He-Ne) laser (632.8 nm, red light) was used as the light source in the instrument. Reflectance from good and defective parts of corn kernel surfaces differed by approximately 40%. Broken, chipped, and starch-cracked kernels were detected with nearly 100% accuracy; while surface-split kernels were detected with about 80% accuracy. (author)

  13. Test results of the experimental laser device for potato tubers radiation treatment

    International Nuclear Information System (INIS)

    Anufrik, S.S.; Korzun, O.S.

    2007-01-01

    Results of 3 year investigation of the influence of the presowing low intensity laser radiation treatment of potato (Solanum tuberosum L.) tubers with the help of laser device with various spectral composition and exposition on plant growth, development and productivity and potato tubers quality and starch content in the conditions of the Republic of Belarus were presented. Presowing tubers treatment of potato cultivars Sante, Yavar and Arkhideya was realized by He-Ne, Ar-, Cu (in course of 3 and 5 minutes) and CO2 (in course of 5 seconds) lasers. Research results have shown that presowing treatment with CO2 laser promoted the higher (on 1,7-6,6%) potato germination capacity in comparison with the control variant without radiation treatment. Height of potato plants of Sante variety after radiation treatment fell behind the control ones. Haulm quantity per one plant and yield quality did not depend on radiation treatment Treatment with CO2 laser exercised the stimulatory action on productivity of Sante variety without changing the starch content in tubers. Tuber weight increased up to 0,4 kg (0,2 kg in the control variant). Similar effect for Arkhideya and Yavar varieties was obtained after Cu-laser treatment in course of 5 minutes. Radiation treatment with He-Ne laser caused the increased starch accumulation (on 0,4-0,6% in comparison with the control variant) in potato tubers of all studied varieties

  14. Pulsed inductive HF laser

    Energy Technology Data Exchange (ETDEWEB)

    Razhev, A M; Kargapol' tsev, E S [Institute of Laser Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk (Russian Federation); Churkin, D S; Demchuk, S V [Novosibirsk State University, Novosibirsk (Russian Federation)

    2016-03-31

    We report the results of experimentally investigated dependences of temporal, spectral and spatial characteristics of an inductive HF-laser generation on the pump conditions. Gas mixtures H{sub 2} – F{sub 2}(NF{sub 3} or SF6{sub 6}) and He(Ne) – H{sub 2} – F{sub 2}(NF{sub 3} or SF{sub 6}) were used as active media. The FWHM pulse duration reached 0.42 μs. This value corresponded to a pulsed power of 45 kW. For the first time, the emission spectrum of an inductive HF laser was investigated, which consisted of seven groups of bands with centres around the wavelengths of 2732, 2736, 2739, 2835, 2837, 2893 and 2913 nm. The cross section profile of the laser beam was a ring with a diameter of about 20 mm and width of about 5 mm. Parameters of laser operation in the repetitively pulsed regime were sufficiently stable. The amplitude instability of light pulses was no greater than 5% – 6%. (lasers)

  15. Polarisabilities and shielding factors for He, Ne and Ar

    International Nuclear Information System (INIS)

    McEachran, R.P.; Ryman, A.G.; Stauffer, A.D.

    1977-01-01

    Multipole polarisabilities and shielding factors for helium, neon and argon have been calculated accurately in the coupled Hartree-Fock approximation. A shell by shell analysis is given for the first four multipoles. (author)

  16. An estimation of the spatial coherency radius of a multimode laser beam by the spectral contrast

    Energy Technology Data Exchange (ETDEWEB)

    Sukhanov, I I

    1983-01-01

    The angular dependency of the spectral contrast behind a diffuser illuminated by an He/Ne laser beam at .63 micrometers on the number of transverse modes is investigated. It is demonstrated that over a wide range of scattering angles, the contrast is determined primarily by the number of transverse modes, i.e. by the radius of the spatial field correlation, and is only slightly dependent on the dimensions and shape of the beam as well as the intensity distribution in the beam. These results may be useful in developing a rapid indication method of the radius of the spatial correlation of laser beams.

  17. Frequency Noise Properties of Lasers for Interferometry in Nanometrology

    Directory of Open Access Journals (Sweden)

    Ondřej Číp

    2013-02-01

    Full Text Available In this contribution we focus on laser frequency noise properties and their influence on the interferometric displacement measurements. A setup for measurement of laser frequency noise is proposed and tested together with simultaneous measurement of fluctuations in displacement in the Michelson interferometer. Several laser sources, including traditional He-Ne and solid-state lasers, and their noise properties are evaluated and compared. The contribution of the laser frequency noise to the displacement measurement is discussed in the context of other sources of uncertainty associated with the interferometric setup, such as, mechanics, resolution of analog-to-digital conversion, frequency bandwidth of the detection chain, and variations of the refractive index of air.

  18. CO laser interferometer for REB-plasma experiments

    International Nuclear Information System (INIS)

    Burmasov, V.S.; Kruglyakov, E.P.

    1996-01-01

    The Michelson carbon oxide laser interferometer for measuring plasma density in studies on REB-plasma interaction is described. A detail description of the interferometer and CO laser is presented. For a selection of a single wavelength laser operation the CaF 2 prism is applied. A Ge:Au photoconductor at 77 deg K is applied as the detector. The CO laser radiation at λ 5.34 μm coincides with the detector maximum sensitivity (of the order of 1000 V/W). This increases the interferometer sensitivity about ten times with respect to the He-Ne laser (λ = 3.39 μm) used as the source of light. The typical interferogram and time evolution of plasma density obtained at GOL-M device are presented. (author). 3 figs., 5 refs

  19. CO laser interferometer for REB-plasma experiments

    Energy Technology Data Exchange (ETDEWEB)

    Burmasov, V S; Kruglyakov, E P [Budker Inst. of Nuclear Physics, Novosibirsk (Russian Federation)

    1997-12-31

    The Michelson carbon oxide laser interferometer for measuring plasma density in studies on REB-plasma interaction is described. A detail description of the interferometer and CO laser is presented. For a selection of a single wavelength laser operation the CaF{sub 2} prism is applied. A Ge:Au photoconductor at 77 deg K is applied as the detector. The CO laser radiation at {lambda} 5.34 {mu}m coincides with the detector maximum sensitivity (of the order of 1000 V/W). This increases the interferometer sensitivity about ten times with respect to the He-Ne laser ({lambda} = 3.39 {mu}m) used as the source of light. The typical interferogram and time evolution of plasma density obtained at GOL-M device are presented. (author). 3 figs., 5 refs.

  20. Spectroscopy Stress Evaluation of Translucid Polymers Using Laser Photoelasticity

    Science.gov (United States)

    Treviño, Marciano Vargas; Gil, Aarón Flores; Rodríguez-Lelis, J. M.; González, Antonio Hernández; Arvizo, Dagoberto Vela; Alarcón, Manuel May; Pliego, Arturo Abundez

    2008-04-01

    Several studies can be found where the mechanical strength of fiber composites is evaluated, but not much can be found regarding the influence of voids, as a second phase, in the same mechanical behavior of materials. In the present work, the influence of bubble presence into translucid polymeric bars is investigated. For this purpose, cubic probes with an anisotropic distribution of bubbles were casted, and other were casted controlling the manufacture process to avoid the bubble formation. Each probe was placed in a He-Ne laser-photoelastic arrangement and subjected to compression by an static load. The transmitted 630 nm, He-Ne laser beam was captured by a single mode fiber optic sensor and then transmitted to a spectrometer and PC. Analysis of the spectrometer signals showed that the maximum stresses are concentrated on the bubbles reducing the surface stresses and inducing damping on the probe. The amount of damping depends on the size of the bubbles formed within the probe and their arrangement, thus it can be anticipated that stresses can be directed for specific arrangements in size of bubbles. A white light was also employed in substitution of the laser to investigated the effect of wave length on the results previously obtained. The effect of damping was also experienced but although more information could be obtained caused of the non-coherent nature of the light, it was no possible to obtain full information of the structure of the probes.

  1. Color Laser Microscope

    Science.gov (United States)

    Awamura, D.; Ode, T.; Yonezawa, M.

    1987-04-01

    A color laser microscope utilizing a new color laser imaging system has been developed for the visual inspection of semiconductors. The light source, produced by three lasers (Red; He-Ne, Green; Ar, Blue; He-Cd), is deflected horizontally by an AOD (Acoustic Optical Deflector) and vertically by a vibration mirror. The laser beam is focused in a small spot which is scanned over the sample at high speed. The light reflected back from the sample is reformed to contain linear information by returning to the original vibration mirror. The linear light is guided to the CCD image sensor where it is converted into a video signal. Individual CCD image sensors are used for each of the three R, G, or B color image signals. The confocal optical system with its laser light source yields a color TV monitor image with no flaring and a much sharper resolution than that of the conventional optical microscope. The AOD makes possible a high speed laser scan and a NTSC or PAL TV video signal is produced in real time without any video memory. Since the light source is composed of R, G, and B laser beams, color separation superior to that of white light illumination is achieved. Because of the photometric linearity of the image detector, the R, G, and B outputs of the system are most suitably used for hue analysis. The CCD linear image sensors in the optical system produce no geometrical distortion, and good color registration is available principally. The output signal can be used for high accuracy line width measuring. The many features of the color laser microscope make it ideally suited for the visual inspection of semiconductor processing. A number of these systems have already been installed in such a capacity. The Color Laser Microscope can also be a very useful tool for the fields of material engineering and biotechnology.

  2. Multiphoton processes in the field of two-frequency circularly polarized plane electromagnetic waves

    International Nuclear Information System (INIS)

    Yu, An

    1997-01-01

    The authors solve Dirac's equation for an electron in the field of a two-frequency plane electromagnetic wave, deriving general formulae for the probabilities of radiation of a photon by the electron, and for the probabilities for pair production by a photon when the two-frequency wave is circularly polarized. In contrast to the case of a monochromatic-plane electromagnetic wave, when an electron is in the field of a two-frequency circularly polarized wave, besides the absorption of multiphotons and emission of simple harmonics of the individual waves, stimulated multiphoton emission processes and various composite harmonic-photon emission processes are occurred: when a high-energy photon is in a such a field, multiphoton processes also follow the pair production processes

  3. Measurements of ocean wave spectra and modulation transfer function with the airborne two-frequency scatterometer

    Science.gov (United States)

    Weissman, D. E.; Johnson, J. W.

    1986-01-01

    The directional spectrum and the microwave modulation transfer function of ocean waves can be measured with the airborne two frequency scatterometer technique. Similar to tower based observations, the aircraft measurements of the Modulation Transfer Function (MTF) show that it is strongly affected by both wind speed and sea state. Also detected are small differences in the magnitudes of the MTF between downwind and upwind radar look directions, and variations with ocean wavenumber. The MTF inferred from the two frequency radar is larger than that measured using single frequency, wave orbital velocity techniques such as tower based radars or ROWS measurements from low altitude aircraft. Possible reasons for this are discussed. The ability to measure the ocean directional spectrum with the two frequency scatterometer, with supporting MTF data, is demonstrated.

  4. Measurements of ocean wave spectra and modulation transfer function with the airborne two frequency scatterometer

    Science.gov (United States)

    Weissman, D. E.; Johnson, J. W.

    1984-01-01

    The directional spectrum and the microwave modulation transfer function of ocean waves can be measured with the airborne two frequency scatterometer technique. Similar to tower based observations, the aircraft measurements of the Modulation Transfer Function (MTF) show that it is strongly affected by both wind speed and sea state. Also detected are small differences in the magnitudes of the MTF between downwind and upwind radar look directions, and variations with ocean wavenumber. The MTF inferred from the two frequency radar is larger than that measured using single frequency, wave orbital velocity techniques such as tower based radars or ROWS measurements from low altitude aircraft. Possible reasons for this are discussed. The ability to measure the ocean directional spectrum with the two frequency scatterometer, with supporting MTF data, is demonstrated.

  5. Using laser to measure stem thickness and cut weed stems

    DEFF Research Database (Denmark)

    Heisel, T.; Schou, Jørgen; Andreasen, C.

    2002-01-01

    Stem thickness of the weed Solanum nigrum and the crop sugarbeet was determined with a He-Ne laser using a novel non-destructive technique measuring stem shadow. Thereafter, the stems were cut close to the soil surface with a CO2 laser. Treatments were carried out on pot plants, grown....... A binary model was also tested. The non-linear model incorporating stem thickness described the data best, indicating that it would be possible to optimize laser cutting by measuring stem thickness before cutting. The general tendency was that more energy was needed the thicker the stem. Energy uses...... in the greenhouse, at two different growth stages, and plant dry matter was measured 2-5 weeks after treatment. The relationship between plant dry weight and laser energy was analysed using two different non-linear dose-response regression models; one model included stem thickness as a variable, the other did not...

  6. Optimal buffer gas pressure for laser-induced fluorescence detection of the iodine-129 isotope in the atmosphere

    International Nuclear Information System (INIS)

    Kireev, S.V.; Pit'ko, A.V.; Shnyrev, S.L.

    1995-01-01

    The effect of atmospheric air pressure on the intensity of iodine-129 vapor fluorescence excited by a He-Ne (633 nm) laser is studied. It is shown that to achieve the maximum intensity of fluorescence of molecular iodine-129, it is advantageous, first, to use a 3 He- 20 Ne laser for excitation, and second, to detect atmospheric iodine impurities in the gas mixture under analysis evacuated to 2 x 10 18 - 4 x 10 18 mol/cm 3 . In this case, the sensitivity increases about twofold. 7 refs., 4 figs

  7. Theoretical-experimental study of the non-thermal effects of the polarized laser radiation in living tissues

    International Nuclear Information System (INIS)

    Ribeiro, M.S.

    1991-01-01

    In the present research we had as a fundamental objective to analyse the non-thermal effects of the laser polarized light in biological tissues. These effects were performed with low power laser output. The theoretical procedure consisted in looking for a simple model which connects the effect of light polarized with microscopically rough tissues using well established physical concepts. Experimentally, we created artificial wounds on the back of animals using liquid nitrogen (this method was chosen because it does not interfere in the biochemistry of the animal tissue). For the wound irradiation we have utilized a He-Ne attached to an optical system. (author)

  8. Demonstration of a tunable two-frequency projected fringe pattern with acousto-optic deflectors

    International Nuclear Information System (INIS)

    Dupont, S.; Kastelik, J. C.

    2008-01-01

    We report on a fringe projector for three-dimensional shape measurement. The developed instrument is able to project a two-frequency fringe pattern, each frequency is independently controlled by electronics. Moreover, each phase of the two fringe patterns is also independently adjusted. The projection system is based on the use of a pair of custom large bandwidth (40 MHz) and high efficiency (60%) TeO 2 deflectors. The developed instrument offers the combined advantages of a static two-frequency fringe projector and of a tunable single frequency fringe projector

  9. Laser interferometer array for Big Dee

    International Nuclear Information System (INIS)

    Fairbanks, E.S.

    1984-01-01

    A twelve channel interferometer array is planned for obtaining electron density profiles on Big Dee. Three of the channels are vertical; the remainder are radial or diagonal in an azimuthal plane. Each channel consists of coaxial CO/sub 2/ and HeNe laser beams. The reference beam is formed by splitting off half of the laser power at each wavelength by using acousto-optic modulators which introduce a 40 MHz frequency shift in the reference beam. In the radial channels the probe beam passes through a barium fluoride window to a plane metal mirror on the inside wall of the vacuum vessel. The reflected beam passes back out of the vacuum vessel, through the same window, to a beam splitter where the probe beam and the reference beam are again combined

  10. Tracking frequency laser distance gauge

    International Nuclear Information System (INIS)

    Phillips, J.D.; Reasenberg, R.D.

    2005-01-01

    Advanced astronomical missions with greatly enhanced resolution and physics missions of unprecedented accuracy will require laser distance gauges of substantially improved performance. We describe a laser gauge, based on Pound-Drever-Hall locking, in which the optical frequency is adjusted to maintain an interferometer's null condition. This technique has been demonstrated with pm performance. Automatic fringe hopping allows it to track arbitrary distance changes. The instrument is intrinsically free of the nm-scale cyclic bias present in traditional (heterodyne) high-precision laser gauges. The output is a radio frequency, readily measured to sufficient accuracy. The laser gauge has operated in a resonant cavity, which improves precision, can suppress the effects of misalignments, and makes possible precise automatic alignment. The measurement of absolute distance requires little or no additional hardware, and has also been demonstrated. The proof-of-concept version, based on a stabilized HeNe laser and operating on a 0.5 m path, has achieved 10 pm precision with 0.1 s integration time, and 0.1 mm absolute distance accuracy. This version has also followed substantial distance changes as fast as 16 mm/s. We show that, if the precision in optical frequency is a fixed fraction of the linewidth, both incremental and absolute distance precision are independent of the distance measured. We discuss systematic error sources, and present plans for a new version of the gauge based on semiconductor lasers and fiber-coupled components

  11. Response of antioxidant defense system to laser radiation apical meristem of Isatis indigotica seedlings exposed to UV-B.

    Science.gov (United States)

    Chen, Yi-Ping

    2009-07-01

    To determine the response of antioxidant defense system to laser radiation apical meristem of Isatis indigotica seedlings, Isatis indigotica seedlings were subjected to UV-B radiation (10.08 kJ m(-2)) for 8 h day(-1) for 8 days (PAR, 220 micromol m(-2) s(-1)) and then exposed to He-Ne laser radiation (633 nm; 5.23 mW mm(-2); beam diameter: 1.5 mm) for 5 min each day without ambient light radiation. Changes in free radical elimination systems were measured, the results indicate that: (1) UV-B radiation enhanced the concentration of Malondialdahyde (MDA) and decreased the activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) in seedlings compared with the control. The concentration of MDA was decreased and the activities of SOD, CAT and POD were increased when seedlings were subjected to elevated UV-B damage followed by laser; (2) the concentration of UV absorbing compounds and proline were increased progressively with UV-B irradiation, laser irradiation and He-Ne laser irradiation plus UV-B irradiation compared with the control. These results suggest that laser radiation has an active function in repairing UV-B-induced lesions in seedlings.

  12. Benefits of low-power lasers on oral soft tissue

    Science.gov (United States)

    Eduardo, Carlos d. P.; Cecchini, Silvia C. M.; Cecchini, Renata C.

    1996-04-01

    The last five years have represented a great advance in relation to laser development. Countries like Japan, United States, French, England, Israel and others, have been working on the association of researches and clinical applications, in the field of laser. Low power lasers like He-Ne laser, emitting at 632,8 nm and Ga-As-Al laser, at 790 nm, have been detached acting not only as a coadjutant but some times as an specific treatment. Low power lasers provide non thermal effect at wavelengths believed to stimulate circulation and cellular activity. These lasers have been used to promote wound healing and reduce inflammation edema and pain. This work presents a five year clinical study with good results related to oral tissue healing. Oral cavity lesions, like herpes and aphthous ulcers were irradiated with Ga-Al- As laser. In both cases, an excellent result was obtained. The low power laser application decrease the painful sintomatology immediately and increase the reparation process of these lesions. An excellent result was obtained with application of low power laser in herpetic lesions associated with a secondary infection situated at the lip commissure covering the internal tissue of the mouth. The healing occurred after one week. An association of Ga-Al-As laser and Nd:YAG laser have been also proven to be good therapy for these kind of lesions. This association of low and high power laser has been done since 1992 and it seems to be a complement of the conventional therapies.

  13. Evaluation of the role of laser bio stimulation on skin and liver of gamma-irradiated mice

    International Nuclear Information System (INIS)

    Salem, E.S.

    2007-01-01

    Low level laser therapy (LLLT) is used in different medical fields due to its therapeutic effects on reparative processes, pain relief and bio stimulation (Castro-e-silva et al., 2003). The present study aimed at evaluating the therapeutic efficacy of He-Ne laser in stimulating the reparative processes after whole body irradiation of mice using a sublethal dose (5 Gy) of gamma rays. Two vital organs were studied, a radio-sensitive one (the skin) as well as a relatively radio-resistant one (the liver) . During the course of the present work, some biochemical parameters as well as histopathological changes in the skin and liver tissues induced by whole body gamma ionizing radiation were studied. Female mice (240) were used and divided into 6 groups and laser therapy was carried out using a computerized scanner emitting He-Ne(C W) with a wavelength of 632.8 nm and the fluence was 5 j/cm 2 . Experimental investigation have been carried out along two main lines: Biochemical investigations for the assessment of serum transferases and histopathological assessment of liver and skin biopsy.On the basis of the current results it could be concluded that mice exposed to whole body gamma irradiation either by the US of the shot or the fractionated sublethal dose suffered an aggravated histopathological changes in the skin and liver tissues which were associated with certain biochemical disturbances of the liver function testes. These undesirable alterations were ameliorated by the early treatment of mice by He -Ne laser immediately post exposure before being irreversibly damaged

  14. Laser source for dimensional metrology: investigation of an iodine stabilized system based on narrow linewidth 633 nm DBR diode

    Science.gov (United States)

    Rerucha, Simon; Yacoot, Andrew; Pham, Tuan M.; Cizek, Martin; Hucl, Vaclav; Lazar, Josef; Cip, Ondrej

    2017-04-01

    We demonstrated that an iodine stabilized distributed Bragg reflector (DBR) diode based laser system lasing at a wavelength in close proximity to λ =633 nm could be used as an alternative laser source to the helium-neon lasers in both scientific and industrial metrology. This yields additional advantages besides the optical frequency stability and coherence: inherent traceability, wider optical frequency tuning range, higher output power and high frequency modulation capability. We experimentally investigated the characteristics of the laser source in two major steps: first using a wavelength meter referenced to a frequency comb controlled with a hydrogen maser and then on an interferometric optical bench testbed where we compared the performance of the laser system with that of a traditional frequency stabilized He-Ne laser. The results indicate that DBR diode laser system provides a good laser source for applications in dimensional (nano)metrology, especially in conjunction with novel interferometric detection methods exploiting high frequency modulation or multiaxis measurement systems.

  15. Breakup of inverse golden mean shearless tori in the two-frequency standard nontwist map

    International Nuclear Information System (INIS)

    Wurm, A.; Martini, K.M.

    2013-01-01

    The breakup of shearless invariant tori with winding number ω=(√(5)−1)/2 (inverse golden mean) is studied using Greene's residue criterion in the recently derived two-frequency or extended standard nontwist map (ESNM). Depending on the frequency ratio, the ESNM has or does not have a particular spatial symmetry. If the symmetry is present, the breakup is shown to be the same as in the standard nontwist map; if not, the results are very different.

  16. Two-frequency radiospectrometer for studying paramagnetics under a strong magnetic field

    International Nuclear Information System (INIS)

    Vertii, A.A.; Gudym, I.Y.; Ivanchenko, I.V.

    1994-01-01

    A two-frequency radiospectrometer for studying electron paramagnetic resonance in the 120-150-GHz band and nuclear magnetic resonance in the 180-200-MHz band is described. The spectrometer is used to measure the properties of paramagnetics by a double-resonance technique in a magnetic field of up to 5 T at a temperature ranging from 1.7 to 20 degrees K

  17. Influence of CdS nanoparticles grain morphology on laser-induced absorption

    Science.gov (United States)

    Ebothé, Jean; Michel, Jean; Kityk, I. V.; Lakshminarayana, G.; Yanchuk, O. M.; Marchuk, O. V.

    2018-06-01

    Using external illumination of a 7 nanosecond (ns) doubled frequency Nd: YAG laser emitting at λ = 532 nm with frequency repetition 10 Hz it was established a possibility of significant changes of the absorption at the probing wavelength 1150 nm of continuous wave (cw) He-Ne laser for the CdS nanoparticles embedded into the PVA polymer matrix. The effect is observed only during the two beam laser coherent treatment and this effect is a consequence of interference of two coherent beams. It is shown a principal role of the grain morphology in the efficiency of the process, which is more important than the nanoparticle sizes. The photoinduced absorption is manifested in the space distribution of the probing laser beam. The principal role of the grain interfaces between the nanoparticle interfaces and the surrounding polymer matrix is shown. The effect is almost independent of the nanoparticle sizes. It may be used for laser operation by nanocomposites.

  18. Continuous anti-Stokes Raman laser operation

    International Nuclear Information System (INIS)

    Feitisch, A.; Muller, T.; Welling, H.; Wellegehausen, B.

    1988-01-01

    The anti-Stokes Raman laser (ASRL) process has proved to be a method that works well for frequency upconversion and for the generation of powerful tunable narrowband (pulsed) laser radiation in the UV and VUV spectral range. This conversion process allows large-frequency shifts in single step, high output energies, and high efficiencies. A basic requirement is population inversion on a two-photon transition, where, in general, the upper level of the transition should be metastable. Up to now the ASRL technique has only been demonstrated for the pulsed regime, where the necessary population inversion was generated by photodissociation or inner shell photoionization. These inversion techniques, however, cannot be transferred to cw operation of an ASRL, and, therefore, other inversion techniques have to be developed. Here a novel approach for the creation of the necessary population inversion is proposed, that uses well-known cw gas lasers as the active material for the conversion process. The basic idea is to use either existing two-photon population inversions in a cw laser material or to generate the necessary population inversion by applying a suitable population transfer process to the material. A natural two-photon inversion situation in a laser material is evident whenever a cascade laser can be operated. Cascade laser-based anti-Stokes schemes are possible in a He-Ne laser discharge, and investigations of these schemes are discussed

  19. Lasers

    CERN Document Server

    Milonni, Peter W

    1988-01-01

    A comprehensive introduction to the operating principles and applications of lasers. Explains basic principles, including the necessary elements of classical and quantum physics. Provides concise discussions of various laser types including gas, solid state, semiconductor, and free electron lasers, as well as of laser resonators, diffraction, optical coherence, and many applications including holography, phase conjugation, wave mixing, and nonlinear optics. Incorporates many intuitive explanations and practical examples. Discussions are self-contained in a consistent notation and in a style that should appeal to physicists, chemists, optical scientists and engineers.

  20. Propagation and stability characteristics of a 500-m-long laser-based fiducial line for high-precision alignment of long-distance linear accelerators.

    Science.gov (United States)

    Suwada, Tsuyoshi; Satoh, Masanori; Telada, Souichi; Minoshima, Kaoru

    2013-09-01

    A laser-based alignment system with a He-Ne laser has been newly developed in order to precisely align accelerator units at the KEKB injector linac. The laser beam was first implemented as a 500-m-long fiducial straight line for alignment measurements. We experimentally investigated the propagation and stability characteristics of the laser beam passing through laser pipes in vacuum. The pointing stability at the last fiducial point was successfully obtained with the transverse displacements of ±40 μm level in one standard deviation by applying a feedback control. This pointing stability corresponds to an angle of ±0.08 μrad. This report contains a detailed description of the experimental investigation for the propagation and stability characteristics of the laser beam in the laser-based alignment system for long-distance linear accelerators.

  1. Efficacy of fractional lasers in treating alopecia: a literature review.

    Science.gov (United States)

    Perper, Marina; Aldahan, Adam S; Fayne, Rachel A; Emerson, Christopher P; Nouri, Keyvan

    2017-11-01

    Hair loss stemming from different types of alopecia, such as androgenic alopecia and alopecia areata, negatively affects over half the population and, in many circumstances, causes serious psychosocial distress. Current treatment options for alopecia, such as minoxidil, anthralin, and intralesional corticosteroids, vary efficacy and side effect profiles. It is known that low-level laser/light therapies (LLLT), or photobiomodulations, such as the US FDA-cleared HairMax Lasercomb®, He-Ne laser, and excimer laser, are relatively affordable, user-friendly, safe, and effective forms of treatment for hair loss. While less is known about the effectiveness of fractional lasers for combating hair loss, research suggests that by creating microscopic thermal injury zones, fractional lasers may cause an increase in hair growth from a wound healing process, making them potential therapeutic options for alopecia. A literature review was performed to evaluate the effectiveness of fractional lasers on hair regrowth. The specific fractional laser therapies include the 1550-nm nonablative fractional erbium-glass laser, the ablative fractional 2940-nm erbium:YAG laser, and the ablative fractional CO 2 fractional laser. Additional randomized controlled trials are necessary to further evaluate the effectiveness of the lasers, as well as to establish appropriate parameters and treatment intervals.

  2. Suppression of cyclotron instability in Electron Cyclotron Resonance ion sources by two-frequency heating

    International Nuclear Information System (INIS)

    Skalyga, V.; Izotov, I.; Mansfeld, D.; Kalvas, T.; Koivisto, H.; Komppula, J.; Kronholm, R.; Laulainen, J.; Tarvainen, O.

    2015-01-01

    Multiple frequency heating is one of the most effective techniques to improve the performance of Electron Cyclotron Resonance (ECR) ion sources. The method increases the beam current and average charge state of the extracted ions and enhances the temporal stability of the ion beams. It is demonstrated in this paper that the stabilizing effect of two-frequency heating is connected with the suppression of electron cyclotron instability. Experimental data show that the interaction between the secondary microwave radiation and the hot electron component of ECR ion source plasmas plays a crucial role in mitigation of the instabilities

  3. Breakup of inverse golden mean shearless tori in the two-frequency standard nontwist map

    Energy Technology Data Exchange (ETDEWEB)

    Wurm, A., E-mail: awurm@wne.edu [Department of Physical and Biological Sciences, Western New England University, Springfield, MA 01119 (United States); Martini, K.M. [Department of Physics, Rochester Institute of Technology, Rochester, NY 14623 (United States)

    2013-03-01

    The breakup of shearless invariant tori with winding number ω=(√(5)−1)/2 (inverse golden mean) is studied using Greene's residue criterion in the recently derived two-frequency or extended standard nontwist map (ESNM). Depending on the frequency ratio, the ESNM has or does not have a particular spatial symmetry. If the symmetry is present, the breakup is shown to be the same as in the standard nontwist map; if not, the results are very different.

  4. Laser doppler perfusion imaging

    International Nuclear Information System (INIS)

    Waardell, K.

    1992-01-01

    Recording of tissue perfusion is important in assessing the influence of peripheral vascular diseases on the microcirculation. This thesis reports on a laser doppler perfusion imager based on dynamic light scattering in tissue. When a low power He-Ne laser beam sequentally scans the tissue, moving blood cells generate doppler components in the back-scattered light. A fraction of this light is detected by a photodetector and converted into an electrical signal. In the processor, a signal proportional to the tissue perfusion at each measurement site is calculated and stored. When the scanning procedure is completed, a color-coded perfusion image is presented on a monitor. To convert important aspects of the perfusion image into more quantitative parameters, data analysis functions are implemented in the software. A theory describing the dependence of the distance between individual measurement points and detector on the system amplification factor is proposed and correction algorithms are presented. The performance of the laser doppler perfusion imager was evaluated using a flow simulator. A linear relationship between processor output signal and flow through the simulator was demonstrated for blood cell concentrations below 0.2%. The median sampling depth of the laser beam was simulated by a Monte Carlo technique and estimated to 235 μm. The perfusion imager has been used in the clinic to study perfusion changes in port wine stains treated with argon laser and to investigate the intensity and extension of the cutaneous axon reflex response after electrical nerve stimulation. The fact that perfusion can be visualized without touching the tissue implies elimination of sterilization problems, thus simplifying clinical investigations of perfusion in association with diagnosis and treatment of peripheral vascular diseases. 22 refs

  5. Interferogram reduction and interpretation as applied to the optical analysis of the 10 kJ LASL laser fusion system

    International Nuclear Information System (INIS)

    Viswanathan, V.K.; Hall, W.S.; Liberman, I.; Lawrence, G.

    1978-01-01

    The LASL 10 kJ Eight-Beam CO 2 Laser Fusion System, currently under construction, has approximately one hundred optical elements per beam. The nominal system is diffraction limited and degradations in performance are primarily caused by imperfect components as well as alignment errors. Consequently, analysis and predictions for the system are very much dependent on the proper description of the imperfect components. The approach taken at LASL has been to characterize the components interferometrically. Interferograms of the various components are made at the 633 nm He--Ne wavelength. Detailed results of the analysis for one complete leg of the eight-beam system is presented

  6. Amplitude and polarization asymmetries in a ring laser

    Science.gov (United States)

    Campbell, L. L.; Buholz, N. E.

    1971-01-01

    Asymmetric amplitude effects between the oppositely directed traveling waves in a He-Ne ring laser are analyzed both theoretically and experimentally. These effects make it possible to detect angular orientations of an inner-cavity bar with respect to the plane of the ring cavity. The amplitude asymmetries occur when a birefringent bar is placed in the three-mirror ring cavity, and an axial magnetic field is applied to the active medium. A simplified theoretical analysis is performed by using a first order perturbation theory to derive an expression for the polarization of the active medium, and a set of self-consistent equations are derived to predict threshold conditions. Polarization asymmetries between the oppositely directed waves are also predicted. Amplitude asymmetries similar in nature to those predicted at threshold occur when the laser is operating in 12-15 free-running modes, and polarization asymmetry occurs simultaneously.

  7. Designing and testing a laser-based vibratory sensor

    Science.gov (United States)

    Nath, G.

    2018-04-01

    Sensor technology has proved its importance, not only in the range of few-meter applications in different fields, but in micro, nano, atomic and sub-atomic-sized objects. The present work describes the designing of a laser-based vibratory sensor using a He-Ne laser as the signal source. The received characteristics of the signal are mainly the frequency and amplitude of the vibration from which the physical parameters such as energy, power and absorption coefficients of the material are determined, which enables us to provide information of the hidden target or object. This laboratory-designed sensor finds application in different local phenomena as well as laboratory practical activity for students.

  8. Strong optical feedback in birefringent dual frequency laser

    Institute of Scientific and Technical Information of China (English)

    Mao Wei; Zhang Shu-Lian

    2006-01-01

    Strong optical feedback in a birefringent dual frequency He-Ne laser with a high reflectivity feedback mirror has been investigated for the first time. The output characteristics of two orthogonally polarized modes are demonstrated in two different optical feedback cases: one is for both modes being fed back and the other is for only one of the modes being fed back. Strong mode competition can be observed between the two modes with strong optical feedback. And when one mode's intensity is near its maximum, the other mode is nearly extinguished. When both modes are fed back into the laser cavity, the mode competition is stronger than when only one mode is fed back. The difference in initial intensity between the two orthogonally polarized modes plays an important role in the mode competition, which has been experimentally and theoretically demonstrated.

  9. Feasibility of laser pumping with neutron fluxes from present-day large tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Jassby, D.L.

    1986-08-01

    The minimum fusion-neutron flux needed to observe nuclear-pumped lasing with tokamaks can be reduced substantially by optimizing neutron scattering into the laser cell, located between adjacent toroidal-field coils. The laser lines most readily pumped are probably the /sup 3/He-Ne lines at 0.633 ..mu.. and in the infrared, where the /sup 3/He-Ne gas is excited by energetic ions produced in the /sup 3/He(n,p)T reaction. These lines are expected to lase at the levels of D-T neutron flux foreseen for the TFTR in 1989 (>>10/sup 12/ n/cm/sup 2//s), while amplification should be observable at the existing levels of D-D neutron flux (greater than or equal to 5 x 10/sup 9/ n/cm/sup 2//s). Lasing on the 1.73 ..mu.. and 2.63 ..mu.. transitions of Xe may be observable at the maximum expected levels of D-T neutron flux in TFTR enhanced by scattering.

  10. Feasibility of laser pumping with neutron fluxes from present-day large tokamaks

    International Nuclear Information System (INIS)

    Jassby, D.L.

    1986-08-01

    The minimum fusion-neutron flux needed to observe nuclear-pumped lasing with tokamaks can be reduced substantially by optimizing neutron scattering into the laser cell, located between adjacent toroidal-field coils. The laser lines most readily pumped are probably the 3 He-Ne lines at 0.633 μ and in the infrared, where the 3 He-Ne gas is excited by energetic ions produced in the 3 He(n,p)T reaction. These lines are expected to lase at the levels of D-T neutron flux foreseen for the TFTR in 1989 (>>10 12 n/cm 2 /s), while amplification should be observable at the existing levels of D-D neutron flux (≥ 5 x 10 9 n/cm 2 /s). Lasing on the 1.73 μ and 2.63 μ transitions of Xe may be observable at the maximum expected levels of D-T neutron flux in TFTR enhanced by scattering

  11. Effect of helium-neon laser irradiation on hair follicle growth cycle of Swiss albino mice.

    Science.gov (United States)

    Shukla, S; Sahu, K; Verma, Y; Rao, K D; Dube, A; Gupta, P K

    2010-01-01

    We report the results of a study carried out to investigate the effect of helium-neon (He-Ne) laser (632.8 nm) irradiation on the hair follicle growth cycle of testosterone-treated and untreated mice. Both histology and optical coherence tomography (OCT) were used for the measurement of hair follicle length and the relative percentage of hair follicles in different growth phases. A positive correlation (R = 0.96) was observed for the lengths of hair follicles measured by both methods. Further, the ratios of the lengths of hair follicles in the anagen and catagen phases obtained by both methods were nearly the same. However, the length of the hair follicles measured by both methods differed by a factor of 1.6, with histology showing smaller lengths. He-Ne laser irradiation (at approximately 1 J/cm(2)) of the skin of both the control and the testosterone-treated mice was observed to lead to a significant increase (p alopecia. (c) 2009 S. Karger AG, Basel.

  12. Optical chirality in AgCl-Ag thin films through formation of laser-induced planar crossed-chain nanostructures

    Science.gov (United States)

    Nahal, Arashmid; Kashani, Somayeh

    2017-09-01

    Irradiation of AgCl-Ag thin films by a linearly polarized He-Ne laser beam results in the formation of self-organized periodic nanostructures. As a result of secondary irradiation of the initially exposed sample by the same linearly polarized He-Ne laser beam, but with different orientations of polarization, a complex crossed-chain nanostructure forms. We found that such a complex nanostructure has noticeable chirality and increased optical anisotropy, resulting in optical activity of the sample. Double exposure produces two gratings, crossing each other with angle α, which leads to the formation of crossed building blocks with chiroptical effects. It is established that the amount and the sign of the angle between the two laser-induced gratings (±α) determine the amount and the direction of rotation of the linearly polarized probe beam, respectively. We have also observed an induced anisotropy-dependent ellipticity for the probe light, which is passed through the sample. It is shown that the amount of ellipticity depends on the angle α.

  13. Physical grounds for biological effect of laser radiation

    International Nuclear Information System (INIS)

    Rubinov, A N

    2003-01-01

    A new approach to the understanding of biological activity caused by low-intensity laser radiation, in which coherence is a factor of paramount importance, has been developed. It is based on the dipole interaction of gradient laser fields with cells, organelles and membranes. The laser intensity gradients in an object arise due to the interference of the light scattered by the tissue with the incident light beam (speckle formation). Apart from speckles, different types of light spatial modulation can be created deliberately using different schemes for beam interference. It is shown that gradient laser fields may cause spatial modulation of the concentration of particles and increase their 'partial temperature'. This paper presents the results of experimental observation of trapping of different types of particles, including human lymphocytes, in the interference fields of the He-Ne laser. The sweep-net effect on particles of different sizes on moving the laser field is demonstrated and crystal-like self-organization of particles in the laser gradient field is observed. The influence of gradient laser fields on erythrocyte rouleaus, on the apoptosis of human lymphocytes as well as on their chromosome aberrations is demonstrated. It may be concluded from the experimental studies that the influence of an interference laser field with a rightly chosen period can stimulate the repair system of a cell, increasing its viability

  14. Editorial special issue on "Laser Doppler vibrometry"

    Science.gov (United States)

    Vanlanduit, Steve; Dirckx, Joris

    2017-12-01

    The invention of the laser in 1960 has opened up many opportunities in the field of measurement science and technology. Just a few years after the invention of the laser, a novel fluid flow measurement technique based on the Doppler effect was introduced: at that moment the laser Doppler anemometer or shortly LDA [1] was born. The technique enabled fluid velocity measurement by using the light of a He-Ne beam which was scattered by very small polystyrene spheres entrained in the fluid. Later on, in the late nineteen seventees it was recognized that the detection of the Doppler frequency shift that occurs when light is scattered by a moving surface can also be used to measure the vibration velocity of an object. The instrument to perform these vibration measurements was called the laser Doppler vibrometer or LDV [2]. In the last decades several technological advances were made in the field of laser Doppler vibrometry. The result is that nowadays, velocity measurements of fluids (using LDA) and vibrating objects (using LDV) are performed in many challenging applications in different fields (microelectronics, civil structures, biomedical engineering, material science, etc.).

