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Sample records for nm laser transition

  1. Hydrocarbon-free resonance transition 795-nm rubidium laser

    SciTech Connect

    Wu, S Q; Soules, T F; Page, R H; Mitchell, S C; Kanz, V K; Beach, R J

    2008-01-09

    An optical resonance transition rubidium laser (5{sup 2}P{sub 1/2} {yields} 5{sup 2}S{sub 1/2}) is demonstrated with a hydrocarbon-free buffer gas. Prior demonstrations of alkali resonance transition lasers have used ethane as either the buffer gas or a buffer gas component to promote rapid fine-structure mixing. However, our experience suggests that the alkali vapor reacts with the ethane producing carbon as one of the reaction products. This degrades long term laser reliability. Our recent experimental results with a 'clean' helium-only buffer gas system pumped by a Ti:sapphire laser demonstrate all the advantages of the original alkali laser system, but without the reliability issues associated with the use of ethane.

  2. A 408 nm Laser System to Drive Stimulated Raman Transitions

    NASA Astrophysics Data System (ADS)

    Archibald, James, II; Erickson, Christopher; Durfee, Dallin

    2011-05-01

    We will discuss a diode laser system that produces two laser beams, differing in frequency by 1 GHz, that can be used to drive Raman transitions in 87Sr+. This system will be used to generate the π and π / 2 pulses in an ion interferometer. The laser consists of a grating stabilized master laser. This is then passed through an AOM and retroreflected back through the AOM in order to provide two frequency-shifted beams. These beams are then used to injection lock two slave lasers, in a scheme similar to the one described in. The AOM can be modulated with a stability better than 1 Hz. Thus we guarantee that the light output from the slaves is at a constant detuning, while drift from the master laser corresponds to common mode drift (to which the Raman transition is less sensitive). We will also discuss a technique used to improve laser stability similar to the scheme described in but using the measured impedance of the diode rather than the amplitude noise on the light to generate an error signal. We will discuss a diode laser system that produces two laser beams, differing in frequency by 1 GHz, that can be used to drive Raman transitions in 87Sr+. This system will be used to generate the π and π / 2 pulses in an ion interferometer. The laser consists of a grating stabilized master laser. This is then passed through an AOM and retroreflected back through the AOM in order to provide two frequency-shifted beams. These beams are then used to injection lock two slave lasers, in a scheme similar to the one described in. The AOM can be modulated with a stability better than 1 Hz. Thus we guarantee that the light output from the slaves is at a constant detuning, while drift from the master laser corresponds to common mode drift (to which the Raman transition is less sensitive). We will also discuss a technique used to improve laser stability similar to the scheme described in but using the measured impedance of the diode rather than the amplitude noise on the light to

  3. A compact ultranarrow high-power laser system for experiments with 578 nm ytterbium clock transition

    SciTech Connect

    Cappellini, G.; Lombardi, P.; Mancini, M.; Pagano, G.; Pizzocaro, M.; Fallani, L.; Catani, J.

    2015-07-15

    In this paper, we present the realization of a compact, high-power laser system able to excite the ytterbium clock transition at 578 nm. Starting from an external-cavity laser based on a quantum dot chip at 1156 nm with an intra-cavity electro-optic modulator, we were able to obtain up to 60 mW of visible light at 578 nm via frequency doubling. The laser is locked with a 500 kHz bandwidth to an ultra-low-expansion glass cavity stabilized at its zero coefficient of thermal expansion temperature through an original thermal insulation and correction system. This laser allowed the observation of the clock transition in fermionic {sup 173}Y b with a <50 Hz linewidth over 5 min, limited only by a residual frequency drift of some 0.1 Hz/s.

  4. A compact ultranarrow high-power laser system for experiments with 578 nm ytterbium clock transition

    NASA Astrophysics Data System (ADS)

    Cappellini, G.; Lombardi, P.; Mancini, M.; Pagano, G.; Pizzocaro, M.; Fallani, L.; Catani, J.