  15. Short distance line of sight laser communication

    International Nuclear Information System (INIS)

    Mudassar, A.A.; Hussain, H.; Jamil-ur-Rehman

    1998-01-01

    Communication methods based on lasers as carrier are well known. In our work we have made a two way laser based communication system for short range (<2 Km) line of sight communication. A small piece of plane mirror (100% reflector) was mounted on the centre of a speaker cone. The speaker was positioned close to the opening of laser such that He-Ne laser beam (10 mW) after reflection from the mirror is directed towards the receiver. There is a pre-amplifier and an amplifier between a microphone and the speaker. When the diagram of the speaker vibrates, it positionally modulates the laser beam. On the receiving end, there is a photo diode, a pre-amplifier, an amplifier and a head phone. So the man on the receiving end can decode the sound signal. On each stage there is a transmitter and a receiver assembled close to each other. So the two way communication is possible in the range 20 to 20 Khz. (author)

  16. Development of a heterodyne laser interferometer for very small high frequency displacements detection

    International Nuclear Information System (INIS)

    Baarmann, P.

    1992-10-01

    A heterodyne laser interferometer with detection electronics has been developed for measuring very small amplitude high frequency vibrations. A laser beam from HeNe-laser is focused and reflected in the vibrating surface and the generated phase shifts are after interference with a reference beam detected with a photo detector and evaluated in a demodulation system. The set-up is a prototype and techniques to improve the accuracy and sensitivity of the system are presented. The present system can detect vibration amplitude from around 1 Angstrom and is linear up to 250 Angstrom (±4%). Frequencies from a few tens of kHz up to tens of MHz are covered. The low frequency region can be greatly improved. The minimum detectable displacement may be improved by narrowing the bandwidth of the detection system to the region of interest

  17. Time resolved x-ray pinhole photography of compressed laser fusion targets

    International Nuclear Information System (INIS)

    Attwood, D.T.

    1976-01-01

    Use of the Livermore x-ray streak camera to temporally record x-ray pinhole images of laser compressed targets is described. Use is made of specially fabricated composite x-ray pinholes which are near diffraction limited for 6 A x-rays, but easily aligned with a He--Ne laser of 6328 A wavelength. With a 6 μm x-ray pinhole, the overall system can be aligned to 5 μm accuracy and provides implosion characteristics with space--time resolutions of approximately 6 μm and 15 psec. Acceptable criteria for pinhole alignment, requisite x-ray flux, and filter characteristics are discussed. Implosion characteristics are presented from our present experiments with 68 μm diameter glass microshell targets and 0.45 terawatt, 70 psec Nd laser pulses. Final implosion velocities in excess of 3 x 10 7 cm/sec are evident

  18. Nonlinear vibration behaviors of suspended cables under two-frequency excitation with temperature effects

    Science.gov (United States)

    Zhao, Yaobing; Huang, Chaohui; Chen, Lincong; Peng, Jian

    2018-03-01

    The aim of this paper is to investigate temperature effects on the nonlinear vibration behaviors of suspended cables under two-frequency excitation. For this purpose, two combination and simultaneous resonances are chosen and studied in detail. First of all, based on the assumptions of the temperature effects, the partial differential equations of the in-plane and out-of-plane motions with thermal effects under multi-frequency excitations are obtained. The Galerkin method is adopted to discretize the nonlinear dynamic equations, and the single-mode planar discretization is considered. Then, in the absence of the primary and internal resonances, the frequency response equations are obtained by using the multiple scales method. The stability analyses are conducted via investigating the nature of the singular points of equations. After that, temperature effects on nonlinear vibration characteristics of the first symmetric mode are studied. Parametric investigations of temperature effects on corresponding non-dimensional factors and coefficients of linear and nonlinear terms are performed. Numerical results are presented to show the temperature effects via the frequency-response curves and detuning-phase curves of four different sag-to-span ratios. It is found out that effects of temperature variations would lead to significant quantitative and/or qualitative changes of the nonlinear vibration properties, and these effects are closely related to the sag-to-span ratio and the degree of the temperature variation. Specifically, the softening/hardening-type spring behaviors, the response amplitude, the range of the resonance, the intersection and number of branches, the number and phase of the steady-state solutions are all affected by the temperature changes.

  19. Effect of bone marrow and low power lasers on fracture healing with destruction of both periosteum and endosteum in rabbits

    Directory of Open Access Journals (Sweden)

    M. G. Thanoon

    2010-01-01

    Full Text Available Ten mature rabbits of local breed were used in this study; weighing between 1.5 to 1.75 kg and aged about 1–2 years. These animals were divided into two equal groups; in group A destruction of both periosteum and endosteum was done one centimeter from each side of mid-shaft femoral bone fracture, then sufficient amount of autogenously bone marrow was injected directly at the fracture site after immobilization by intramedullary pin. In group B a similar procedure was achieved as in group A, but in additional to that He-Ne infrared laser therapy was used for several sessions. The result of radiological findings indicated that, the fracture healing occurred within group B at fifteen weeks, whereas in group A the healing occurred at eighteen weeks after operation. The implantation of autologous bone marrow enhanced the fracture healing, whereas using of combinations of autologous bone marrow and He-Ne infrared laser therapy hastened the healing.

  20. Fundamental study on laser manipulation of contamination particles with determining shape, size and species

    International Nuclear Information System (INIS)

    Shimizu, Isao; Fujii, Taketsugu

    1995-01-01

    It has been desired to eliminate or collect the contamination particles of radioisotope in each sort of species or shape and size non-invasively. The shape and size of particle can be determined from the shape and distribution of diffraction pattern of particle in the parallel laser beam, the species of particle can be discriminated by the fluorescence from resonance of laser beam, or by the laser Raman scattering, and the particle suspended in the air or falling down in a vacuum can be levitated against the gravity and trapped by the radiation force and the trapping force of the focussed laser beam in the atmosphere or in a vacuum. For the purpose of the non-invasive manipulation of contamination particles, the laser manipulation technique, image processing technique with Multiplexed Matched Spatial Filter and the determination technique of laser Raman scattering or fluorescence from resonance of laser light were combined in the experiments. The shape, size and species of particles trapped in the focal plane of focused Ar laser beam can be determined simultaneously and instantaneously from the shape and intensity distributions of diffraction patterns of the particles in the irradiation of parallel coherent beam of He-Ne laser, and fluorescence from the resonance of YAG laser beam with variable wave length. In this research, a new technique is proposed to manipulate non-invasively the contamination particles determined with the shape, size and species in the atmosphere or in a vacuum, by laser beam. (author)

  1. Photobiomodulation by helium neon and diode lasers in an excisional wound model: A single blinded trial

    Directory of Open Access Journals (Sweden)

    Snehil Dixit

    2012-01-01

    Full Text Available Background: Application of different kinds of lasers in clinical and experimental studies causes photobiomodulation that works at localized cellular and humoral level on various biological systems. Increased numbers of fibroblasts, myofibroblast, and degranulation of mast cells have been the observed benefits post-irradiation. Objective: Was to find out the effect of irradiation with energy densities of 3.38 J/cm 2 , 8 J/cm 2 , and 18 J/cm 2 on animal tissue (albino wistar rats in an excisional wound model and to assess changes in biochemical (hydroxyproline and histopathological levels in excisional wound model. Materials and Methods: The animals were divided into 4 groups, which were labeled as L1, diode laser (18 J/cm 2 , L2 Helium-neon (He-Ne, 8 J/cm 2 , L3 diode laser (3.38 J/cm 2 , and sham treatment for control was depicted by C, respectively. Histological and hydroxyproline analysis was performed on 7, 14, 21 days of post-wounding. One-way analysis of variance, ANOVA and Bonferroni′s multiple comparison tests were done for tissue hydroxyproline levels. Results: There was no significant increase in the hydroxyproline content (P < 0.005 when observed in study group and compared to controls. Whereas significant epithelizations was seen in group treated with He-Ne laser of intensity of 8 J/cm 2 . Conclusion: The experimental observations suggest that low intensity helium-neon laser of 8 J/cm 2 intensity facilitated photo stimulation by tissue repair, but failed to show significant tissue hydroxyproline levels in excisional wound model.

  2. Nonlinear optical measurements of conducting copolymers of aniline under CW laser excitation

    Science.gov (United States)

    Pramodini, S.; Poornesh, P.

    2015-08-01

    Synthesis and measurements of third-order optical nonlinearity and optical limiting of conducting copolymers of aniline are presented. Single beam z-scan technique was employed for the nonlinear optical studies. Continuous wave He-Ne laser operating at 633 nm was used as the source of excitation. Copolymer samples exhibited reverse saturable absorption (RSA) process. The nonlinear refraction studies depict that the copolymers exhibit self-defocusing property. The estimated values of βeff, n2 and χ(3) were found to be of the order of 10-2 cm/W, 10-5 esu and 10-7 esu respectively. Self-diffraction rings were observed due to refractive index change when exposed to the laser beam. A good optical limiting and clamping of power of ∼0.9 mW and ∼0.05 mW was observed. Therefore, copolymers of aniline emerge as a potential candidate for photonic device applications.

  3. Non-intrusive, fast and sensitive ammonia detection by laser photothermal deflection

    International Nuclear Information System (INIS)

    Vries, H.S.M. de; Harren, F.J.M.; Wyers, G.P.; Otjes, R.P.; Slanina, J.; Reuss, J.

    1995-01-01

    A recently developed non-intrusive photothermal deflection (PTD) instrument allows sensitive, rapid and quantitative detection of local ammonia concentrations in the air. Ammonia is vibrationally excited by an infrared CO 2 laser in an intracavity configuration. A HeNe beam passing over the CO 2 laser beam (multipass arrangement) is deflected by the induced refractive index gradient. The detection limit for ammonia in ambient air is 0.5 ppbv with a spatial resolution of a few mm 3 . The time resolution is 0.1 s (single line) or 15 s (multi line). The system is fully automated and suited for non-stop measuring periods of at least one week. Results were compared to those obtained with a continuous-flow denuder (CFD). (author)

  4. Hartmann-Shack wave front measurements for real time determination of laser beam propagation parameters

    International Nuclear Information System (INIS)

    Schaefer, B.; Luebbecke, M.; Mann, K.

    2006-01-01

    The suitability of the Hartmann-Shack technique for the determination of the propagation parameters of a laser beam is faced against the well known caustic approach according to the ISO 11146 standard. A He-Ne laser (543 nm) was chosen as test beam, both in its fundamental mode as well as after intentional distortion, introducing a moderate amount of spherical aberration. Results are given for the most important beam parameters M 2 , divergence, and beam widths, indicating an agreement of better than 10% and for adapted beam diameter <5%. Furthermore, the theoretical background, pros and cons, as well as some features of the software implementation for the Hartmann-Shack sensor are briefly reviewed

  5. Effect of seed treatment with low-potency laser in peppers plants (Capsicum annuum L.

    Directory of Open Access Journals (Sweden)

    Alexander Álvarez Fonseca,

    2014-01-01

    Full Text Available The influence of seed treatment with low-potency laser radiation on some physiological parameters and yield of peppers plants, California Wonder variety, was studied. The seeds were irradiated with a laser He- Ne, 25 mW powers, at different exposure periods 5, 10, 20, 30 and 60 seconds, using untreated seeds as controls. We evaluated plant height (mm, root length (mm, stem diameter (mm, polar average diameter (mm equatorial mean diameter (mm, mean fruit mass (g and yield per plant (kg.plant-1. The results showed a significant increase (p?0.001 in the indicators of plants height (50 %, root length (13 %, stem diameter (17 %, equatorial mean diameter (7 %, mean fruit mass (13 % and yield per plant (67 %, compared to control.

  6. Laser effects on the growth and photosynthesis process in mustard plants (Sinapis Alba)

    Science.gov (United States)

    Anghel, Sorin; Stanescu, Constantin S.; Giosanu, Dana; Flenacu, Monica; Iorga-Siman, Ion

    2001-06-01

    In this paper we present the results of our experiments concerning the influence of the low energy laser (LEL) radiation on the germination, growth and photosyntheses processes in mustard plants (sinapis alba). We used a He-Ne laser ((lambda) equals 632.8 nm, P equals 6 mW) to irradiate the mustard seeds with different exposure times. The seeds were sowed and some determinations (the germination and growth intensity, chlorophyll quantity, and respiration intensity) were made on the plant culture. We ascertained that the germination and growth of the plants are influenced by the irradiation. Also, the chlorophyll quantity is the same for both plants from irradiated and non-irradiated seeds but the respiration and photosynthesis processes are influenced by the irradiation.

  7. Absolute distance measurement with extension of nonambiguity range using the frequency comb of a femtosecond laser

    Science.gov (United States)

    Jang, Yoon-Soo; Lee, Keunwoo; Han, Seongheum; Lee, Joohyung; Kim, Young-Jin; Kim, Seung-Woo

    2014-12-01

    We revisit the method of synthetic wavelength interferometry (SWI) for absolute measurement of long distances using the radio-frequency harmonics of the pulse repetition rate of a mode-locked femtosecond laser. Our intention here is to extend the nonambiguity range (NAR) of the SWI method using a coarse virtual wavelength synthesized by shifting the pulse repetition rate. The proposed concept of NAR extension is experimentally verified by measuring a ˜13-m distance with repeatability of 9.5 μm (root-mean-square). The measurement precision is estimated to be 31.2 μm in comparison with an incremental He-Ne laser interferometer. This extended SWI method is found to be well suited for long-distance measurements demanded in the fields of large-scale precision engineering, geodetic survey, and future space missions.

  8. Laser biostimulation of articular cartilage: in vitro evaluation

    Science.gov (United States)

    Jia, Yali; Guo, Zhouyi; Yang, Xiaohong; Zeng, Chang-Chun

    2004-07-01

    In the orthopaedic field, the repair of ariticular cartilage is still a difficult problem, because of the physiological characters of cartilaginous tissues and chondrocytes. To find an effective method of stimulating their regeneration, this in vitro study focuses on the biostimulation of rabbit articular chondrocytes by low-power He-Ne laser. The articular chondrocytes isolated from the cartilage of the medial condyle of the femur of the rabbit were incubated in HamF12 medium. The second passage culture were spread on 24 petri dishes and were irradiated with laser at power density of 2 - 12 mW/cm2 for 6.5 minutes, corresponding to the energy density of 1-6 J/cm2. Laser treatment was performed three times at a 24-hour interval. After lasering, incubation was continued for 24 hours. Non-irradiated cells were kept under the same conditions as the irradiated ones. The cell proliferation activity was evaluated with a XTT colorimetric method. Irradiation of 4 - 6 J/cm2 revealed a considerably higher cell proliferation activity comparing to control cultures. Thereinto, the energy density of 4 and 5 J/cm2 remarkably increased cell growth (P<0.01). The present study showed that a particular laser irradiation stimulates articular chondrocytes proliferation. These findings might be clinically relevant, indicating that low-power laser irradiation treatment is likely to achieve the repair of articular cartilage in clinic.

  9. CSF-2F control apparatus using eddy currents of two frequencies. Case of the Fessenheim 1 exchangers

    International Nuclear Information System (INIS)

    Pigeon, Michel; Saglio, Robert.

    1976-01-01

    The CFS-2F is a control apparatus using eddy currents which, through a proper choice of two frequencies can eliminate non-essential defects given by dimensional variations, plates, dudgeoning, etc... which could hide actual defects. An application of this apparatus for the control of exchanger tubes for Fessenheim 1 is then described [fr

  10. Nonlinear oscillations of the FitzHugh-Nagumo equations under combined external and two-frequency parametric excitations

    International Nuclear Information System (INIS)

    Tatchim Bemmo, D.; Siewe Siewe, M.; Tchawoua, C.

    2011-01-01

    The continuous FitzHugh-Nagumo (FHN for short) model is transformed into modified van der Pol oscillator with asymmetry under external and two-frequency parametric excitations. At the first, the dependence of the solutions on a combined external and two-frequency parametric stimulus forcing is investigated. By using the multiple scale method, ranges of applied current and/or parametric forcing in which nonlinear oscillations are observed are described. Second, when the multiple scale method cannot be used, we numerically prove that in the modified van der Pol oscillator with asymmetry under external and two-frequency parametric excitations, chaos and periodic solution depending on the combination between different frequencies of the model should appear. We also show that the amplitude of the oscillations can be reduced or increased. To do this, we perform the study of the FHN model by choosing a range of parameters exhibiting Hopf bifurcation and two qualitative different regimes in phase portrait. - Highlights: → We model both external and two-frequency parametric excitations in FHN equations. → We examine effects of harmonic forcing on coupled nonlinear oscillator. → Jump and hysteresis phenomena are observed in the dynamical response. → By increasing the constant stimulus we obtain limit cycle. → Some combinations of frequencies produce limit cycle and chaos for other.

  11. Long life gas laser system and method

    International Nuclear Information System (INIS)

    Hochuli, E.E.

    1975-01-01

    A long life gas discharge laser having an improved self-repairing cathode system is described. In a specific embodiment, water vapor having a partial pressure below about 10 -5 torr incorporated in a molecular sieve is used to provide impurities (in this case water vapor) for repairing the cathode surface by regenerating the oxide surface and/or preventing same from deteriorating. Other impurities may be incorporated in the molecular sieve such as hydrogen, oxygen, for example. In some cases CO 2 may be used. This application includes material disclosed in a paper entitled ''Continuation of the Investigation into Material Properties Affecting the Frequency Stability and Reliability of He-Ne Laser Structures'' submitted to the Office of Naval Research dated June 1972 by the inventor hereof and also a paper entitled ''Investigations of the Long Term Frequency Stability of Stable Laser Structures'' Progress Report for ONR Contract N00014-67-A-D239-0016 July 1972 by the inventor hereof. A royalty free license is hereby granted to the United States for use of the invention for all government purposes. (auth)

  12. Effect of liquid film on near-threshold laser ablation of a solid surface

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dongsik; Oh, Bukuk; Lee, Ho

    2004-01-30

    Enhancement of material ablation and photoacoustic excitation by an artificially deposited liquid film in the process of pulsed-laser ablation (PLA) is investigated in this paper. Ablation threshold, ablation rate, surface topography, and acoustic-transient emission are also measured for dry and liquid film-coated surfaces. The physical mechanisms of enhanced ablation in the liquid-assisted process are analyzed at relatively low laser fluences with negligible effect of laser-produced plasma. Particularly, correlation between material ablation and acoustic-transient generation is examined. In the experiment, aluminum thin-films and bulk foils are ablated by Q-switched Nd:YAG laser pulses. The dependence of ablation rate and laser-induced topography on liquid film thickness and chemical composition is also examined. Photoacoustic emission is measured by the probe beam deflection method utilizing a CW HeNe laser and a microphone. In comparison with a dry ablation process, the liquid-assisted ablation process results in substantially augmented ablation efficiency and reduced ablation threshold. The results indicate that both increased laser-energy coupling, i.e., lowered reflectance, and amplified photoacoustic excitation in explosive vaporization of liquid are responsible for the enhanced material ablation.

  13. Investigation of collisional excitation-transfer processes in a plasma by laser perturbation method

    International Nuclear Information System (INIS)

    Sakurai, Takeki

    1983-01-01

    The theoretical background and the experimental method of the laser perturbation method applied to the study of collisional excitation transfer process in plasma are explained. The atomic density at some specified level can be evaluated theoretically. By using the theoretical results and the experimentally obtained data, the total attenuation probability, the collisional transfer probability and natural emission probability were estimated. For the experiments, continuous wave laser (cw) and pulse laser are employed. It is possible by using pulse dye laser to observe the attenuation curve directly, and to bring in resonance to any atomic spectra. At the beginning, the experimental studies were made on He-Ne discharge. The pulse dye laser has been used for the excitation of alkali atoms. The first application of pulse laser to the study of plasma physics was the study on He. The cross section of disalignment has also been studied by the laser perturbation. The alignment of atoms, step and cascade transfer, the confinement of radiation and optogalvanic effect are discussed in this paper. (Kato, T.)

  14. Treatment of Infantile Diarrhea by Acupuncture and Laser Irradiation - A Report of 60 Cases

    Institute of Scientific and Technical Information of China (English)

    丁渡明

    2004-01-01

    @@ Infantile diarrhea is a common disease in babies of less than 2 years old in summer or autumn. It is due to acute dyspepsia mainly caused by improper feeding or attack of cold or damp pathogens.Clinically, it is characterized by increased times of defecation (5-6, or even dozens of times a day),yellow-green or blue-green thin feces intermingled with mucus, milk-mass and indigested food which have a sour and fetid odor, accompanied with loss of appetite, abdominal distending pain, nausea,vomiting, and even fever, irritability, dehydration and electrolyte disturbance in severe cases. The microscopy reveals that there are leukocytes and fat globules in feces. We have treated 60 cases of infantile diarrhea with acupuncture and He-Ne laser point irradiation and obtained satisfactory therapeutic results.

  15. Observation of plasma motion in a coaxial plasma opening switch with a chordal laser interferometer

    International Nuclear Information System (INIS)

    Teramoto, Y.; Urakami, H.; Akiyama, H.; Kohno, S.; Katsuki, S.

    2002-01-01

    Electron densities in a coaxial plasma opening switch were measured at many lines-of-slight. In the present experiment, electron density was measured by a He-Ne laser interferometer with chordal lines-of sight. In order to observe the motion of the POS plasma, the electron density contours during the conduction, opening and post-opening phases were drawn by combining the results of interferometer experiments. The radial and axial motion of POS plasma was investigated from the density contours. As conduction time progressed, the POS plasma moved toward downstream. At 800 ns, which corresponds to the time of opening in the current waveform, low-density region less than 10 15 cm -2 is seen at 10 mm from the cathode. After the opening was completed, the low-density gap disappeared and the shape of the corn-shape-like plasma was distorted. (author)

  16. Surface roughness studies with DALLAS-detector array for laser light angular scattering

    Science.gov (United States)

    Vorburger, T. V.; Teague, E. C.; Scire, F. E.; Mclay, M. J.; Gilsinn, D. E.

    1984-01-01

    An attempt is made to develop a better mathematical description of optical scattering phenomena, in order to construct an optical scattering apparatus for reliable and routine measurements of roughness parameters without resorting to comparator standards. After a brief outline of optical scattering theory, a description is presented of an experimental instrument for measuring surface roughness which incorporates optical scattering principles. The instrument has a He-Ne laser which illuminates the test surface at a variable angle of incidence. Scattered light distribution is detected by an array of 87 fiber-optic sensors positioned in a rotating semicircular yoke. The output from the detector is digitized and analyzed in a laboratory computer. For a comparison with experimental data, theoretical distributions are calculated by substituting the roughness profiles into the operand of and integral equation for electromagnetic scattering developed by Beckmann and Spizzichino (1963). A schematic diagram of the instrument is provided and the general implications of the experimental results are discussed.

  17. Observation of plasma motion in a coaxial plasma opening switch with a chordal laser interferometer

    Energy Technology Data Exchange (ETDEWEB)

    Teramoto, Y.; Urakami, H.; Akiyama, H. [Kumamoto Univ., Graduate School of Science and Technology, Kumamoto (Japan); Kohno, S. [Ariake National College of Technology, Dept. of Electrical Engineering, Fukuoka (Japan); Katsuki, S. [Kumamoto Univ., Dept. of Electrical and Computer Engineering, Kumamoto (Japan)

    2002-06-01

    Electron densities in a coaxial plasma opening switch were measured at many lines-of-slight. In the present experiment, electron density was measured by a He-Ne laser interferometer with chordal lines-of sight. In order to observe the motion of the POS plasma, the electron density contours during the conduction, opening and post-opening phases were drawn by combining the results of interferometer experiments. The radial and axial motion of POS plasma was investigated from the density contours. As conduction time progressed, the POS plasma moved toward downstream. At 800 ns, which corresponds to the time of opening in the current waveform, low-density region less than 10{sup 15} cm{sup -2} is seen at 10 mm from the cathode. After the opening was completed, the low-density gap disappeared and the shape of the corn-shape-like plasma was distorted. (author)

  18. Two-frequency method for measuring Hall emf in high-resistive materials with charge-carrier low mobility

    International Nuclear Information System (INIS)

    Aleksandrov, A.L.; Vedeneev, A.S.; Gulyaev, I.B.; Zhdan, A.G.

    1982-01-01

    A facility for measuring Hall emf in high-resistive materials with low mobility of charge carriers by the two-frequency method using digital synchronous integration is described. The facility permits to detect the minimum Hall emf approxamatety equat to 5 μV at approximatety equal to 1 T Ohm of the investigated.sample resistance during the measuring time of approximately equal to 2000 s. Sensitivity by Hall mobility makes up >= 0.01 cm 2 /Vxs at the same measuring time. Measuring results of the Hall emf on GaAs monocrystals, CdSe films and island film of gold are presented

  19. Effect of single-dose low-level helium-neon laser irradiation on orthodontic pain: a split-mouth single-blind placebo-controlled randomized clinical trial.

    Science.gov (United States)

    Sobouti, Farhad; Khatami, Maziar; Chiniforush, Nasim; Rakhshan, Vahid; Shariati, Mahsa

    2015-01-01

    Pain is the most common complication of orthodontic treatment. Low-level laser therapy (LLLT) has been suggested as a new analgesic treatment free of the adverse effects of analgesic medications. However, it is not studied thoroughly, and the available studies are quite controversial. Moreover, helium neon (He-Ne) laser has not been assessed before. This split-mouth placebo-controlled randomized clinical trial was performed on 16 male and 14 female orthodontic patients requiring bilateral upper canine retraction. The study was performed at a private clinic in Sari, Iran, in 2014. It was single blind: patients, orthodontist, and personnel were blinded of the allocations, but the laser operator (periodontist) was not blinded. Once canine retractor was activated, a randomly selected maxillary quarter received a single dose of He-Ne laser irradiation (632.8 nm, 10 mw, 6 j/cm(2) density). The other quarter served as the placebo side, treated by the same device but powered off. In the first, second, fourth, and seventh days, blinded patients rated their pain sensed on each side at home using visual analog scale (VAS) questionnaires. There was no harm identified during or after the study. Pain changes were analyzed using two- and one-way repeated-measures ANOVA, Bonferroni, and t-test (α = 0.01, β > 0.99). This trial was not registered. It was self-funded by the authors. Sixteen males and 11 females remained in the study (aged 12-21). Average pain scores sensed in all 4 intervals on control and laser sides were 4.06 ± 2.85 and 2.35 ± 1.77, respectively (t-test P < 0.0001). One-way ANOVA showed significant pain declines over time, in each group (P < 0.0001). Two-way ANOVA showed significant effects for LLLT (P < 0.0001) and time (P = <0.0001). Single-dose He-Ne laser therapy might reduce orthodontic pain caused by retracting maxillary canines.

  20. Theoretical and practical aspects of pre-sowing laser biostimulation of the seeds

    International Nuclear Information System (INIS)

    Gładyszewska, B.; Kornas-Czuczwar, B.; Koper, R.; Lipski, S.

    1998-01-01

    Against the background of recent literature review basic aspects of the mechanism responsible for pre-sowing laser bio-stimulation of the seeds were discussed. Developed by professor W. Sedlak theory of bioplasma was the main point of reference. Presented results of own research works proved the positive influence of pre-sowing laser treatment of seeds on their yielding and nutritive value. The yield rises caused by pre-sowing laser seed bio-stimulation for some examined plant crops were as follows: maize (from 10 to 15%), spring wheat (from 20 to 30%), spring barley (from 20 to 25%), sugar beets (from 10 to 30%), rape seeds (from 10 to 15%). The quality of crops frawn from the laser treated seeds was also better than the control ones. For example, the protein content in grain of spring wheat grown from the seeds bio-stimulated with a the He-Ne laser increased from about 12 up to 14%. Similarly, in roots of the sugar beets grown from laser treated seeds, the sugar content rose from about 15 up to about 17% [pl

  1. Degradation of polyimide by 100 keV He+, Ne+, Ar+ and Kr+ ions

    Czech Academy of Sciences Publication Activity Database

    Hnatowicz, Vladimír; Peřina, Vratislav; Macková, Anna; Švorčík, V.; Rybka, V.; Fink, V.; Heitz, J.

    2001-01-01

    Roč. 175, - (2001), s. 437-441 ISSN 0168-583X R&D Projects: GA ČR GA203/99/1626; GA AV ČR IAA7011908; GA AV ČR KSK1010104 Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.041, year: 2001

  2. Bending , Heating and Pressure Effects of He-Ne Laserin Single Mode Fiber

    Directory of Open Access Journals (Sweden)

    Nizar Salim Shnan

    2017-12-01

    Full Text Available In this paper a single mode fiber have been chosen with a refractive index (1.50 to the core, and (1.485 to the cladding, with length of (2 m. It was exposed this optical fiber to a bending with different diameters, and to a different temperatures as well as pressure due to putting different weights to study dispersion phenomenon which affects on a pulse shape that travels in optical fiber. Experimental results explain when a bending diameter for an optical fiber increases it will decrease the dispersion and pulse shape will approximate from a Gaussian shape , and the increasing in temperature will increasing  the attenuation in the pulse transfer through the optical fiber .                                                                                                 But when increasing pressure, the dispersion will increases and the pulse shape will be distorted

  3. A noncontact laser system for measuring soil surface topography

    International Nuclear Information System (INIS)

    Huang, C.; White, I.; Thwaite, E.G.; Bendeli, A.

    1988-01-01

    Soil surface topography profoundly influences runoff hydrodynamics, soil erosion, and surface retention of water. Here we describe an optical noncontact system for measuring soil surface topography. Soil elevation is measured by projecting a laser beam onto the surface and detecting the position of the interception point. The optical axis of the detection system is oriented at a small angle to the incident beam. A low-power HeNe (Helium-Neon) laser is used as the laser source, a photodiode array is used as the laser image detector and an ordinary 35-mm single lens reflex camera provides the optical system to focus the laser image onto the diode array. A wide spectrum of measurement ranges (R) and resolutions are selectable, from 1 mm to 1 m. These are determined by the laser-camera distance and angle, the focal length of the lens, and the sensing length of the diode array and the number of elements (N) contained in the array. The resolution of the system is approximately R/2N. We show for the system used here that this resolution is approximately 0.2%. In the configuration selected, elevation changes of 0.16 mm could be detected over a surface elevation range of 87 mm. The sampling rate of the system is 1000 Hz, which permits soil surfaces to be measured at speeds of up to 1 m s −1 with measurements taken at 1-mm spacing. Measurements of individual raindrop impacts on the soil and of soil surfaces before and after rain show the versatility of the laser surface profiler, which has applications in studies of erosion processes, surface storage and soil trafficability

  4. Os efeitos do laser hélio-neônio de baixa intensidade na cicatrização de lesões cutâneas induzidas em ratos Effects of low-level helium-neon laser on induced wound healing in rats

    Directory of Open Access Journals (Sweden)

    Viviane L. Busnardo

    2010-02-01

    Full Text Available OBJETIVO: Avaliar os efeitos do laser de baixa potência hélio e neônio (HeNe na cicatrização de feridas cutâneas de ratos. MÉTODOS: Sessenta ratos Wistar foram divididos em grupos controle e experimento. Utilizou-se ferida incisional, longitudinal, dorso-mediana, suturada com pontos separados simples. No grupo experimento, as feridas foram irradiadas diariamente com aparelho de laser de HeNe com potência contínua máxima de 5mW, comprimento de onda de 632,8 nm, visível com densidade de energia de 4J/cm², área de raio do laser de 0,015cm², durante 36 segundos, em três pontos da lesão. As feridas foram avaliadas no 3º, no 7º e no 14º dia de pós-operatório. Cortes histológicos foram corados com hematoxilina-eosina (H&E e avaliados segundo protocolo de Vizzotto et al. (2003* para identificar o tipo de reação inflamatória e com Picrosirius para identificar os colágenos I e III e o índice de maturidade da cicatriz (IMaC. Utilizou-se imunoistoquímica com anti-CD45-LCA para o reconhecimento das células inflamatórias. RESULTADOS: Ambos os grupos mostraram o mesmo padrão inflamatório. No grupo experimento, observaram-se menos células inflamatórias nos três tempos estudados (pOBJECTIVE: To evaluate the effects of low-level helium-neon (HeNe laser on cutaneous wound healing in rats. METHODS: Sixty Wistar rats were divided into control group and experimental group. A sutured longitudinal, dorsal-medial incision was made, with simple separate stitches. The experimental group was irradiated daily in three areas of the wound with HeNe laser (5mW maximum continuous power, 632.8 nm wavelength, 4 J/cm² energy density and 0.015 cm² laser beam area for 36 seconds. The areas were evaluated on the third, seventh and fourteenth days postoperative. Histological sections were stained with hematoxylin-eosin to determine the type of inflammatory reaction according to the protocol by Vizzotto et al. (2003* and with Picrosirius to identify

  5. UV laser incorporation of dopants in silicon: comparison of two processes

    International Nuclear Information System (INIS)

    Fogarassy, E.P.; Narayan, J.; Lowndes, D.H.; White, C.H.

    1985-01-01

    The rapid deposition of pulsed-laser energy into the near-surface region of silicon leads to melting of crystal, followed by liquid phase epitaxial regrowth from the underlying substrate at a growth velocity of several meters per second. During rapid solidification, implanted or deposited group III and V impurities can be incorporated into substitutional sites in the silicon lattice with concentrations far in excess of their equilibrium solubility limit. The authors have investigated and compared the incorporation of implanted or deposited antimony into the silicon lattice during laser annealing with a pulsed KrF UV laser (lambda = 0.249 μm, Z = 35 ns). The surface melting dynamics resulting from laser irradiation have been studied by time-resolved reflectivity. In the two cases, the sharp transition to the high reflectivity phase (R = 72%, at lambda = 0.633 μm of the HeNe laser probe) is characteristic of molten silicon. Surface melt durations measured on implanted Sb (150 KeV, 5 x 10 16 cm -2 ) and deposited Sb (80 A thick on crystalline silicon) are significantly larger than those for virgin silicon

  6. CO-ANALYSIS OF SOLAR MICROWAVE AND HARD X-RAY SPECTRAL EVOLUTIONS. I. IN TWO FREQUENCY OR ENERGY RANGES

    International Nuclear Information System (INIS)

    Song Qiwu; Huang Guangli; Nakajima, Hiroshi

    2011-01-01

    Solar microwave and hard X-ray spectral evolutions are co-analyzed in the 2000 June 10 and 2002 April 10 flares, and are simultaneously observed by the Owens-Valley Solar Array in the microwave band and by Yohkoh/Hard X-ray Telescope or RHESSI in the hard X-ray band, with multiple subpeaks in their light curves. The microwave and hard X-ray spectra are fitted by a power law in two frequency ranges of the optical thin part and two photon energy ranges, respectively. Similar to an earlier event in Shao and Huang, the well-known soft-hard-soft pattern of the lower energy range changed to the hard-soft-hard (HSH) pattern of the higher energy range during the spectral evolution of each subpeak in both hard X-ray flares. This energy dependence is actually supported by a positive correlation between the overall light curves and spectral evolution in the lower energy range, while it becomes an anti-correlation in the higher energy range. Regarding microwave data, the HSH pattern appears in the spectral evolution of each subpeak in the lower frequency range, which is somewhat similar to Huang and Nakajima. However, it returns back to the well-known pattern of soft-hard-harder for the overall spectral evolution in the higher frequency range of both events. This frequency dependence is confirmed by an anti-correlation between the overall light curves and spectral evolution in the lower frequency range, but it becomes a positive correlation in the higher frequency range. The possible mechanisms are discussed, respectively, for reasons why hard X-ray and microwave spectral evolutions have different patterns in different energy and frequency intervals.

  7. An in vitro study of the effects of low-level laser radiation on human blood

    Science.gov (United States)

    Siposan, Dan G.; Lukacs, Adalbert

    2003-12-01

    In the last time the study of the effects of LLLR on the blood is considered to be a subject of great importance in elucidating the mechanisms of action between LLLR and biologic tissues. Different methods of therapy by blood irradiation have been developed and used in clinical purposes with benefic effects. This study investigates some in vitro effects of LLLR on some selected rheologic indices of human blood. After establishing whether or not damaging effects could appear due to laser irradiation of the blood, we tried to find a new method for rejuvenating the blood preserved in MacoPharma-type bags. Blood samples were obtained from adult regular donors (volunteers). HeNe laser and laser diodes were used as radiation source, in a wide range of wavelengths, power densities, doses and other parameters of irradiation protocol. In the first series of experiments we established that LLLR does not alter the fresh blood from healthy donors, for doses between 0 and 10 J/cm3 and power densities between 30 and 180 mW/cm3. In the second series of experiments we established that LLLR does have, in some specific conditions, a revitalizing effect on the erythrocytes in preserved blood. We concluded that laser irradiation of the preserved blood, following a selected protocol of irradiation, could be used as a new method to improve the performances of preservation: prolonging the period of storage and blood rejuvenation before transfusion.

  8. Investigations of the potential functions of weakly bound diatomic molecules and laser-assisted excitive Penning ionization

    International Nuclear Information System (INIS)

    Goble, J.H. Jr.

    1982-05-01

    Three variations on the Dunham series expansion function of the potential of a diatomic molecule are compared. The differences among these expansions lie in the choice of the expansion variable, lambda. The functional form of these variables are lambda/sub s/ = l-r/sub e//r for the Simon-Parr-Finlan version, lambda/sub T/ - 1-(r/sub e//r)/sup p/ for that of Thakkar, and lambda/sub H/ = 1-exp(-rho(r/r/sub e/-1) for that of Huffaker. A wide selection of molecular systems are examined. It is found that, for potentials in excess of thirty kcal/mole, the Huffaker expansion provides the best description of the three, extrapolating at large internuclear separation to a value within 10% of the true dissociation energy. For potentials that result from the interaction of excited states, all series expansions show poor behavior away from the equilibrium internuclear separation of the molecule. The series representation of the potentials of weakly bound molecules are examined in more detail. The ground states of BeAr + , HeNe + , NaAr, and Ar 2 and the excited states of HeNe+, NaNe, and NaAr are best described by the Thakkar expansion. Finally, the observation of laser-assisted excitive Penning ionization in a flowing afterglow is reported. The reaction Ar( 3 P 2 ) + Ca + h nu → Ar + Ca + (5p 2 P/sub J/) + e - occurs when the photon energy, h nu, is approximately equal to the energy difference between the metastable argon and one of the fine structure levels of the ion's doublet. By monitoring the cascade fluorescence of the above reaction and comparing it to the flourescence from the field-free process Ar( 3 P 2 ) + Ca → Ar + Ca + (4p 2 P/sub J/) + e - a surprisingly large cross section of 6.7 x 10 3 A 2 is estimated

  9. The development of laser surgery and medicine in China

    Science.gov (United States)

    Chen, Mingzhe

    2005-07-01

    acne scar, osmidrosis etc. For ophthalmology, excimer laser are used for myopia or hyperopia; argon green laser, krypton yellow laser are adopted in coagulation for retinal detachment and neovascularization etc. Lasers are often used for the canaliculoplasty in the lacrimal canal. Low level lasers had been used very often on the acupuncture points and for many chronic diseases. Intravascular low level laser irradiation adopting semiconductor lasers and He-Ne laser were reported to use for comatose patients, schizophrenia, vascular dementia, Alzeimer"s disease and coronary disease. Reports from laboratory studies in the field of low level laser demonstrated the stimulation effect on the cells and immunology system; inhibitory effect on proliferation; it improved the biomedical data in hemorrheology; promoted the spinal motor nerve cell function, axonal regeneration; increased epidermal Langerhams cell to improve the antigen function, increased myocardial capillary permeability. Intra-coronary low power red laser irradiation assisted coronary interventional therapy showed its prevention effect on restenosis. Studies about the effects of various kinds of lasers, their wavelength, power densities and doses on various kinds of tissues were reported.

  10. Efficient plasma and bubble generation underwater by an optimized laser excitation and its application for liquid analyses by laser-induced breakdown spectroscopy

    International Nuclear Information System (INIS)

    Lazic, Violeta; Jovicevic, Sonja; Fantoni, Roberta; Colao, Francesco

    2007-01-01

    Laser-induced breakdown spectroscopy (LIBS) measurements were performed on bulk water solutions by applying a double-pulse excitation from a Q-Switched (QS) Nd:YAG laser emitting at 1064 nm. In order to optimize the LIBS signal, laser pulse energies were varied through changing of the QS trigger delays with respect to the flash-lamp trigger. We had noted that reduction of the first pulse energy from 92 mJ to 72 mJ drastically improves the signal, although the second pulse energy was also lowered from 214 mJ to 144 mJ. With lower pulse energies, limit of detection (LOD) for Mg in pure water was reduced for one order of magnitude (34 ppb instead of 210 ppb). In order to explain such a phenomenon, we studied the dynamics of the gas bubble generated after the first laser pulse through measurements of the HeNe laser light scattered on the bubble. The influence of laser energy on underwater bubble and plasma formation and corresponding plasma emission intensity were also studied by photographic technique. From the results obtained, we conclude that the optimal first pulse energy should be kept close to the plasma elongation threshold, in our case about 65 mJ, where the gas bubble has its maximum lateral expansion and the secondary plasma is still well-localized. The importance of a multi-pulse sequence on the LIBS signal was also analyzed, where the pulse sequence after the first QS aperture was produced by operating the laser close to the lasing threshold, with the consequent generation of relaxation oscillations. Low-energy multi-pulses might keep the bubble expansion large prior to the probing pulse, but preventing the formation of secondary weak plasmas in multiple sites, which reduces the LIBS signal. The short interval between the pre-pulses and the probing pulse is another reason for the observed LIBS signal enhancement

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

    Science.gov (United States)

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

    2000-05-01

    Laser irradiation of hyaline cartilage result in stable shape changes due to temperature dependent stress relaxation. In this study, we determined the structural changes in chondrocytes within porcine nasal septal cartilage tissue over a 4-day period using a two-photon laser scanning microscope (TPM) following Nd:YAG laser irradiation (lambda equals 1.32 micrometer) using parameters that result in mechanical stress relaxation (6.0 W, 5.4 mm spot diameter). TPM excitation (780 nm) result in induction of fluorescence from endogenous agents such as NADH, NADPH, and flavoproteins in the 400 - 500 nm spectral region. During laser irradiation diffuse reflectance (from a probe HeNe laser, (lambda) equals 632.8 nm), surface temperature, and stress relaxation were measured dynamically. Each specimen received one, two, or three sequential laser exposures (average irradiation times of 5, 6, and 8 seconds). The cartilage reached a peak surface temperature of about 70 degrees Celsius during irradiation. Cartilage denatured in 50% EtOH (20 minutes) was used as a positive control. TPM was performed using a mode-locked 780 nm Titanium:Sapphire (Ti:Al203) beam with a, 63X, 1.2 N.A. water immersion objective (working distance of 200 mm) to detect the fluorescence emission from the chondrocytes. Images of chondrocytes were obtained at depths up to 150 microns (lateral resolution equals 35 micrometer X 35 micrometer). Images were obtained immediately following laser exposure, and also after 4 days in culture. In both cases, the irradiated and non-irradiated specimens do not show any discernible difference in general shape or auto fluorescence. In contrast, positive controls (immersed in 50% ethanol), show markedly increased fluorescence relative to both the native and irradiated specimens, in the cytoplasmic region.

  12. Effects of Near-Infrared Laser on Neural Cell Activity

    International Nuclear Information System (INIS)

    Mochizuki-Oda, Noriko; Kataoka, Yosky; Yamada, Hisao; Awazu, Kunio

    2004-01-01

    Near-infrared laser has been used to relieve patients from various kinds of pain caused by postherpetic neuralgesia, myofascial dysfunction, surgical and traumatic wound, cancer, and rheumatoid arthritis. Clinically, He-Ne (λ=632.8 nm, 780 nm) and Ga-Al-As (805 ± 25 nm) lasers are used to irradiate trigger points or nerve ganglion. However the precise mechanisms of such biological actions of the laser have not yet been resolved. Since laser therapy is often effective to suppress the pain caused by hyperactive excitation of sensory neurons, interactions with laser light and neural cells are suggested. As neural excitation requires large amount of energy liberated from adenosine triphosphate (ATP), we examined the effect of 830-nm laser irradiation on the energy metabolism of the rat central nervous system and isolated mitochondria from brain. The diode laser was applied for 15 min with irradiance of 4.8 W/cm2 on a 2 mm-diameter spot at the brain surface. Tissue ATP content of the irradiated area in the cerebral cortex was 19% higher than that of the non-treated area (opposite side of the cortex), whereas the ADP content showed no significant difference. Irradiation at another wavelength (652 nm) had no effect on either ATP or ADP contents. The temperature of the brain tissue was increased 4.5-5.0 deg. C during the irradiation of both 830-nm and 652-nm laser light. Direct irradiation of the mitochondrial suspension did not show any wavelength-dependent acceleration of respiration rate nor ATP synthesis. These results suggest that the increase in tissue ATP content did not result from the thermal effect, but from specific effect of the laser operated at 830 nm. Electrophysiological studies showed the hyperpolarization of membrane potential of isolated neurons and decrease in membrane resistance with irradiation of the laser, suggesting an activation of potassium channels. Intracellular ATP is reported to regulate some kinds of potassium channels. Possible mechanisms

  13. Low energy helium-neon laser prevents oral mucositis after high-dose chemo-radiotherapy: results of a double-blind randomized trial

    International Nuclear Information System (INIS)

    Cowen, Didier; Tardieu, Corinne; Resbeut, Michel; Hannoun-Levi, Jean-Michel; Alzieu, Claude; Schubert, Marc; Franquin, Jean-Claude

    1996-01-01

    Purpose: To evaluate the efficiency of Helium-Neon (He-Ne) laser in the prevention of oral mucositis (OM) induced by high dose chemoradiotherapy before bone marrow transplantation (BMT). Methods and materials: Between 1993 and 1995, 30 consecutive patients (pts) receiving an autologous peripheral stem-cell or bone marrow transplant (BMT) after high dose chemoradiotherapy were randomized to receive or not prophylactic laser applications to the oral mucosa. Chemotherapy consisted of cyclophosphamide, 60 mg/kg intravenously (IV) on day (d)-5 and d-4 in 27 cases, or melphalan 140 mg/kg IV on d-4 in 3 cases. Total body irradiation consisted of 12 Gy midplane dose in six fractions and 3 days. He-Ne laser (632.8 nm wavelength, power 60 mW) applications were performed daily from d-5 to d-1 on 5 anatomic sites of the oral mucosa. Oral examination was performed daily from d0 to d+20. Mucositis was scored according to an oral exam guide with a 16 items scale of which 4 were assessed by the pts themselves. Mean daily scores of pain, ability to swallow and saliva production were measured. A daily mucositis index (DMI) and a cumulative score of oral mucositis (CSOM) were established. Requirement for narcotics and parenteral nutrition were measured. Validation of the grading scale was carried out using the Cronbach alpha coefficient for the internal validation and the test-retest correlation coefficient for the reproducibility analysis. The U Mann Whitney test was used to test for differences among groups. Patients were assigned to either laser treatment (L+) or sham-treatment (L-) by computer blocked randomization. Results: No pt was excluded for failure to complete the laser application protocol. Laser applications were well tolerated and no side effects were reported. The items were highly interrelated as well as the index considered as a whole: over 21 days, α = 0.97. Reproducibility analysis between the nurses in charge with the oral examination showed a significant

  14. Plasma measurement by feedback-stabilized dual-beam laser interferometer

    International Nuclear Information System (INIS)

    Yasuda, Akio; Kawahata, Kazuo; Kanai, Yasubumi.

    1982-03-01

    The plasma density in a dynamic magneto arcjet is measured by a stabilized dual-beam laser interferometer proposed by the authors. The fringe shift for a 0.63 μm beam of He-Ne laser is used to stabilize the interferometer against the effect of mechanical vibration by means of a feedback controlled speaker coil, while the other beam of 3.39 μm, for which the effect of mechanical vibrations is excluded, is used to measure plasma density. Stability of --1/500 of one fringe for 0.63 μm is obtained during a long period for frequencies lower than a few Hertz. Stability for higher frequencies, which determines the accuracy of the present measurement, is limited to --1/30 of one fringe for 0.63 μm, which corresponds to --1/200 of one fringe and a line electron density of --1.5 x 10 14 cm - 2 for 3.39 μm, by acoustic noise picked up by the speaker coil. The advantage of this technique over the single-laser technique is that the frequency response of the interferometer extends down to zero frequency. Since the effect of the neutral gas background is practically reduced to zero, the present interferometer is to be applied advantageously to the diagnostics of the plasma produced in high pressure gases. (author)

  15. A laser scanner for imaging fluorophore labeled molecules in electrophoretic gels

    Energy Technology Data Exchange (ETDEWEB)

    Fisk, D.J.; Sutherland, J.C. [Brookhaven National Lab., Upton, NY (United States). Biology Dept.

    1995-08-01

    A laser scanner for imaging electrophoretic gels was constructed and tested. The scanner incorporates a green helium-neon (HeNe) laser (543.5nm wavelength) and can achieve a spatial resolution of 19{micro}m. The instrument can function in two modes : snap-shot and finish-line. In snapshot mode, all samples are electrophoresed for the same time and the gel is scanned after completion of electrophoresis, while in finish-line mode, fluorophore labeled samples are electrophoresed for a constant distance and the image is formed as the samples pass under the detector. The resolving power of the finish-line mode of imaging is found to be greater than that of the snapshot mode of imaging. This laser scanner is also compared with a Charge Coupled Device (CCD) camera and in terms of resolving power is found to be superior. Sensitivity of the instrument is presented in terms of the minimum amount of DNA that can be detected verses its molecular length.

  16. Vegetation Detection in Stress of Moisture Shortage Based on Laser Speckle Recognition

    Science.gov (United States)

    Ishizawa, Hiroaki; Matsuo, Tsukasa; Miki, Takashi

    This paper describes a new measuring method of plant vigor by using Laser speckle pattern. Furthermore, this proposes a practical application of this presented measurement system. The measuring instrument is consisted by a He-Ne Laser as the light source, and a set of optics, such as reflectors, a beam expander. The speckle pattern could be measured by a CCD camera through lenses. A Pothos (Epiremnum aureum) and Japanese morning glory (Ipomoea nil) were used as the sample plant. Their intact leaves were measured the speckle pattern images. Visible but small vigor veins could be clearly observed in the images obtained by the speckle patterns. On the other hand, withered ones have shown different images. The relationship has been obtained between the feature of the images and the chlorophyll degradation. It would be expected that the symptom of plant against some stress could be detected by measuring the Laser speckle pattern. It could be used as the sensor of the field server system at every field monitoring site.

  17. A primary standard for low-g shock calibration by laser interferometry

    Science.gov (United States)

    Sun, Qiao; Wang, Jian-lin; Hu, Hong-bo

    2014-07-01

    This paper presents a novel implementation of a primary standard for low-g shock acceleration calibration by laser interferometry based on rigid body collision at National Institute of Metrology, China. The mechanical structure of the standard device and working principles involved in the shock acceleration exciter, laser interferometers and virtual instruments are described. The novel combination of an electromagnetic exciter and a pneumatic exciter as the mechanical power supply of the standard device can deliver a wide range of shock acceleration levels. In addition to polyurethane rubber, two other types of material are investigated to ensure a wide selection of cushioning pads for shock pulse generation, with pulse shapes and data displayed. A heterodyne He-Ne laser interferometer is preferred for its precise and reliable measurement of shock acceleration while a homodyne one serves as a check standard. Some calibration results of a standard acceleration measuring chain are shown in company with the uncertainty evaluation budget. The expanded calibration uncertainty of shock sensitivity of the acceleration measuring chain is 0.8%, k = 2, with the peak acceleration range from 20 to 10 000 m s-2 and pulse duration from 0.5 to 10 ms. This primary shock standard can meet the traceability requirements of shock acceleration from various applications of industries from automobile to civil engineering and therefore is used for piloting the ongoing shock comparison of Technical Committee of Acoustics, Ultrasound and Vibration (TCAUV) of Asia Pacific Metrology Program (APMP), coded as APMP.AUV.V-P1.

  18. Optical response of laser-doped silicon carbide for an uncooled midwave infrared detector.

    Science.gov (United States)

    Lim, Geunsik; Manzur, Tariq; Kar, Aravinda

    2011-06-10

    An uncooled mid-wave infrared (MWIR) detector is developed by doping an n-type 4H-SiC with Ga using a laser doping technique. 4H-SiC is one of the polytypes of crystalline silicon carbide and a wide bandgap semiconductor. The dopant creates an energy level of 0.30  eV, which was confirmed by optical spectroscopy of the doped sample. This energy level corresponds to the MWIR wavelength of 4.21  μm. The detection mechanism is based on the photoexcitation of electrons by the photons of this wavelength absorbed in the semiconductor. This process modifies the electron density, which changes the refractive index, and, therefore, the reflectance of the semiconductor is also changed. The change in the reflectance, which is the optical response of the detector, can be measured remotely with a laser beam, such as a He-Ne laser. This capability of measuring the detector response remotely makes it a wireless detector. The variation of refractive index was calculated as a function of absorbed irradiance based on the reflectance data for the as-received and doped samples. A distinct change was observed for the refractive index of the doped sample, indicating that the detector is suitable for applications at the 4.21  μm wavelength.

  19. Dynamics of laser ablative shock waves from one dimensional periodic structured surfaces

    Science.gov (United States)

    Paturi, Prem Kiran; Chelikani, Leela; Pinnoju, Venkateshwarlu; Acrhem Team

    2015-06-01

    Spatio-temporal evolution of Laser ablative shock waves (LASWs) from one dimensional periodic structured surfaces (1D-PSS) of Aluminum is studied using time resolved defocused shadowgraphy technique. LASWs are generated by focusing 7 ns pulses from second harmonic of Nd:YAG (532 nm, 10 Hz) laser on to 1D-PSS with sinusoidal and triangular modulations of varying periodicity. An expanded He-Ne laser (632.8 nm) is used as probe beam for shadowgraphy. Evolution of ablative shock front (SF) with 1.5 ns temporal resolution is used to measure position of the SF, its nature, density and pressure behind the SF. The effect of surface modulation on the LASW and contact front dynamics was compared to those from a flat surface (FS) of Aluminum. SWs from FS and PSS obeyed Taylor's solution for spherical and planar nature, respectively. The velocity of SF from 1D PSS had a twofold increase compared to the FS. This was further enhanced for structures whose periodicity is of the order of excitation wavelength. Variation of SF properties with varying periodicity over a range of 3.3 μm to 0.55 μm has the potential to tailor shockwaves of required parameters. The work is supported by Defence Research and Developement Organization, India through Grants-in-Aid Program. The periodic surfaces were procured with financial support from BRFST project No. NFP-MAT-A12-04.

  20. Laser Raman Spectroscopy with Different Excitation Sources and Extension to Surface Enhanced Raman Spectroscopy

    Directory of Open Access Journals (Sweden)

    Md. Wahadoszamen

    2015-01-01

    Full Text Available A dispersive Raman spectrometer was used with three different excitation sources (Argon-ion, He-Ne, and Diode lasers operating at 514.5 nm, 633 nm, and 782 nm, resp.. The system was employed to a variety of Raman active compounds. Many of the compounds exhibit very strong fluorescence while being excited with a laser emitting at UV-VIS region, hereby imposing severe limitation to the detection efficiency of the particular Raman system. The Raman system with variable excitation laser sources provided us with a desired flexibility toward the suppression of unwanted fluorescence signal. With this Raman system, we could detect and specify the different vibrational modes of various hazardous organic compounds and some typical dyes (both fluorescent and nonfluorescent. We then compared those results with the ones reported in literature and found the deviation within the range of ±2 cm−1, which indicates reasonable accuracy and usability of the Raman system. Then, the surface enhancement technique of Raman spectrum was employed to the present system. To this end, we used chemically prepared colloidal suspension of silver nanoparticles as substrate and Rhodamine 6G as probe. We could observe significant enhancement of Raman signal from Rhodamine 6G using the colloidal solution of silver nanoparticles the average magnitude of which is estimated to be 103.

  1. Low energy helium-neon laser in the prevention of oral mucositis in patients undergoing bone marrow transplant: results of a double blind randomized trial

    International Nuclear Information System (INIS)

    Cowen, Didier; Tardieu, Corrine; Schubert, Mark; Peterson, Douglas; Resbeut, Michel; Faucher, Catherine; Franquin, Jean-Claude

    1997-01-01

    Purpose: To evaluate the efficiency of Helium-Neon (He-Ne) laser in the prevention of oral mucositis induced by high dose chemoradiotherapy before autologous bone marrow transplantation (BMT). Methods and Materials: Between 1993 and 1995, 30 consecutive patients receiving an autologous peripheral stem-cell or bone marrow transplant (BMT) after high dose chemoradiotherapy were randomized to possibly receive prophylactic laser to the oral mucosa after giving informed consent. Chemotherapy consisted of cyclophosphamide, 60 mg/kg intravenously (IV) on day (d)-5 and d-4 in 27 cases, or melphalan 140 mg/kg IV on d-4 in three cases. Total body irradiation (TBI) consisted of 12 Gy midplane dose in six fractions (4 Gy/day for three days). He-Ne laser (632.8 nm wavelength, power 60 mW) applications were performed daily from d-5 to d-1 on five anatomic sites of the oral mucosa. Oral examination was performed daily from d0 to d + 20. Mucositis was scored according to an oral exam guide with a 16 item scale of which four were assessed by the patients themselves. Mean daily self assessment scores for oral pain, ability to swallow and oral dryness were measured. A daily mucositis index (DMI) and a cumulative oral mucositis score (COMS) were established. Requirement for narcotics and parenteral nutrition was recorded. Results: The COMS was significantly reduced among laser treated (L+) patients (p = 0.04). The improvement of DMI in L+ patients was also statistically significant (p < 0.05) from d + 2 to d + 7. Occurrence and duration of grade III oral mucositis were reduced in L+ patients (p = 0.01). Laser applications reduced oral pain as assessed by patients (p = 0.05) and L+ patients required less morphine (p = 0.05). Xerostomia and ability to swallow were improved among the L+ patients (p = 0.005 and p = 0.01, respectively). Requirement for parenteral nutrition was not reduced (p = NS). Conclusion: Helium-Neon laser treatment was well tolerated, feasible in all cases, and

  2. An automated, noncontact laser profile meter for measuring soil roughness in situ

    International Nuclear Information System (INIS)

    Bertuzzi, P.; Caussignac, J.M.; Stengel, P.; Morel, G.; Lorendeau, J.Y.; Pelloux, G.

    1990-01-01

    This paper describes a new optical technique for measuring in situ soil surface roughness profiles using a laser profile meter. The described method uses a low-power HeNe (helium-neon) laser as a laser source and a matrix-array detector, as the laser image. The matrix-array detector gives a defect-of-focus laser image of the soil. Soil elevation is measured by projecting a laser beam normally onto the soil surface and measuring the ratio (Ir/It) on the matrix-array detector between the referenced intensity of the return Laser beam (Ir), measured by the central cell of the detector and the total intensity (It), measured by all the cells of the detector. The measured profile leads to 1001 sampled values (volt, range 0 to 10 V) of the surface height profile, at a constant increment of 0.002 m, registered automatically on a microcomputer. A calibration is made in the laboratory in order to convert the electrical measurements into elevation data. The method is universal and can be adapted to different scales of soil surface roughness. Changing the scale is done by changing the lens. Tests were carried out to improve this method for field use and to compare this technique with a method of reference. This technique is considerably quicker and causes no disturbance to the soil. The accuracy on height measurement depends on the choice of the lens. The small focal lens is convenient for smooth soil surfaces. The accuracy on height measurement is less than 0.75 mm. The wide focal lens is convenient for rough soil surfaces. The accuracy on height measurement is estimated at about 1.0 to 1.5 mm

  3. Photo-stimulatory effect of low energy helium-neon laser irradiation on excisional diabetic wound healing dynamics in wistar rats

    Directory of Open Access Journals (Sweden)

    Maiya Arun

    2009-01-01

    Full Text Available Background: Generally, the significances of laser photo stimulation are now accepted, but the laser light facilitates wound healing and tissue repair remains poorly understood. Aims: We have examined the hypothesis that the laser photo stimulation can enhance the collagen production in diabetic wounds using the excision wound model in the Wistar rat model. Methods: The circular wounds were created on the dorsum of the back of the animals. The animals were divided into two groups. The study group (N = 24 wound was treated with 632.8 nm He-Ne laser at a dose of 3-9J/cm 2 for 5 days a week until the wounds healed completely. The control group was sham irradiated. Result: A significant increase in the hydroxyproline content and reduction in the wound size were observed in the study group. The pro-healing actions seem to be due to increased collagen deposition as well as better alignment and maturation. Conclusion: The biochemical analysis and clinical observation suggested that 3-6 J/cm 2 laser photo stimulation facilitates the tissue repair process by accelerating collagen production in diabetic wound healing.

  4. Lasers '89

    International Nuclear Information System (INIS)

    Harris, D.G.; Shay, T.M.

    1990-01-01

    This book covers the following topics: XUV, X-Ray and Gamma-Ray Lasers, excimer lasers, chemical lasers, nuclear pumped lasers, high power gas lasers, solid state lasers, laser spectroscopy. The paper presented include: Development of KrF lasers for fusion and Nuclear driven solid-state lasers

  5. Application of Phase Shifted, Laser Feedback Interferometry to Fluid Physics

    Science.gov (United States)

    Ovryn, Ben; Eppell, Steven J.; Andrews, James H.; Khaydarov, John

    1996-01-01

    We have combined the principles of phase-shifting interferometry (PSI) and laser-feedback interferometry (LFI) to produce a new instrument that can measure both optical path length (OPL) changes and discern sample reflectivity variations. In LFI, coherent feedback of the incident light either reflected directly from a surface or reflected after transmission through a region of interest will modulate the output intensity of the laser. LFI can yield a high signal-to-noise ratio even for low reflectivity samples. By combining PSI and LFI, we have produced a robust instrument, based upon a HeNe laser, with high dynamic range that can be used to measure either static (dc) or oscillatory changes along the optical path. As with other forms of interferometry, large changes in OPL require phase unwrapping. Conversely, small phase changes are limited by the fraction of a fringe that can be measured. We introduce the phase shifts with an electro-optic modulator (EOM) and use either the Carre or Hariharan algorithms to determine the phase and visibility. We have determined the accuracy and precision of our technique by measuring both the bending of a cantilevered piezoelectric bimorph and linear ramps to the EOM. Using PSI, sub-nanometer displacements can be measured. We have combined our interferometer with a commercial microscope and scanning piezoelectric stage and have measured the variation in OPL and visibility for drops of PDMS (silicone oil) on coated single crystal silicon. Our measurement of the static contact angle agrees with the value of 68 deg stated in the literature.

  6. Laser light interaction for texture evaluation of native woods and Eucalyptus grandis W. Hill ex Maiden

    International Nuclear Information System (INIS)

    Silva, M.R.; Mori, F.A.; Rabelo, G.F.; Braga Junior, R.A.

    2005-01-01

    This work had the objective of study in patterns of the ''speckle'' as function of the wood texture of Bowdichia virgilioides check for this species in other resources (sucupira), Swietenia macrophylla check for this species in other resources (mogno), Balfourodendron riedelianum check for this species in other resources (paumarfim) and Eucalyptus grandis wood. The He-Ne laser 10 mW was used to illuminate the wood samples and a digital camera captured the result of the interaction of the wood with the laser light. The results obtained from image analysis were compared with the pattern obtained by microscopic methodology. The captured images show the intensities of each pixel, varying between 0 and 255 in the gray scale. From the images, a central area of 16x16 pixels was removed and analyzed by the application of the convolution function and its Fourier Transform, resulting in the power density spectrum. The results showed that the information obtained by the power density spectrum of the ''speckle'' space variation allow classing samples of woods with different texture [pt

  7. Silica-based microstructures on nonplanar substrates by femtosecond laser-induced nonlinear lithography

    International Nuclear Information System (INIS)

    Mizoshiri, M; Nishiyama, H; Hirata, Y; Nishii, J

    2009-01-01

    We developed a technique for the formation of nonplanar surfaces of inorganic optical materials by a combined process of nonlinear lithography and plasma etching. This technique can be used to fabricate structures even on non-flat substrates, which is difficult using current semiconductor technology. Three-dimensional patterns were written directly inside a positive-tone photoresist using femtosecond laser-induced nonlinear optical absorption. The patterns were then transferred to underlying nonplanar substrates by the ion beam etching technique. For the lithographic process, we obtained a minimum feature size of 900 nm, which is below the diffraction limit. We demonstrated the fabrication of silica-based hybrid diffractive-refractive lenses. Fresnel zone plates with smooth surfaces were obtained on convex microlenses. When a 633-nm-wavelength He-Ne laser was coupled normally to the hybrid lens, the primary focal length was measured as 630 μm. This hybridization shifted the focal length by 200 μm, which agreed with the theoretical value. Our process is useful for the precise fabrication of nonplanar structures based on inorganic materials.

  8. Analysis of Ni-HYDRIDE Thin Film after Surface Plasmon Generation by Laser Technique

    Science.gov (United States)

    Violante, V.; Castagna, E.; Sibilia, C.; Paoloni, S.; Sarto, F.

    2005-12-01

    A nickel hydride thin film was studied by the attenuated total reflection method. The differences in behavior between a "black" film, and a pure nickel film "blank," are shown. The black nickel hydride film has been obtained by a short electrolysis with 1 M Li2SO4 electrolyte in light water, A shift in the minimum of the observed reflected light occurs, together with a change in the minimum shape (i.e. its half-height width increases). These two phenomenon are due to the change in the electronic band structure of the metal induced by electrons added to the lattice by hydrogen. The change of the electronic structure, revealed by the laser coupling conditions, leads us to consider that a hydride phase was created. Both the blank (not hydrogenated) and black (hydrogenated) specimens were taken under He-Ne laser beam at the reflectance minimum angle for about three hours. A SIMS analysis was also implemented to reveal differences in the isotopic composition of Cu, as marker element between the blank and black films, in order to study the coupled effect of electrolysis and plasmon-polariton excitation on LENR processes in condensed matter.

  9. Laser Micromachining and Information Discovery Using a Dual Beam Interferometry

    Energy Technology Data Exchange (ETDEWEB)

    Theppakuttaikomaraswamy, Senthil P. [Iowa State Univ., Ames, IA (United States)

    2001-01-01

    Lasers have proven to be among the most promising tools for micromachining because they can process features down to the size of the laser wavelength (smaller than 1 micrometer) and they provide a non-contact technology for machining. The demand for incorporating in-situ diagnostics technology into the micromachining environment is driven by the increasing need for producing micro-parts of high quality and accuracy. Laser interferometry can be used as an on-line monitoring tool and it is the aim of this work to enhance the understanding and application of Michelson interferometry principle for the in-situ diagnostics of the machining depth on the sub-micron and micron scales. micromachining is done on two different materials and a comprehensive investigation is done to control the width and depth of the machined feature. To control the width of the feature, laser micromachining is done on copper and a detailed analysis is performed. The objective of this experiment is to make a precision mask for sputtering with an array of holes on it using an Nd:YAG laser of 532 nm wavelength. The diameter of the hole is 50 μm and the spacing between holes (the distance between the centers) is 100 μm. Michelson interferometer is integrated with a laser machining system to control the depth of machining. An excimer laser of 308 nm wavelength is used for micromachining. A He-Ne laser of 632.8 nm wavelength is used as the light source for the interferometer. Interference patterns are created due to the change in the path length between the two interferometer arms. The machined depth information is obtained from the interference patterns on an oscilloscope detected by a photodiode. To compare the predicted depth by the interferometer with the true machining depth, a surface profilometer is used to measure the actual machining depth on the silicon. It is observed that the depths of machining obtained by the surface profile measurement are in accordance with the interferometer

  10. Interaction of low-intensity linearly polarized laser radiation with living tissues: effects on tissular acceleration of skin wound healing

    International Nuclear Information System (INIS)

    Ribeiro, Martha Simoes

    2000-01-01

    According to the Maxwell's equations to optical properties of surfaces, the energy deposition efficiency in a microroughness interface depends on the electrical field polarization component. Considering a linearly polarized beam, this efficiency will depend on the roughness parameters to p-polarized light and it will not depend on such parameters to s-polarized light. In this work it was investigated the effects of low-intensity, linearly polarized He-Ne laser beam on skin wounds healing, considering two orthogonal directions of polarization. We have considered a preferential axis as the animals' spinal column and we aligned the linear laser polarization first parallel, then perpendicular to this direction. Burns about 6 mm in diameter were created with liquid N 2 on the back of the animals and the lesions were irradiated on days 3, 7, 10 and 14 post-wounding, D= 1,0 J/cm 2 . Control lesions were not irradiated. The theoretical model consisted in describing linearly polarized light propagation in biological tissues using transport theory. The degree of polarization was measured in normal and pathological skin samples. It was verified that linearly polarized light can survive in the superficial layers of skin and it can be more preserved in skin under pathological condition when compared with health skin. The analysis of skin wound healing process has demonstrated that the relative direction of the laser polarization plays an important role on the wound healing process by light microscopy, transmission electron microscopy and radioautography. (author)

  11. Detection using visible laser of palm oil quality affected by heating process

    International Nuclear Information System (INIS)

    El-Rahman, A.A.; Badawy, H.A.

    2010-01-01

    Palm oil was heated at 180 degree C for six times (3, 6, 9, 12, 15, and 18 hours) to measure some physical, chemical and optical properties. Palm oil was exposure to laser beam to determine optical properties of oils using (He-Ne) lasers with wavelengths 632.8 and 543.5 nm. The obtained results are as follows: (1) Chemical properties such as oxidized fatty acid, acid value and peroxide value were increased by increasing heating time, but the iodine value was decreased. Meanwhile, physical properties such as viscosity and reflective index were increased at the same of heating times., (2) By increasing heating time of palm oil from 3 to 18 hrs, the absorbed of wavelengths of laser beam with wavelength 543.5 nm was more absorbed than 632.8 nm. Meanwhile, the transmission of laser beam with wavelength 543.5 nm was more high transmission than 632.8 nm., (3) The deterioration of palm oil was started after 16 hours of heating at the light intensity 228 and 368 lux of transmission for wavelengths of 543.5 and 632.8 nm., (4) There are high relation between heating time and chemical, physical, optical properties. The R square was ranged from 0.83 to 0.97, from 0.89 to 0.96 and from 0.95 to 0.98 for chemical, physical, and optical properties with heating, and (5) From optical properties we can determine the quality of oil using the laser transmission or absorbed as a detector of oil quality.

  12. Laser Materials and Laser Spectroscopy - A Satellite Meeting of IQEC '88

    Science.gov (United States)

    Wang, Zhijiang; Zhang, Zhiming

    1989-03-01

    Langmuir-Blodgett Monolayer by Surface Enhanced Raman Scattering * Dynamics of Laser-induced Etching of Si(III) Surface of Chlorine * Fourier Transform Heterodyne Spectroscopy of Liquid Interfaces * Generation of High Power UV Femtosecond Pulses * Femtosecond Photon Echoes * Transition Radiation of Femtosecond Optical Pulses * Observation of DFWN in a Saturable Absorber inside the CPM Ring Dye Laser Cavity * Study on the Induced Spectral Superbroadening of Ultrafast Laser Pulse in a Nonlinear Medium * Laser Cooling and Trapping of Atoms * Femtosecond Absorption Spectroscopy of Primary Processes in Bacterial Photosynthesis Reaction Centers * Observation of the Motion of Slow Atoms in a Standing Wave Field * The Interrelation between the Optical Properties and the MBE Growth Control of Quantum Well Structures * Ionic Excimers * Optical SHG Study on Polymerization of Langmuir-Blodgett Molecular Layers * Weak Localization of Light * Statistical Fragmentation Patterns of Metastable Ion: Comparison with Experiment * Oxygeneration Reaction of Cerium with XeCl Laser * Measurement of Verdet Coefficient and Magneto-optic Spectroscopy in terms of Beats * Study on Rhodamine 6G/Xylene and Red B Laser Dye Mixture System * Ultranarrow Absorption Resonances of Cold Particles and their Application in Spectroscopy and Optical Frequency Standards * The Dynamics of Ion Clouds in Paul Traps: Implications for Frequency Standard Applications * Frequency Stability Measurement of Zeeman Stabilized He-Ne Laser * Multi-wavelength CW He-Ne Laser and its Frequency Stabilization * Efficient Isotope Separation using Semiconductor Lasers * Multi-beam Circularly Polarized Holography * Ring Laser Opticity Meter * Improved Rademacher Functions and Rademacher Transform * Note

  13. Development of high resolution Michelson interferometer for stable phase-locked ultrashort pulse pair generation.

    Science.gov (United States)

    Okada, Takumi; Komori, Kazuhiro; Goshima, Keishiro; Yamauchi, Shohgo; Morohashi, Isao; Sugaya, Takeyoshi; Ogura, Mutsuo; Tsurumachi, Noriaki

    2008-10-01

    We developed a high resolution Michelson interferometer with a two-frequency He-Ne laser positioning system in order to stabilize the relative phase of a pulse pair. The control resolution corresponded to a 12 as time resolution or a phase of 1.5 degrees at 900 nm. This high resolution Michelson interferometer can generate a phase-locked pulse pair either with a specific relative phase such as 0 or pi radians or with an arbitrary phase. Coherent control of an InAs self-assembled quantum dot was demonstrated using the high resolution Michelson interferometer with a microspectroscopy system.

  14. Laser Technology.

    Science.gov (United States)

    Gauger, Robert

    1993-01-01

    Describes lasers and indicates that learning about laser technology and creating laser technology activities are among the teacher enhancement processes needed to strengthen technology education. (JOW)

  15. A photothermal Mach-Zehnder interferometer for measuring caffeine and proteins in aqueous solutions using external cavity quantum cascade lasers

    Science.gov (United States)

    Kristament, Christian; Schwaighofer, Andreas; Montemurro, Milagros; Lendl, Bernhard

    2018-02-01

    One of the advantages of mid-IR spectroscopy in biomedical research lies in its capability to provide direct information on the secondary structure of proteins in their natural, often aqueous, environment. One impediment of direct absorption measurements in the correspondent spectral region is the strong absorbance of the native solvent (H2O). In this regard, the advent of broadly-tunable external cavity quantum cascade lasers (EC-QCL) allowed to significantly increasing the optical path length employed in transmission measurements due to their high spectral power densities. Low measured S/N ratios were improved by elaborated data analysis protocols that corrected mechanical flaws in the tuning mechanism of ECQCLs and allow for S/N ratios comparable to research grade FTIR spectrometers. Recent development of new optical set-ups outpacing direct absorption measurements led to further advancements. We present a dedicated Mach-Zehnder interferometer for photothermal measurements in balanced detection mode. In this highly sensitive design, the interferometer is illuminated by a HeNe laser to detect the refractive index change induced by the heat insertion of the EC-QCL. Here, we present photothermal phase shift interferometry measurements of caffeine in ethanol as well as casein in water. Further, the dependency of the signal amplitude on varying modulation frequencies was investigated for different liquids.

  16. Evaluation of Laser Stabilization and Imaging Systems for LCLS-II - Final Paper

    Energy Technology Data Exchange (ETDEWEB)

    Barry, Matthew [Auburn Univ., AL (United States)

    2015-08-20

    By combining the top performing commercial laser beam stabilization system with the most ideal optical imaging configuration, the beamline for the Linear Accelerator Coherent Light Source II (LCLS-II) will deliver the highest quality and most stable beam to the cathode. To determine the optimal combination, LCLS-II beamline conditions were replicated and the systems tested with a He-Ne laser. The Guidestar-II and MRC active laser beam stabilization systems were evaluated for their ideal positioning and stability. Both a two and four lens optical imaging configuration was then evaluated for beam imaging quality, magnification properties, and natural stability. In their best performances when tested over fifteen hours, Guidestar-II kept the beam stable over approximately 70-110um while the MRC system kept it stable over approximately 90-100um. During short periods of time, Guidestar-II kept the beam stable between 10-20um, but was more susceptible to drift over time, while the MRC system maintained the beam between 30-50um with less overall drift. The best optical imaging configuration proved to be a four lens system that images to the iris located in the cathode room and from there, imaged to the cathode. The magnification from the iris to the cathode was 2:1, within an acceptable tolerance to the expected 2.1:1 magnification. The two lens configuration was slightly more stable in small periods of time (less than 10 minutes) without the assistance of a stability system, approximately 55um compared to approximately 70um, but the four lens configurations beam image had a significantly flatter intensity distribution compared to the two lens configuration which had a Gaussian distribution. A final test still needs to be run with both stability systems running at the same time through the four lens system. With this data, the optimal laser beam stabilization system can be determined for the beamline of LCLS-II.

  17. Multi-image acquisition-based distance sensor using agile laser spot beam.

    Science.gov (United States)

    Riza, Nabeel A; Amin, M Junaid

    2014-09-01

    We present a novel laser-based distance measurement technique that uses multiple-image-based spatial processing to enable distance measurements. Compared with the first-generation distance sensor using spatial processing, the modified sensor is no longer hindered by the classic Rayleigh axial resolution limit for the propagating laser beam at its minimum beam waist location. The proposed high-resolution distance sensor design uses an electronically controlled variable focus lens (ECVFL) in combination with an optical imaging device, such as a charged-coupled device (CCD), to produce and capture different laser spot size images on a target with these beam spot sizes different from the minimal spot size possible at this target distance. By exploiting the unique relationship of the target located spot sizes with the varying ECVFL focal length for each target distance, the proposed distance sensor can compute the target distance with a distance measurement resolution better than the axial resolution via the Rayleigh resolution criterion. Using a 30 mW 633 nm He-Ne laser coupled with an electromagnetically actuated liquid ECVFL, along with a 20 cm focal length bias lens, and using five spot images captured per target position by a CCD-based Nikon camera, a proof-of-concept proposed distance sensor is successfully implemented in the laboratory over target ranges from 10 to 100 cm with a demonstrated sub-cm axial resolution, which is better than the axial Rayleigh resolution limit at these target distances. Applications for the proposed potentially cost-effective distance sensor are diverse and include industrial inspection and measurement and 3D object shape mapping and imaging.

  18. Mutation breeding of Bacillus subtilis YTB4 with high yield of ...

    African Journals Online (AJOL)

    DR TONUKARI NYEROVWO

    2012-07-17

    Jul 17, 2012 ... Helium-neon (He-Ne) laser irradiation is a highly efficient mutation breeding technology and is widely applied to various fields of biological science. Using Bacillus subtilis YTB4 with high yield of multienzyme complex as original strain, mutation breeding was carried out by He-Ne laser irradiation in.

  19. Mutation breeding of Bacillus subtilis YTB4 with high yield of ...

    African Journals Online (AJOL)

    Helium-neon (He-Ne) laser irradiation is a highly efficient mutation breeding technology and is widely applied to various fields of biological science. Using Bacillus subtilis YTB4 with high yield of multienzyme complex as original strain, mutation breeding was carried out by He-Ne laser irradiation in this study. Based on the ...