    2015-07-01

    In this paper, we present the realization of a compact, high-power laser system able to excite the ytterbium clock transition at 578 nm. Starting from an external-cavity laser based on a quantum dot chip at 1156 nm with an intra-cavity electro-optic modulator, we were able to obtain up to 60 mW of visible light at 578 nm via frequency doubling. The laser is locked with a 500 kHz bandwidth to an ultra-low-expansion glass cavity stabilized at its zero coefficient of thermal expansion temperature through an original thermal insulation and correction system. This laser allowed the observation of the clock transition in fermionic 173Y b with a <50 Hz linewidth over 5 min, limited only by a residual frequency drift of some 0.1 Hz/s.

  5. Resonance transition 795-nm Rubidium laser using 3He buffer gas

    SciTech Connect

    Wu, S S; Soules, T F; Page, R H; Mitchell, S C; Kanz, V K; Beach, R J

    2007-08-02

    We report the first demonstration of a 795-nm Rubidium resonance transition laser using a buffer gas consisting of pure {sup 3}He. This follows our recent demonstration of a hydrocarbon-free 795-nm Rubidium resonance laser which used naturally-occurring He as the buffer gas. Using He gas that is isotopically enriched with {sup 3}He yields enhanced mixing of the Rb fine-structure levels. This enables efficient lasing at reduced He buffer gas pressure, improving thermal management in high average power Rb lasers and enhancing the power scaling potential of such systems.

  6. Study of transitions in thulium atoms in the 410-420-nm range for laser cooling

    SciTech Connect

    Akimov, A V; Chebakov, K Yu; Tolstikhina, I Yu; Sokolov, A V; Rodionov, P B; Kanorsky, S I; Sorokin, V N; Kolachevsky, N N

    2008-10-31

    The possibility of laser cooling of thulium atoms is considered. The hyperfine structure of almost cyclic 4f{sup 13}6s{sup 2} (J{sub g} = 7/2) {r_reversible} 4f{sup 12}5d{sub 3/2}6s{sup 2} (J{sub e} = 9/2) and 4f{sup 13}6s{sup 2} (J{sub g} = 7/2) {r_reversible} 4f{sup 12}5d{sub 5/2}6s{sup 2} (J{sub e} = 9/2) transitions at 410.6 and 420.4 nm, respectively, is studied by the method of sub-Doppler saturation spectroscopy in counterpropagating laser beams. The hyperfine splitting of excited levels involved in these transitions is measured and the natural linewidths of these transitions are determined. The structure of the neighbouring 4f{sup 13}6s6p (J{sub e} = 5/2) and 4f{sup 12}5d{sub 5/2}6s{sup 2} (J{sub e} = 7/2) levels is studied for the first time by this method. The decay probabilities of the J{sub e} = 9/2 levels via channels removing atoms from the cooling cycle are calculated. It is found that the branching ratio for the strong transition at 410.6 nm (A = 6x10{sup 7} s{sup -1}) is smaller than 2x10{sup -5}, which makes this transition most promising for laser cooling. The laser cooling of atoms in a Zeeman cooler at this transition is simulated. The possibility of using a laser-cooled cloud of thulium atoms to study the metrological transition at 1.14 {mu}m is discussed. (laser cooling of atoms)

  7. LASER COOLING OF ATOMS: Study of transitions in thulium atoms in the 410-420-nm range for laser cooling

    NASA Astrophysics Data System (ADS)

    Akimov, A. V.; Chebakov, K. Yu; Tolstikhina, I. Yu; Sokolov, A. V.; Rodionov, P. B.; Kanorsky, S. I.; Sorokin, V. N.; Kolachevsky, N. N.

    2008-10-01

    The possibility of laser cooling of thulium atoms is considered. The hyperfine structure of almost cyclic 4f136s2 (Jg = 7/2) <--> 4f125d3/26s2 (Je = 9/2) and 4f136s2 (Jg = 7/2) <--> 4f125d5/26s2 (Je = 9/2) transitions at 410.6 and 420.4 nm, respectively, is studied by the method of sub-Doppler saturation spectroscopy in counterpropagating laser beams. The hyperfine splitting of excited levels involved in these transitions is measured and the natural linewidths of these transitions are determined. The structure of the neighbouring 4f136s6p (Je = 5/2) and 4f125d5/26s2 (Je = 7/2) levels is studied for the first time by this method. The decay probabilities of the Je = 9/2 levels via channels removing atoms from the cooling cycle are calculated. It is found that the branching ratio for the strong transition at 410.6 nm (A = 6×107 s-1) is smaller than 2×10-5, which makes this transition most promising for laser cooling. The laser cooling of atoms in a Zeeman cooler at this transition is simulated. The possibility of using a laser-cooled cloud of thulium atoms to study the metrological transition at 1.14 μm is discussed.

  8. Frequency stabilization of a 1083 nm fiber laser to ⁴He transition lines with optical heterodyne saturation spectroscopies.

    PubMed

    Gong, W; Peng, X; Li, W; Guo, H

    2014-07-01

    Two kinds of optical heterodyne saturation spectroscopies, namely, frequency modulation spectroscopy (FMS) and modulation transfer spectroscopy (MTS), are demonstrated for locking a fiber laser to the transition lines of metastable (4)He atoms around 1083 nm. The servo-loop error signals of FMS and MTS for stabilizing laser frequency are optimized by studying the dependence of the peak-to-peak amplitude and slope on the optical power of pump and probe beams. A comparison of the stabilization performances of FMS/MTS and polarization spectroscopy (PS) is presented, which shows that MTS exhibits relatively superior performance with the least laser frequency fluctuation due to its flat-background dispersive signal, originated from the four-wave mixing process. The Allan deviation of the stabilized laser frequency is 5.4 × 10(-12)@100 s with MTS for data acquired in 1000 s, which is sufficiently applicable for fields like laser cooling, optical pumping, and optical magnetometry. PMID:25085123

  9. Frequency stabilization of a 1083 nm fiber laser to {sup 4}He transition lines with optical heterodyne saturation spectroscopies

    SciTech Connect

    Gong, W.; Peng, X. Li, W.; Guo, H.

    2014-07-15

    Two kinds of optical heterodyne saturation spectroscopies, namely, frequency modulation spectroscopy (FMS) and modulation transfer spectroscopy (MTS), are demonstrated for locking a fiber laser to the transition lines of metastable {sup 4}He atoms around 1083 nm. The servo-loop error signals of FMS and MTS for stabilizing laser frequency are optimized by studying the dependence of the peak-to-peak amplitude and slope on the optical power of pump and probe beams. A comparison of the stabilization performances of FMS/MTS and polarization spectroscopy (PS) is presented, which shows that MTS exhibits relatively superior performance with the least laser frequency fluctuation due to its flat-background dispersive signal, originated from the four-wave mixing process. The Allan deviation of the stabilized laser frequency is 5.4 × 10{sup −12}@100 s with MTS for data acquired in 1000 s, which is sufficiently applicable for fields like laser cooling, optical pumping, and optical magnetometry.

  10. Frequency stabilization of a 1083 nm fiber laser to 4He transition lines with optical heterodyne saturation spectroscopies

    NASA Astrophysics Data System (ADS)

    Gong, W.; Peng, X.; Li, W.; Guo, H.

    2014-07-01

    Two kinds of optical heterodyne saturation spectroscopies, namely, frequency modulation spectroscopy (FMS) and modulation transfer spectroscopy (MTS), are demonstrated for locking a fiber laser to the transition lines of metastable 4He atoms around 1083 nm. The servo-loop error signals of FMS and MTS for stabilizing laser frequency are optimized by studying the dependence of the peak-to-peak amplitude and slope on the optical power of pump and probe beams. A comparison of the stabilization performances of FMS/MTS and polarization spectroscopy (PS) is presented, which shows that MTS exhibits relatively superior performance with the least laser frequency fluctuation due to its flat-background dispersive signal, originated from the four-wave mixing process. The Allan deviation of the stabilized laser frequency is 5.4 × 10-12@100 s with MTS for data acquired in 1000 s, which is sufficiently applicable for fields like laser cooling, optical pumping, and optical magnetometry.