  20. Measurement of ejected electrons from collisions of He+ ions with He, Ne, and Ar at the intermediate energies

    International Nuclear Information System (INIS)

    Tokoro, Nobuhiro; Oda, Nobuo

    1985-01-01

    The doubly differential cross sections for electron production, differential in angle and energy of the electrons, for 5-25 keV He + impact on helium, neon and argon have been measured in the electron energy range of 2-200 eV at the ejection angles from 30 0 to 150 0 with respect to the incident ion beam. The characteristic features of continnum parts of ejected electron spectra are described for each collision system. (author)

  1. Photo-orientation of azobenzene side chain polymers parallel or perpendicular to the polarization of red HeNe light

    International Nuclear Information System (INIS)

    Kempe, Christian; Rutloh, Michael; Stumpe, Joachim

    2003-01-01

    The mechanism of the light-induced orientation process of azobenzene-containing polymers caused by irradiation with linearly polarized red light is investigated. This process is surprising because there is almost no absorption at 633 nm. Depending on the photochemical pre-treatment and the exposure time, the azobenzene moieties can undergo two different orientation processes resulting in either a parallel or a perpendicular orientation with respect to the electric field vector of the incident light. The fast orientation of the photochromic groups with their long axis in the direction of the light polarization requires a photochemical pre-treatment in which non-polarized UV light generates Z-isomers. Due to this procedure the film becomes 'photochemically activated' for the subsequent polarized irradiation with red light. But on continued exposure a second, much slower reorientation process occurs which establishes an orientation of the azobenzene groups perpendicular to the electric field vector. The fast mechanism is probably caused by an angle-selective photo-isomerization of the Z-isomers to the E-isomers, while the subsequent slow reorientation process is caused by the well-known conventional photo-orientation taking place via the accumulation of a number of photoselection steps and the rotational diffusion minimizing the absorbance of the E-isomer. This process occurs in the steady state but at this wavelength with a very small concentration of Z-isomers. The competing mechanisms take place in the same polymer film under almost identical irradiation conditions, differing only in the actual concentration of the Z-isomers

  2. Synchronisation in the phase model of three coupled lasers

    International Nuclear Information System (INIS)

    Kuznetsov, A P; Sataev, I R; Tyuryukina, L V; Chernyshov, N Yu

    2014-01-01

    The problem of synchronisation of three lasers is considered within the phase approximation. The domains of complete synchronisation, partial synchronisation, two-frequency resonant regimes, and three-frequency quasi-periodicity have been found using bifurcation analysis, the method of Lyapunov exponent maps, and construction of phase portraits. The differences in the properties of a three-element chain and ring, as well as the influence of the coupling type, are discussed. (control of laser radiation parameters)

  3. Feedback-stabilized dual-beam laser interferometer for plasma measurements

    International Nuclear Information System (INIS)

    Yasuda, A.; Kanai, Y.; Kusunoki, J.; Kawahata, K.; Takeda, S.

    1980-01-01

    A stabilized laser interferometer is proposed with two beams as the light source. The fringe shift for a 0.63 μm beam of a He--Ne laser is used to stabilize the interferometer against the effect of mechanical vibrations via a feedback controlled speaker coil, while another beam of 3.39 μm, for which consequently the effect of the mechanical vibrations is excluded, is used to measure the plasma density. A stability of approx.1/500 of one fringe for 0.63 μm is obtained during a long period for frequencies lower than a few Hz. The stability for higher frequencies is limited to approx.1/30 of one fringe for 0.63 μm, which correspondes to approx.1/200 of one fringe for 3.39 μm, by the acoustic noise picked up by the speaker coil. Furthermore, the total accuracy is limited by the detector noise to approx.1/60 of one fringe for 3.39 μm, which corresponds to a line electron density of approx.5 x 10 14 cm -2 . The detector noise may be reduced by cooling the detector. The advantage of this technique over the single-laser technique is that the frequency response of the interferometer extends down to zero frequency. The interferometer is tested with the measurement of a plasma in a dynamic magnetic arcjet. Since the effect of the neutral gas background is reduced in the present interferometer, the application has an advantage for the diagnostics of plasmas produced in high pressure gases

  4. Cognitive Demands during Quiet Standing Elicit Truncal Tremor in Two Frequency Bands: Differential Relations to Tissue Integrity of Corticospinal Tracts and Cortical Targets

    Directory of Open Access Journals (Sweden)

    Edith V Sullivan

    2015-04-01

    Full Text Available The ability to stand quietly is disturbed by degradation of cerebellar systems. Given the complexity of sensorimotor integration invoked to maintain upright posture, the integrity of supratentorial brain structures may also contribute to quiet standing and consequently be vulnerable to interference from cognitive challenges. As cerebellar system disruption is a common concomitant of alcoholism, we examined 46 alcoholics and 43 controls with a force platform to derive physiological indices of quiet standing during cognitive (solving simple, mental arithmetic problems and visual (eyes closed challenges. Also tested were relations between tremor velocity and regional gray matter and white matter tissue quality measured with the diffusion tensor imaging (DTI metric of mean diffusivity (MD, indexing disorganized microstructure. Spectral analysis of sway revealed greater tremor in alcoholic men than alcoholic women or controls. Cognitive dual-tasking elicited excessive tremor in two frequency bands, each related to DTI signs of degradation in separate brain systems: tremor velocity at a low power (2-5 Hz/0-2 Hz correlated with higher MD in the cerebellar hemispheres and superior cingulate bundles, whereas tremor velocity at a higher power (5-7 Hz correlated with higher MD in the motor cortex and internal capsule. These brain sites may represent tremorgenic networks that when disturbed by disease and exacerbated by cognitive dual-tasking contribute to postural instability, putting affected individuals at heightened risk for falling.

  5. Investigations of the potential functions of weakly bound diatomic molecules and laser-assisted excitive Penning ionization

    Energy Technology Data Exchange (ETDEWEB)

    Goble, J.H. Jr.

    1982-05-01

    Three variations on the Dunham series expansion function of the potential of a diatomic molecule are compared. The differences among these expansions lie in the choice of the expansion variable, lambda. The functional form of these variables are lambda/sub s/ = l-r/sub e//r for the Simon-Parr-Finlan version, lambda/sub T/ - 1-(r/sub e//r)/sup p/ for that of Thakkar, and lambda/sub H/ = 1-exp(-rho(r/r/sub e/-1) for that of Huffaker. A wide selection of molecular systems are examined. It is found that, for potentials in excess of thirty kcal/mole, the Huffaker expansion provides the best description of the three, extrapolating at large internuclear separation to a value within 10% of the true dissociation energy. For potentials that result from the interaction of excited states, all series expansions show poor behavior away from the equilibrium internuclear separation of the molecule. The series representation of the potentials of weakly bound molecules are examined in more detail. The ground states of BeAr/sup +/, HeNe/sup +/, NaAr, and Ar/sub 2/ and the excited states of HeNe+, NaNe, and NaAr are best described by the Thakkar expansion. Finally, the observation of laser-assisted excitive Penning ionization in a flowing afterglow is reported. The reaction Ar(/sup 3/P/sub 2/) + Ca + h nu ..-->.. Ar + Ca/sup +/(5p /sup 2/P/sub J/) + e/sup -/ occurs when the photon energy, h nu, is approximately equal to the energy difference between the metastable argon and one of the fine structure levels of the ion's doublet. By monitoring the cascade fluorescence of the above reaction and comparing it to the flourescence from the field-free process Ar(/sup 3/P/sub 2/) + Ca ..-->.. Ar + Ca/sup +/(4p /sup 2/P/sub J/) + e/sup -/ a surprisingly large cross section of 6.7 x 10/sup 3/ A/sup 2/ is estimated.

  6. Temporal evolution of electron density in a low pressure pulsed two-frequency (60 MHz/2 MHz) capacitively coupled plasma discharge

    International Nuclear Information System (INIS)

    Sirse, N; Ellingboe, A R; Jeon, M H; Yeom, G Y

    2014-01-01

    Time-resolved electron density, n e , is measured in a low pressure pulsed two-frequency capacitively coupled plasma discharge sustained in Ar and in Ar/CF 4 /O 2 (80 : 10 : 10) gas mixture using a floating resonance hairpin probe. The top electrode is powered by 60 MHz in pulse mode and the bottom electrode is powered by 2 MHz in continuous wave mode. The dependence of time-resolved n e on the low frequency (LF) and high frequency (HF) power levels, operating gas pressure, pulse repetition frequency (PRF) and duty cycle are investigated. It is found that the steady state n e in the long on-phase is greatly influenced by the HF power level and slightly affected by the LF power level in both Ar and Ar/CF 4 /O 2 plasma. The decay time of n e is slow (∼30–90 µs) in the case of Ar plasma and strongly depends on the LF power level, whereas in the case of Ar/CF 4 /O 2 gas mixture it is very fast (∼15 µs) and marginally dependent on LF power level. In Ar plasma the steady state n e is increasing with a rise in operating gas pressure, however, in Ar/CF 4 /O 2 plasma it first increases with gas pressure reaching to the maximum (at 20 mTorr) value and then decreases. The pressure dependence of decay time constant mimics the pressure variation of steady state n e . Furthermore, it is observed that the on-phase electron density is greatly affected by changing the PRF and duty cycle. This effect is more prominent in Ar/CF 4 /O 2 plasma when compared to Ar discharge. In addition, n e is observed to overshoot the steady state densities in the beginning of the on-phase in Ar/CF 4 /O 2 gas mixture, but this effect is either small or absent in the case of Ar plasma. (paper)

  7. The Newest Laser Processing

    International Nuclear Information System (INIS)

    Lee, Baek Yeon

    2007-01-01

    This book mentions laser processing with laser principle, laser history, laser beam property, laser kinds, foundation of laser processing such as laser oscillation, characteristic of laser processing, laser for processing and its characteristic, processing of laser hole including conception of processing of laser hole and each material, and hole processing of metal material, cut of laser, reality of cut, laser welding, laser surface hardening, application case of special processing and safety measurement of laser.

  8. Detection of bacterial infection of agave plants by laser-induced fluorescence

    Science.gov (United States)

    Cervantes-Martinez, Jesus; Flores-Hernandez, Ricardo; Rodriguez-Garay, Benjamin; Santacruz-Ruvalcaba, Fernando

    2002-05-01

    Greenhouse-grown plants of Agave tequilana Weber var. azul were inoculated with Erwinia carotovora, the causal agent of stem soft rot. We investigated the laser-induced fluorescence (LIF) of agave plants to determine whether LIF can be used as a noninvasive sensing tool for pathological studies. The LIF technique was also investigated as a means of detecting the effect of the polyamine biosynthesis inhibitor beta-hydroxyethylhydrazine as a bactericide against the pathogenic bacterium Erwinia carotovora. A He-Ne laser at 632.8 nm was used as the excitation source, and in vivo fluorescence emission spectra were recorded in the 660-790-range. Fluorescence maxima were at 690 and 740 nm. The infected plants that were untreated with the bactericide showed a definite increase in fluorescence intensity at both maxima within the first three days after infection. Beginning on the fifth day, a steady decrease in fluorescence intensity was observed, with a greater effect at 740 than at 690 nm. After 30 days there was no fluorescence. The infected plants that had been treated with the bactericide showed no significant change in fluorescence compared with that of the uninfected plants. The ratio of fluorescence intensities was determined to be F 690 nm/F 740 nm for all treatments. These studies indicate that LIF measurements of agave plants may be used for the early detection of certain types of disease and for determining the effect of a bactericide on bacteria. The results also showed that fluorescence intensity ratios can be used as a reliable indicator of the progress of disease.

  9. Widely tunable quantum cascade laser-based terahertz source.

    Science.gov (United States)

    Danylov, Andriy A; Light, Alexander R; Waldman, Jerry; Erickson, Neal; Qian, Xifeng

    2014-07-10

    A compact, tunable, ultranarrowband terahertz source, Δν∼1  MHz, is demonstrated by upconversion of a 2.324 THz, free-running quantum cascade laser with a THz Schottky-diode-balanced mixer using a swept, synthesized microwave source to drive the nonlinearity. Continuously tunable radiation of 1 μW power is demonstrated in two frequency regions: ν(Laser) ± 0 to 50 GHz and ν(Laser) ± 70 to 115 GHz. The sideband spectra were characterized with a Fourier-transform spectrometer, and the radiation was tuned through CO, HDO, and D2O rotational transitions.

  10. Clinical results from low-level laser therapy in patients with autosomal dominant cone-rod dystrophy

    Science.gov (United States)

    Koev, K.; Avramov, L.; Borissova, E.

    2018-03-01

    The objective of this study is to examine long-term effects of low-level laser therapy (LLLT) in patients with autosomal dominant cone-rod dystrophy (CRDs). A He-Ne Laser with continuous emission at 633 nm (01 mW/cm2) was used on five patients with autosomal dominant pedigree of Romani origin with non-syndromic CRDs. The laser radiation was applied transpupillary to the macula six times for three minutes every other day. The experiment was conducted for a period of three years. The clinical evaluation included best corrected visual acuity determination, funduscopy, Humphrey perimetry, Farnsworth Hue-28 color testing, fluorescein angiography, and full-field electroretinogram (ERG). All affected individuals presented reduced visual acuity (0.01 – 0.4) and photophobia. The funduscopic examination and fluorescein angiography revealed advanced changes including bone spicule-like pigment deposits in the midperiphery and the macular area, along with retinal atrophy, narrowing of the vessels, and waxy optic discs. The visual fields demonstrated central scotoma. The electrophysiologic examination of the patients detected an abnormal cone-rod ERG (20 – 30 μV) with photopic amplitudes more markedly reduced than the scotopic. Flicker responses were missing and Farnsworth Hue-28 test found protanopia. There was a statistically significant increase in the visual acuity (p<0.001, end of study versus baseline) for CRDs patients for the period of three years after the treatment with LLLT. Following the LLLT, the central absolute scotoma in CRDs was reduced, as was the prevalence of metamorphopsia in CRDs. This study shows that LLLT may prove be a novel long-lasting therapeutic option for both forms of CRDs. It is a highly effective treatment resulting in a long-term improvement of the visual acuity.

  11. Low level laser therapy for concurrent chemoradiotherapy induced oral mucositis in head and neck cancer patients – A triple blinded randomized controlled trial

    International Nuclear Information System (INIS)

    Gautam, Ajay Prashad; Fernandes, Donald J.; Vidyasagar, Mamidipudi S.; Maiya, Arun G.; Vadhiraja, Bejadi M.

    2012-01-01

    Background and purpose: Oral mucositis (OM) is most cumbersome acute side effect of concurrent chemoradiotherapy (CCRT) for head and neck cancer (HNC). OM associated pain affects oral functions and nutrition of the patient that may result in discontinuity of treatment. Several modalities have been tried to prevent and treat OM, but none proved completely successful until date. We used prophylactic low level laser therapy (LLLT) for the prevention and treatment of CCRT induced OM. Materials and methods: In this triple blinded study, 221 HNC patients scheduled to undergo CCRT (Cisplatin (1, 22, 43 day) + RT = 66 Grays (2 Gy/fraction), 33 fractions, 5 fractions/week, for 45 days) were block randomized into laser (n = 111) and placebo (n = 110) group. Laser group received LLLT (HeNe, λ = 632.8 nm, power-density = 24 mW, dosage = 3.0 J/point, total dosage/session = 36–40 J, spot-size = 1 cm 2 , 5 sessions/week) while placebo received sham treatment daily prior to radiation. OM (RTOG/EORTC Scale), oral pain (VAS), dysphagia (FIS), weight loss and CCRT break were assessed. Data were analyzed using frequencies and percentage, generalized estimating equations (GEE) and odds ratio. Results: There was significant reduction in incidence of severe OM (F = 16.64, df = 8876, p < 0.0001) and its associated pain (F = 25.06, df = 8876, p < 0.0001), dysphagia (F = 20.17, df = 8876, p < 0.0001) and opioid analgesics use (p < 0.0001) in laser than placebo group patients. Conclusions: LLLT decreased the incidence of CCRT induced severe OM and its associated pain, dysphagia and opioid analgesics use.

  12. Progress in coherent lithography using table-top extreme ultraviolet lasers

    Science.gov (United States)

    Li, Wei

    interference pattern whose lattice is modified by a custom designed Talbot mask. In other words, this method enables filling the arbitrary Talbot cell with ultra-fine interference nanofeatures. Detailed optics modeling, system design and experiment results using He-Ne laser and table top EUV laser are included. The last part of chapter IV will analyze its exclusive advantages over traditional Talbot or interference lithography.

  13. Laser Therapy

    Science.gov (United States)

    ... for Every Season How to Choose the Best Skin Care Products In This Section Dermatologic Surgery What is dermatologic ... for Every Season How to Choose the Best Skin Care Products Laser Resurfacing Uses for Laser Resurfacing Learn more ...

  14. Lasers technology

    International Nuclear Information System (INIS)

    2014-01-01

    The Laser Technology Program of IPEN is developed by the Center for Lasers and Applications (CLA) and is committed to the development of new lasers based on the research of new optical materials and new resonator technologies. Laser applications and research occur within several areas such as Nuclear, Medicine, Dentistry, Industry, Environment and Advanced Research. Additional goals of the Program are human resource development and innovation, in association with Brazilian Universities and commercial partners

  15. YCOB lasers

    International Nuclear Information System (INIS)

    Richardson, Martin; Hammons, Dennis; Eichenholz, Jason; Chai, Bruce; Ye, Qing; Jang, Won; Shah, Lawrence

    1999-01-01

    We review new developments with a new laser host material, YCa 4 O(BO 3 ) 3 or YCOB. Lasers based on this host material will open new opportunities for the development of compact, high-power, frequency-agile visible and near IR laser sources, as well as sources for ultrashort pulses. Efficient diode-pumped laser action with both Nd-doped and Yb-doped YCOB has already been demonstrated. Moreover, since these materials are biaxial, and have high nonlinear optical coefficients, they have become the first laser materials available as efficient self-frequency-doubled lasers, capable of providing tunable laser emission in several regions of the visible spectrum. Self-frequency doubling eliminates the need for inclusion of a nonlinear optical element within or external to the laser resonator. These laser materials possess excellent thermal and optical properties, have high laser-damage thresholds, and can be grown to large sizes. In addition they are non-hygroscopic. They therefore possess all the characteristics necessary for laser materials required in rugged, compact systems. Here we summarize the rapid progress made in the development of this new class of lasers, and review their potential for a number of applications. (author)

  16. Laser sampling

    International Nuclear Information System (INIS)

    Gorbatenko, A A; Revina, E I

    2015-01-01

    The review is devoted to the major advances in laser sampling. The advantages and drawbacks of the technique are considered. Specific features of combinations of laser sampling with various instrumental analytical methods, primarily inductively coupled plasma mass spectrometry, are discussed. Examples of practical implementation of hybrid methods involving laser sampling as well as corresponding analytical characteristics are presented. The bibliography includes 78 references

  17. HF laser

    International Nuclear Information System (INIS)

    Suzuki, Kazuya; Iwasaki, Matae

    1977-01-01

    A review is made of the research and development of HF chemical laser and its related work. Many gaseous compounds are used as laser media successfully; reaction kinetics and technological problems are described. The hybrid chemical laser of HF-CO 2 system and the topics related to the isotope separation are also included. (auth.)

  18. Measurement of microvascular blood flow in cancellous bone using laser Doppler flowmetry and 133Xe-clearance

    International Nuclear Information System (INIS)

    Hellem, S.; Jacobsson, L.S.; Nilsson, G.E.; Lewis, D.H.

    1983-01-01

    Blood flow in cancelleous bone with varying vascular density was investigated simultaneously with Laser Doppler Flowmeter (LDF) and 113 Xe-clearance. The cancellous bone subapical to 2 contralateral incisors in the mandibles of 17 young pigs was used as an experimental model. Light from a 2 mW He-Ne-laser was guided through an optical fibre to a flowmeter probe. Stainless steel probe-holders firmly inserted in the pulpal canals of the two incisors served as the probe entrance to cancellous bone for blood flow recording. Due to the Doppler effect, the light scattered by circulating blood cells undergoes a frequency shift. The back-scattered light picked up by optical fibres in the probe, was guided to a photosensitive device, where it was demodulated. After signal processing, a signal referred to as the Blood Flow Value (BFV) was recorded on a pen recorder. Rhythmical variations (vasomotion) in BFV with frequencies from 2-11 cycles/min were observed in 6% of recordings made initially after probeholder implantation, and in 34% of the recordings made 5 weeks later. On this occasion, a marked increase in BFV was recorded. Histological examination showed increased vascularity in the bone tissue. The reproducibility error of LDF was 7.4% and temporal changes in BFV, apart from vasomotion, were 8.3%, provided no injections or manipulations of the probe were made. Spatial variations in BFV were found to be related to the vascular density. 2 successive recordings by LDF from the same bone area were highly correlated (r=0.98). The corresponding figure for 2 logarithmic decay rates of locally injected 133 Xe was 0.76. No correlation between BFV and 133 Xe-clearance could be demonstrated. (author)

  19. Five-year follow-up of low-level laser therapy (LLLT) in patients with age-related macular degeneration (AMD)

    Science.gov (United States)

    Koev, K.; Avramov, L.; Borissova, E.

    2018-03-01

    The objective of this study was to examine long-term effects of low-level laser therapy (LLLT) in patients with age-related macular degeneration (AMD). The research was implemented for a period of five years. For LLLT, a He-Ne Laser with continuous emission at 633 nm (0.1 mW/cm2) was used in patients with AMD of all stages (dry to wet exudative forms were included). In total, 33 patients (16 men and 17 women – 66 eyes) with AMD of various stages and a mean age of 68.7 ± 4.2 years were included in the study. Progressive, exudative AMD was diagnosed in 8 eyes. 58 eyes had drusen or were depigmented. Laser radiation was applied transpupillary to the macula for six times for three minutes once in two days; 22 patients with AMD (44 eyes) were randomly selected to receive mock treatment (control group 10 men and 12 women with a mean age of 69.3 ± 4.8 years). The visual acuity was followed for a five-year period. The perimetry and Amsler test were used to screen central scotomas. The fluorescein angiography of AMD and the control groups was examined. The visual acuity remained unchanged in all patients in the control group. There was a statistically significant increase in the visual acuity (p<0.001, end of study versus baseline) for AMD patients for the period of five years after the treatment. The edema and hemorrhage in the patients with progressive, exudative AMD significantly decreased. No side effects were observed during the therapy. The prevalence of metamorphopsia, scotoma in AMD group was reduced. In conclusion, this study shows that LLLT may be a novel long-lasting therapeutic option for both forms of AMD. It is a highly-effective treatment that results in a long-term improvement of the visual acuity.

  20. Decay of a laser generated shock wave in an aluminium target

    International Nuclear Information System (INIS)

    Werdiger, M.

    1993-09-01

    When a shock wave arrives at the near surface of a solid material, a radical and fast change occurs in the reflection properties of the material. The phenomenon is used in the present work in order to develop a new way to measure the transit time of a shock wave in a target. A 10 milliwatt He:Ne laser is directed toward the rear surface of the target. The reflected beam arrives at a photo-diode with a fast rise time of 150 psec which detects the instant of the change in the reflection. This technique, called 'continuous back lightning', is used in experiments with aluminium foil thickness in the range of 40μm ≤x≥ 1000μm. The shock wave is induced by a laser pulse of an intensity of 3*10 13 W/cm 2 . The results show two main physical regimes: in the first one 40μ ≤x≥ 210μm, there is a constant shock wave velocity which in our experiments was measured to be (12.81±0.67)km/s. In the second range of the thickness where 300μm there is a decay of the shock velocity. For x ≥ 210μm the geometry is one dimensional for our experimental conditions, while for x ≥ 300μm the 1-D geometry changes to 2 dimensional (2-D) geometry. The 2-D shock wave decay asymptotically (x→∞ to an acoustic wave. shock wave is described by a pressure scaling as x -n (n is a positive constant). The phenomenological equation of the state is taken to be P=A**u s + B*u s 2 +Bu s , where P is the pressure, u s - the shock velocity, A and B are constants. Applying our experimental results to the solution of the differential equation in this model A*x 2 ± B*x=C*x -n yields a value of n in the range 3.16 ≤n≥ 3.51. This pressure scaling law agrees with the self-similar solution of a concentrated impact on a surface between two media. This situation is well simulated by the laser deposition energy on a metal surface. In the experiment a 5% accuracy is achieved. Such a good accuracy has not been achieved so far in a laser induced shock-wave measurements in solids. (author). 52 refs

  1. Elsa: an infrared free electron laser

    International Nuclear Information System (INIS)

    Guimbal, P.; Chaix, P.

    1998-01-01

    Since the first experiments, twenty years ago, free-electron lasers (FEL) have known a strong development because of their promise: broadband tunability from X-rays to microwaves and high (peak or average) power, limited only by technological issues. ELSA has been designed as a research tool to investigate the physics of high-power FELs. After a brief introduction of the FEL field of research, we point out the unique characteristics of ELSA and why it is a valuable tool for the study of FEL interaction in the strong electron-photon coupling. The main experimental results are reviewed. We conclude on the concept of Two-Frequency-Wiggler. (author)

  2. Láser helio-neón combinado con clorhexidina al 0,2 %.: Efectos clínicos y microbiológicos en el tratamiento de la gingivitis crónica Helium-neon laser combined with 0.2% chlorhexidine: Clinical and microbiological effects in the treatment of chronic gingivitis.

    Directory of Open Access Journals (Sweden)

    Tatiana Peña Ruiz

    2007-09-01

    Full Text Available La gingivitis crónica constituye una de las formas más frecuentes de enfermedad periodontal, caracterizada por la inflamación crónica de la encías, tumefacción, enrojecimiento y sangramiento. Su principal factor de riesgo lo constituye la microbiota del surco gingival, que resulta necesario, pero no suficiente para desencadenarla. Se realizó un ensayo clínico-terapéutico fase II, controlado, aleatorizado y a simple ciegas, para evaluar los efectos clínicos y microbiológicos del tratamiento combinado de la radiación láser helio-neón (He-Ne con la clorhexidina al 0,2 %. Todos los pacientes recibieron tratamiento inicial; al mes de finalizado este, se distribuyeron aleatoriamente en 2 grupos: un grupo estudio que recibió la combinación láser-neón y clorhexidina al 0,2 % y otro grupo control que solo recibió clorhexidina al 0,2 %. Se realizó una evaluación a los 15, 30 y 45 días, con criterios de eficacia clínicos y microbiológicos. Los resultados clínicos fueron satisfactorios en el grupo estudio con predominio de los morfotipos I, caracterizados por cocos gramnegativos y positivos, compatibles con un periodonto sano. Los eventos adversos detectados con esta terapéutica fueron mínimos, todos relacionados con la somnolencia.Chronic gingivitis is one of the most common periodontal diseases that is characterized by chronic inflammation, tumefaction, redness and bleeding. The main risk factor is gingival sulcus microbiota that is essential but not enough to unleash it. A phase II controlled randomized blind clinical/therapeutical assay was conducted to evaluate the clinical and microbiological effects of the combined treatment based on helium-neon laser (He-Ne with 0.2% chlorhexidine. All the patients were initially treated; after a month, they were randomly distributed into two groups, that is, the study group received a helium-neon laser plus 0.2% chlorhexidine combination and the control group was treated with 0

  3. Interaction of low-intensity linearly polarized laser radiation with living tissues: effects on tissular acceleration of skin wound healing; Interacao da radiacao laser linearmente polarizada de baixa intensidade com tecidos vivos: efeitos na acelaracao de cicatrizacao tissular em lesoes de pele

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Martha Simoes

    2000-07-01

    According to the Maxwell's equations to optical properties of surfaces, the energy deposition efficiency in a microroughness interface depends on the electrical field polarization component. Considering a linearly polarized beam, this efficiency will depend on the roughness parameters to p-polarized light and it will not depend on such parameters to s-polarized light. In this work it was investigated the effects of low-intensity, linearly polarized He-Ne laser beam on skin wounds healing, considering two orthogonal directions of polarization. We have considered a preferential axis as the animals' spinal column and we aligned the linear laser polarization first parallel, then perpendicular to this direction. Burns about 6 mm in diameter were created with liquid N{sub 2} on the back of the animals and the lesions were irradiated on days 3, 7, 10 and 14 post-wounding, D= 1,0 J/cm{sup 2}. Control lesions were not irradiated. The theoretical model consisted in describing linearly polarized light propagation in biological tissues using transport theory. The degree of polarization was measured in normal and pathological skin samples. It was verified that linearly polarized light can survive in the superficial layers of skin and it can be more preserved in skin under pathological condition when compared with health skin. The analysis of skin wound healing process has demonstrated that the relative direction of the laser polarization plays an important role on the wound healing process by light microscopy, transmission electron microscopy and radioautography. (author)

  4. Biphotonic holographic gratings in azobenzene polyesters: Surface relief phenomena and polarization effects

    DEFF Research Database (Denmark)

    Sánchez, C.; Alcalá, R.; Hvilsted, Søren

    2000-01-01

    Biphotonic holographic gratings have been recorded in a side-chain azobenzene liquid crystalline polyester using a blue incoherent source and a He-Ne laser. Intensity gratings and the appearance of surface relief have been observed when two linearly polarized beams from a He-Ne laser are made...... to interfere on a film illuminated with blue light. Polarized holographic gratings are also created with two orthogonally circularly polarized He-Ne beams. All these gratings are stable in darkness but can be erased with blue light. (C) 2000 American Institute of Physics....

  5. Laser fusion

    International Nuclear Information System (INIS)

    Eliezer, S.

    1982-02-01

    In this paper, the physics of laser fusion is described on an elementary level. The irradiated matter consists of a dense inner core surrounded by a less dense plasma corona. The laser radiation is mainly absorbed in the outer periphery of the plasma. The absorbed energy is transported inward to the ablation surface where plasma flow is created. Due to this plasma flow, a sequence of inward going shock waves and heat waves are created, resulting in the compression and heating of the core to high density and temperature. The interaction physics between laser and matter leading to thermonuclear burn is summarized by the following sequence of events: Laser absorption → Energy transport → Compression → Nuclear Fusion. This scenario is shown in particular for a Nd:laser with a wavelength of 1 μm. The wavelength scaling of the physical processes is also discussed. In addition to the laser-plasma physics, the Nd high power pulsed laser is described. We give a very brief description of the oscillator, the amplifiers, the spatial filters, the isolators and the diagnostics involved. Last, but not least, the concept of reactors for laser fusion and the necessary laser system are discussed. (author)

  6. Biocavity Lasers

    Energy Technology Data Exchange (ETDEWEB)

    Gourley, P.L.; Gourley, M.F.

    2000-10-05

    Laser technology has advanced dramatically and is an integral part of today's healthcare delivery system. Lasers are used in the laboratory analysis of human blood samples and serve as surgical tools that kill, burn or cut tissue. Recent semiconductor microtechnology has reduced the size o f a laser to the size of a biological cell or even a virus particle. By integrating these ultra small lasers with biological systems, it is possible to create micro-electrical mechanical systems that may revolutionize health care delivery.

  7. Measurement of large nonlinear refractive index of natural pigment extracted from Hibiscus rosa-sinensis leaves with a low power CW laser and by spatial self-phase modulation technique

    Science.gov (United States)

    Biswas, S.; Kumbhakar, P.

    2017-02-01

    We have reported here, for the first time, to the best of our knowledge, a high nonlinear refractive index (n2e) of a natural pigment extracted from Hibiscus rosa-sinensis leaves by using spatial self-phase modulation technique (SSPM) with a low power CW He-Ne laser radiation at 632.8 nm. It is found by UV-Vis absorption spectroscopic analysis that chlrophyll-a, chlrophyll-b and carotenoid are present in the pigment extract with 56%, 25% and 19%, respectively. The photoluminescence (PL) emission characteristics of the extracted samples have also been measured at room temperature as well as in the temperature range of 283-333 K to investigate the effect of temperature on luminescent properties of the sample. By analyzing the SSPM experimental data, the nonlinear refractive index value of pigment extract has been determined to be 3.5 × 10- 5 cm2/W. The large nonlinear refractive index has been assigned due to asymmetrical structure, molecular reorientation and thermally induced nonlinearity in the sample. The presented results might open new avenues for the green and economical technique of syntheses of organic dyes with such a large nonlinear optical property.

  8. High power lasers & systems

    OpenAIRE

    Chatwin, Chris; Young, Rupert; Birch, Philip

    2015-01-01

    Some laser history;\\ud Airborne Laser Testbed & Chemical Oxygen Iodine Laser (COIL);\\ud Laser modes and beam propagation;\\ud Fibre lasers and applications;\\ud US Navy Laser system – NRL 33kW fibre laser;\\ud Lockheed Martin 30kW fibre laser;\\ud Conclusions

  9. Low-power laser irradiation improves histomorphometrical parameters and bone matrix organization during tibia wound healing in rats.

    Science.gov (United States)

    Garavello-Freitas, I; Baranauskas, V; Joazeiro, P P; Padovani, C R; Dal Pai-Silva, M; da Cruz-Höfling, Maria Alice

    2003-01-01

    The influence of daily energy doses of 0.03, 0.3 and 0.9 J of He-Ne laser irradiation on the repair of surgically produced tibia damage was investigated in Wistar rats. Laser treatment was initiated 24 h after the trauma and continued daily for 7 or 14 days in two groups of nine rats (n=3 per laser dose and period). Two control groups (n=9 each) with injured tibiae were used. The course of healing was monitored using morphometrical analysis of the trabecular area. The organization of collagen fibers in the bone matrix and the histology of the tissue were evaluated using Picrosirius-polarization method and Masson's trichrome. After 7 days, there was a significant increase in the area of neoformed trabeculae in tibiae irradiated with 0.3 and 0.9 J compared to the controls. At a daily dose of 0.9 J (15 min of irradiation per day) the 7-day group showed a significant increase in trabecular bone growth compared to the 14-day group. However, the laser irradiation at the daily dose of 0.3 J produced no significant decrease in the trabecular area of the 14-day group compared to the 7-day group, but there was significant increase in the trabecular area of the 15-day controls compared to the 8-day controls. Irradiation increased the number of hypertrophic osteoclasts compared to non-irradiated injured tibiae (controls) on days 8 and 15. The Picrosirius-polarization method revealed bands of parallel collagen fibers (parallel-fibered bone) at the repair site of 14-day-irradiated tibiae, regardless of the dose. This organization improved when compared to 7-day-irradiated tibiae and control tibiae. These results show that low-level laser therapy stimulated the growth of the trabecular area and the concomitant invasion of osteoclasts during the first week, and hastened the organization of matrix collagen (parallel alignment of the fibers) in a second phase not seen in control, non-irradiated tibiae at the same period. The active osteoclasts that invaded the regenerating site were

  10. Statistical properties of visible and infrared beams retroreflected through a turbulent atmosphere

    International Nuclear Information System (INIS)

    Slatkine, M.; Bensimon, D.; Englander, A.; Shtrikman, S.; Treves, D.

    1980-01-01

    Statistical properties of HeNe and CO 2 laser beams retroreflected through a turbulent atmosphere are investigated experimentally for round paths of 1 km and 12 km. Both heterodyne and direct detection are used

  11. Fulltext PDF

    Indian Academy of Sciences (India)

    2013-01-10

    Jan 10, 2013 ... of triangular pulses is apparently altered in accordance with the instantaneous values of a .... an optical fiber by considering a mitochondrion as 'core' and ... and plasma membrane irradiated at 633 nm (HeNe laser).

  12. Laser Dyes

    Indian Academy of Sciences (India)

    amplification or generation of coherent light waves in the UV,. VIS, and near IR region. .... ciency in most flashlamp pumped dye lasers. It is used as reference dye .... have led to superior laser dyes with increased photostabilities. For instance ...

  13. EFFICACY OF LASER PULSE FREQUENCIES ON BLOOD FLOW IN TYPE 2 DIABETIC PATIENTS

    Directory of Open Access Journals (Sweden)

    Amir Nazih Wadee

    2017-04-01

    Full Text Available Background: Research reports had noted an apparent increase in cutaneous and deep blood flow as a result of low-intensity laser therapy (LLLT in normal subjects. The purpose of te study was to investigate the effective laser pulse frequency either (200 or 2000 Hz on improving blood flow in type 2 diabetic patients. Forty-five diabetic patients selected from out clinic of Kasr El-Aini Hospital, Cairo University assigned randomly into three groups. The blood flow volume, blood flow velocity and caliper of the blood vessel were evaluated before laser application and after twelve sessions using duplex Doppler ultrasound. Methods: Combined He-Ne and infrared LILT was administered three times a week for twelve sessions at intensity of 3 J, power 500 mW, 808 nm duration 15 min and pulse frequency 200 Hz for group I, 2000 Hz for group II, and sham LILT for group III on the sural artery at posterior aspect of dominant leg. Result: Paired t-test revealed that low pulse frequency (200 Hz LILT produced significant improvement in blood flow volume and blood flow velocity (t= 1.76, p= 0.001 and t= 2.8, p= 0.01 respectively (P<0.05. While there was no significant changes in caliper of the blood vessel of group I, blood flow volume, blood flow velocity or caliper of the blood vessel of group II and group III (t= 2.15, p= 1, t= 2.15, p= 1, t= 1.11 p= 0.31, t= 1.54, p= 0.15, t= 2.51, p= 1, t= 1.21 p= 0.33, t= 1.45, p= 0.15 respectively (P<0.05. ANOVA test in between groups revealed insignificant changes in all pre and post- measures except significant results in blood flow volume and velocity which indicating the superiority of group I on both group II and III by post hoc test. Conclusion: low pulse frequency of LILT (200 Hz could improve blood flow than high pulse frequency (2000 Hz.

  14. Uso combinado da laserterapia de baixa potência e da inibição da ciclooxigenase-2 na reepitelização de ferida incisional em pele de camundongos: um estudo pré-clínico Combined use of low level laser therapy and cyclooxygenase-2 selective inhibition on skin incisional wound reepithelialization in mice: a preclinical study

    Directory of Open Access Journals (Sweden)

    Cíntia Helena Santuzzi

    2011-04-01

    Full Text Available FUNDAMENTOS: A laserterapia de baixa potência e os inibidores seletivos da ciclooxigenase-2 (ICOX2 vem sendo muito utilizados para modular a resposta inflamatória, entretanto, os seus efeitos na reepitelização de feridas não são bem compreendidos. OBJETIVO: Avaliar os efeitos isolados e combinados da laserterapia de baixa potência e da ICOX2 na reepitelização de ferida incisional na pele de camundongos. MÉTODO: Foi induzida uma ferida de 1 cm no dorso de cada camundongo, que foram divididos em quatro grupos (N=20: Controle, Laserterapia, Tratados com celecoxib e Terapia conjugada. Os animais dos grupos celecoxib e Terapia conjugada foram tratados com celecoxib por 10 dias antes da incisão cutânea. As feridas experimentais foram irradiadas com laserterapia de baixa potência He-Ne (632nm, dose: 4J/cm2 em varredura, por 12 segundos durante três dias consecutivos nos grupos Laserterapia e Terapia conjugada. Os animais foram sacrificados no 3º dia de pós-operatório. Amostras das feridas foram coletadas e coradas (Tricromio de Masson para análise histomorfométrica. RESULTADOS: Tanto o grupo Laserterapia, quanto o grupo celecoxib, mostrou aumento da reepitelização cutânea em relação ao grupo Controle, entretanto, o grupo Terapia conjugada não apresentou diferenças. Quanto à queratinização o grupo Laserterapia e Terapia conjugada apresentaram redução dos queratinócitos, comparados com o grupo Controle. CONCLUSÕES: Os resultados mostram que o uso da laserterapia de baixa potência e da ICOX2 isoladamente aumentam as células epiteliais, mas somente a laserterapia de baixa potência reduziu os queratinócitos cutâneos. O tratamento conjugado restabelece a reepitelização inata e dimunui a queratinização, embora ocorra uma acelerada contração da ferida com melhora na organização da ferida na pele de camundongos.BACKGROUND: Low level laser therapy and cyclooxygenase-2 (ICOX2 selective inhibitors have been widely used

  15. Comb-Resolved Dual-Comb Spectroscopy Stabilized by Free-Running Continuous-Wave Lasers

    Science.gov (United States)

    Kuse, Naoya; Ozawa, Akira; Kobayashi, Yohei

    2012-11-01

    We demonstrate dual-comb spectroscopy with relatively phase-locked two frequency combs, instead of frequency combs firmly fixed to the absolute frequency references. By stabilizing two beat frequencies between two mode-locked lasers at different wavelengths observed via free-running continuous-wave (CW) lasers, two combs are tightly phase locked to each other. The frequency noise of the CW lasers barely affects the performance of dual-comb spectroscopy because of the extremely fast common-mode noise rejection. Transform-limited comb-resolved dual-comb spectroscopy with a 6 Hz radio frequency linewidth is demonstrated by the use of Yb-fiber oscillators.