  11. 469nm Fiber Laser Source

    SciTech Connect

    Drobshoff, A; Dawson, J W; Pennington, D M; Payne, S A; Beach, R

    2005-01-20

    We have demonstrated 466mW of 469nm light from a frequency doubled continuous wave fiber laser. The system consisted of a 938nm single frequency laser diode master oscillator, which was amplified in two stages to 5 Watts using cladding pumped Nd{sup 3+} fiber amplifiers and then frequency doubled in a single pass through periodically poled KTP. The 3cm long PPKTP crystal was made by Raicol Crystals Ltd. with a period of 5.9 {micro}m and had a phase match temperature of 47 degrees Centigrade. The beam was focused to a 1/e{sup 2} diameter in the crystal of 29 {micro}m. Overall conversion efficiency was 11% and the results agreed well with standard models. Our 938nm fiber amplifier design minimizes amplified spontaneous emission at 1088nm by employing an optimized core to cladding size ratio. This design allows the 3-level transition to operate at high inversion, thus making it competitive with the 1088nm 4-level transition. We have also carefully chosen the fiber coil diameter to help suppress propagation of wavelengths longer than 938 nm. At 2 Watts, the 938nm laser had an M{sup 2} of 1.1 and good polarization (correctable with a quarter and half wave plate to >10:1).

  12. Diode-pumped Nd:YVO4 laser emitting at 1074 nm based on the 4 F 3/2-4 I 11/2 transition

    NASA Astrophysics Data System (ADS)

    Ma, Z. Y.; Li, C. L.; Liang, W.; Wang, J. G.

    2011-09-01

    We report a diode-pumped Nd:YVO4 laser emitting at 1074 nm, based on the 4 F 3/2-4 I 11/2 transition, generally used for a 1064 nm emission. A power of 323 mW at 1074 nm has been achieved in continuouswave (CW) operation with a fiber-coupled laser diode emitting 18.2 W at 808 nm. Intracavity second-harmonic generation in CW mode has also been demonstrated with a power of 18 mW at 537 nm by using a LiB3O5 (LBO) nonlinear crystal.

  13. Retinal thermal damage threshold dependence on exposure duration for the transitional near-infrared laser radiation at 1319 nm

    PubMed Central

    Wang, Jiarui; Jiao, Luguang; Jing, Xiaomin; Chen, Hongxia; Hu, Xiangjun; Yang, Zaifu

    2016-01-01

    The retinal damage effects induced by transitional near-infrared (NIR) lasers have been investigated for years. However, the damage threshold dependence on exposure duration has not been revealed. In this paper, the in-vivo retinal damage ED50 thresholds were determined in chinchilla grey rabbits for 1319 nm laser radiation for exposure durations from 0.1 s to 10 s. The incident corneal irradiance diameter was fixed at 5 mm. The ED50 thresholds given in terms of the total intraocular energy (TIE) for exposure durations of 0.1, 1 and 10 s were 1.36, 6.33 and 28.6 J respectively. The ED50 thresholds were correlated by a power law equation, ED50 = 6.31t0.66 [J] where t is time [s], with correlation coefficient R = 0.9999. There exists a sufficient safety margin (factor of 28~60) between the human ED50 thresholds derived from the rabbit and the maximum permissible exposure (MPE) values in the current laser safety standards. PMID:27231639

  14. Retinal thermal damage threshold dependence on exposure duration for the transitional near-infrared laser radiation at 1319 nm.