  16. The effect of laser and X-rays on the invasive capability of the larvae of Fasciola hepatica L

    International Nuclear Information System (INIS)

    Bielecki, A.

    1986-01-01

    The material comprised eggs and larvae of F. hepatica and its hosts: intermediate - Galba truncatula (L.) and final (Mus. sp.). The eggs and larvae of F. hepatica were exposed to X-rays hard, 240 KV 20 R/s intensity and L-rays of a laser HE-Ne of low power 0.82 mW, light wave length 632.8 mm. The eggs were exposed at the first day of culture while the miracidia at the first hour of their life, using the doses of 1, 100, 200, 400, 600, 800, 1200 R in the case of X-rays and 5, 10, 15 and 30 min in the case of L-rays. In order to express the effect of irradiation on the invasive capability of the miracidia developing inside egg capsules those hatching of the eggs and of the adolescariae, the invasion index was calculated. In the case of miracidia all the doses of X-rays used in the experiment limit the number of adolescariae and adult flukes. The X-rays used at low doses in the case of adolescariae (1 R) increase the intensity of mouse infection with adult flukes, while higher doses (e.g. 1200 R) decrease the infection. The L-rays applied to miracidia cause an inrease in the number of cercariae developing per snail and the intensity of mouse infection also grows. In the case of adolescariae they decrease the intensity of mouse infection. In the flukes developing from larvae (miracidia, adolescariae) exposed to X- and L-rays the lack of eggs in the uterus was observed as well as the decrease of size. 43 refs., 5 figs., 6 tabs. (author)

  17. Laser spectroscopy

    CERN Document Server

    Demtröder, Wolfgang

    2008-01-01

    Keeping abreast of the latest techniques and applications, this new edition of the standard reference and graduate text on laser spectroscopy has been completely revised and expanded. While the general concept is unchanged, the new edition features a broad array of new material, e.g., frequency doubling in external cavities, reliable cw-parametric oscillators, tunable narrow-band UV sources, more sensitive detection techniques, tunable femtosecond and sub-femtosecond lasers (X-ray region and the attosecond range), control of atomic and molecular excitations, frequency combs able to synchronize independent femtosecond lasers, coherent matter waves, and still more applications in chemical analysis, medical diagnostics, and engineering.

  18. Laser spectroscopy

    CERN Document Server

    Demtröder, Wolfgang

    Keeping abreast of the latest techniques and applications, this new edition of the standard reference and graduate text on laser spectroscopy has been completely revised and expanded. While the general concept is unchanged, the new edition features a broad array of new material, e.g., ultrafast lasers (atto- and femto-second lasers) and parametric oscillators, coherent matter waves, Doppler-free Fourier spectroscopy with optical frequency combs, interference spectroscopy, quantum optics, the interferometric detection of gravitational waves and still more applications in chemical analysis, medical diagnostics, and engineering.

  19. Il laser

    CERN Document Server

    Smith, William V

    1974-01-01

    Verso il 1960, il laser era ancora "una soluzione alla ricerca di un problema", ma fin dagli anni immediatamente successivi si è rivelato uno strumento insostituibile per le applicazioni più svariate.

  20. Laser Refractography

    CERN Document Server

    Rinkevichyus, B.S; Raskovskaya, I.L

    2010-01-01

    This book describes the basic principles of laser refractography, a flexible new diagnostic tool for measuring optically inhomogeneous media and flows. Laser refractography is based on digital imaging and computer processing of structured laser beam refraction (SLR) in inhomogeneous transparent media. Laser refractograms provide both qualitative and quantitative measurements and can be used for the study of fast and transient processes. In this book, the theoretical basis of refractography is explored in some detail, and experimental setups are described for measurement of transparent media using either 2D (passed radiation) or 3D (scattered radiation) refractograms. Specific examples and applications are discussed, including visualization of the boundary layer near a hot or cold metallic ball in water, and observation of edge effects and microlayers in liquids and gases. As the first book to describe this new and exciting technique, this monograph has broad cross-disciplinary appeal and will be of interest t...

  1. Laser fusion

    International Nuclear Information System (INIS)

    Ashby, D.E.T.F.

    1976-01-01

    A short survey is given on laser fusion its basic concepts and problems and the present theoretical and experimental methods. The future research program of the USA in this field is outlined. (WBU) [de

  2. Laser spectroscopy

    International Nuclear Information System (INIS)

    Letokhov, V.S.

    1981-01-01

    This article describes recent progress in the application of laser atomic spectroscopy to study parameters of nuclei available in very small quantities; radioactive nuclei, rare isotopes, nuclear isomers, etc, for which study by conventional spectroscopic methods is difficult. (author)

  3. Laser fusion

    International Nuclear Information System (INIS)

    Key, M.H.; Oxford Univ.

    1990-04-01

    The use of lasers to drive implosions for the purpose of inertially confined fusion is an area of intense activity where progress compares favourably with that made in magnetic fusion and there are significant prospects for future development. In this brief review the basic concept is summarised and the current status is outlined both in the area of laser technology and in the most recent results from implosion experiments. Prospects for the future are also considered. (author)

  4. Laser Resurfacing

    OpenAIRE

    Janik, Joseph P.; Markus, Jodi L.; Al-Dujaili, Zeena; Markus, Ramsey F.

    2007-01-01

    In a society desiring images of beauty and youthfulness, the world of cutaneous surgery offers the gifts of facial rejuvenation for those determined to combat the signs of aging. With the development of novel laser and plasma technology, pigmentary changes, scarring, and wrinkles can be conquered providing smoother, healthier, younger-looking skin. This review highlights five of the most popular resurfacing technologies in practice today including the carbon dioxide (CO2) laser, the erbium:yt...

  5. Green lasers

    DEFF Research Database (Denmark)

    Jensen, Ole Bjarlin

    2010-01-01

    Well over a dozen papers at this year's Photonics West meeting in San Francisco boasted improvements in harmonic generation to produce visible laser beams, most of them in the green spectral range......Well over a dozen papers at this year's Photonics West meeting in San Francisco boasted improvements in harmonic generation to produce visible laser beams, most of them in the green spectral range...

  6. Campargue-type supersonic beam sources : absolute intensities, skimmer transmission and scaling laws for mono-atomic gases He, Ne and Ar

    NARCIS (Netherlands)

    Beijerinck, H.C.W.; van Gerwen, R.J.F.; Kerstel, E.R.T.; Martens, J.F.M.; van Vliembergen, E.J.W.; Smits, M.R.T.; Kaashoek, G.H.

    1985-01-01

    The process of beam formation in a supersonic expansion into a high pressure (10-2 -1 Torr) expansion chamber, a so-called Campargue-type beam source, has been investigated, using the theoretical frame work of an ideal undisturbed expansion as a reference. Absolute values of the centre-line

  7. Reply to projectile- and target-charge dependent effects in ionizing collisions of H sup + and He sup 2+ with He, Ne and Ar atoms

    Energy Technology Data Exchange (ETDEWEB)

    Bernardi, G.; Suarez, S.; Fainstein, P.; Garibotti, C.; Meckbach, W.; Focke, P. (Comision Nacional de Energia Atomica, San Carlos de Bariloche (Argentina). Centro Atomico Bariloche)

    1990-12-28

    The consistency of our previous results, for He ionization by H{sup +} and He{sub 3}{sup 2+} impact, with recent theoretical calculations is briefly commented upon. The results do not support the hypothesis of an independent saddle-point mechanism at the projectile energies studied. (author).

  8. Laser material processing

    CERN Document Server

    Steen, William

    2010-01-01

    This text moves from the basics of laser physics to detailed treatments of all major materials processing techniques for which lasers are now essential. New chapters cover laser physics, drilling, micro- and nanomanufacturing and biomedical laser processing.

  9. Laser therapy for cancer

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000905.htm Laser therapy for cancer To use the sharing features ... Lasers are also used on the skin. How Laser Therapy is Used Laser therapy can be used ...

  10. Lasers in Cancer Treatment

    Science.gov (United States)

    ... the advantages of laser therapy? What are the disadvantages of laser therapy? What does the future hold ... therapy is appropriate for them. What are the disadvantages of laser therapy? Laser therapy also has several ...

  11. Practical laser safety

    International Nuclear Information System (INIS)

    Winburn, D.C.

    1985-01-01

    This book includes discussions of the following topics: characteristics of lasers; eye components; skin damage thresholds; classification of lasers by ANSI Z136.1; selecting laser-protective eyewear; hazards associated with lasers; and, an index

  12. A novel non-contact profiler design for measuring synchrotron radiation mirrors

    International Nuclear Information System (INIS)

    Lin, Yao; Takacs, P.Z.; Furenlid, K.; DeBiasse, R.A.; Wang, Run-Wen

    1990-08-01

    A novel optical profiler is described in this paper for measurement of surface profiles of synchrotron radiation (SR) mirrors. The measurement is based on a combination of an optical heterodyne technique and a precise phase measurement procedure without a reference surface. A Zeeman two-frequency He-Ne laser is employed as the light source. The common-path optical system, which uses a birefringent lens as the beam splitter, minimizes the effects of air turbulence, sample vibration and temperature variation. A special autofocus system allows the profiler to measure the roughness and shape of a sample surface. The optical system is mounted on a large linear air-bearing slide, and is capable of scanning over distances covering the spatial period range from several microns to nearly one meter with a high measurement accuracy. 9 refs., 5 figs

  13. Laser acceleration

    Science.gov (United States)

    Tajima, T.; Nakajima, K.; Mourou, G.

    2017-02-01

    The fundamental idea of Laser Wakefield Acceleration (LWFA) is reviewed. An ultrafast intense laser pulse drives coherent wakefield with a relativistic amplitude robustly supported by the plasma. While the large amplitude of wakefields involves collective resonant oscillations of the eigenmode of the entire plasma electrons, the wake phase velocity ˜ c and ultrafastness of the laser pulse introduce the wake stability and rigidity. A large number of worldwide experiments show a rapid progress of this concept realization toward both the high-energy accelerator prospect and broad applications. The strong interest in this has been spurring and stimulating novel laser technologies, including the Chirped Pulse Amplification, the Thin Film Compression, the Coherent Amplification Network, and the Relativistic Mirror Compression. These in turn have created a conglomerate of novel science and technology with LWFA to form a new genre of high field science with many parameters of merit in this field increasing exponentially lately. This science has triggered a number of worldwide research centers and initiatives. Associated physics of ion acceleration, X-ray generation, and astrophysical processes of ultrahigh energy cosmic rays are reviewed. Applications such as X-ray free electron laser, cancer therapy, and radioisotope production etc. are considered. A new avenue of LWFA using nanomaterials is also emerging.

  14. Laser acceleration

    International Nuclear Information System (INIS)

    Tajima, T.; Nakajima, K.; Mourou, G.

    2017-01-01

    The fundamental idea of LaserWakefield Acceleration (LWFA) is reviewed. An ultrafast intense laser pulse drives coherent wakefield with a relativistic amplitude robustly supported by the plasma. While the large amplitude of wake fields involves collective resonant oscillations of the eigenmode of the entire plasma electrons, the wake phase velocity ∼ c and ultra fastness of the laser pulse introduce the wake stability and rigidity. A large number of worldwide experiments show a rapid progress of this concept realization toward both the high-energy accelerator prospect and broad applications. The strong interest in this has been spurring and stimulating novel laser technologies, including the Chirped Pulse Amplification, the Thin Film Compression, the Coherent Amplification Network, and the Relativistic Mirror Compression. These in turn have created a conglomerate of novel science and technology with LWFA to form a new genre of high field science with many parameters of merit in this field increasing exponentially lately. This science has triggered a number of worldwide research centers and initiatives. Associated physics of ion acceleration, X-ray generation, and astrophysical processes of ultrahigh energy cosmic rays are reviewed. Applications such as X-ray free electron laser, cancer therapy, and radioisotope production etc. are considered. A new avenue of LWFA using nano materials is also emerging.

  15. Laser Heterodyning

    CERN Document Server

    Protopopov, Vladimir V

    2009-01-01

    Laser heterodyning is now a widespread optical technique, based on interference of two waves with slightly different frequencies within the sensitive area of a photo-detector. Its unique feature – preserving phase information about optical wave in the electrical signal of the photo-detector – finds numerous applications in various domains of applied optics and optoelectronics: in spectroscopy, polarimetry, radiometry, laser radars and Lidars, microscopy and other areas. The reader may be surprised by a variety of disciplines that this book covers and satisfied by detailed explanation of the phenomena. Very well illustrated, this book will be helpful for researches, postgraduates and students, working in applied optics.

  16. Laser polarimetry

    International Nuclear Information System (INIS)

    Goldstein, D.H.

    1989-01-01

    Polarimetry, or transmission ellipsometry, is an important experimental technique for the determination of polarization properties of bulk materials. In this technique, source radiation of known polarization is passed through bulk samples to determine, for example, natural or induced birefringence and dichroism. The laser is a particularly appropriate source for this technique because of its monochromaticity, collimation, and radiant intensity. Lasers of many different wavelengths in different spectral regions are now available. Laser polarimetry can be done in any of these wavelength regions where polarizing elements are available. In this paper, polarimetry is reviewed with respect to applications, sources used, and polarization state generator and analyzer configurations. Scattering ellipsometry is also discussed insofar as the forward scattering measurement is related to polarimetry. The authors then describe an infrared laser polarimeter which we have designed and constructed. This instrument can operate over large wavelength regions with only a change in source. Polarization elements of the polarimeter are in a dual rotating retarder configuration. Computer controlled rotary stages and computer monitored detectors automate the data collection. The Mueller formulation is used to process the polarization information. Issues and recent progress with this instrument are discussed

  17. excimer laser

    Indian Academy of Sciences (India)

    2014-01-07

    Jan 7, 2014 ... is necessary to deposit one order higher input electric power into gas medium than ... cross-sectional view of the laser system is shown in figure 2A. The system mainly consists ... Considering the simplicity and reliability of the.

  18. Laser device

    DEFF Research Database (Denmark)

    2013-01-01

    The present invention provides a light source for light circuits on a silicon platform. A vertical laser cavity is formed by a gain region arranged between a first mirror structure and a second mirror structure, both acting as mirrors, by forming a grating region including an active material...

  19. Nanowire Lasers

    Directory of Open Access Journals (Sweden)

    Couteau C.

    2015-05-01

    Full Text Available We review principles and trends in the use of semiconductor nanowires as gain media for stimulated emission and lasing. Semiconductor nanowires have recently been widely studied for use in integrated optoelectronic devices, such as light-emitting diodes (LEDs, solar cells, and transistors. Intensive research has also been conducted in the use of nanowires for subwavelength laser systems that take advantage of their quasione- dimensional (1D nature, flexibility in material choice and combination, and intrinsic optoelectronic properties. First, we provide an overview on using quasi-1D nanowire systems to realize subwavelength lasers with efficient, directional, and low-threshold emission. We then describe the state of the art for nanowire lasers in terms of materials, geometry, andwavelength tunability.Next,we present the basics of lasing in semiconductor nanowires, define the key parameters for stimulated emission, and introduce the properties of nanowires. We then review advanced nanowire laser designs from the literature. Finally, we present interesting perspectives for low-threshold nanoscale light sources and optical interconnects. We intend to illustrate the potential of nanolasers inmany applications, such as nanophotonic devices that integrate electronics and photonics for next-generation optoelectronic devices. For instance, these building blocks for nanoscale photonics can be used for data storage and biomedical applications when coupled to on-chip characterization tools. These nanoscale monochromatic laser light sources promise breakthroughs in nanophotonics, as they can operate at room temperature, can potentially be electrically driven, and can yield a better understanding of intrinsic nanomaterial properties and surface-state effects in lowdimensional semiconductor systems.

  20. Excimer Laser Technology

    CERN Document Server

    Basting, Dirk

    2005-01-01

    This comprehensive survey on Excimer Lasers investigates the current range of the technology, applications and devices of this commonly used laser source, as well as the future of new technologies, such as F2 laser technology. Additional chapters on optics, devices and laser systems complete this compact handbook. A must read for laser technology students, process application researchers, engineers or anyone interested in excimer laser technology. An effective and understandable introduction to the current and future status of excimer laser technology.

  1. Laser ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Bykovskij, Yu

    1979-02-01

    The characteristics a laser source of multiply-ionized ions are described with regard to the interaction of laser radiation and matter, ion energy spectrum, angular ion distribution. The amount of multiple-ionization ions is evaluated. Out of laser source applications a laser injector of multiple-ionization ions and nuclei, laser mass spectrometry, laser X-ray microradiography, and a laser neutron generators are described.

  2. Dual frequency comb metrology with one fiber laser

    Science.gov (United States)

    Zhao, Xin; Takeshi, Yasui; Zheng, Zheng

    2016-11-01

    Optical metrology techniques based on dual optical frequency combs have emerged as a hotly studied area targeting a wide range of applications from optical spectroscopy to microwave and terahertz frequency measurement. Generating two sets of high-quality comb lines with slightly different comb-tooth spacings with high mutual coherence and stability is the key to most of the dual-comb schemes. The complexity and costs of such laser sources and the associated control systems to lock the two frequency combs hinder the wider adoption of such techniques. Here we demonstrate a very simple and rather different approach to tackle such a challenge. By employing novel laser cavity designs in a mode-locked fiber laser, a simple fiber laser setup could emit dual-comb pulse output with high stability and good coherence between the pulse trains. Based on such lasers, comb-tooth-resolved dual-comb optical spectroscopy is demonstrated. Picometer spectral resolving capability could be realized with a fiber-optic setup and a low-cost data acquisition system and standard algorithms. Besides, the frequency of microwave signals over a large range can be determined based on a simple setup. Our results show the capability of such single-fiber-laser-based dual-comb scheme to reduce the complexity and cost of dual-comb systems with excellent quality for different dual-comb applications.

  3. Dermatological laser treatment

    International Nuclear Information System (INIS)

    Moerk, N.J.; Austad, J.; Helland, S.; Thune, P.; Volden, G.; Falk, E.

    1991-01-01

    The article reviews the different lasers used in dermatology. Special emphasis is placed on the treatment of naevus flammeus (''portwine stain'') where lasers are the treatment of choice. Argon laser and pulsed dye laser are the main lasers used in vascular skin diseases, and the article focuses on these two types. Copper-vapour laser, neodymium-YAG laser and CO 2 laser are also presented. Information is provided about the availability of laser technology in the different health regions in Norway. 5 refs., 2 figs

  4. CO2-laser fusion

    International Nuclear Information System (INIS)

    Stark, E.E. Jr.

    1978-01-01

    The basic concept of laser fusion is described, with a set of requirements on the laser system. Systems and applications concepts are presented and discussed. The CO 2 laser's characteristics and advantages for laser fusion are described. Finally, technological issues in the development of CO 2 laser systems for fusion applications are discussed

  5. Project LASER

    Science.gov (United States)

    1990-01-01

    NASA formally launched Project LASER (Learning About Science, Engineering and Research) in March 1990, a program designed to help teachers improve science and mathematics education and to provide 'hands on' experiences. It featured the first LASER Mobile Teacher Resource Center (MTRC), is designed to reach educators all over the nation. NASA hopes to operate several MTRCs with funds provided by private industry. The mobile unit is a 22-ton tractor-trailer stocked with NASA educational publications and outfitted with six work stations. Each work station, which can accommodate two teachers at a time, has a computer providing access to NASA Spacelink. Each also has video recorders and photocopy/photographic equipment for the teacher's use. MTRC is only one of the five major elements within LASER. The others are: a Space Technology Course, to promote integration of space science studies with traditional courses; the Volunteer Databank, in which NASA employees are encouraged to volunteer as tutors, instructors, etc; Mobile Discovery Laboratories that will carry simple laboratory equipment and computers to provide hands-on activities for students and demonstrations of classroom activities for teachers; and the Public Library Science Program which will present library based science and math programs.

  6. A contribution to the future prospect of uranium laser-isotope separation

    International Nuclear Information System (INIS)

    Becker, F.S.

    1981-01-01

    The two-frequency multiphoton-dissociation of UF 6 seems promising, using a high-power laser, which is tunable in the 16 μm spectral region due to the frequency shift of the 10 μm CO 2 -laser radiation, induced by the stimulated rotational Raman effect of para-hydrogen. In the present experiments the isotope selectivity of the multiphoton-dissociation process is studied in order to contribute to the solution of some questions, as for example the influence of high fluorine concentrations on the optical dissociation of UF 6 . (DG) [de

  7. Laser Research Lab

    Data.gov (United States)

    Federal Laboratory Consortium — The Laser Research lab is thecenter for the development of new laser sources, nonlinear optical materials, frequency conversion processes and laser-based sensors for...

  8. Laser therapy (image)

    Science.gov (United States)

    A laser is used for many medical purposes. Because the laser beam is so small and precise, it enables ... without injuring surrounding tissue. Some uses of the laser are retinal surgery, excision of lesions, and cauterization ...

  9. Laser fusion: an overview

    International Nuclear Information System (INIS)

    Boyer, K.

    1975-01-01

    The laser fusion concept is described along with developments in neodymium and carbon dioxide lasers. Fuel design and fabrication are reviewed. Some spin-offs of the laser fusion program are discussed. (U.S.)

  10. Laser power supply

    International Nuclear Information System (INIS)

    Bernstein, D.

    1975-01-01

    The laser power supply includes a regulator which has a high voltage control loop based on a linear approximation of a laser tube negative resistance characteristic. The regulator has independent control loops for laser current and power supply high voltage

  11. Bleaching Dengan Teknologi Laser

    OpenAIRE

    Eliwaty

    2008-01-01

    Penulisan tentang bleaching dengan laser dimaksudkan untuk menambah wawasan serta pengetahuan dari pembaca di bidang kedokteran gigi. Macam-macam laser yang dipergunakan dalam bleaching yaitu argon, CO2 serta dioda laser. Contoh merek produk laser yaitu Blulaze, Dentcure untuk argonlaser, Novapulse untuk C02 serta Opus 5 untuk dioda laser. Laser bleaching hasilnya dapat dicapai dalam satu kunjungan saja, cepat, efisien namun biayanya relatif mahal, dapat menimbulkan burn, sensitivitas se...

  12. Laser safety at high profile laser facilities

    International Nuclear Information System (INIS)

    Barat, K.

    2010-01-01

    Complete text of publication follows. Laser safety has been an active concern of laser users since the invention of the laser. Formal standards were developed in the early 1970's and still continue to be developed and refined. The goal of these standards is to give users guidance on the use of laser and consistent safety guidance and requirements for laser manufacturers. Laser safety in the typical research setting (government laboratory or university) is the greatest challenge to the laser user and laser safety officer. This is due to two factors. First, the very nature of research can put the user at risk; consider active manipulation of laser optics and beam paths, and user work with energized systems. Second, a laser safety culture that seems to accept laser injuries as part of the graduate student educational process. The fact is, laser safety at research settings, laboratories and universities still has long way to go. Major laser facilities have taken a more rigid and serious view of laser safety, its controls and procedures. Part of the rationale for this is that these facilities draw users from all around the world presenting the facility with a work force of users coming from a wide mix of laser safety cultures. Another factor is funding sources do not like bad publicity which can come from laser accidents and a poor safety record. The fact is that injuries, equipment damage and lost staff time slow down progress. Hence high profile/large laser projects need to adapt a higher safety regimen both from an engineering and administrative point of view. This presentation will discuss all these points and present examples. Acknowledgement. This work has been supported by the University of California, Director, Office of Science.

  13. Semiconductor Laser Measurements Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Semiconductor Laser Measurements Laboratory is equipped to investigate and characterize the lasing properties of semiconductor diode lasers. Lasing features such...

  14. Laser Protection TIL

    Data.gov (United States)

    Federal Laboratory Consortium — The Laser Protection TIL conducts research and analysis of laser protection materials along with integration schemes. The lab's objectives are to limit energy coming...

  15. Laser Propulsion - Quo Vadis

    International Nuclear Information System (INIS)

    Bohn, Willy L.

    2008-01-01

    First, an introductory overview of the different types of laser propulsion techniques will be given and illustrated by some historical examples. Second, laser devices available for basic experiments will be reviewed ranging from low power lasers sources to inertial confinement laser facilities. Subsequently, a status of work will show the impasse in which the laser propulsion community is currently engaged. Revisiting the basic relations leads to new avenues in ablative and direct laser propulsion for ground based and space based applications. Hereby, special attention will be devoted to the impact of emerging ultra-short pulse lasers on the coupling coefficient and specific impulse. In particular, laser sources and laser propulsion techniques will be tested in microgravity environment. A novel approach to debris removal will be discussed with respect to the Satellite Laser Ranging (SRL) facilities. Finally, some non technical issues will be raised aimed at the future prospects of laser propulsion in the international community

  16. Laser safety and practice

    International Nuclear Information System (INIS)

    Low, K.S.

    1995-01-01

    Lasers are finding increasing routine applications in many areas of science, medicine and industry. Though laser radiation is non-ionizing in nature, the usage of high power lasers requires specific safety procedures. This paper briefly outlines the properties of laser beams and various safety procedures necessary in their handling and usage. (author)

  17. Diode lasers and arrays

    International Nuclear Information System (INIS)

    Streifer, W.

    1988-01-01

    This paper discusses the principles of operation of III-V semiconductor diode lasers, the use of distributed feedback, and high power laser arrays. The semiconductor laser is a robust, miniature, versatile device, which directly converts electricity to light with very high efficiency. Applications to pumping solid-state lasers and to fiber optic and point-to-point communications are reviewed

  18. Laser cladding with powder

    NARCIS (Netherlands)

    Schneider, M.F.; Schneider, Marcel Fredrik

    1998-01-01

    This thesis is directed to laser cladding with powder and a CO2 laser as heat source. The laser beam intensity profile turned out to be an important pa6 Summary rameter in laser cladding. A numerical model was developed that allows the prediction of the surface temperature distribution that is

  19. Semiconductor laser shearing interferometer

    International Nuclear Information System (INIS)

    Ming Hai; Li Ming; Chen Nong; Xie Jiaping

    1988-03-01

    The application of semiconductor laser on grating shearing interferometry is studied experimentally in the present paper. The method measuring the coherence of semiconductor laser beam by ion etching double frequency grating is proposed. The experimental result of lens aberration with semiconductor laser shearing interferometer is given. Talbot shearing interferometry of semiconductor laser is also described. (author). 2 refs, 9 figs

  20. Visible Solid State Lasers

    NARCIS (Netherlands)

    Hikmet, R.A.M.

    2007-01-01

    Diode lasers can be found in various applications most notably in optical communication and optical storage. Visible lasers were until recently were all based on IR diode lasers. Using GaN, directly blue and violet emitting lasers have also been introduced to the market mainly in the area of optical

  1. Laser Microdissection.

    Science.gov (United States)

    Frost, Andra R; Eltoum, Isam-Eldin; Siegal, Gene P; Emmert-Buck, Michael R; Tangrea, Michael A

    2015-10-01

    Laser microdissection (LM) offers a relatively rapid and precise method of isolating and removing specified cells from complex tissues for subsequent analysis of their RNA, DNA, protein or metabolite content, thereby allowing assessment of the role of different cell types in the normal physiological or disease processes being studied. In this unit, protocols for the preparation of mammalian frozen tissues, fixed tissues, and cytologic specimens for LM, including tissue freezing, tissue processing and paraffin embedding, histologic sectioning, cell processing, hematoxylin and eosin staining, immunohistochemistry, and image-guided cell targeting are presented. Also provided are recipes for generating lysis buffers for the recovery of nucleic acids and proteins. The Commentary section addresses the types of specimens that can be utilized for LM and approaches to staining of specimens for cell visualization. Emphasis is placed on the preparation of tissue or cytologic specimens as this is critical to effective LM. Copyright © 2015 John Wiley & Sons, Inc.

  2. Laser EXAFS

    International Nuclear Information System (INIS)

    Mallozzi, P.J.; Epstein, H.M.; Schwenzel, R.E.; Campbell, B.E.

    1983-01-01

    Apparatus for obtaining EXAFS data of a material, comprising means for directing radiant energy from a laser onto a target in such manner as to produce X-rays at the target of a selected spectrum and intensity, suitable for obtaining the EXAFS spectrum of the material, means for directing X-rays from the target onto spectral dispersive means so located as to direct the spectrally resolved X-rays therefrom onto recording means, and means for positioning a sample of material in the optical path of the X-rays, the recording means providing a reference spectrum of X-rays not affected by the sample and absorption spectrum of X-rays modified by transmission through the sample

  3. Multibeam Fibre Laser Cutting

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove

    The appearance of the high power high brilliance fibre laser has opened for new possibilities in laser materials processing. In laser cutting this laser has demonstrated high cutting performance compared to the dominating cutting laser, the CO2-laser. However, quality problems in fibre......-laser cutting have until now limited its application in metal cutting. In this paper the first results of proof-of-principle studies applying a new approach (patent pending) for laser cutting with high brightness short wavelength lasers will be presented. In the approach, multi beam patterns are applied...... to control the melt flow out of the cut kerf resulting in improved cut quality in metal cutting. The beam patterns in this study are created by splitting up beams from 2 single mode fibre lasers and combining these beams into a pattern in the cut kerf. The results are obtained with a total of 550 W of single...

  4. Multibeam fiber laser cutting

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove; Hansen, Klaus Schütt; Nielsen, Jakob Skov

    2009-01-01

    The appearance of the high power high brilliance fiber laser has opened for new possibilities in laser materials processing. In laser cutting this laser has demonstrated high cutting performance compared to the dominating Cutting laser, the CO2 laser. However, quality problems in fiber......-laser cutting have until now limited its application to metal cutting. In this paper the first results of proof-of-principle Studies applying a new approach (patent pending) for laser cutting with high brightness and short wavelength lasers will be presented. In the approach, multibeam patterns are applied...... to control the melt flow out of the cut kerf resulting in improved cut quality in metal cutting. The beam patterns in this study are created by splitting up beams from two single mode fiber lasers and combining these beams into a pattern in the cut kerf. The results are obtained with a total of 550 W...

  5. History and principle of lasers

    International Nuclear Information System (INIS)

    Townes, Ch.H.; Schwob, C.; Julien, J.; Forget, S.; Robert-Philip, I.; Balcou, Ph.

    2010-01-01

    In the first article C.H. Townes, the inventor of the maser, describes the work and ideas that led to the invention of the laser. The second article explains how a laser operate and the third article reviews the main different types of laser: solid lasers, gas lasers, diode lasers and dye lasers

  6. Technological laser application

    International Nuclear Information System (INIS)

    Shia, D.O.; Kollen, R.; Rods, U.

    1980-01-01

    Problems of the technological applications of lasers are stated in the popular form. Main requirements to a technological laser as well as problems arising in designing any system using lasers have been considered. Areas of the laser applications are described generally: laser treatment of materials, thermal treatment, welding, broach and drilling of holes, scribing, microtreatment and adjustment of resistors, material cutting, investigations into controlled thermonuclear fussion

  7. Laser ablation principles and applications

    CERN Document Server

    1994-01-01

    Laser Ablation provides a broad picture of the current understanding of laser ablation and its many applications, from the views of key contributors to the field. Discussed are in detail the electronic processes in laser ablation of semiconductors and insulators, the post-ionization of laser-desorbed biomolecules, Fourier-transform mass spectroscopy, the interaction of laser radiation with organic polymers, laser ablation and optical surface damage, laser desorption/ablation with laser detection, and laser ablation of superconducting thin films.

  8. New power lasers

    International Nuclear Information System (INIS)

    Yamanaka, Masanobu; Daido, Hiroyuki; Imasaki, Kazuo.

    1989-01-01

    As the new power lasers which are expected to exert large extending effect to the fields of advanced science and technology including precision engineering as well as laser nuclear fusion, LD-excited solid laser, X-ray laser and free electron laser are taken up and outlined. Recently, the solid laser using high power output, high efficiency semiconductor laser as the exciting beam source has been developed. This is called laser diode (LD)-excited solid laser, and the heightening of power output and efficiency and the extension of life are planned. Its present status and application to medical use, laser machining, laser soldering and so on are described. In 1960, the laser in visible region appeared, however in 1985, the result of observing induced emission beam by electron collision exciting method was reported in USA. In the wavelength range of 200 A, holography and contact X-ray microscope applications were verified. The various types of soft X-ray laser and the perspective hereafter are shown. The principle of free electron laser is explained. In the free electron laser, wavelength can be changed by varying electron beam energy, the period of wiggler magnetic field and the intensity of magnetic field. Further, high efficiency and large power output are possible. Its present status, application and the perspective hereafter are reported. (K.I.)

  9. Laser applications in materials processing

    International Nuclear Information System (INIS)

    Ready, J.F.

    1980-01-01

    The seminar focused on laser annealing of semiconductors, laser processing of semiconductor devices and formation of coatings and powders, surface modification with lasers, and specialized laser processing methods. Papers were presented on the theoretical analysis of thermal and mass transport during laser annealing, applications of scanning continuous-wave and pulsed lasers in silicon technology, laser techniques in photovoltaic applications, and the synthesis of ceramic powders from laser-heated gas-phase reactants. Other papers included: reflectance changes of metals during laser irradiation, surface-alloying using high-power continuous lasers, laser growth of silicon ribbon, and commercial laser-shock processes

  10. Raman fiber lasers

    CERN Document Server

    2017-01-01

    This book serves as a comprehensive, up-to-date reference about this cutting-edge laser technology and its many new and interesting developments. Various aspects and trends of Raman fiber lasers are described in detail by experts in their fields. Raman fiber lasers have progressed quickly in the past decade, and have emerged as a versatile laser technology for generating high power light sources covering a spectral range from visible to mid-infrared. The technology is already being applied in the fields of telecommunication, astronomy, cold atom physics, laser spectroscopy, environmental sensing, and laser medicine. This book covers various topics relating to Raman fiber laser research, including power scaling, cladding and diode pumping, cascade Raman shifting, single frequency operation and power amplification, mid-infrared laser generation, specialty optical fibers, and random distributed feedback Raman fiber lasers. The book will appeal to scientists, students, and technicians seeking to understand the re...

  11. Ceramic Laser Materials

    Directory of Open Access Journals (Sweden)

    Guillermo Villalobos

    2012-02-01

    Full Text Available Ceramic laser materials have come a long way since the first demonstration of lasing in 1964. Improvements in powder synthesis and ceramic sintering as well as novel ideas have led to notable achievements. These include the first Nd:yttrium aluminum garnet (YAG ceramic laser in 1995, breaking the 1 KW mark in 2002 and then the remarkable demonstration of more than 100 KW output power from a YAG ceramic laser system in 2009. Additional developments have included highly doped microchip lasers, ultrashort pulse lasers, novel materials such as sesquioxides, fluoride ceramic lasers, selenide ceramic lasers in the 2 to 3 μm region, composite ceramic lasers for better thermal management, and single crystal lasers derived from polycrystalline ceramics. This paper highlights some of these notable achievements.

  12. Infrared laser system

    International Nuclear Information System (INIS)

    Cantrell, C.D.; Carbone, R.J.

    1977-01-01

    An infrared laser system and method for isotope separation may comprise a molecular gas laser oscillator to produce a laser beam at a first wavelength, Raman spin flip means for shifting the laser to a second wavelength, a molecular gas laser amplifier to amplify said second wavelength laser beam to high power, and optical means for directing the second wavelength, high power laser beam against a desired isotope for selective excitation thereof in a mixture with other isotopes. The optical means may include a medium which shifts the second wavelength high power laser beam to a third wavelength, high power laser beam at a wavelength coincidental with a corresponding vibrational state of said isotope and which is different from vibrational states of other isotopes in the gas mixture

  13. Ceramic Laser Materials

    Science.gov (United States)

    Sanghera, Jasbinder; Kim, Woohong; Villalobos, Guillermo; Shaw, Brandon; Baker, Colin; Frantz, Jesse; Sadowski, Bryan; Aggarwal, Ishwar

    2012-01-01

    Ceramic laser materials have come a long way since the first demonstration of lasing in 1964. Improvements in powder synthesis and ceramic sintering as well as novel ideas have led to notable achievements. These include the first Nd:yttrium aluminum garnet (YAG) ceramic laser in 1995, breaking the 1 KW mark in 2002 and then the remarkable demonstration of more than 100 KW output power from a YAG ceramic laser system in 2009. Additional developments have included highly doped microchip lasers, ultrashort pulse lasers, novel materials such as sesquioxides, fluoride ceramic lasers, selenide ceramic lasers in the 2 to 3 μm region, composite ceramic lasers for better thermal management, and single crystal lasers derived from polycrystalline ceramics. This paper highlights some of these notable achievements. PMID:28817044

  14. Spectroscopic and imaging diagnostics of pulsed laser deposition laser plasmas

    International Nuclear Information System (INIS)

    Thareja, Raj K.

    2002-01-01

    An overview of laser spectroscopic techniques used in the diagnostics of laser ablated plumes used for thin film deposition is given. An emerging laser spectroscopic imaging technique for the laser ablation material processing is discussed. (author)

  15. Lasers in periodontics.

    Science.gov (United States)

    Elavarasu, Sugumari; Naveen, Devisree; Thangavelu, Arthiie

    2012-08-01

    Laser is one of the most captivating technologies in dental practice since Theodore Maiman in 1960 invented the ruby laser. Lasers in dentistry have revolutionized several areas of treatment in the last three and a half decades of the 20(th) century. Introduced as an alternative to mechanical cutting device, laser has now become an instrument of choice in many dental applications. Evidence suggests its use in initial periodontal therapy, surgery, and more recently, its utility in salvaging implant opens up a wide range of applications. More research with better designs are a necessity before lasers can become a part of dental armamentarium. This paper gives an insight to laser in periodontics.

  16. Excimer laser applications

    International Nuclear Information System (INIS)

    Fantoni, R.

    1988-01-01

    This lecture deals with laser induced material photoprocessing, especially concerning those processes which are initiated by u.v. lasers (mostly excimer laser). Advantages of using the u.v. radiation emitted by excimer lasers, both in photophysical and photochemical processes of different materials, are discussed in detail. Applications concerning microelectronics are stressed with respect to other applications in different fields (organic chemistry, medicine). As further applications of excimer lasers, main spectroscopic techniques for ''on line'' diagnostics which employ excimer pumped dye lasers, emitting tunable radiation in the visible and near u.v. are reviewed

  17. Lasers in chemical processing

    International Nuclear Information System (INIS)

    Davis, J.I.

    1982-01-01

    The high cost of laser energy is the crucial issue in any potential laser-processing application. It is expensive relative to other forms of energy and to most bulk chemicals. We show those factors that have previously frustrated attempts to find commercially viable laser-induced processes for the production of materials. Having identified the general criteria to be satisfied by an economically successful laser process and shown how these imply the laser-system requirements, we present a status report on the uranium laser isotope separation (LIS) program at the Lawrence Livermore National Laboratory

  18. Laser in urology. Laser i urologien

    Energy Technology Data Exchange (ETDEWEB)

    Breisland, H.O. (Aker Sykehus, Oslo (Norway))

    1991-09-01

    The neodymium YAG laser is particularly suited for endoscopic urologic surgery because the YAG laser light can be conducted in flexible fibers. Superficial bladder tumours can be treated under local anaesthesia in the outpatient department. The frequency of local recurrences is low, significantly lower than after electrosection or electrocoagulation. Selected cases of T2-muscle invasive bladder tumours can be cured with laser coagulation applied subsequently to transurethral resection. Combined treatment with electrosection and laser coagulation of localized prostatic cancer is a promising method which compares favourably with results obtained by other treatment modalities. Tumours in the upper urinary tract can be laser-treated through ureteroscopes or nephroscopes, but the treatment should be limited to low stage, low grade tumours. Laser is the treatment of choice for intraurethral condylomatas. Laser treatment of penil carcinoma gives excellent cosmetic and functional results and few local recurrences. Laser lithotripsy is a new technique for treatment of ureteric stones and photodynamic laser therapy is a promising tecnique for treatment of carcinoma in situ in the bladder empithelium. However, neither of these techniques are available for clinical use in Norway as yet. 17 refs., 3 figs., 1 tabs.