    PubMed

    Wang, Jiarui; Jiao, Luguang; Jing, Xiaomin; Chen, Hongxia; Hu, Xiangjun; Yang, Zaifu

    2016-05-01

    The retinal damage effects induced by transitional near-infrared (NIR) lasers have been investigated for years. However, the damage threshold dependence on exposure duration has not been revealed. In this paper, the in-vivo retinal damage ED50 thresholds were determined in chinchilla grey rabbits for 1319 nm laser radiation for exposure durations from 0.1 s to 10 s. The incident corneal irradiance diameter was fixed at 5 mm. The ED50 thresholds given in terms of the total intraocular energy (TIE) for exposure durations of 0.1, 1 and 10 s were 1.36, 6.33 and 28.6 J respectively. The ED50 thresholds were correlated by a power law equation, ED50 = 6.31t (0.66) [J] where t is time [s], with correlation coefficient R = 0.9999. There exists a sufficient safety margin (factor of 28~60) between the human ED50 thresholds derived from the rabbit and the maximum permissible exposure (MPE) values in the current laser safety standards. PMID:27231639

  15. Diode laser operating on an atomic transition limited by an isotope ⁸⁷Rb Faraday filter at 780 nm.

    PubMed

    Tao, Zhiming; Hong, Yelong; Luo, Bin; Chen, Jingbiao; Guo, Hong

    2015-09-15

    We demonstrate an extended cavity Faraday laser system using an antireflection-coated laser diode as the gain medium and the isotope (87)Rb Faraday anomalous dispersion optical filter (FADOF) as the frequency selective device. Using this method, the laser wavelength works stably at the highest transmission peak of the isotope (87)Rb FADOF over the laser diode current from 55 to 140 mA and the temperature from 15°C to 35°C. Neither the current nor the temperature of the laser diode has significant influence on the output frequency. Compared with previous extended cavity laser systems operating at frequencies irrelevant to spectacular atomic transition lines, the laser system realized here provides a stable laser source with the frequency operating on atomic transitions for many practical applications. PMID:26371933

  16. 750 mW continuous-wave solid-state deep ultraviolet laser source at the 253.7 nm transition in mercury.

    PubMed

    Scheid, Martin; Markert, Frank; Walz, Jochen; Wang, Jiayu; Kirchner, Martin; Hänsch, Theodor W

    2007-04-15

    A high-power continuous-wave coherent light source at 253.7 nm is described. It is based on a solid-state Yb:YAG disk laser with two successive frequency doubling stages and is capable of generating stable output powers of up to 750 mW. Spectroscopy of the 6 (1)S(0)-6 (3)P(1) transition of mercury has been demonstrated. PMID:17375166

  17. Dependence of gain and laser power for Cu-II 780.8-nm transition on the diameter of a segmented hollow cathode discharge

    SciTech Connect

    Szalai, L.; Donko, Z.; Rozsa, K.; Tobin, R.C.

    1995-08-01

    The dependence of laser performance and discharge characteristics on the diameter of a segmented hollow cathode discharge for the Cu-II 780.8 nm transition is presented. This transition has a special importance since its upper level is common to potential CW VUV laser transitions (150--170 nm). Laser tubes with internal diameters of 2, 3, 4, and 5 mm were investigated. Decreasing the diameter resulted in an increased gain for a given current (up to 100%/m in the 2-mm diameter, 5-cm-long tube at 1-A current). The highest output power was obtained from the large-diameter tubes (20 mW from a 5-cm-long, 5-mm-diameter tube at 2-A current, without optimizing the output coupler). This work is a part of a series of investigations aimed at the optimization of the segmented hollow cathode discharge which has already been found to be the most efficient type of discharge for cathode sputtered metal ion lasers.

  18. Multi-watt 589nm fiber laser source

    SciTech Connect

    DAWSON, J W; DROBSHOFF, A D; BEACH, R J; MESSERLY, M J; PAYNE, S A; BROWN, A; PENNINGTON, D M; BAMFORD, D J; SHARPE, S J; COOK, D J

    2006-01-19

    We have demonstrated 3.5W of 589nm light from a fiber laser using periodically poled stoichiometric Lithium Tantalate (PPSLT) as the frequency conversion crystal. The system employs 938nm and 1583nm fiber lasers, which were sum-frequency mixed in PPSLT to generate 589nm light. The 938nm fiber laser consists of a single frequency diode laser master oscillator (200mW), which was amplified in two stages to >15W using cladding pumped Nd{sup 3+} fiber amplifiers. The fiber amplifiers operate at 938nm and minimize amplified spontaneous emission at 1088nm by employing a specialty fiber design, which maximizes the core size relative to the cladding diameter. This design allows the 3-level laser system to operate at high inversion, thus making it competitive with the competing 1088nm 4-level laser transition. At 15W, the 938nm laser has an M{sup 2} of 1.1 and good polarization (correctable with a quarter and half wave plate to >15:1). The 1583nm fiber laser consists of a Koheras 1583nm fiber DFB laser that is pre-amplified to 100mW, phase modulated and then amplified to 14W in a commercial IPG fiber amplifier. As a part of our research efforts we are also investigating pulsed laser formats and power scaling of the 589nm system. We will discuss the fiber laser design and operation as well as our results in power scaling at 589nm.

  19. Compact Fiber Laser for 589nm Laser Guide Star Generation

    NASA Astrophysics Data System (ADS)

    Pennington, D.; Drobshoff, D.; Mitchell, S.; Brown, A.

    Laser guide stars are crucial to the broad use of astronomical adaptive optics, because they facilitate access to a large fraction of possible locations on the sky. Lasers tuned to the 589 nm atomic sodium resonance can create an artificial beacon at altitudes of 95-105 km, thus coming close to reproducing the light path of starlight. The deployment of multiconjugate adaptive optics on large aperture telescopes world-wide will require the use of three to nine sodium laser guide stars in order to achieve uniform correction over the aperture with a high Strehl value. Current estimates place the minimum required laser power at > 10 W per laser for a continuous wave source, though a pulsed format, nominally 6?s in length at ~ 16.7 kHz, is currently preferred as it would enable tracking the laser through the Na layer to mitigate spot elongation. The lasers also need to be compact, efficient, robust and turnkey. We are developing an all-fiber laser system for generating a 589 nm source for laser-guided adaptive optics. Fiber lasers are more compact and insensitive to alignment than their bulk laser counterparts, and the heat-dissipation characteristics of fibers, coupled with the high efficiencies demonstrated and excellent spatial mode characteristics, make them a preferred candidate for many high power applications. Our design is based on sum-frequency mixing an Er/Yb:doped fiber laser operating at 1583 nm with a 938 nm Nd:silica fiber laser in a periodically poled crystal to generate 589 nm. We have demonstrated 14 W at 1583 nm with an Er/Yb:doped fiber laser, based on a Koheras single frequency fiber oscillator amplified in an IPG Photonics fiber amplifier. The Nd:silica fiber laser is a somewhat more novel device, since the Nd3+ ions must operate on the resonance transition (i.e. 4F3/2-4I9/2), while suppressing ASE losses at the more conventional 1088 nm transition. Optimization of the ratio of the fiber core and cladding permits operation of the laser at room

  20. Characterizing temperature-dependent photo-oxidation to explain the abrupt transition from thermal to non-thermal laser damage mechanisms at 413 nm

    NASA Astrophysics Data System (ADS)

    Denton, Michael L.; Clark, C. D., III; Noojin, Gary D.; Estlack, Larry E.; Schenk, Adam C.; Burney, Curtis W.; Rockwell, Benjamin A.; Thomas, Robert J.