  19. Laser materials processing with diode lasers

    OpenAIRE

    Li, Lin; Lawrence, Jonathan; Spencer, Julian T.

    1996-01-01

    Laser materials processing is currently dominated by CO2, Nd-YAG and Excimer lasers. Continuous advances in semiconductor laser technology over the last decade have increased the average power output of the devices annualy by two fold, resulting in the commercial availability of the diode lasers today with delivery output powers in excess of 60W in CW mode and 5kW in qasi-CW mode. The advantages of compactness, high reliability, high efficiency and potential low cost, due to the mass producti...

  20. 1982 laser program annual report

    International Nuclear Information System (INIS)

    Hendricks, C.D.; Grow, G.R.

    1983-08-01

    This annual report covers the following eight sections: (1) laser program review, (2) laser systems and operation, (3) target design, (4) target fabrication, (5) fusion experiments program, (6) Zeus laser project, (7) laser research and development, and (8) energy applications

  1. Effect of laser pulse shaping parameters on the fidelity of quantum logic gates.

    Science.gov (United States)

    Zaari, Ryan R; Brown, Alex

    2012-09-14

    The effect of varying parameters specific to laser pulse shaping instruments on resulting fidelities for the ACNOT(1), NOT(2), and Hadamard(2) quantum logic gates are studied for the diatomic molecule (12)C(16)O. These parameters include varying the frequency resolution, adjusting the number of frequency components and also varying the amplitude and phase at each frequency component. A time domain analytic form of the original discretized frequency domain laser pulse function is derived, providing a useful means to infer the resulting pulse shape through variations to the aforementioned parameters. We show that amplitude variation at each frequency component is a crucial requirement for optimal laser pulse shaping, whereas phase variation provides minimal contribution. We also show that high fidelity laser pulses are dependent upon the frequency resolution and increasing the number of frequency components provides only a small incremental improvement to quantum gate fidelity. Analysis through use of the pulse area theorem confirms the resulting population dynamics for one or two frequency high fidelity laser pulses and implies similar dynamics for more complex laser pulse shapes. The ability to produce high fidelity laser pulses that provide both population control and global phase alignment is attributed greatly to the natural evolution phase alignment of the qubits involved within the quantum logic gate operation.

  2. Photonic bandgap fiber lasers and multicore fiber lasers for next generation high power lasers

    DEFF Research Database (Denmark)

    Shirakawa, A.; Chen, M.; Suzuki, Y.

    2014-01-01

    Photonic bandgap fiber lasers are realizing new laser spectra and nonlinearity mitigation that a conventional fiber laser cannot. Multicore fiber lasers are a promising tool for power scaling by coherent beam combination. © 2014 OSA....

  3. Laser in operative dentistry

    Directory of Open Access Journals (Sweden)

    E. Yasini

    1994-06-01

    Full Text Available Today laser has a lot of usage in medicine and dentistry. In the field of dentistry, laser is used in soft tissue surgery, sterilization of canals (in root canal therapy and in restorative dentistry laser is used for cavity preparation, caries removal, sealing the grooves (in preventive dentistry, etching enamel and dentin, composite polymerization and removal of tooth sensitivity. The use of Co2 lasers and Nd: YAG for cavity preparation, due to creating high heat causes darkness and cracks around the region of laser radiation. Also due to high temperature of these lasers, pulp damage is inevitable. So today, by using the Excimer laser especially the argon floride type with a wavelength of 193 nm, the problem of heat stress have been solved, but the use of lasers in dentistry, especially for cavity preparation needs more researches and evaluations.

  4. Laser for fusion energy

    International Nuclear Information System (INIS)

    Holzrichter, J.F.

    1995-01-01

    Solid state lasers have proven to be very versatile tools for the study and demonstration of inertial confinement fusion principles. When lasers were first contemplated to be used for the compression of fusion fuel in the late 1950s, the laser output energy levels were nominally one joule and the power levels were 10 3 watts (pulse duration's of 10 -3 sec). During the last 25 years, lasers optimized for fusion research have been increased in power to typically 100,000 joules with power levels approaching 10 14 watts. As a result of experiments with such lasers at many locations, DT target performance has been shown to be consistent with high gain target output. However, the demonstration of ignition and gain requires laser energies of several megajoules. Laser technology improvements demonstrated over the past decade appear to make possible the construction of such multimegajoule lasers at affordable costs. (author)

  5. Radiological protection against lasers

    Energy Technology Data Exchange (ETDEWEB)

    Ballereau, P

    1974-04-01

    A brief description of the biological effects of laser beams is followed by a review of the factors involved in eye and skin damage (factors linked with the nature of lasers and those linked with the organ affected) and a discussion of the problems involved in the determination of threshold exposure levels. Preventive measures are recommended, according to the type of laser (high-energy pulse laser, continuous laser, gas laser). No legislation on the subject exists in France or in Europe. Types of lasers marketed, threshold exposure levels for eye and skin, variations of admissible exposure levels according to wavelength, etc. are presented in tabular form. Nomogram for determination of safe distance for direct vision of a laser is included.

  6. Advances in Fiber Lasers

    National Research Council Canada - National Science Library

    Morse, T

    1999-01-01

    Most of the time of this contract has been devoted toward improvements in optical fiber lasers and toward gathering experience to improve our program in high power, cladding pumped optical fiber lasers...

  7. Laser Processing and Chemistry

    CERN Document Server

    Bäuerle, Dieter

    2011-01-01

    This book gives an overview of the fundamentals and applications of laser-matter interactions, in particular with regard to laser material processing. Special attention is given to laser-induced physical and chemical processes at gas-solid, liquid-solid, and solid-solid interfaces. Starting with the background physics, the book proceeds to examine applications of lasers in “standard” laser machining and laser chemical processing (LCP), including the patterning, coating, and modification of material surfaces. This fourth edition has been enlarged to cover the rapid advances in the understanding of the dynamics of materials under the action of ultrashort laser pulses, and to include a number of new topics, in particular the increasing importance of lasers in various different fields of surface functionalizations and nanotechnology. In two additional chapters, recent developments in biotechnology, medicine, art conservation and restoration are summarized. Graduate students, physicists, chemists, engineers, a...

  8. Fiber Laser Array

    National Research Council Canada - National Science Library

    Simpson, Thomas

    2002-01-01

    ...., field-dependent, loss within the coupled laser array. During this program, Jaycor focused on the construction and use of an experimental apparatus that can be used to investigate the coherent combination of an array of fiber lasers...

  9. ISTEF Laser Radar Program

    National Research Council Canada - National Science Library

    Stryjewski, John

    1998-01-01

    The BMDO Innovative Science and Technology Experimentation Facility (BMDO/ISTEF) laser radar program is engaged in an ongoing program to develop and demonstrate advanced laser radar concepts for Ballistic Missile Defense (BMD...

  10. Wavelength sweepable laser source

    DEFF Research Database (Denmark)

    2014-01-01

    Wavelength sweepable laser source is disclosed, wherein the laser source is a semiconductor laser source adapted for generating laser light at a lasing wavelength. The laser source comprises a substrate, a first reflector, and a second reflector. The first and second reflector together defines...... and having a rest position, the second reflector and suspension together defining a microelectromechanical MEMS oscillator. The MEMS oscillator has a resonance frequency and is adapted for oscillating the second reflector on either side of the rest position.; The laser source further comprises electrical...... connections adapted for applying an electric field to the MEMS oscillator. Furthermore, a laser source system and a method of use of the laser source are disclosed....

  11. Laser surgery - skin

    Science.gov (United States)

    ... Bleeding Problem not going away Infection Pain Scarring Skin color changes Some laser surgery is done when you are asleep and ... TG, Elston DM, eds. Andrews' Diseases of the Skin: Clinical ... lasers, lights, and tissue interactions. In: Hruza GJ, Avram ...

  12. Laser in operative dentistry

    OpenAIRE

    E. Yasini; Gh. Rahbari; A. Matorian

    1994-01-01

    Today laser has a lot of usage in medicine and dentistry. In the field of dentistry, laser is used in soft tissue surgery, sterilization of canals (in root canal therapy) and in restorative dentistry laser is used for cavity preparation, caries removal, sealing the grooves (in preventive dentistry), etching enamel and dentin, composite polymerization and removal of tooth sensitivity. The use of Co2 lasers and Nd: YAG for cavity preparation, due to creating high heat causes darkness and cracks...

  13. Tunable laser optics

    CERN Document Server

    Duarte, FJ

    2015-01-01

    This Second Edition of a bestselling book describes the optics and optical principles needed to build lasers. It also highlights the optics instrumentation necessary to characterize laser emissions and focuses on laser-based optical instrumentation. The book emphasizes practical and utilitarian aspects of relevant optics including the essential theory. This revised, expanded, and improved edition contains new material on tunable lasers and discusses relevant topics in quantum optics.

  14. Laser cutting system

    Science.gov (United States)

    Dougherty, Thomas J

    2015-03-03

    A workpiece cutting apparatus includes a laser source, a first suction system, and a first finger configured to guide a workpiece as it moves past the laser source. The first finger includes a first end provided adjacent a point where a laser from the laser source cuts the workpiece, and the first end of the first finger includes an aperture in fluid communication with the first suction system.

  15. Application of Various Lasers to Laser Trimming Resistance System

    Institute of Scientific and Technical Information of China (English)

    SUN Ji-feng

    2007-01-01

    Though the laser trimming resistance has been an old laser machining industry for over 30 years, the development of technology brings new alternative lasers which can be used for the traditional machining. The paper describes application of various lasers to laser trimming resistance system including early traditional krypton arc lamp pumped Nd:YAG to laser, modern popular diode pumped solid state laser and the present advanced harmonic diode pumped solid state laser. Using the new alternative lasers in the laser trimming resistance system can dramatically improve the yields and equipment performance.

  16. Laser technologies for laser accelerators. Annual report

    International Nuclear Information System (INIS)

    1985-01-01

    The primary result of the work reported is the determination of laser system architectures that satsify the requirements of high luminosity, high energy (about 1 TeV), electron accelerators. It has been found that high laser efficiency is a very hard driver for these accelerators as the total average laser output optical power is likely to fall above 10 MW. The luminosity requires rep rates in the kHz range, and individual pulse lengths in the 1-10 psec range are required to satisfy acceleration gradient goals. CO 2 and KrF lasers were chosen for study because of their potential to simultaneously satisfy the given requirements. Accelerator luminosity is reviewed, and requirements on laser system average power and rep rate are determined as a function of electron beam bunch parameters. Laser technologies are reviewed, including CO 2 , excimers, solid state, and free electron lasers. The proposed accelerator mechanisms are summarized briefly. Work on optical transport geometries for near and far field accelerators are presented. Possible exploitation of the CO 2 and DrF laser technology to generate the required pulse lengths, rep rates, and projected efficiencies is illustrated and needed development work is suggested. Initial efforts at developing a 50 GeV benchmark conceptual design and a 100 MeV demonstration experiment conceptual design are presented

  17. Laser induced pyrolysis techniques

    International Nuclear Information System (INIS)

    Vanderborgh, N.E.

    1976-01-01

    The application of laser pyrolysis techniques to the problems of chemical analysis is discussed. The processes occurring during laser pyrolysis are first briefly reviewed. The problems encountered in laser pyrolysis gas chromatography are discussed using the analysis of phenanthrene and binary hydrocarbons. The application of this technique to the characterization of naturally occurring carbonaceous material such as oil shales and coal is illustrated

  18. Solar pumped laser

    Science.gov (United States)

    Lee, J. H.; Hohl, F.; Weaver, W. R. (Inventor)

    1984-01-01

    A solar pumped laser is described in which the lasant is a gas that will photodissociate and lase when subjected to sunrays. Sunrays are collected and directed onto the gas lasant to cause it to lase. Applications to laser propulsion and laser power transmission are discussed.

  19. Introducing the Yellow Laser

    Science.gov (United States)

    Lincoln, James

    2018-01-01

    The author has acquired a yellow laser with the specific wavelength of 589 nm. Because this is the first time such a laser has been discussed in this journal, I feel it is appropriate to provide a discussion of its function and capabilities. Normal laser safety should be employed, such as not pointing it into eyes or at people, and using eye…

  20. Coatings for laser fusion

    International Nuclear Information System (INIS)

    Lowdermilk, W.H.

    1981-01-01

    Optical coatings are used in lasers systems for fusion research to control beam propagation and reduce surface reflection losses. The performance of coatings is important in the design, reliability, energy output, and cost of the laser systems. Significant developments in coating technology are required for future lasers for fusion research and eventual power reactors

  1. uv dye lasers

    International Nuclear Information System (INIS)

    Abakumov, G.A.; Fadeev, V.V.; Khokhlov, R.V.; Simonov, A.P.

    1975-01-01

    The most important property of visible dye lasers, that is, continuous wavelength tuning, stimulated the search for dyes capable to lase in uv. They were found in 1968. Now the need for tunable uv lasers for applications in spectroscopy, photochemistry, isotope separation, remote air and sea probing, etc. is clearly seen. A review of some recent advances in uv dye lasers is reviewed

  2. LaserFest Celebration

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Alan Chodos; Elizabeth A. Rogan

    2011-08-25

    LaserFest was the yearlong celebration, during 2010, of the 50th anniversary of the demonstration of the first working laser. The goals of LaserFest were: to highlight the impact of the laser in its manifold commercial, industrial and medical applications, and as a tool for ongoing scientific research; to use the laser as one example that illustrates, more generally, the route from scientific innovation to technological application; to use the laser as a vehicle for outreach, to stimulate interest among students and the public in aspects of physical science; to recognize and honor the pioneers who developed the laser and its many applications; to increase awareness among policymakers of the importance of R&D funding as evidenced by such technology as lasers. One way in which LaserFest sought to meet its goals was to encourage relevant activities at a local level all across the country -- and also abroad -- that would be identified with the larger purposes of the celebration and would carry the LaserFest name. Organizers were encouraged to record and advertise these events through a continually updated web-based calendar. Four projects were explicitly detailed in the proposals: 1) LaserFest on the Road; 2) Videos; 3) Educational material; and 4) Laser Days.

  3. Laser beam cutting method. Laser ko ni yoru kaitai koho

    Energy Technology Data Exchange (ETDEWEB)

    Kutsumizu, A. (Obayashi Corp., Osaka (Japan))

    1991-07-01

    In this special issue paper concerning the demolition of concrete structures, was introduced a demolition of concrete structures using laser, of which practical application is expected due to the remarkable progress of generating power and efficiency of laser radiator. The characteristics of laser beam which can give a temperature of one million centigrade at the irradiated spot, the laser radiator consisting of laser medium, laser resonator and pumping apparatus, and the laser kinds for working, such as CO{sub 2} laser, YAG laser and CO laser, were described. The basic constitution of laser cutting equipment consisting of large generating power radiator, beam transmitter, beam condenser, and nozzle for working was also illustrated. Furthermore, strong and weak points in the laser cutting for concrete and reinforcement were enumerated. Applications of laser to cutting of reinforced and unreinforced concrete constructions were shown, and the concept and safety measure for application of laser to practical demolition was discussed. 5 refs., 8 figs.

  4. Introduction to laser technology

    CERN Document Server

    Hitz, C Breck; Hecht, Jeff; Hitz, C Breck; John Wiley & Sons

    2001-01-01

    Electrical Engineering Introduction to Laser Technology , Third Edition. Would you like to know how a laser works, and how it can be modified for your own specific tasks? This intuitive third edition-previously published as Understanding Laser Technology , First and Second Editions-introduces engineers, scientists, technicians, and novices alike to the world of modern lasers, without delving into the mathematical details of quantum electronics. It is the only introductory text on the market today that explains the underlying physics and engineering applicable to all lasers. A unique combinatio.

  5. Quantum well lasers

    CERN Document Server

    Zory, Jr, Peter S; Kelley, Paul

    1993-01-01

    This book provides the information necessary for the reader to achieve a thorough understanding of all aspects of QW lasers - from the basic mechanism of optical gain, through the current technolgoical state of the art, to the future technologies of quantum wires and quantum dots. In view of the growing importance of QW lasers, this book should be read by all those with an active interest in laser science and technology, from the advanced student to the experienced laser scientist.* The first comprehensive book-length treatment of quantum well lasers* Provides a detailed treatment

  6. Coherent laser beam combining

    CERN Document Server

    Brignon, Arnaud

    2013-01-01

    Recently, the improvement of diode pumping in solid state lasers and the development of double clad fiber lasers have allowed to maintain excellent laser beam quality with single mode fibers. However, the fiber output power if often limited below a power damage threshold. Coherent laser beam combining (CLBC) brings a solution to these limitations by identifying the most efficient architectures and allowing for excellent spectral and spatial quality. This knowledge will become critical for the design of the next generation high-power lasers and is of major interest to many industrial, environme

  7. The laser thermonuclear fusion

    International Nuclear Information System (INIS)

    Coutant, J.; Dautray, R.; Decroisette, M.; Watteau, J.P.

    1987-01-01

    Principle of the thermonuclear fusion by inertial confinement: required characteristics of the deuterium-tritium plasma and of the high power lasers to be used Development of high power lasers: active media used; amplifiers; frequency conversion; beam quality; pulse conditioning; existing large systems. The laser-matter interaction: collision and collective interaction of the laser radiation with matter; transport of the absorbed energy; heating and compression of deuterium-tritium; diagnoses and their comparison with the numerical simulation of the experiment; performances. Conclusions: difficulties to overcome; megajoule lasers; other energy source: particles beams [fr

  8. Laser Cutting, Development Trends

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove

    1999-01-01

    In this paper a short review of the development trends in laser cutting will be given.The technology, which is the fastest expanding industrial production technology will develop in both its core market segment: Flat bed cutting of sheet metal, as it will expand in heavy industry and in cutting...... of 3-dimensional shapes.The CO2-laser will also in the near future be the dominating laser source in the market, although the new developments in ND-YAG-lasers opens for new possibilities for this laser type....

  9. Lasers in space.

    CSIR Research Space (South Africa)

    Michaelis, MM

    2008-04-01

    Full Text Available cube, laser beam reflectors, placed on the Moon half a century ago. These early achievements will soon be followed by a plethora of experiments involving lasers in low earth orbit (LEO) or at Lagrange points. And not much later, laser communications... will stretch out as far as Mars and beyond. One important low Earth orbit (LEO) application is the removal of space debris by Earth based or LEO relayed lasers as promoted by Phipps et al.3. Another is military communication. The prominent L1 laser space...

  10. Tunable laser applications

    CERN Document Server

    Duarte, FJ

    2008-01-01

    Introduction F. J. Duarte Spectroscopic Applications of Tunable Optical Parametric Oscillators B. J. Orr, R. T. White, and Y. He Solid-State Dye Lasers Costela, I. García-Moreno, and R. Sastre Tunable Lasers Based on Dye-Doped Polymer Gain Media Incorporating Homogeneous Distributions of Functional Nanoparticles F. J. Duarte and R. O. James Broadly Tunable External-Cavity Semiconductor Lasers F. J. Duarte Tunable Fiber Lasers T. M. Shay and F. J. Duarte Fiber Laser Overview and Medical Applications

  11. New solid laser: Ceramic laser. From ultra stable laser to ultra high output laser

    International Nuclear Information System (INIS)

    Ueda, Kenichi

    2006-01-01

    An epoch-making solid laser is developed. It is ceramic laser, polycrystal, which is produced as same as glass and shows ultra high output. Ti 3+ :Al 2 O 3 laser crystal and the CPA (chirped pulse amplification) technique realized new ultra high output lasers. Japan has developed various kinds of ceramic lasers, from 10 -2 to 67 x 10 3 w average output, since 1995. These ceramic lasers were studied by gravitational radiation astronomy. The scattering coefficient of ceramic laser is smaller than single crystals. The new fast ignition method is proposed by Institute of Laser Engineering of Osaka University, Japan. Ultra-intense short pulse laser can inject the required energy to the high-density imploded core plasma within the core disassembling time. Ti 3+ :Al 2 O 3 crystal for laser, ceramic YAG of large caliber for 100 kW, transparent laser ceramic from nano-crystals, crystal grain and boundary layer between grains, the scattering coefficient of single crystal and ceramic, and the derived release cross section of Yb:YAG ceramic are described. (S.Y.)

  12. Advanced lasers for fusion

    International Nuclear Information System (INIS)

    Krupke, W.F.; George, E.V.; Haas, R.A.

    1979-01-01

    Laser drive systems' performance requirements for fusion reactors are developed following a review of the principles of inertial confinement fusion and of the technical status of fusion research lasers (Nd:glass; CO 2 , iodine). These requirements are analyzed in the context of energy-storing laser media with respect to laser systems design issues: optical damage and breakdown, medium excitation, parasitics and superfluorescence depumping, energy extraction physics, medium optical quality, and gas flow. Three types of energy-storing laser media of potential utility are identified and singled out for detailed review: (1) Group VI atomic lasers, (2) rare earth solid state hybrid lasers, and (3) rare earth molecular vapor lasers. The use of highly-radiative laser media, particularly the rare-gas monohalide excimers, are discussed in the context of short pulse fusion applications. The concept of backward wave Raman pulse compression is considered as an attractive technique for this purpose. The basic physics and device parameters of these four laser systems are reviewed and conceptual designs for high energy laser systems are presented. Preliminary estimates for systems efficiencies are given. (Auth.)

  13. Micromachining with copper lasers

    Science.gov (United States)

    Knowles, Martyn R. H.; Bell, Andy; Foster-Turner, Gideon; Rutterford, Graham; Chudzicki, J.; Kearsley, Andrew J.

    1997-04-01

    In recent years the copper laser has undergone extensive development and has emerged as a leading and unique laser for micromachining. The copper laser is a high average power (10 - 250 W), high pulse repetition rate (2 - 32 kHz), visible laser (511 nm and 578 nm) that produces high peak power (typically 200 kW), short pulses (30 ns) and very good beam quality (diffraction limited). This unique set of laser parameters results in exceptional micro-machining in a wide variety of materials. Typical examples of the capabilities of the copper laser include the drilling of small holes (10 - 200 micrometer diameter) in materials as diverse as steel, ceramic, diamond and polyimide with micron precision and low taper (less than 1 degree) cutting and profiling of diamond. Application of the copper laser covers the electronic, aerospace, automotive, nuclear, medical and precision engineering industries.

  14. Laser Applications in Orthodontics

    Science.gov (United States)

    Heidari, Somayeh; Torkan, Sepideh

    2013-01-01

    A laser is a collimated single wavelength of light which delivers a concentrated source of energy. Soon after different types of lasers were invented, investigators began to examine the effects of different wavelengths of laser energy on oral tissues, routine dental procedures and experimental applications. Orthodontists, along with other specialist in different fields of dentistry, can now benefit from several different advantages that lasers provide during the treatment process, from the beginning of the treatment, when separators are placed, to the time of resin residues removal from the tooth surface at the end of orthodontic treatment. This article outlines some of the most common usages of laser beam in orthodontics and also provides a comparison between laser and other conventional method that were the standard of care prior to the advent of laser in this field. PMID:25606324

  15. ORION laser target diagnostics

    International Nuclear Information System (INIS)

    Bentley, C. D.; Edwards, R. D.; Andrew, J. E.; James, S. F.; Gardner, M. D.; Comley, A. J.; Vaughan, K.; Horsfield, C. J.; Rubery, M. S.; Rothman, S. D.; Daykin, S.; Masoero, S. J.; Palmer, J. B.; Meadowcroft, A. L.; Williams, B. M.; Gumbrell, E. T.; Fyrth, J. D.; Brown, C. R. D.; Hill, M. P.; Oades, K.

    2012-01-01

    The ORION laser facility is one of the UK's premier laser facilities which became operational at AWE in 2010. Its primary mission is one of stockpile stewardship, ORION will extend the UK's experimental plasma physics capability to the high temperature, high density regime relevant to Atomic Weapons Establishment's (AWE) program. The ORION laser combines ten laser beams operating in the ns regime with two sub ps short pulse chirped pulse amplification beams. This gives the UK a unique combined long pulse/short pulse laser capability which is not only available to AWE personnel but also gives access to our international partners and visiting UK academia. The ORION laser facility is equipped with a comprehensive suite of some 45 diagnostics covering optical, particle, and x-ray diagnostics all able to image the laser target interaction point. This paper focuses on a small selection of these diagnostics.

  16. ORION laser target diagnostics.

    Science.gov (United States)

    Bentley, C D; Edwards, R D; Andrew, J E; James, S F; Gardner, M D; Comley, A J; Vaughan, K; Horsfield, C J; Rubery, M S; Rothman, S D; Daykin, S; Masoero, S J; Palmer, J B; Meadowcroft, A L; Williams, B M; Gumbrell, E T; Fyrth, J D; Brown, C R D; Hill, M P; Oades, K; Wright, M J; Hood, B A; Kemshall, P

    2012-10-01

    The ORION laser facility is one of the UK's premier laser facilities which became operational at AWE in 2010. Its primary mission is one of stockpile stewardship, ORION will extend the UK's experimental plasma physics capability to the high temperature, high density regime relevant to Atomic Weapons Establishment's (AWE) program. The ORION laser combines ten laser beams operating in the ns regime with two sub ps short pulse chirped pulse amplification beams. This gives the UK a unique combined long pulse/short pulse laser capability which is not only available to AWE personnel but also gives access to our international partners and visiting UK academia. The ORION laser facility is equipped with a comprehensive suite of some 45 diagnostics covering optical, particle, and x-ray diagnostics all able to image the laser target interaction point. This paper focuses on a small selection of these diagnostics.

  17. Robot-laser system

    International Nuclear Information System (INIS)

    Akeel, H.A.

    1987-01-01

    A robot-laser system is described for providing a laser beam at a desired location, the system comprising: a laser beam source; a robot including a plurality of movable parts including a hollow robot arm having a central axis along which the laser source directs the laser beam; at least one mirror for reflecting the laser beam from the source to the desired location, the mirror being mounted within the robot arm to move therewith and relative thereto to about a transverse axis that extends angularly to the central axis of the robot arm; and an automatic programmable control system for automatically moving the mirror about the transverse axis relative to and in synchronization with movement of the robot arm to thereby direct the laser beam to the desired location as the arm is moved

  18. Laser safety in dentistry

    Science.gov (United States)

    Wigdor, Harvey A.

    1997-05-01

    One of the major causes of anxiety in the dental clinic is the dental handpiece. Because dentists wish to provide a method which can replace the drill there has often been a premature use of the laser in dentistry. Various lasers have been introduced into the clinic before research has shown the laser used is of clinical benefit. Any new treatment method must not compromise the health of the patient being treated. Thus a method of evaluating the clinical abilities of dentists and their understanding the limitations of the laser used must be developed. Dentist must be trained in the basic interaction of the laser on oral tissues. The training has to concentrate on the variation of the laser wavelength absorption in the different tissues of the oral cavity. Because of the differences in the optical properties of these tissues great care must be exercised by practitioners using lasers on patients.

  19. Lasers in materials science

    CERN Document Server

    Ossi, Paolo; Zhigilei, Leonid

    2014-01-01

    This book covers various aspects of lasers in materials science, including a comprehensive overview on basic principles of laser-materials interactions and applications enabled by pulsed laser systems.  The material is organized in a coherent way, providing the reader with a harmonic architecture. While systematically covering the major current and emerging areas of lasers processing applications, the Volume provides examples of targeted modification of material properties achieved through careful control of the processing conditions and laser irradiation parameters. Special emphasis is placed on specific strategies aimed at nanoscale control of material structure and properties to match the stringent requirements of modern applications.  Laser fabrication of novel nanomaterials, which expands to the domains of photonics, photovoltaics, sensing, and biomedical applications, is also discussed in the Volume. This book assembles chapters based on lectures delivered at the Venice International School on Lasers...

  20. Alternate laser fusion drivers

    International Nuclear Information System (INIS)

    Pleasance, L.D.

    1979-11-01

    One objective of research on inertial confinement fusion is the development of a power generating system based on this concept. Realization of this goal will depend on the availability of a suitable laser or other system to drive the power plant. The primary laser systems used for laser fusion research, Nd 3+ : Glass and CO 2 , have characteristics which may preclude their use for this application. Glass lasers are presently perceived to be incapable of sufficiently high average power operation and the CO 2 laser may be limited by and issues associated with target coupling. These general perceptions have encouraged a search for alternatives to the present systems. The search for new lasers has been directed generally towards shorter wavelengths; most of the new lasers discovered in the past few years have been in the visible and ultraviolet region of the spectrum. Virtually all of them have been advocated as the most promising candidate for a fusion driver at one time or another

  1. Flexible Laser Metal Cutting

    DEFF Research Database (Denmark)

    Villumsen, Sigurd; Jørgensen, Steffen Nordahl; Kristiansen, Morten

    2014-01-01

    This paper describes a new flexible and fast approach to laser cutting called ROBOCUT. Combined with CAD/CAM technology, laser cutting of metal provides the flexibility to perform one-of-a-kind cutting and hereby realises mass production of customised products. Today’s laser cutting techniques...... possess, despite their wide use in industry, limitations regarding speed and geometry. Research trends point towards remote laser cutting techniques which can improve speed and geometrical freedom and hereby the competitiveness of laser cutting compared to fixed-tool-based cutting technology...... such as punching. This paper presents the concepts and preliminary test results of the ROBOCUT laser cutting technology, a technology which potentially can revolutionise laser cutting....

  2. Lasers: principles, applications and energetic measures

    International Nuclear Information System (INIS)

    Subran, C.; Sagaut, J.; Lapointe, S.

    2009-01-01

    After having recalled the principles of a laser and the properties of the laser beam, the authors describe the following different types of lasers: solid state lasers, fiber lasers, semiconductor lasers, dye lasers and gas lasers. Then, their applications are given. Very high energy lasers can reproduce the phenomenon of nuclear fusion of hydrogen atoms. (O.M.)

  3. Lasers in space

    Science.gov (United States)

    Michaelis, M. M.; Forbes, A.; Bingham, R.; Kellett, B. J.; Mathye, A.

    2008-05-01

    A variety of laser applications in space, past, present, future and far future are reviewed together with the contributions of some of the scientists and engineers involved, especially those that happen to have South African connections. Historically, two of the earliest laser applications in space, were atmospheric LIDAR and lunar ranging. These applications involved atmospheric physicists, several astronauts and many of the staff recruited into the Soviet and North American lunar exploration programmes. There is a strong interest in South Africa in both LIDAR and lunar ranging. Shortly after the birth of the laser (and even just prior) theoretical work on photonic propulsion and space propulsion by laser ablation was initiated by Georgii Marx, Arthur Kantrowitz and Eugen Saenger. Present or near future experimental programs are developing in the following fields: laser ablation propulsion, possibly coupled with rail gun or gas gun propulsion; interplanetary laser transmission; laser altimetry; gravity wave detection by space based Michelson interferometry; the de-orbiting of space debris by high power lasers; atom laser interferometry in space. Far future applications of laser-photonic space-propulsion were also pioneered by Carl Sagan and Robert Forward. They envisaged means of putting Saenger's ideas into practice. Forward also invented a laser based method for manufacturing solid antimatter or SANTIM, well before the ongoing experiments at CERN with anti-hydrogen production and laser-trapping. SANTIM would be an ideal propellant for interstellar missions if it could be manufactured in sufficient quantities. It would be equally useful as a power source for the transmission of information over light year distances. We briefly mention military lasers. Last but not least, we address naturally occurring lasers in space and pose the question: "did the Big Bang lase?"

  4. Laser system using ultra-short laser pulses

    Science.gov (United States)

    Dantus, Marcos [Okemos, MI; Lozovoy, Vadim V [Okemos, MI; Comstock, Matthew [Milford, MI

    2009-10-27

    A laser system using ultrashort laser pulses is provided. In another aspect of the present invention, the system includes a laser, pulse shaper and detection device. A further aspect of the present invention employs a femtosecond laser and binary pulse shaping (BPS). Still another aspect of the present invention uses a laser beam pulse, a pulse shaper and a SHG crystal.

  5. Designing of Raman laser

    International Nuclear Information System (INIS)

    Zidan, M. D.; Al-Awad, F.; Alsous, M. B.

    2005-01-01

    In this work, we describe the design of the Raman laser pumped by Frequency doubled Nd-YAG laser (λ=532 nm) to generate new laser wavelengths by shifting the frequency of the Nd-YAG laser to Stokes region (λ 1 =683 nm, λ 2 =953.6 nm, λ 3 =1579.5 nm) and Antistokes region (λ ' 1 =435 nm, λ ' 2 =369.9 nm, λ ' 3=319.8 nm). Laser resonator has been designed to increase the laser gain. It consists of two mirrors, the back mirror transmits the pump laser beam (λ=532 nm) through the Raman tube and reflects all other generated Raman laser lines. Four special front mirrors were made to be used for the four laser lines λ 1 =683 nm, λ 2 =953.6 nm and λ ' 1 = 435 nm, λ ' 2 =369.9 nm. The output energy for the lines υ 1 s, υ 2 s, υ 1 as,υ 2 as was measured. The output energy of the Raman laser was characterized for different H 2 pressure inside the tube. (Author)

  6. Laser program overview

    International Nuclear Information System (INIS)

    Storm, E.; Coleman, L.W.

    1985-01-01

    The objectives of the Lawrence Livermore National Laboratory Laser Fusion program are to understand and develop the science and technology of inertial confinement fusion (ICF), and to utilize ICF in short- and long-term military applications, and, in the long-term, as a candidate for central-station civilian power generation. In 1984, using the Novette laser system, the authors completed experiments showing the very favorable scaling of laser-plama interactions with short-wavelength laser light. Their Novette experiments have unequivocally shown that short laser wavelength, i.e., less than 1 μm, is required to provide the drive necessary for efficient compression, ignition, and burn of DT fusion fuel. In other experiments with Novette, the authors made the first unambiguous observation of amplified spontaneous emission in the soft x-ray regime. The authors also conducted military applications and weapons physics experiments, which they discuss in detail in the classified volume of our Laser Program Annual Report. In the second thrust, advanced laser studies, they develop and test the concepts, components, and materials for present and future laser systems. Over the years, this has meant providing the technology base and scientific advances necessary to construct and operate a succession of six evermore-powerful laser systems. The latest of these, Nova, a 100-TW/100-kJ-class laser system, was completed in 1984. The Nd:glass laser continues to be the most effective and versatile tool for ICF and weapons physics because of its scalability in energy, the ability to efficiently convert its 1=μm output to shorter wavelengths, its ability to provide flexible, controlled pulse shaping, and its capability to adapt to a variety of irradiation and focusing geometries. For these reasons, many of our advanced laser studies are in areas appropriate to solid state laser technologies

  7. Laser pumped lasers for isotope separation

    International Nuclear Information System (INIS)

    Fry, S.M.

    1976-01-01

    A study of the isotope separation laser requirements reveals that high pressure polyatomic molecular gas laser pumped lasers can attain the necessary characteristics including tunability, energy output, pulse width, and repetition rate. The results of a search, made for molecules meeting the appropriate requirements for one of several pump schemes utilizing a CO 2 laser and with output in the 12 μm or 16μm wavelength range, are presented. Several methods of pumping are reviewed and two novel pump schemes are presented. A laser pumped laser device design is given, and operation of this device and associated diagnostic equipment is confirmed by repeating experiments in OCS and NH 3 . The results of OCS laser experiments show that an improvement in pump rate and output per unit length is obtained with the device, using a wedged transverse pumping scheme. A new multi-line laser system in NH 3 pumped by a TEA CO 2 laser is reported. More than forty transitions spanning the wavelength range of 9.2 to 13.8 μm are observed and identified. A strong output at 12.08 μm is one of the closest lines yet found to the required laser isotope separation wavelength. Far infrared emission near 65 μm is observed and is responsible for populating levels which lase in pure ammonia near 12.3 μm. Buffer gas (e.g., N 2 or He) pressures of approximately 40--800 torr cause energy transfer by collision-induced rotationaltransitions from the pumped antisymmetric to the lasing symmetric levels in the nu 2 = 1 band of ammonia. Most of the observed lines are aP(J,K) transitions which originate from the nu 2 /sup s/ band. Measurements of the pressure dependence of the laser output shows that some lines lase at pressures greater than one atmosphere. Transient behavior of the 12.08 μm line is calculated from a simplified analytic model and these calculations are compared to the experimental results

  8. Scintillation reduction for laser beams propagating through turbulent atmosphere

    International Nuclear Information System (INIS)

    Berman, G P; Gorshkov, V N; Torous, S V

    2011-01-01

    We numerically examine the spatial evolution of the structure of coherent and partially coherent laser beams, including the optical vortices, propagating in turbulent atmospheres. The influence of beam fragmentation and wandering relative to the axis of propagation (z-axis) on the value of the scintillation index (SI) of the signal at the detector is analysed. These studies were performed for different dimensions of the detector, distances of propagation, and strengths of the atmospheric turbulence. Methods for significantly reducing the SI are described. These methods utilize averaging of the signal at the detector over a set of partially coherent beams (PCBs). It is demonstrated that the most effective approach is using a set of PCBs with definite initial directions of propagation relative to the z-axis. This approach results in a significant compensation of the beam wandering which in many cases is the main contributor to the SI. A novel method is to generate the PCBs by combining two laser beams-Gaussian and vortex beams, with different frequencies (the difference between these two frequencies being significantly smaller than the frequencies themselves). In this case, the effective suppression of the SI does not require high-frequency modulators. This result is important for achieving gigabit data rates in long-distance laser communication through turbulent atmospheres.

  9. Scintillation reduction for laser beams propagating through turbulent atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Berman, G P; Gorshkov, V N [Theoretical Division, T-4 and CNLS MS B213, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Torous, S V, E-mail: gpb@lanl.gov [National Technical University of Ukraine ' KPI' , 37 Peremogy Avenue, Building 7, Kiev-56, 03056 (Ukraine)

    2011-03-14

    We numerically examine the spatial evolution of the structure of coherent and partially coherent laser beams, including the optical vortices, propagating in turbulent atmospheres. The influence of beam fragmentation and wandering relative to the axis of propagation (z-axis) on the value of the scintillation index (SI) of the signal at the detector is analysed. These studies were performed for different dimensions of the detector, distances of propagation, and strengths of the atmospheric turbulence. Methods for significantly reducing the SI are described. These methods utilize averaging of the signal at the detector over a set of partially coherent beams (PCBs). It is demonstrated that the most effective approach is using a set of PCBs with definite initial directions of propagation relative to the z-axis. This approach results in a significant compensation of the beam wandering which in many cases is the main contributor to the SI. A novel method is to generate the PCBs by combining two laser beams-Gaussian and vortex beams, with different frequencies (the difference between these two frequencies being significantly smaller than the frequencies themselves). In this case, the effective suppression of the SI does not require high-frequency modulators. This result is important for achieving gigabit data rates in long-distance laser communication through turbulent atmospheres.

  10. Pattern Laser Annealing by a Pulsed Laser

    Science.gov (United States)

    Komiya, Yoshio; Hoh, Koichiro; Murakami, Koichi; Takahashi, Tetsuo; Tarui, Yasuo

    1981-10-01

    Preliminary experiments with contact-type pattern laser annealing were made for local polycrystallization of a-Si, local evaporation of a-Si and local formation of Ni-Si alloy. These experiments showed that the mask patterns can be replicated as annealed regions with a resolution of a few microns on substrates. To overcome shortcomings due to the contact type pattern annealing, a projection type reduction pattern laser annealing system is proposed for resistless low temperature pattern forming processes.

  11. Electron acceleration by CO/sub 2/ laser

    International Nuclear Information System (INIS)

    Fujita, H.; Kitagawa, Y.; Daido, H.

    1986-01-01

    Experiments on electron acceleration have been performed by LEKKO VIII CO/sub 2/ laser system. The laser light was focused by an off-axis parabolic mirror with the F-number of 1.5 and irradiated to thin foil and pipe targets in order to obtain uniform underdense plasmas. Energy spectrum of electrons was measured by an electron spectrometer in the range of 0.3-1.1 MeV. In the single frequency case, electrons up to 1 MeV were observed in the direction of the laser axis for the laser intensity above 1.6 x 10/sup 14/ W/cm/sup 2/ which was equal to the estimated threshold for forward Raman scattering. Amount of high energy electrons depended on the interaction length and the background hot electron temperature. More electrons could resonate with the plasma wave for the higher hot electron temperature. This was confirmed by particle simulation. In most experiments, the plasma density was estimated of about 0.1 n/sub c/. When the plasma density was reduced to 0.01 n/sub c/ using pre-pulse, high energy electrons were not observed because of the low background hot electron temperature and the higher instability threshold. In the two frequency case, energetic electron beam injection is planned for efficient coupling with fast plasma wave. Pipe target seems to be hopeful because 1) the laser light is confined by the plasma fiber and 2) the phase velocity of the plasma wave is controlled by the transverse mode

  12. High energy HF pulsed lasers

    International Nuclear Information System (INIS)

    Patterson, E.L.; Gerber, R.A.

    1976-01-01

    Recent experiments show that pulsed HF lasers are capable of producing high energy with good efficiency. Preliminary experiments show that the laser radiation from the high-gain medium can be controlled with a low-power probe laser beam or with low-level feedback. These results indicate that the HF laser may have potential for second-generation laser fusion experiments

  13. Mjollnir Rotational Line Scan Diagnostics.

    Science.gov (United States)

    1981-05-19

    using long cavity. M8 Removable Pellicle Beam Splitter for He-Ne Lineup Beam. Removed before HF or DF laser is turned on. 27 A 27 * A r of the chopper...three probe laser lines, however three lines were sequentially measured to verify the diagnostic equipment. Two of the three lines have been monitored

  14. Continuous pneumothorax monitoring by remittance measurement

    NARCIS (Netherlands)

    Beek, J. F.; Sterenborg, H. J.; van Gemert, M. J.

    1993-01-01

    The feasibility of a noninvasive method, based on a remittance measurement, to monitor continuously for the occurrence of pneumothorax in neonates under ventilation, was investigated through animal experiments. Light from a He-Ne laser (632.8 nm) or a semiconductor laser (790 nm) was incident on the

  15. Direct and inverse Staebler-Wronski effects observed in carbon-doped hydrogenated amorphous silicon photo-detectors

    International Nuclear Information System (INIS)

    Arce, P.; Barcala, J.M.; Calvo, E.; Ferrando, A.; Josa, M.I.; Molinero, A.; Navarrete, J.; Oller, J.C.; Yuste, C.; Brochero, J.; Calderon, A.; Fernandez, M.G.; Gomez, G.; Gonzalez-Sanchez, F.J.; Martinez-Rivero, C.; Matorras, F.; Rodrigo, T.; Ruiz-Arbol, P.; Scodellaro, L.; Sobron, M.

    2011-01-01

    The photo-response behaviour of Amorphous Silicon Position Detectors (ASPDs) under prolonged illumination with a 681 nm diode-laser and a 633 nm He-Ne laser is presented. Both direct and inverse Staebler-Wronski effects are observed.

  16. Laser Safety Inspection Criteria

    International Nuclear Information System (INIS)

    Barat, K

    2005-01-01

    A responsibility of the Laser Safety Officer (LSO) is to perform laser safety audits. The American National Standard Z136.1 Safe use of Lasers references this requirement in several sections: (1) Section 1.3.2 LSO Specific Responsibilities states under Hazard Evaluation, ''The LSO shall be responsible for hazards evaluation of laser work areas''; (2) Section 1.3.2.8, Safety Features Audits, ''The LSO shall ensure that the safety features of the laser installation facilities and laser equipment are audited periodically to assure proper operation''; and (3) Appendix D, under Survey and Inspections, it states, ''the LSO will survey by inspection, as considered necessary, all areas where laser equipment is used''. Therefore, for facilities using Class 3B and or Class 4 lasers, audits for laser safety compliance are expected to be conducted. The composition, frequency and rigueur of that inspection/audit rests in the hands of the LSO. A common practice for institutions is to develop laser audit checklists or survey forms. In many institutions, a sole Laser Safety Officer (LSO) or a number of Deputy LSO's perform these audits. For that matter, there are institutions that request users to perform a self-assessment audit. Many items on the common audit list and the associated findings are subjective because they are based on the experience and interest of the LSO or auditor in particular items on the checklist. Beam block usage is an example; to one set of eyes a particular arrangement might be completely adequate, while to another the installation may be inadequate. In order to provide more consistency, the National Ignition Facility Directorate at Lawrence Livermore National Laboratory (NIF-LLNL) has established criteria for a number of items found on the typical laser safety audit form. These criteria are distributed to laser users, and they serve two broad purposes: first, it gives the user an expectation of what will be reviewed by an auditor, and second, it is an

  17. Single frequency semiconductor lasers

    CERN Document Server

    Fang, Zujie; Chen, Gaoting; Qu, Ronghui

    2017-01-01

    This book systematically introduces the single frequency semiconductor laser, which is widely used in many vital advanced technologies, such as the laser cooling of atoms and atomic clock, high-precision measurements and spectroscopy, coherent optical communications, and advanced optical sensors. It presents both the fundamentals and characteristics of semiconductor lasers, including basic F-P structure and monolithic integrated structures; interprets laser noises and their measurements; and explains mechanisms and technologies relating to the main aspects of single frequency lasers, including external cavity lasers, frequency stabilization technologies, frequency sweeping, optical phase locked loops, and so on. It paints a clear, physical picture of related technologies and reviews new developments in the field as well. It will be a useful reference to graduate students, researchers, and engineers in the field.

  18. Nuclear-pumped lasers

    CERN Document Server

    Prelas, Mark

    2016-01-01

    This book focuses on Nuclear-Pumped Laser (NPL) technology and provides the reader with a fundamental understanding of NPLs, a review of research in the field, and exploration of large scale NPL system design and applications. Early chapters look at the fundamental properties of lasers, nuclear-pumping and nuclear reactions that may be used as drivers for nuclear-pumped lasers. The book goes on to explore the efficient transport of energy from the ionizing radiation to the laser medium and then the operational characteristics of existing nuclear-pumped lasers. Models based on Mathematica, explanations and a tutorial all assist the reader’s understanding of this technology. Later chapters consider the integration of the various systems involved in NPLs and the ways in which they can be used, including beyond the military agenda. As readers will discover, there are significant humanitarian applications for high energy/power lasers, such as deflecting asteroids, space propulsion, power transmission and mining....

  19. Power Laser Ablation Symposia

    CERN Document Server

    Phipps, Claude

    2007-01-01

    Laser ablation describes the interaction of intense optical fields with matter, in which atoms are selectively driven off by thermal or nonthermal mechanisms. The field of laser ablation physics is advancing so rapidly that its principal results are seen only in specialized journals and conferences. This is the first book that combines the most recent results in this rapidly advancing field with authoritative treatment of laser ablation and its applications, including the physics of high-power laser-matter interaction. Many practical applications exist, ranging from inertial confinement fusion to propulsion of aerostats for pollution monitoring to laser ignition of hypersonic engines to laser cleaning nanoscale contaminants in high-volume computer hard drive manufacture to direct observation of the electronic or dissociative states in atoms and molecules, to studying the properties of materials during 200kbar shocks developed in 200fs. Selecting topics which are representative of such a broad field is difficu...

  20. Laser induced nuclear reactions

    International Nuclear Information System (INIS)

    Ledingham, Ken; McCanny, Tom; Graham, Paul; Fang Xiao; Singhal, Ravi; Magill, Joe; Creswell, Alan; Sanderson, David; Allott, Ric; Neely, David; Norreys, Peter; Santala, Marko; Zepf, Matthew; Watts, Ian; Clark, Eugene; Krushelnick, Karl; Tatarakis, Michael; Dangor, Bucker; Machecek, Antonin; Wark, Justin

    1998-01-01

    Dramatic improvements in laser technology since 1984 have revolutionised high power laser technology. Application of chirped-pulse amplification techniques has resulted in laser intensities in excess of 10 19 W/cm 2 . In the mid to late eighties, C. K. Rhodes and K. Boyer discussed the possibility of shining laser light of this intensity onto solid surfaces and to cause nuclear transitions. In particular, irradiation of a uranium target could induce electro- and photofission in the focal region of the laser. In this paper it is shown that μCi of 62 Cu can be generated via the (γ,n) reaction by a laser with an intensity of about 10 19 Wcm -2

  1. Lasers for isotope separation

    International Nuclear Information System (INIS)

    O'Hair, E.A.; Piltch, M.S.

    1976-01-01

    The Los Alamos Scientific Laboratory is conducting research on uranium enrichment. All processes being studied employ uranium molecules and use lasers to provide isotopic selectivity and enrichment. There are four well-defined infrared frequencies and two ultraviolet frequency bands of interest. The infrared frequencies are outside the range of the available lasers and an extensive research and development activity is currently underway. Lasers are available in the uv bands, however, much development work remains. The specification for the commercial uranium enrichment plant lasers will depend upon the results of the current enrichment experiments, the laser capital cost, reliability, and maintenance cost. For the processes under investigation there are specific photon requirements but latitude in how these requirements can be met. The final laser selections for the pilot plant need not be made until the mid-1980's. Between now and that time as extensive as possible a research and development effort will be maintained

  2. Inertial fusion by laser

    International Nuclear Information System (INIS)

    Dautray, R.; Watteau, J.-P.

    1980-01-01

    Following a brief historical survey of research into the effects of interaction of laser with matter, the principles of fusion by inertial confinement are described and the main parameters and possible levels given. The development of power lasers is then discussed with details of performances of the main lasers used in various laboratories, and with an assessment of the respective merits of neodymium glass, carbon dioxide or iodine lasers. The phenomena of laser radiation and its interaction with matter is then described, with emphasis on the results of experiments concerned with target implosion with the object of compressing and heating the mixture of heavy hydrogen and tritium to be ignited. Finally, a review is made of future possibilities opened up by the use of large power lasers which have recently become operational or are being constructed, and the ground still to be covered before a reactor can be produced [fr

  3. Principles of Lasers

    CERN Document Server

    Svelto, Orazio

    2010-01-01

    This new Fifth Edition of Principles of Lasers incorporates corrections to the previous edition. The text’s essential mission remains the same: to provide a wide-ranging yet unified description of laser behavior, physics, technology, and current applications. Dr. Svelto emphasizes the physical rather than the mathematical aspects of lasers, and presents the subject in the simplest terms compatible with a correct physical understanding. Praise for earlier editions: "Professor Svelto is himself a longtime laser pioneer and his text shows the breadth of his broad acquaintance with all aspects of the field … Anyone mastering the contents of this book will be well prepared to understand advanced treatises and research papers in laser science and technology." (Arthur L. Schawlow, 1981 Nobel Laureate in Physics) "Already well established as a self-contained introduction to the physics and technology of lasers … Professor Svelto’s book, in this lucid translation by David Hanna, can be strongly recommended for...

  4. Atomic iodine laser

    International Nuclear Information System (INIS)

    Fisk, G.A.; Gusinow, M.A.; Hays, A.K.; Padrick, T.D.; Palmer, R.E.; Rice, J.K.; Truby, F.K.; Riley, M.E.

    1978-05-01

    The atomic iodine photodissociation laser has been under intensive study for a number of years. The physics associated with this system is now well understood and it is possible to produce a 0.1 nsec (or longer) near-diffraction-limited laser pulse which can be amplified with negligible temporal distortion and little spatial deformation. The output of either a saturated or unsaturated amplifier consists of a high-fidelity near-diffraction-limited, energetic laser pulse. The report is divided into three chapters. Chapter 1 is a survey of the important areas affecting efficient laser operation and summarizes the findings of Chap. 2. Chapter 2 presents detailed discussions and evaluations pertinent to pumps, chemical regeneration, and other elements in the overall laser system. Chapter 3 briefly discusses those areas that require further work and the nature of the work required to complete the full-scale evaluation of the applicability of the iodine photodissociation laser to the inertial confinement program

  5. Strong field laser physics

    CERN Document Server

    2008-01-01

    Since the invention of the laser in the 1960s, people have strived to reach higher intensities and shorter pulse durations. High intensities and ultrashort pulse durations are intimately related. Recent developments have shown that high intensity lasers also open the way to realize pulses with the shortest durations to date, giving birth to the field of attosecond science (1 asec = 10-18s). This book is about high-intensity lasers and their applications. The goal is to give an up to date introduction to the technology behind these laser systems and to the broad range of intense laser applications. These applications include AMO (atomic molecular and optical) physics, x-ray science, attosecond science, plasma physics and particle acceleration, condensed matter science and laser micromachining, and finally even high-energy physics.

  6. Arduino based laser control

    OpenAIRE

    Bernal Muñoz, Ferran

    2015-01-01

    ARDUINO is a vey usefull platform for prototypes. In this project ARDUINO will be used for controling a Semiconductor Tuneable Laser. [ANGLÈS] Diode laser for communications control based on an Arduino board. Temperature control implementation. Software and hardware protection for the laser implementation. [CASTELLÀ] Control de un láser de comunicaciones ópticas desde el ordenador utilizando una placa Arduino. Implementación de un control de temperatura y protección software y hardware ...

  7. Shiva laser system performance

    International Nuclear Information System (INIS)

    Glaze, J.; Godwin, R.O.; Holzrichter, J.F.

    1978-01-01

    On November 18, 1977, after four years of experimentation, innovation, and construction, the Shiva High Energy Laser facility produced 10.2 kJ of focusable laser energy delivered in a 0.95 ns pulse. The Shiva laser, with its computer control system and delta amplifiers, demonstrated its versatility on May 18, 1978, when the first 20-beam target shot with delta amplifiers focused 26 TW on a target and produced a yield of 7.5 x 10 9 neutrons

  8. Lasers in Ophthalmology

    Institute of Scientific and Technical Information of China (English)

    1992-01-01

    In recent years,lasers have entered every fieldof medicine and especially so in ophthalmol-ogy.The scientific basis of lasers in ophthal-mology is based on three mechanisms:1.Photothermal effectLasers:argon,krypton,dye and diodeA thermal effect is generated when laserenergy is absorbed by pigment leading to in-creased vibration and therefore heat content.A

  9. Laser Journal (Selected Articles),

    Science.gov (United States)

    1982-09-10

    laser is described. The apparatus structure and some experimental results are reported. MATERIAL AND ELEMENT MAGNETO -OPTIC PROPERTIES OF Pr dYb),(1oAI...with a magneto -optical modulator. The measuring system is simple and sensitive, with reading accuracy of ±0.0050 and error 45%. STUDY ON EXPERIMENTAL...laser radiation therapy . He Fang de East Chiia Hospital APPLICATION OF N4d,:Y q LASER TO TREAT INTERNAL HEMERRHOID Zhuo Ruilin Zu Songlin (Shanghai

  10. Laser precision microfabrication

    CERN Document Server

    Sugioka, Koji; Pique, Alberto

    2010-01-01

    Miniaturization and high precision are rapidly becoming a requirement for many industrial processes and products. As a result, there is greater interest in the use of laser microfabrication technology to achieve these goals. This book composed of 16 chapters covers all the topics of laser precision processing from fundamental aspects to industrial applications to both inorganic and biological materials. It reviews the sate of the art of research and technological development in the area of laser processing.

  11. Lasers for the SILVA laser isotope separation process

    International Nuclear Information System (INIS)

    Lapierre, Y.

    1997-01-01

    The main principles of the laser isotope separation process for the production of enriched uranium at lower cost, are reviewed and the corresponding optimal laser characteristics are described. The development of the SILVA laser isotope separation process involved researches in the various domains of pump lasers, dye lasers, laser and optics systems and two test facilities for the feasibility studies which are expected for 1997

  12. High power lasers

    CERN Document Server

    Niku-Lari, A

    1989-01-01

    The use of lasers for the working and treatment of materials is becoming increasingly common in industry. However, certain laser applications, for example, in welding, cutting and drilling, are more widely exploited than others. Whilst the potential of lasers for the surface treatment of metals is well recognised, in practice, this particular application is a relative newcomer. The 24 papers in this volume present the latest research and engineering developments in the use of lasers for processes such as surface melting, surface alloying and cladding, and machining, as well as discussing th

  13. Degenerate band edge laser

    Science.gov (United States)

    Veysi, Mehdi; Othman, Mohamed A. K.; Figotin, Alexander; Capolino, Filippo

    2018-05-01

    We propose a class of lasers based on a fourth-order exceptional point of degeneracy (EPD) referred to as the degenerate band edge (DBE). EPDs have been found in parity-time-symmetric photonic structures that require loss and/or gain; here we show that the DBE is a different kind of EPD since it occurs in periodic structures that are lossless and gainless. Because of this property, a small level of gain is sufficient to induce single-frequency lasing based on a synchronous operation of four degenerate Floquet-Bloch eigenwaves. This lasing scheme constitutes a light-matter interaction mechanism that leads also to a unique scaling law of the laser threshold with the inverse of the fifth power of the laser-cavity length. The DBE laser has the lowest lasing threshold in comparison to a regular band edge laser and to a conventional laser in cavities with the same loaded quality (Q ) factor and length. In particular, even without mirror reflectors the DBE laser exhibits a lasing threshold which is an order of magnitude lower than that of a uniform cavity laser of the same length and with very high mirror reflectivity. Importantly, this novel DBE lasing regime enforces mode selectivity and coherent single-frequency operation even for pumping rates well beyond the lasing threshold, in contrast to the multifrequency nature of conventional uniform cavity lasers.

  14. Gigashot Optical Laser Demonstrator

    Energy Technology Data Exchange (ETDEWEB)

    Deri, R. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-10-13

    The Gigashot Optical Laser Demonstrator (GOLD) project has demonstrated a novel optical amplifier for high energy pulsed lasers operating at high repetition rates. The amplifier stores enough pump energy to support >10 J of laser output, and employs conduction cooling for thermal management to avoid the need for expensive and bulky high-pressure helium subsystems. A prototype amplifier was fabricated, pumped with diode light at 885 nm, and characterized. Experimental results show that the amplifier provides sufficient small-signal gain and sufficiently low wavefront and birefringence impairments to prove useful in laser systems, at repetition rates up to 60 Hz.

  15. Notes on Laser Acceleration

    International Nuclear Information System (INIS)

    Tajima, T.

    2008-01-01

    This note intends to motivate our effort toward the advent of new methods of particle acceleration, utilizing the fast rising laser technology. By illustrating the underlying principles in an intuitive manner and thus less jargon-clad fashion, we seek a direction in which we shall be able to properly control and harness the promise of laser acceleration. First we review the idea behind the laser wakefield. We then go on to examine ion acceleration by laser. We examine the sheath acceleration in particular and look for the future direction that allows orderly acceleration of ions in high energies

  16. X-ray lasers

    CERN Document Server

    Elton, Raymond C

    2012-01-01

    The first in its field, this book is both an introduction to x-ray lasers and a how-to guide for specialists. It provides new entrants and others interested in the field with a comprehensive overview and describes useful examples of analysis and experiments as background and guidance for researchers undertaking new laser designs. In one succinct volume, X-Ray Lasers collects the knowledge and experience gained in two decades of x-ray laser development and conveys the exciting challenges and possibilities still to come._Add on for longer version of blurb_M>The reader is first introduced

  17. Lasers in materials processing

    International Nuclear Information System (INIS)

    Davis, J.I.; Rockower, E.B.

    1981-01-01

    A status report on the uranium Laser Isotope Separation (LIS) Program at the Lawrence Livermore National Laboratory is presented. Prior to this status report, process economic analysis is presented so as to understand how the unique properties of laser photons can be best utilized in the production of materials and components despite the high cost of laser energy. The characteristics of potential applications that are necessary for success are identified, and those factors that have up to now frustrated attempts to find commercially viable laser induced chemical and physical process for the production of new or existing materials are pointed out

  18. Mid-Infrared Lasers

    Data.gov (United States)

    National Aeronautics and Space Administration — Mid infrared solid state lasers for Differential Absorption Lidar (DIAL) systems required for understanding atmospheric chemistry are not available. This program...

  19. Laser fusion program overview

    International Nuclear Information System (INIS)

    Emmett, J.L.

    1977-01-01

    This program is structured to proceed through a series of well defined fusion milestones to proof of the scientific feasibility, of laser fusion with the Shiva Nova system. Concurrently, those key technical areas, such as advanced lasers, which are required to progress beyond proof of feasibility, are being studied. We have identified and quantified the opportunities and key technical issues in military applications, such as weapons effects simulations, and in civilian applications, such as central-station electric power production. We summarize the current status and future plans for the laser fusion program at LLL, emphasizing the civilian applications of laser fusion

  20. Physics of semiconductor lasers

    CERN Document Server

    Mroziewicz, B; Nakwaski, W

    2013-01-01

    Written for readers who have some background in solid state physics but do not necessarily possess any knowledge of semiconductor lasers, this book provides a comprehensive and concise account of fundamental semiconductor laser physics, technology and properties. The principles of operation of these lasers are therefore discussed in detail with the interrelations between their design and optical, electrical and thermal properties. The relative merits of a large number of laser structures and their parameters are described to acquaint the reader with the various aspects of the semiconductor l

  1. Principles of laser dynamics

    CERN Document Server

    Khanin, YI

    1995-01-01

    This monograph summarizes major achievements in laser dynamics over the past three decades. The book begins with two introductory Chapters. Chapter 1 offers general considerations on quantum oscillators, formulates the requirements for the laser key elements and shows how these requirements are met in different laser systems. The second Chapter proposes the mathematical models used in semiclassical laser theory, discusses the approximations and simplifications in particular cases, and specifies the range of applicability of these models. In Chapters 3-5 attention is given primarily to the stea

  2. Laser transmitter system

    International Nuclear Information System (INIS)

    Dye, R.A.

    1975-01-01

    A laser transmitter system is disclosed which utilizes mechanical energy for generating an output pulse. The laser system includes a current developing device such as a piezoelectric crystal which charges a storage device such as a capacitor in response to a mechanical input signal. The capacitor is coupled to a switching device, such as a silicon controlled rectifier (SCR). The switching device is coupled to a laser transmitter such as a GaAs laser diode, which provides an output signal in response to the capacitor being discharged

  3. Laser in urology

    International Nuclear Information System (INIS)

    Breisland, H.O.

    1991-01-01

    The neodymium YAG laser is particularly suited for endoscopic urologic surgery because the YAG laser light can be conducted in flexible fibers. Superficial bladder tumours can be treated under local anaesthesia in the outpatient department. The frequency of local recurrences is low, significantly lower than after electrosection or electrocoagulation. Selected cases of T2-muscle invasive bladder tumours can be cured with laser coagulation applied subsequently to transurethral resection. Combined treatment with electrosection and laser coagulation of localized prostatic cancer is a promising method which compares favourably with results obtained by other treatment modalities. Tumours in the upper urinary tract can be laser-treated through ureteroscopes or nephroscopes, but the treatment should be limited to low stage, low grade tumours. Laser is the treatment of choice for intraurethral condylomatas. Laser treatment of penil carcinoma gives excellent cosmetic and functional results and few local recurrences. Laser lithotripsy is a new technique for treatment of ureteric stones and photodynamic laser therapy is a promising tecnique for treatment of carcinoma in situ in the bladder empithelium. However, neither of these techniques are available for clinical use in Norway as yet. 17 refs., 3 figs., 1 tabs

  4. Tunable Microfluidic Dye Laser

    DEFF Research Database (Denmark)

    Olsen, Brian Bilenberg; Helbo, Bjarne; Kutter, Jörg Peter

    2003-01-01

    We present a tunable microfluidic dye laser fabricated in SU-8. The tunability is enabled by integrating a microfluidic diffusion mixer with an existing microfluidic dye laser design by Helbo et al. By controlling the relative flows in the mixer between a dye solution and a solvent......, the concentration of dye in the laser cavity can be adjusted, allowing the wavelength to be tuned. Wavelength tuning controlled by the dye concentration was demonstrated with macroscopic dye lasers already in 1971, but this principle only becomes practically applicable by the use of microfluidic mixing...

  5. Trends in laser micromachining

    Science.gov (United States)

    Gaebler, Frank; van Nunen, Joris; Held, Andrew

    2016-03-01

    Laser Micromachining is well established in industry. Depending on the application lasers with pulse length from μseconds to femtoseconds and wavelengths from 1064nm and its harmonics up to 5μm or 10.6μm are used. Ultrafast laser machining using pulses with pico or femtosecond duration pulses is gaining traction, as it offers very precise processing of materials with low thermal impact. Large-scale industrial ultrafast laser applications show that the market can be divided into various sub segments. One set of applications demand low power around 10W, compact footprint and are extremely sensitive to the laser price whilst still demanding 10ps or shorter laser pulses. A second set of applications are very power hungry and only become economically feasible for large scale deployments at power levels in the 100+W class. There is also a growing demand for applications requiring fs-laser pulses. In our presentation we would like to describe these sub segments by using selected applications from the automotive and electronics industry e.g. drilling of gas/diesel injection nozzles, dicing of LED substrates. We close the presentation with an outlook to micromachining applications e.g. glass cutting and foil processing with unique new CO lasers emitting 5μm laser wavelength.

  6. High Power Vanadate lasers

    CSIR Research Space (South Africa)

    Strauss

    2006-07-01

    Full Text Available stream_source_info Strauss1_2006.pdf.txt stream_content_type text/plain stream_size 3151 Content-Encoding UTF-8 stream_name Strauss1_2006.pdf.txt Content-Type text/plain; charset=UTF-8 Laser Research Institute... University of Stellenbosch www.laser-research.co.za High Power Vanadate lasers H.J.Strauss, Dr. C. Bollig, R.C. Botha, Prof. H.M. von Bergmann, Dr. J.P. Burger Aims 1) To develop new techniques to mount laser crystals, 2) compare the lasing properties...

  7. Laser adaptive holographic hydrophone

    Energy Technology Data Exchange (ETDEWEB)

    Romashko, R V; Kulchin, Yu N; Bezruk, M N; Ermolaev, S A [Institute of Automation and Control Processes, Far Eastern Branch of the Russian Academy of Sciences, Vladivostok (Russian Federation)

    2016-03-31

    A new type of a laser hydrophone based on dynamic holograms, formed in a photorefractive crystal, is proposed and studied. It is shown that the use of dynamic holograms makes it unnecessary to use complex optical schemes and systems for electronic stabilisation of the interferometer operating point. This essentially simplifies the scheme of the laser hydrophone preserving its high sensitivity, which offers the possibility to use it under a strong variation of the environment parameters. The laser adaptive holographic hydrophone implemented at present possesses the sensitivity at a level of 3.3 mV Pa{sup -1} in the frequency range from 1 to 30 kHz. (laser hydrophones)

  8. Introduction to laser technology

    CERN Document Server

    Hitz, C Breck; Hecht, Jeff

    2012-01-01

    The only introductory text on the market today that explains the underlying physics and engineering applicable to all lasersAlthough lasers are becoming increasingly important in our high-tech environment, many of the technicians and engineers who install, operate, and maintain them have had little, if any, formal training in the field of electro-optics. This can result in less efficient usage of these important tools. Introduction to Laser Technology, Fourth Edition provides readers with a good understanding of what a laser is and what it can and cannot do. The book explains what types of las.

  9. Laser-induced interactions

    International Nuclear Information System (INIS)

    Green, W.R.

    1979-01-01

    This dissertation discusses some of the new ways that lasers can be used to control the energy flow in a medium. Experimental and theoretical considerations of the laser-induced collision are discussed. The laser-induced collision is a process in which a laser is used to selectively transfer energy from a state in one atomic or molecular species to another state in a different species. The first experimental demonstration of this process is described, along with later experiments in which lasers were used to create collisional cross sections as large as 10 - 13 cm 2 . Laser-induced collisions utilizing both a dipole-dipole interaction and dipole-quadrupole interaction have been experimentally demonstrated. The theoretical aspects of other related processes such as laser-induced spin-exchange, collision induced Raman emission, and laser-induced charge transfer are discussed. Experimental systems that could be used to demonstrate these various processes are presented. An experiment which produced an inversion of the resonance line of an ion by optical pumping of the neutral atom is described. This type of scheme has been proposed as a possible method for constructing VUV and x-ray lasers

  10. Jet laser ion source

    International Nuclear Information System (INIS)

    Dem'yanov, A.V.; Sidorov, S.V.

    1994-01-01

    External laser injector of multicharged ions (MCI) is developed in which wide-aperture aberration-free wire gauze spherical shape electrodes are applied for effective MCI extraction from laser plasma and beam focusing. Axial plasma compression by solenoid magnetic field is used to reduce ion losses due to transverse movement of the scattering laser plasma. Transverse magnetic field created by another solenoid facilitates the effective laser plasma braking and consequently, leads to the narrowing of energy spectrum of plasma ions and its shift towards lower energies. 2 refs.; 3 figs

  11. Free electron laser

    International Nuclear Information System (INIS)

    Ortega, J.M.; Billardon, M.

    1986-01-01

    Operation principle of a laser and an oscillator are recalled together with the klystron one. In the free electron laser, electrons go through an undulator or an optical klystron. Principles of the last one are given. The two distinct ways of producing coherent radiation with an undulator and an optical klystron are presented. The first one is the use of the free electron laser, the second is to make use of the spontaneous emission generation (harmonics generation). The different current types of free electron lasers are presented (Stanford, Los Alamos, Aco at Orsay). Prospects and applications are given in conclusion [fr

  12. Laser cooling of solids

    CERN Document Server

    Petrushkin, S V

    2009-01-01

    Laser cooling is an important emerging technology in such areas as the cooling of semiconductors. The book examines and suggests solutions for a range of problems in the development of miniature solid-state laser refrigerators, self-cooling solid-state lasers and optical echo-processors. It begins by looking at the basic theory of laser cooling before considering such topics as self-cooling of active elements of solid-state lasers, laser cooling of solid-state information media of optical echo-processors, and problems of cooling solid-state quantum processors. Laser Cooling of Solids is an important contribution to the development of compact laser-powered cryogenic refrigerators, both for the academic community and those in the microelectronics and other industries. Provides a timely review of this promising field of research and discusses the fundamentals and theory of laser cooling Particular attention is given to the physics of cooling processes and the mathematical description of these processes Reviews p...

  13. Laser beam diagnostics for kilowatt power pulsed YAG laser

    International Nuclear Information System (INIS)

    Liu, Yi; Leong, Keng H.

    1992-01-01

    There is a growing need for high power YAG laser beam diagnostics with the recent introduction of such lasers in laser material processing. In this paper, we will describe the use of a commercially available laser beam analyzer (Prometec) to profile the laser beam from a 1600 W pulsed Nd:YAG laser that has a 1 mm fiber optic beam delivery system. The selection of laser pulse frequency and pulse width for the measurement is discussed. Laser beam propagation parameters by various optical components such as fibers and lenses can be determined from measurements using this device. The importance of such measurements will be discussed

  14. Laser Program annual report 1987

    Energy Technology Data Exchange (ETDEWEB)

    O' Neal, E.M.; Murphy, P.W.; Canada, J.A.; Kirvel, R.D.; Peck, T.; Price, M.E.; Prono, J.K.; Reid, S.G.; Wallerstein, L.; Wright, T.W. (eds.)

    1989-07-01

    This report discusses the following topics: target design and experiments; target materials development; laboratory x-ray lasers; laser science and technology; high-average-power solid state lasers; and ICF applications studies.

  15. Laser Program annual report 1987

    International Nuclear Information System (INIS)

    O'Neal, E.M.; Murphy, P.W.; Canada, J.A.; Kirvel, R.D.; Peck, T.; Price, M.E.; Prono, J.K.; Reid, S.G.; Wallerstein, L.; Wright, T.W.

    1989-07-01

    This report discusses the following topics: target design and experiments; target materials development; laboratory x-ray lasers; laser science and technology; high-average-power solid state lasers; and ICF applications studies

  16. Temperature controller of semiconductor laser

    Czech Academy of Sciences Publication Activity Database

    Matoušek, Vít; Číp, Ondřej

    2003-01-01

    Roč. 73, č. 3 (2003), s. 10 - 12 ISSN 0928-5008 Institutional research plan: CEZ:AV0Z2065902 Keywords : temperature controller * semiconductor laser * laser diode Subject RIV: BH - Optics, Masers, Lasers

  17. LASERS: A cryogenic slab CO laser

    Science.gov (United States)

    Ionin, Andrei A.; Kozlov, A. Yu; Seleznev, L. V.; Sinitsyn, D. V.

    2009-03-01

    A compact capacitive transverse RF-discharge-pumped slab CO laser with cryogenically cooled electrodes, which operates both in the cw and repetitively pulsed regimes, is fabricated. The laser operation is studied in the free running multifrequency regime at the vibrational - rotational transitions of the fundamental (V + 1 → V) vibrational bands of the CO molecule in the spectral region from 5.1 to 5.4 μm. Optimal operation conditions (gas mixture composition and pressure, RF pump parameters) are determined. It is shown that only gas mixtures with a high content of oxygen (up to 20% with respect to the concentration of CO molecules) can be used as an active medium of this laser. It is demonstrated that repetitively pulsed pumping is more efficient compared to cw pumping. In this case, quasi-cw lasing regime can be obtained. The maximum average output power of ~12 W was obtained for this laser operating on fundamental bands and its efficiency achieved ~14 %. The frequency-selective operation regime of the slab RF-discharge-pumped CO laser was realised at ~ 100 laser lines in the spectral region from 5.0 to 6.5 μm with the average output power of up to several tens of milliwatts in each line. Lasing at the transitions of the first vibrational overtone (V + 2 → V) of the CO molecule is obtained in the spectral region from 2.5 to 3.9 μm. The average output power of the overtone laser achieved 0.3 W. All the results were obtained without the forced gas mixture exchange in the discharge chamber. Under fixed experimental conditions, repetitively pulsed lasing (with fluctuations of the output characteristics no more than ±10 %) was stable for more than an hour.

  18. Power balancing of multibeam laser fusion lasers

    International Nuclear Information System (INIS)

    Seka, W.; Morse, S.; Letzring, S.; Kremens, R.; Kessler, T.J.; Jaanimagi, P.; Keck, R.; Verdon, C.; Brown, D.

    1989-01-01

    The success of laser fusion depends to a good degree on the ability to compress the target to very high densities of ≥1000 times liquid DT. To achieve such compressions require that the irradiation nonuniformity must not exceed ∼1% rms over the whole time of the compression, particularly during the early phases of irradiation. The stringent requirements for the irradiation uniformity for laser fusion have been known for quite some time but until recently the energy balance was mistakenly equated to power balance. The authors describe their effort on energy balance and irradiation patterns on the target. They significantly improved the laser performance with respect to overall intensity distributions on target including the implementation of distributed (random) phase plates in each high power beam. However, the slightly varying performance of the third harmonic conversion crystals in the twenty-four beams of their laser system was generally compensated for by appropriately adjusted 1.054μm input laser energy. Computational analysis of the results of the recent high density campaign are shown

  19. Laser Stabilization with Laser Cooled Strontium

    DEFF Research Database (Denmark)

    Christensen, Bjarke Takashi Røjle

    The frequency stability of current state-of-the-art stabilized clock lasers are limited by thermal fluctuations of the ultra-stable optical reference cavities used for their frequency stabilization. In this work, we study the possibilities for surpassing this thermal limit by exploiting the nonli......The frequency stability of current state-of-the-art stabilized clock lasers are limited by thermal fluctuations of the ultra-stable optical reference cavities used for their frequency stabilization. In this work, we study the possibilities for surpassing this thermal limit by exploiting...... the nonlinear effects from coupling of an optical cavity to laser cooled atoms having a narrow transition linewidth. Here, we have realized such a system where a thermal sample of laser cooled strontium-88 atoms are coupled to an optical cavity. The strontium-88 atoms were probed on the narrow 1S0-3P1 inter......-combination line at 689 nm in a strongly saturated regime. The dynamics of the atomic induced phase shift and absorption of the probe light were experimentally studied in details with the purpose of applications to laser stabilization. The atomic sample temperature was in the mK range which brought this system out...

  20. High-power pulsed lasers

    International Nuclear Information System (INIS)

    Holzrichter, J.F.

    1980-01-01

    The ideas that led to the successful construction and operation of large multibeam fusion lasers at the Lawrence Livermore Laboratory are reviewed. These lasers are based on the use of Nd:glass laser materials. However, most of the concepts are applicable to any laser being designed for fusion experimentation. This report is a summary of lectures given by the author at the 20th Scottish University Summer School in Physics, on Laser Plasma Interaction. This report includes basic concepts of the laser plasma system, a discussion of lasers that are useful for short-pulse, high-power operation, laser design constraints, optical diagnostics, and system organization

  1. Laser safety tools and training

    CERN Document Server

    Barat, Ken

    2008-01-01

    Lasers perform many unique functions in a plethora of applications, but there are many inherent risks with this continually burgeoning technology. Laser Safety: Tools and Training presents simple, effective ways for users in a variety of facilities to evaluate the hazards of any laser procedure and ensure they are following documented laser safety standards.Designed for use as either a stand-alone volume or a supplement to Laser Safety Management, this text includes fundamental laser and laser safety information and critical laser use information rarely found in a single source. The first lase

  2. Laser biostimulation in pediatrics

    Science.gov (United States)

    Utz, Irina A.; Lagutina, L. E.; Tuchin, Valery V.

    1995-01-01

    In the present paper the method and apparatus for percutaneous laser irradiation of blood (PLIB) in vessels (veins) are described. Results of clinical investigations of biostimulating effects under PLIB by red laser light (633 nm) in Cubiti and Saphena Magna veins are presented.

  3. Metallic DFB lasers

    NARCIS (Netherlands)

    Marell, M.J.H.; Nötzel, R.; Smit, M.K.; Hill, M.T.; Pozo, J.; Mortensen, M.; Urbach, P.; Leijtens, X.; Yousefi, M.

    2010-01-01

    In this paper we present our latest results on the design, fabrication and characterization of metal coated DFB lasers. These devices are based on a specialform of the metal-insulator-metal waveguides, which support plasmon gap modes. The distributed feedback provides control over the laser ~

  4. Laser processing of materials

    Indian Academy of Sciences (India)

    M. Senthilkumar (Newgen Imaging) 1461 1996 Oct 15 13:05:22

    The initial foundation of laser theory was laid by Einstein [11]. ..... general definition and scope of the processes as understood in conventional practice, but is ..... [54]. Laser welding of Ti-alloys. Welding. 2001 TiNi shape memory alloys. CW–CO2. Study corrosion, mechanical and shape memory properties of weldments.

  5. Microfluidic Dye Lasers

    DEFF Research Database (Denmark)

    Kristensen, Anders; Balslev, Søren; Gersborg-Hansen, Morten

    2006-01-01

    A technology for miniaturized, polymer based lasers, suitable for integration with planar waveguides and microfluidic networks is presented. The microfluidic dye laser device consists of a microfluidic channel with an embedded optical resonator. The devices are fabricated in a thin polymer film...

  6. Laser trabeculotomy versus trabeculoplasty

    International Nuclear Information System (INIS)

    Ticho, U.; Frucht, J.

    1984-01-01

    Although laser trabeculotomy has failed in glaucoma management, the laser trabeculoplasty (LTP) procedure has proved to be helpful. LTP was found to improve glaucoma control in 80-90% of open angle glaucoma patients, and less in secondary glaucoma and low tension glaucoma (50%). The procedure is more successful in dark iris eyes and complications are transient. (Auth.)