    2011-03-01

    Laser exposure duration dictates whether tissues subjected to short visible wavelengths ( <= 514 nm) are damaged by thermal (e.g. 0.1 s) or non-thermal ( >= 100 s) mechanisms. Somewhere between these extremes, an abrupt transition between the two damage mechanisms has been found for both in vitro and animal retinal models (J. Biomed. Opt. 15, 030512, 2010). Non-thermal (photochemical) damage is characterized by an inverse relationship between damage threshold irradiance and exposure duration (irradiance reciprocity). We have found that exposures of 40 - 60 s in an in vitro retinal model require radiant exposures well above the expected requirement for nonthermal damage, introducing the concept that damage was forced to be thermal in mechanism. Here we quantify and compare photo-oxidative processes at ambient temperatures between 35 - 50 °C.

  1. Diode laser (980nm) cartilage reshaping

    NASA Astrophysics Data System (ADS)

    El Kharbotly, A.; El Tayeb, T.; Mostafa, Y.; Hesham, I.

    2011-03-01

    Loss of facial or ear cartilage due to trauma or surgery is a major challenge to the otolaryngologists and plastic surgeons as the complicated geometric contours are difficult to be animated. Diode laser (980 nm) has been proven effective in reshaping and maintaining the new geometric shape achieved by laser. This study focused on determining the optimum laser parameters needed for cartilage reshaping with a controlled water cooling system. Harvested animal cartilages were angulated with different degrees and irradiated with different diode laser powers (980nm, 4x8mm spot size). The cartilage specimens were maintained in a deformation angle for two hours after irradiation then released for another two hours. They were serially measured and photographed. High-power Diode laser irradiation with water cooling is a cheep and effective method for reshaping the cartilage needed for reconstruction of difficult situations in otorhinolaryngologic surgery. Key words: cartilage,diode laser (980nm), reshaping.

  2. 308nm excimer laser in dermatology.

    PubMed

    Mehraban, Shadi; Feily, Amir

    2014-01-01

    308nm xenon-chloride excimer laser, a novel mode of phototherapy, is an ultraviolet B radiation system consisting of a noble gas and halide. The aim of this systematic review was to investigate the literature and summarize all the experiments, clinical trials and case reports on 308-nm excimer laser in dermatological disorders. 308-nm excimer laser has currently a verified efficacy in treating skin conditions such as vitiligo, psoriasis, atopic dermatitis, alopecia areata, allergic rhinitis, folliculitis, granuloma annulare, lichen planus, mycosis fungoides, palmoplantar pustulosis, pityriasis alba, CD30+ lympho proliferative disorder, leukoderma, prurigo nodularis, localized scleroderma and genital lichen sclerosus. Although the 308-nm excimer laser appears to act as a promising treatment modality in dermatology, further large-scale studies should be undertaken in order to fully affirm its safety profile considering the potential risk, however minimal, of malignancy, it may impose. PMID:25606333

  3. High Power 938nm Cladding Pumped Fiber Laser

    SciTech Connect

    Dawson, J; Beach, R; Brobshoff, A; Liao, Z; Payne, S; Pennington, D; Taylor, L; Hackenberg, W; Bonaccini, D

    2002-12-26

    We have developed a Nd:doped cladding pumped fiber amplifier, which operates at 938nm with greater than 2W of output power. The core co-dopants were specifically chosen to enhance emission at 938nm. The fiber was liquid nitrogen cooled in order to achieve four-level laser operation on a laser transition that is normally three level at room temperature, thus permitting efficient cladding pumping of the amplifier. Wavelength selective attenuation was induced by bending the fiber around a mandrel, which permitted near complete suppression of amplified spontaneous emission at 1088nm. We are presently seeking to scale the output of this laser to 10W. We will discuss the fiber and laser design issues involved in scaling the laser to the 10W power level and present our most recent results.

  4. Laser damage database at 1064 nm

    SciTech Connect

    Rainer, F.; Gonzales, R.P.; Morgan, A.J.