  7. 5. Laser plasma interaction

    International Nuclear Information System (INIS)

    Labaune, C.; Fuchs, J.; Bandulet, H.

    2002-01-01

    Imprint elimination, smoothing and preheat control are considerable problems in inertial fusion and their possible solution can be achieved by using low-density porous materials as a buffer in target design. The articles gathered in this document present various aspects of the laser-plasma interaction, among which we have noticed: -) numerical algorithmic improvements of the Vlasov solver toward the simulation of the laser-plasma interaction are proposed, -) the dependence of radiation temperatures and X-ray conversion efficiencies of hohlraum on the target structures and laser irradiation conditions are investigated, -) a study of laser interaction with ultra low-density (0,5 - 20 mg/cm 3 ) porous media analyzing backscattered light at incident laser frequency ω 0 and its harmonics 3*ω 0 /2 and 2*ω 0 is presented, -) investigations of laser interaction with solid targets and crater formation are carried out with the objective to determine the ablation loading efficiency, -) a self organization in an intense laser-driven plasma and the measure of the relative degree of order of the states in an open system based on the S-theorem are investigated, and -) the existence and stability of electromagnetic solitons generated in a relativistic interaction of an intense laser light with uniform under-dense cold plasma are studied

  8. Laser Interference Lithography

    NARCIS (Netherlands)

    van Wolferen, Hendricus A.G.M.; Abelmann, Leon; Hennessy, Theodore C.

    In this chapter we explain how submicron gratings can be prepared by Laser Interference Lithography (LIL). In this maskless lithography technique, the standing wave pattern that exists at the intersection of two coherent laser beams is used to expose a photosensitive layer. We show how to build the

  9. Levitated droplet dye laser

    DEFF Research Database (Denmark)

    Azzouz, H.; Alkafadiji, L.; Balslev, Søren

    2006-01-01

    a high quality optical resonator. Our 750 nL lasing droplets consist of Rhodamine 6G dissolved in ethylene glycol, at a concentration of 0.02 M. The droplets are optically pumped at 532 nm light from a pulsed, frequency doubled Nd:YAG laser, and the dye laser emission is analyzed by a fixed grating...

  10. Laser induced energy transfer

    International Nuclear Information System (INIS)

    Falcone, R.W.

    1979-01-01

    Two related methods of rapidly transferring stored energy from one excited chemical species to another are described. The first of these, called a laser induced collision, involves a reaction in which the energy balance is met by photons from an intense laser beam. A collision cross section of ca 10 - 17 cm 2 was induced in an experiment which demonstrated the predicted dependence of the cross section on wavelength and power density of the applied laser. A second type of laser induced energy transfer involves the inelastic scattering of laser radiation from energetically excited atoms, and subsequent absorption of the scattered light by a second species. The technique of producing the light, ''anti-Stokes Raman'' scattering of visible and infrared wavelength laser photons, is shown to be an efficient source of narrow bandwidth, high brightness, tunable radiation at vacuum ultraviolet wavelengths by using it to excite a rare gas transition at 583.7 A. In addition, this light source was used to make the first measurement of the isotopic shift of the helium metastable level at 601 A. Applications in laser controlled chemistry and spectroscopy, and proposals for new types of lasers using these two energy transfer methods are discussed

  11. Coaxial short pulsed laser

    Science.gov (United States)

    Nelson, M.A.; Davies, T.J.

    1975-08-01

    This invention relates to a laser system of rugged design suitable for use in a field environment. The laser itself is of coaxial design with a solid potting material filling the space between components. A reservoir is employed to provide a gas lasing medium between an electrode pair, each of which is connected to one of the coaxial conductors. (auth)

  12. LASER EN LARYNGOLOGIE

    African Journals Online (AJOL)

    9 mai 2013 ... permettant selon les besoins, coagulation, section ou vaporisation. ... tés par laser au service d'ORL et de chirurgie cervico-. LASER EN .... nose était de siège glottique pur à type de palmure dans. 3 cas et supra glottique ...

  13. Lasers in nuclear physics

    International Nuclear Information System (INIS)

    Inamura, T.T.

    1988-01-01

    The hyperfine interaction has been reviewed from a point of view of nuclear physics. Recent progress of nuclear spectroscopy with lasers is presented as one of laser studies of fundamental physics currently pursued in Japan. Especially, the hyperfine anomaly is discussed in connection with the origin of nuclear magnetism. (author)

  14. for aqueous dye lasers

    Indian Academy of Sciences (India)

    2014-02-12

    Feb 12, 2014 ... inclusion complex of RhB with the container molecule cucurbit[7]uril (CB[7]). Keywords. Temperature-dependent fluorescence; Rhodamine B; cucurbit[7]uril; host–guest complex; dye laser. PACS Nos 36.20.kd; 83.60.pq; 87.64.kv. 1. Introduction. Rhodamine B (RhB) is an efficient and photostable laser dye ...

  15. Electrodeless excimer laser

    International Nuclear Information System (INIS)

    Lisi, N.

    2001-01-01

    In this paper it is proposed how to build an excimer laser based on an electrodeless discharge (or Dielectric Barrier Discharge). Such laser could operate with a low energy per pulse ( 2 excimer molecule, whose emission wavelength in the VUV range (157 nm) at high reprate is particularly interesting in the micro-lithography field [it

  16. Combining Raman and laser induced breakdown spectroscopy by double pulse lasing.

    Science.gov (United States)

    Lednev, Vasily N; Pershin, Sergey M; Sdvizhenskii, Pavel A; Grishin, Mikhail Ya; Fedorov, Alexander N; Bukin, Vladimir V; Oshurko, Vadim B; Shchegolikhin, Alexander N

    2018-01-01

    A new approach combining Raman spectrometry and laser induced breakdown spectrometry (LIBS) within a single laser event was suggested. A pulsed solid state Nd:YAG laser running in double pulse mode (two frequency-doubled sequential nanosecond laser pulses with dozens microseconds delay) was used to combine two spectrometry methods within a single instrument (Raman/LIBS spectrometer). First, a low-energy laser pulse (power density far below ablation threshold) was used for Raman measurements while a second powerful laser pulse created the plasma suitable for LIBS analysis. A short time delay between two successive pulses allows measuring LIBS and Raman spectra at different moments but within a single laser flash-lamp pumping. Principal advantages of the developed instrument include high quality Raman/LIBS spectra acquisition (due to optimal gating for Raman/LIBS independently) and absence of target thermal alteration during Raman measurements. A series of high quality Raman and LIBS spectra were acquired for inorganic salts (gypsum, anhydrite) as well as for pharmaceutical samples (acetylsalicylic acid). To the best of our knowledge, the quantitative analysis feasibility by combined Raman/LIBS instrument was demonstrated for the first time by calibration curves construction for acetylsalicylic acid (Raman) and copper (LIBS) in gypsum matrix. Combining ablation pulses and Raman measurements (LIBS/Raman measurements) within a single instrument makes it an efficient tool for identification of samples hidden by non-transparent covering or performing depth profiling analysis including remote sensing. Graphical abstract Combining Raman and laser induced breakdown spectroscopy by double pulse lasing.

  17. Auricular Acupuncture with Laser

    Science.gov (United States)

    Bahr, Frank

    2013-01-01

    Auricular acupuncture is a method which has been successfully used in various fields of medicine especially in the treatment of pain relief. The introduction of lasers especially low-level lasers into medicine brought besides the already existing stimulation with needles and electricity an additional technique to auricular acupuncture. This literature research looks at the historical background, the development and the anatomical and neurological aspects of auricular acupuncture in general and auricular laser acupuncture in detail. Preliminary scientific findings on auricular acupuncture with laser have been described in detail and discussed critically in this review article. The results of the studies have shown evidence of the effect of auricular laser acupuncture. However, a comparison of these studies was impossible due to their different study designs. The most important technical as well as study parameters were described in detail in order to give more sufficient evidence and to improve the quality of future studies. PMID:23935695

  18. Powering laser diode systems

    CERN Document Server

    Trestman, Grigoriy A

    2017-01-01

    This Tutorial Text discusses the competent design and skilled use of laser diode drivers (LDDs) and power supplies (PSs) for the electrical components of laser diode systems. It is intended to help power-electronic design engineers during the initial design stages: the choice of the best PS topology, the calculation of parameters and components of the PS circuit, and the computer simulation of the circuit. Readers who use laser diode systems for research, production, and other purposes will also benefit. The book will help readers avoid errors when creating laser systems from ready-made blocks, as well as understand the nature of the "mystical failures" of laser diodes (and possibly prevent them).

  19. Laser Beam Focus Analyser

    DEFF Research Database (Denmark)

    Nielsen, Peter Carøe; Hansen, Hans Nørgaard; Olsen, Flemming Ove

    2007-01-01

    the obtainable features in direct laser machining as well as heat affected zones in welding processes. This paper describes the development of a measuring unit capable of analysing beam shape and diameter of lasers to be used in manufacturing processes. The analyser is based on the principle of a rotating......The quantitative and qualitative description of laser beam characteristics is important for process implementation and optimisation. In particular, a need for quantitative characterisation of beam diameter was identified when using fibre lasers for micro manufacturing. Here the beam diameter limits...... mechanical wire being swept through the laser beam at varying Z-heights. The reflected signal is analysed and the resulting beam profile determined. The development comprised the design of a flexible fixture capable of providing both rotation and Z-axis movement, control software including data capture...

  20. Introducing the yellow laser

    Science.gov (United States)

    Lincoln, James

    2018-02-01

    The author has acquired a yellow laser with the specific wavelength of 589 nm. Because this is the first time such a laser has been discussed in this journal, I feel it is appropriate to provide a discussion of its function and capabilities. Normal laser safety should be employed, such as not pointing it into eyes or at people, and using eye protection for the young and inexperienced. It is important to note that 589 nm is the same wavelength as the Sodium-D line (doublet). This allows for the laser to serve as a replacement for sodium lamps, and, considering its rather high price, this added value should be balanced against its cost. What follows is a list of activities that showcase the yellow laser's unique promise as an engaging piece of technology that can be used in the teaching of physics.

  1. Regenerative similariton laser

    Directory of Open Access Journals (Sweden)

    Thibault North

    2016-05-01

    Full Text Available Self-pulsating lasers based on cascaded reshaping and reamplification (2R are capable of initiating ultrashort pulses despite the accumulation of large amounts of nonlinearities in all-fiber resonators. The spectral properties of pulses in self-similar propagation are compatible with cascaded 2R regeneration by offset filtering, making parabolic pulses suitable for the design of a laser of this recently introduced class. A new type of regenerative laser giving birth to similaritons is numerically investigated and shows that this laser is the analog of regenerative sources based solely on self-phase modulation and offset filtering. The regenerative similariton laser does not suffer from instabilities due to excessive nonlinearities and enables ultrashort pulse generation in a simple cavity configuration.

  2. Femtosecond Laser Filamentation

    CERN Document Server

    Chin, See Leang

    2010-01-01

    Femtosecond Laser Filamentation gives a comprehensive review of the physics of propagation of intense femtosecond laser pulses in optical media (principally air) and the applications and challenges of this new technique. This book presents the modern understanding of the physics of femtosecond laser pulse propagation, including unusual new effects such as the self-transformation of the pulse into a white light laser pulse, intensity clamping, the physics of multiple filamentation and competition, and how filaments’ ability to melt glass leads to wave guide writing. The potential applications of laser filamentation in atmospheric sensing and the generation of other electromagnetic pulses from the UV to the radio frequency are treated, together with possible future challenges in the excitation of super-excited states of molecules. Exciting new phenomena such as filament induced ultrafast birefringence and the excitation of molecular rotational wave packets and their multiple revivals in air (gases) will also ...

  3. NASA Space Laser Technology

    Science.gov (United States)

    Krainak, Michael A.

    2015-01-01

    Over the next two decades, the number of space based laser missions for mapping, spectroscopy, remote sensing and other scientific investigations will increase several fold. The demand for high wall-plug efficiency, low noise, narrow linewidth laser systems to meet different systems requirements that can reliably operate over the life of a mission will be high. The general trends will be for spatial quality very close to the diffraction limit, improved spectral performance, increased wall-plug efficiency and multi-beam processing. Improved spectral performance will include narrower spectral width (very near the transform limit), increased wavelength stability and or tuning (depending on application) and lasers reaching a wider range of wavelengths stretching into the mid-infrared and the near ultraviolet. We are actively developing high efficiency laser transmitter and high-sensitivity laser receiver systems that are suitable for spaceborne applications.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-04-01

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

  5. Laser Safety Inspection Criteria

    International Nuclear Information System (INIS)

    Barat, K.

    2005-01-01

    A responsibility of the Laser Safety Officer (LSO) is to perform laser audits. The American National Standard Z136.1 Safe Use of Lasers references this requirement through several sections. One such reference is Section 1.3.2.8, Safety Features Audits, ''The LSO shall ensure that the safety features of the laser installation facilities and laser equipment are audited periodically to assure proper operation''. The composition, frequency and rigor of that inspection/audit rests in the hands of the LSO. A common practice for institutions is to develop laser audit checklists or survey forms It is common for audit findings from one inspector or inspection to the next to vary even when reviewing the same material. How often has one heard a comment, ''well this area has been inspected several times over the years and no one ever said this or that was a problem before''. A great number of audit items, and therefore findings, are subjective because they are based on the experience and interest of the auditor to particular items on the checklist. Beam block usage, to one set of eyes might be completely adequate, while to another, inadequate. In order to provide consistency, the Laser Safety Office of the National Ignition Facility Directorate has established criteria for a number of items found on the typical laser safety audit form. The criteria are distributed to laser users. It serves two broad purposes; first, it gives the user an expectation of what will be reviewed by an auditor. Second, it is an opportunity to explain audit items to the laser user and thus the reasons for some of these items, such as labelling of beam blocks

  6. Laser requirements for a laser fusion energy power plant

    Institute of Scientific and Technical Information of China (English)

    Stephen; E.Bodner; Andrew; J.Schmitt; John; D.Sethian

    2013-01-01

    We will review some of the requirements for a laser that would be used with a laser fusion energy power plant, including frequency, spatial beam smoothing, bandwidth, temporal pulse shaping, efficiency, repetition rate, and reliability. The lowest risk and optimum approach uses a krypton fluoride gas laser. A diode-pumped solid-state laser is a possible contender.

  7. Measurements of laser parameters for the Shiva laser fusion facility

    International Nuclear Information System (INIS)

    Ozarski, R.G.

    1979-01-01

    Large laser systems require numerous laser diagnostics to provide configuration, performance and maintenance data to permit efficient operation. The following diagnostics for a large laser system named Shiva are discussed: (1) description of Shiva laser system, (2) what measurements are desired and or required and why, (3) what measurement techniques and packages are employed and a brief description of the operating principles of the sensors employed, and (4) the laser diagnostic data acquisition and display system

  8. LASER PROCESSING ON SINGLE CRYSTALS BY UV PULSE LASER

    OpenAIRE

    龍見, 雅美; 佐々木, 徹; 高山, 恭宜

    2009-01-01

    Laser processing by using UV pulsed laser was carried out on single crystal such as sapphire and diamond in order to understand the fundamental laser processing on single crystal. The absorption edges of diamond and sapphire are longer and shorter than the wave length of UV laser, respectively. The processed regions by laser with near threshold power of processing show quite different state in each crystal.

  9. Laser diode technology and applications

    International Nuclear Information System (INIS)

    Figueroa, L.

    1989-01-01

    This book covers a wide range of semiconductor laser technology, from new laser structures and laser design to applications in communications, remote sensing, and optoelectronics. The authors report on new laser diode physics and applications and present a survey of the state of the art as well as progress in new developments

  10. 1982 laser program annual report

    Energy Technology Data Exchange (ETDEWEB)

    Hendricks, C.D.; Grow, G.R. (eds.)

    1983-08-01

    This annual report covers the following eight sections: (1) laser program review, (2) laser systems and operation, (3) target design, (4) target fabrication, (5) fusion experiments program, (6) Zeus laser project, (7) laser research and development, and (8) energy applications. (MOW)

  11. Fractional laser skin resurfacing.

    Science.gov (United States)

    Alexiades-Armenakas, Macrene R; Dover, Jeffrey S; Arndt, Kenneth A

    2012-11-01

    Laser skin resurfacing (LSR) has evolved over the past 2 decades from traditional ablative to fractional nonablative and fractional ablative resurfacing. Traditional ablative LSR was highly effective in reducing rhytides, photoaging, and acne scarring but was associated with significant side effects and complications. In contrast, nonablative LSR was very safe but failed to deliver consistent clinical improvement. Fractional LSR has achieved the middle ground; it combined the efficacy of traditional LSR with the safety of nonablative modalities. The first fractional laser was a nonablative erbium-doped yttrium aluminum garnet (Er:YAG) laser that produced microscopic columns of thermal injury in the epidermis and upper dermis. Heralding an entirely new concept of laser energy delivery, it delivered the laser beam in microarrays. It resulted in microscopic columns of treated tissue and intervening areas of untreated skin, which yielded rapid reepithelialization. Fractional delivery was quickly applied to ablative wavelengths such as carbon dioxide, Er:YAG, and yttrium scandium gallium garnet (2,790 nm), providing more significant clinical outcomes. Adjustable laser parameters, including power, pitch, dwell time, and spot density, allowed for precise determination of percent surface area, affected penetration depth, and clinical recovery time and efficacy. Fractional LSR has been a significant advance to the laser field, striking the balance between safety and efficacy.

  12. The argon excimer laser

    International Nuclear Information System (INIS)

    Wrobel, W.G.

    1981-02-01

    The electron-beam-pumped argon eximer laser is investigated and tuned for the first time. The electron beam is generated by means of an improved coaxial field emmision diode in which argon gas is excited with power densities of 0.3 GW/cm 3 for 18 ns. The processes in the excited gas of 20 to 65 bar are described in the context of a kinetic model as a sequence of stationary states. Investigations of the amplified spontaneous emission (superfluorescence) confirm the predictions of this model. Only the absorption due to the excited Ar atoms is anomalously high. Reproducible operation of the argon eximer laser was achieved in a wide pressure range with various resonator arrangements. The wavelength of this shortest wavelength of this shortest wavelength excimer laser is 126 nm, the laser line width approx. 1.7 nm, the pulse length 7 to 13 ns, and the laser power 250 kW. The laser emission is tuned from 123.2 nm to 128.4 nm by two different methods (diffraction grating and prism). This tunable laser is thus the one with the shortest wavelength at present. Its line width is 0.25 to 0.4 nm, and the power ue 1.7 kW. (orig.)

  13. Laser wakefield acceleration

    International Nuclear Information System (INIS)

    Esarey, E.; Ting, A.; Sprangle, P.

    1989-01-01

    The laser wakefield accelerator (LWFA) is a novel plasma based electron acceleration scheme which utilizes a relativistic optical guiding mechanism for laser pulse propagation. In the LWFA, a short, high power, single frequency laser pulse is propagated through a plasma. As the laser pulse propagates, its radial and axial ponderomotive forces nonresonantly generate large amplitude plasma waves (wakefields) with a phase velocity equal to the group velocity of the pulse. A properly phased electron bunch may then be accelerated by the axial wakefield and focused by the transverse wakefield. Optical guiding of the laser pulse in the plasma is necessary in order to achieve high energies in a single stage of acceleration. At sufficiently high laser powers, optical guiding may be achieved through relativistic effects associated with the plasma electrons. Preliminary analysis indicates that this scheme may overcome some of the difficulties present in the plasma beat wave accelerator and in the plasma wakefield accelerator. Analytical and numerical calculations are presented which study both laser pulse propagation within a plasma as well as the subsequent generation of large amplitude plasma waves. In addition, the generation of large amplitude plasma waves in regimes where the plasma waves become highly nonlinear is examined

  14. Excimer laser decontamination

    Science.gov (United States)

    Sentis, Marc L.; Delaporte, Philippe C.; Marine, Wladimir; Uteza, Olivier P.

    2000-04-01

    The application of excimer laser ablation process to the decontamination of radioactive surfaces is discussed. This technology is very attractive because it allows to efficiently remove the contaminated particles without secondary waste production. To demonstrate the capability of such technology to efficiently decontaminate large area, we studied and developed a prototype which include a XeCl laser, an optical fiber delivery system and an ablated particles collection cell. The main physical processes taking place during UV laser ablation will be explained. The influence of laser wavelength, pulse duration and absorption coefficient of material will be discussed. Special studies have been performed to understand the processes which limit the transmission of high average power excimer laser through optical fiber, and to determine the laser conditions to optimize the value of this transmission. An in-situ spectroscopic analysis of laser ablation plasma allows the real time control of the decontamination. The results obtained for painting or metallic oxides removal from stainless steel surfaces will be presented.

  15. Dye laser principles with applications

    CERN Document Server

    Duarte, Frank J; Liao, Peter F; Kelley, Paul

    1990-01-01

    A tutorial introduction to the field of dye lasers, Dye Laser Principles also serves as an up-to-date overview for those using dye lasers as research and industrial tools. A number of the issues discussed in this book are pertinent not only to dye lasers but also to lasers in general. Most of the chapters in the book contain problem sets that expand on the material covered in the chapter.Key Features* Dye lasers are among the most versatile and successful laser sources currently available in use Offering both pulsed and continuous-wave operation and tunable from the near ultraviole

  16. Temperature stabilization of injection lasers

    International Nuclear Information System (INIS)

    Albanese, A.

    1987-01-01

    Apparatus which stabilizes the temperature, and thereby the output wavelength, of an injection laser. Means monitor the laser terminal voltage across a laser and derive a voltage therefrom which is proportional to the junction voltage of the laser. Means compares the voltage to a reference value from source and a temperature controller adjusts the laser temperature in response to the results of the comparison. Further embodiments of the present invention vary the output wavelength of the laser by varying the reference value from source against which the laser junction voltage is compared. (author)

  17. Latest development of laser cutting

    OpenAIRE

    Wetzig, Andreas; Herwig, Patrick; Hauptmann, Jan; Goppold, Cindy; Baumann, Robert; Fürst, Andreas; Rose, Michael; Pinder, Thomas; Mahrle, Achim; Beyer, Eckhard

    2016-01-01

    Laser cutting was one of the first applications of laser material processing. Today, laser cutting is the most widespread application among laser material processing besides laser marking. Meanwhile, nearly each material can be cut by means of a laser, in particular since ultra short pulse lasers are available in the power range of up to 100 W. The to be cut material can come with thicknesses from a few microns till tens of millimeters as flat stock or as free form shapes. The paper will conc...

  18. Color speckle in laser displays

    Science.gov (United States)

    Kuroda, Kazuo

    2015-07-01

    At the beginning of this century, lighting technology has been shifted from discharge lamps, fluorescent lamps and electric bulbs to solid-state lighting. Current solid-state lighting is based on the light emitting diodes (LED) technology, but the laser lighting technology is developing rapidly, such as, laser cinema projectors, laser TVs, laser head-up displays, laser head mounted displays, and laser headlamps for motor vehicles. One of the main issues of laser displays is the reduction of speckle noise1). For the monochromatic laser light, speckle is random interference pattern on the image plane (retina for human observer). For laser displays, RGB (red-green-blue) lasers form speckle patterns independently, which results in random distribution of chromaticity, called color speckle2).

  19. Teradiode's high brightness semiconductor lasers

    Science.gov (United States)

    Huang, Robin K.; Chann, Bien; Burgess, James; Lochman, Bryan; Zhou, Wang; Cruz, Mike; Cook, Rob; Dugmore, Dan; Shattuck, Jeff; Tayebati, Parviz

    2016-03-01

    TeraDiode is manufacturing multi-kW-class ultra-high brightness fiber-coupled direct diode lasers for industrial applications. A fiber-coupled direct diode laser with a power level of 4,680 W from a 100 μm core diameter, BPP) of 3.5 mm-mrad and is the lowest BPP multi-kW-class direct diode laser yet reported. This laser is suitable for industrial materials processing applications, including sheet metal cutting and welding. This 4-kW fiber-coupled direct diode laser has comparable brightness to that of industrial fiber lasers and CO2 lasers, and is over 10x brighter than state-of-the-art direct diode lasers. We have also demonstrated novel high peak power lasers and high brightness Mid-Infrared Lasers.

  20. Organic solid-state lasers

    CERN Document Server

    Forget, Sébastien

    2013-01-01

    Organic lasers are broadly tunable coherent sources, potentially compact, convenient and manufactured at low-costs. Appeared in the mid 60’s as solid-state alternatives for liquid dye lasers, they recently gained a new dimension after the demonstration of organic semiconductor lasers in the 90's. More recently, new perspectives appeared at the nanoscale, with organic polariton and surface plasmon lasers. After a brief reminder to laser physics, a first chapter exposes what makes organic solid-state organic lasers specific. The laser architectures used in organic lasers are then reviewed, with a state-of-the-art review of the performances of devices with regard to output power, threshold, lifetime, beam quality etc. A survey of the recent trends in the field is given, highlighting the latest developments with a special focus on the challenges remaining for achieving direct electrical pumping of organic semiconductor lasers. A last chapter covers the applications of organic solid-state lasers.

  1. Laser Hazards Bibliography

    Science.gov (United States)

    1989-10-31

    light on mandibular fracture healing, Stomatologiia, 57(5): 5-9 (1978). 42 Laser Hazards Bibliography 177. Van Gemert, M.J.C., Schets, G.A.C.M., Bishop...U., Laser-coagulation of ruptured fixation suture after lens implantation, J Am Intraocul Implant Soc, 4(2): 54 (1978). 49. Federman, J. L., Ando, F...laser in pediatric surgery, J Ped Surg, 3: 263-270 (April 1968). 82. Hennessy, R. T., and Leibowitz, H., Subjective measurement of accommodation with

  2. Optimising laser tattoo removal

    Directory of Open Access Journals (Sweden)

    Kabir Sardana

    2015-01-01

    Full Text Available Lasers are the standard modality for tattoo removal. Though there are various factors that determine the results, we have divided them into three logical headings, laser dependant factors such as type of laser and beam modifications, tattoo dependent factors like size and depth, colour of pigment and lastly host dependent factors, which includes primarily the presence of a robust immune response. Modifications in the existing techniques may help in better clinical outcome with minimal risk of complications. This article provides an insight into some of these techniques along with a detailed account of the factors involved in tattoo removal.

  3. Ultrashort Laser Pulse Phenomena

    CERN Document Server

    Diels, Jean-Claude

    2006-01-01

    Ultrashort Laser Pulse Phenomena, 2e serves as an introduction to the phenomena of ultra short laser pulses and describes how this technology can be used to examine problems in areas such as electromagnetism, optics, and quantum mechanics. Ultrashort Laser Pulse Phenomena combines theoretical backgrounds and experimental techniques and will serve as a manual on designing and constructing femtosecond (""faster than electronics"") systems or experiments from scratch. Beyond the simple optical system, the various sources of ultrashort pulses are presented, again with emphasis on the basic

  4. Laser-driven accelerators

    International Nuclear Information System (INIS)

    Anon.

    1982-01-01

    Several devices for using laser fields have been proposed and they can be classified in three broad categories - 'far-field' accelerators (such as the principle of inverse free electron lasers), 'media' accelerators (which, for example, use the inverse Cherenkov effect or laser-controlled plasma waves), and 'near-field' accelerators (using a loaded guiding structure such as cavities or gratings). These different approaches come from the fact that a particle cannot be accelerated by the absorption of single photons (because of momentum conservation) and thus some other element has to intervene. (orig./HSI).

  5. Regenerative laser system

    International Nuclear Information System (INIS)

    Biancardi, F.R.; Landerman, A.; Melikian, G.

    1975-01-01

    Regenerative apparatus for exhausting the working medium from the optical cavity of a laser and for supplying preheated diluent to the reaction chamber of a laser is disclosed. In an aftercooler thermal energy is exchanged between the working medium exhausted from the optical cavity and a cryogenic coolant which is subsequently utilized as the motive fluid for an ejector and as a diluent in the production of laser gas. Highly toxic and corrosive gases are condensed out of the working medium as the cryogenic coolant is evaporated and superheated. A preheater transfers additional heat to the diluent before the diluent enters the reaction chamber. (U.S.)

  6. Tunable excimer lasers

    International Nuclear Information System (INIS)

    Sze, R.C.

    1990-01-01

    The wide bandwidth nature of the rare-gas halide excimer transitions allow reasonable tuning of the laser oscillation wavelength that makes it useful for a number of applications. At the same time this wide bandwidth makes narrow band operation difficult and special techniques are needed to insure narrow frequency lasing as well as absolute frequency resettability. The author discusses briefly some of the classical frequency narrowing techniques and then goes on to some recent work that require lasers of special frequency characteristics for special applications including KrF laser fusion

  7. Diatomic gasdynamic lasers.

    Science.gov (United States)

    Mckenzie, R. L.

    1972-01-01

    Predictions from a numerical model of the vibrational relaxation of anharmonic diatomic oscillators in supersonic expansions are used to show the extent to which the small anharmonicity of gases like CO can cause significant overpopulations of upper vibrational states. When mixtures of CO and N2 are considered, radiative gain on many of the vibration-rotation transitions of CO is predicted. Experiments are described that qualitatively verify the predictions by demonstrating laser oscillation in CO-N2 expansions. The resulting CO-N2 gasdynamic laser displays performance characteristics that equal or exceed those of similar CO2 lasers.

  8. Gas dynamic lasers

    International Nuclear Information System (INIS)

    Hill, R.J.; Jewell, N.T.

    1975-01-01

    In a high powered laser system it is proposed that combustion gases be bled off from a gas turbine engine and their composition adjusted by burning extra fuel in the bleed gases or adding extra substances. Suitable aerodynamic expansion produces a population inversion resulting in laser action in the CO 2 species. Alternatively, bleed gases may be taken from the high pressure compressor of the gas turbine engine and an appropriate fuel burned therein. If required, other adjustments may also be made to the composition and the resulting gaseous mixture subjected to aerodynamic expansion to induce laser action as before. (auth)

  9. Monoenergetic laser wakefield acceleration

    Directory of Open Access Journals (Sweden)

    N. E. Andreev

    2000-02-01

    Full Text Available Three dimensional test particle simulations are applied to optimization of the plasma-channeled laser wakefield accelerator (LWFA operating in a weakly nonlinear regime. Electron beam energy spread, emittance, and luminosity depend upon the proportion of the electron bunch size to the plasma wavelength. This proportion tends to improve with the laser wavelength increase. We simulate a prospective two-stage ∼1GeV LWFA with controlled energy spread and emittance. The input parameters correspond to realistic capabilities of the BNL Accelerator Test Facility that features a picosecond-terawatt CO_{2} laser and a high-brightness electron gun.

  10. Simulations of laser undulators

    Science.gov (United States)

    Milton, S. V.; Biedron, S. B.; Einstein, J. E.

    2016-09-01

    We perform a series of single-pass, one-D free-electron laser simulations based on an electron beam from a standard linear accelerator coupled with a so-called laser undulator, a specialized device that is more compact than a standard undulator based on magnetic materials. The longitudinal field profiles of such lasers undulators are intriguing as one must and can tailor the profile for the needs of creating the virtual undulator. We present and discuss several results of recent simulations and our future steps.

  11. Diatomic gasdynamic lasers

    International Nuclear Information System (INIS)

    McKenzie, R.L.

    1971-12-01

    Predictions from a numerical model of the vibrational relaxation of anharmonic diatomic oscillators in supersonic expansions are used to show the extent to which the small anharmonicity of gases like CO can cause significant over-populations of upper vibrational states. When mixtures of CO and N 2 are considered, radiative gain on many of the vibration-rotation transitions of CO is predicted. Experiments are described that qualitatively verify the predictions by demonstrating laser oscillation in CO-N 2 expansions. The resulting CO-N 2 gasdynamic laser displays performance characteristics that equal or exceed those of similar CO 2 lasers

  12. High power excimer laser

    International Nuclear Information System (INIS)

    Oesterlin, P.; Muckenheim, W.; Basting, D.

    1988-01-01

    Excimer lasers emitting more than 200 W output power are not commercially available. A significant increase requires new technological efforts with respect to both the gas circulation and the discharge system. The authors report how a research project has yielded a laser which emits 0.5 kW at 308 nm when being UV preionized and operated at a repetition rate of 300 Hz. The laser, which is capable of operating at 500 Hz, can be equipped with an x-ray preionization module. After completing this project 1 kW output power will be available

  13. Plasmonic colour laser printing

    DEFF Research Database (Denmark)

    Zhu, Xiaolong; Vannahme, Christoph; Højlund-Nielsen, Emil

    2016-01-01

    -beam lithography (EBL) or focused ion beam (FIB), both expensive and not scalable processes that are not suitable for post-processing customization. Here we show a method of colour printing on nanoimprinted plasmonic metasurfaces using laser post-writing. Laser pulses induce transient local heat generation...... that leads to melting and reshaping of the imprinted nanostructures. Depending on the laser pulse energy density, different surface morphologies that support different plasmonic resonances leading to different colour appearances can be created. Using this technique we can print all primary colours...

  14. Optimising Laser Tattoo Removal

    Science.gov (United States)

    Sardana, Kabir; Ranjan, Rashmi; Ghunawat, Sneha

    2015-01-01

    Lasers are the standard modality for tattoo removal. Though there are various factors that determine the results, we have divided them into three logical headings, laser dependant factors such as type of laser and beam modifications, tattoo dependent factors like size and depth, colour of pigment and lastly host dependent factors, which includes primarily the presence of a robust immune response. Modifications in the existing techniques may help in better clinical outcome with minimal risk of complications. This article provides an insight into some of these techniques along with a detailed account of the factors involved in tattoo removal. PMID:25949018

  15. Laser welding engineering

    International Nuclear Information System (INIS)

    Bhieh, N. M.; El Eesawi, M. E.; Hashkel, A. E.

    2007-01-01

    Laser welding was in its early life used mainly for unusual applications where no other welding process would be suitable that was twenty five years ago. Today, laser welding is a fully developed part of the metal working industry, routinely producing welds for common items such as cigarette lighters, which springs, motor/transformer lamination, hermetic seals, battery and pacemaker cans and hybrid circuit packages. Yet very few manufacturing engineering have seriously considers employing lasers in their own operations. Why? There are many reasons, but a main one must be not acquainted with the operation and capabilities of a laser system. Other reasons, such as a relatively high initial cost and a concern about using lasers in the manufacturing environment, also are frequently cited, and the complexity of the component and flexibility of the light delivery system. Laser welding could be used in place of many different standard processes, such as resistance (spot or seam), submerged arc, RF induction, high-frequency resistance, ultrasonic and electronic and electron-beam. while each of these techniques has established an independent function in the manufacturing world, the flexible laser welding approach will operate efficiently and economically in many different applications. Its flexibility will even permit the welding system to be used for other machining function, such as drilling, scribing, sealing and serializing. In this article, we will look at how laser welding works and what benefits it can offer to manufacturing engineers. Some industry observers state that there are already 2,000 laser machine tools being used for cutting, welding and drilling and that the number could reach 30,000 over the next 15 years as manufacturing engineers become more aware of the capabilities of lasers [1). While most laser applications are dedicated to one product or process that involves high-volume, long-run manufacturing, the flexibility of a laser to supply energy to hard

  16. Laser Megajoule synchronization system

    International Nuclear Information System (INIS)

    Luttmann, M.; Pastor, J.F; Drouet, V.; Prat, M.; Raimbourg, J.; Adolf, A.

    2011-01-01

    This paper describes the synchronisation system under development on the Laser Megajoule (LMJ) in order to synchronize the laser quads on the target to better than 40 ps rms. Our architecture is based on a Timing System (TS) which delivers trigger signals with jitter down to 15 ps rms coupled with an ultra precision timing system with 5 ps rms jitter. In addition to TS, a sensor placed at the target chamber center measures the arrival times of the 3 omega nano joule laser pulses generated by front end shots. (authors)

  17. Laser applications in neurosurgery

    Science.gov (United States)

    Cerullo, Leonard J.

    1985-09-01

    The "false start" of the laser in neurosurgery should not be misconstrued as a denial of the inherent advantages of precision and gentleness in dealing with neural tissue. Rather, early investigators were frustrated by unrealistic expectations, cumbersome equipment, and a general ignorance of microtechnique. By the early 70s, microneurosurgery was well established, surgical laser equipment for free hand and microlinked application had been developed, and a more realistic view of the limitations of the laser had been established. Consequently, the late 70s really heralded the renaissance of the laser in neurosurgery. Since then, there has been an overwhelming acceptance of the tool in a variety of clinical situations, broadly categorized in five groups. 1)|Perhaps the most generally accepted area is in the removal of extra-axial tumors of the brain and spinal cord. These tumors, benign by histology but treacherous by location, do not present until a significant amount of neurological compensation has already occurred. The application of additional trauma to the neural tissue, whether by further tumor growth or surgical manipulation, frequently results in irreversible damage. Here, the ability of the laser to vaporize tissue, in a fairly hemostatic fashion, without mechanical or thermal damage to sensitive surrounding tissues, is essential. 2)|The ability to incise delicate neural tissue with minimal spread of thermal destruction to adjacent functioning tissue makes the laser the ideal instrument when tumors deep under the surface are encountered in the brain or spinal cord. Thus, the second group of applications is in the transgression of normal neural structures to arrive at deeper pathological tissue. 3)|The third area of benefit for the laser in neurosurgery has been in the performance of neuroablative procedures, calling for deliberate destruction of functioning neural tissue in a controlled fashion. Again, the precision and shape confinement of the destructive

  18. Laser tests of silicon detectors

    International Nuclear Information System (INIS)

    Dolezal, Zdenek; Escobar, Carlos; Gadomski, Szymon; Garcia, Carmen; Gonzalez, Sergio; Kodys, Peter; Kubik, Petr; Lacasta, Carlos; Marti, Salvador; Mitsou, Vasiliki A.; Moorhead, Gareth F.; Phillips, Peter W.; Reznicek, Pavel; Slavik, Radan

    2007-01-01

    This paper collects experiences from the development of a silicon sensor laser testing setup and from tests of silicon strip modules (ATLAS End-cap SCT), pixel modules (DEPFET) and large-area diodes using semiconductor lasers. Lasers of 1060 and 680 nm wavelengths were used. A sophisticated method of focusing the laser was developed. Timing and interstrip properties of modules were measured. Analysis of optical effects involved and detailed discussion about the usability of laser testing for particle detectors are presented

  19. Beam Diagnostics for Laser Undulator Based on Compton Backward Scattering

    CERN Document Server

    Kuroda, R

    2005-01-01

    A compact soft X-ray source is required in various research fields such as material and biological science. The laser undulator based on Compton backward scattering has been developed as a compact soft X-ray source for the biological observation at Waseda University. It is performed in a water window region (250eV - 500 eV) using the interaction between 1047 nm Nd:YLF laser (10ps FWHM) and about 5 MeV high quality electron beam (10ps FWHM) generated from rf gun system. The range of X-ray energy in the water window region has K-shell absorption edges of Oxygen, Carbon and Nitrogen, which mainly constitute of living body. Since the absorption coefficient of water is much smaller than the protein's coefficient in this range, a dehydration of the specimens is not necessary. To generate the soft X-ray pulse stably, the electron beam diagnostics have been developed such as the emittance measurement using double slit scan technique, the bunch length measurement using two frequency analysis technique. In this confere...

  20. Multispot fiber laser welding

    DEFF Research Database (Denmark)

    Schutt Hansen, Klaus

    This dissertation presents work and results achieved in the field of multi beam fiber laser welding. The project has had a practical approach, in which simulations and modelling have been kept at a minimum. Different methods to produce spot patterns with high power single mode fiber lasers have...... been examined and evaluated. It is found that both diamond turned DOE’s in zinc sulphide and multilevel etched DOE’s (Diffractive Optical Elements) in fused silica have a good performance. Welding with multiple beams in a butt joint configuration has been tested. Results are presented, showing it has...... been possible to control the welding width in incremental steps by adding more beams in a row. The laser power was used to independently control the keyhole and consequently the depth of fusion. An example of inline repair of a laser weld in butt joint configuration was examined. Zinc powder was placed...