    1990-03-01

    In conjunction with our diversification of laser damage testing capabilities, we have expanded upon a database of threshold measurements and parameter variations at 1064 nm. This includes all tests at low pulse-repetition frequencies (PRF) ranging from single shots to 120 Hz. These tests were conducted on the Reptile laser facility since 1987 and the Variable Pulse Laser (VPL) facility since 1988. Pulse durations ranged from 1 to 16 ns. 10 refs., 14 figs.

  5. Simultaneous triple 914 nm, 1084 nm, and 1086 nm operation of a diode-pumped Nd:YVO4 laser

    NASA Astrophysics Data System (ADS)

    Lü, Yanfei; Xia, Jing; Liu, Huilong; Pu, Xiaoyun

    2014-10-01

    We report a diode-pumped continuous-wave (cw) triple-wavelength Nd:YVO4 laser operating at 914, 1084, and 1086 nm. A theoretical analysis has been introduced to determine the threshold conditions for simultaneous triple-wavelength laser. Using a T-shaped cavity, we realized an efficient triple-wavelength operation at 4F3/2→4I9/2 and 4F3/2→4I11/2 transitions for Nd:YVO4 crystal, simultaneously. At an absorbed pump power of 16 W (or 25 W of incident pump power), the maximum output power was 2.3 W, which included 914 nm, 1084 nm, and 1086 nm three wavelengths, and the optical conversion efficiency with respect to the absorbed pump power was 14.4%.

  6. Efficient laser operation of Nd3+:Lu2O3 at various wavelengths between 917 nm and 1463 nm

    NASA Astrophysics Data System (ADS)

    von Brunn, P.; Heuer, A. M.; Fornasiero, L.; Huber, G.; Kränkel, C.

    2016-08-01

    Even though the first Nd3+-doped sesquioxide lasers have been realized more than 50 years ago, up to now no reports on efficient laser operation of Nd3+:doped sesquioxides can be found. In this work, we review the favorable spectroscopic properties of the sesquioxide Nd3+:Lu2O3 in terms of ground state absorption, stimulated emission, and excited state absorption cross sections as well as the upper level lifetime. Making use of these properties, we achieved efficient laser performance on eight different laser transitions in the wavelength range between 917 nm and 1463 nm under Ti:sapphire laser pumping using state-of-the-art HEM-grown Nd3+:Lu2O3 crystals with good optical quality. At the strongest transition around 1076 nm we determined a slope efficiency of 69%, which represents the highest efficiency ever obtained for a Nd3+-doped sesquioxide. Furthermore, we could generate watt level output powers and high slope efficiencies for seven other transitions. Lasers at 917 nm, 1053 nm, 1108 nm and 1463 nm were realized for the first time and the latter represents one of the longest laser wavelengths obtained on the 4F3/2  →  4I13/2 transition in Nd3+-doped materials.

  7. Detection of chloride in reinforced concrete using a dualpulsed laser-induced breakdown spectrometer system: comparative study of the atomic transition lines of Cl I at 594.85 and 837.59 nm.

    PubMed

    Gondal, Mohammed Ashraf; Dastageer, Mohamed Abdulkader; Maslehuddin, Mohammed; Alnehmi, Abdul Jabar; Al-Amoudi, Omar Saeed Baghabra

    2011-07-10

    The presence of chloride in reinforced concrete can cause severe damage to the strength and durability of buildings and bridges. The detection of chloride in concrete structures at early stages of the corrosion buildup process is, therefore, very important. However, detection of chlorine in trace amounts in concrete is not a simple matter. A dual-pulsed laser-induced breakdown spectrometer (LIBS) has been developed at our laboratory for the detection of chloride contents in reinforced concrete by using two atomic transition lines of neutral chlorine (Cl I) at 594.8 and 837.5 nm. A calibration curve was also established by using standard samples containing chloride in known concentration in the concrete. Our dual-pulsed LIBS system demonstrated a substantial improvement in the signal level at both wavelengths (594.8 and 837.5 nm). However, the new atomic transition line at 594.8 nm shows a significant improvement compared to the line at 837.5 nm in spite of the fact that the relative intensity of the former is 0.1% of the latter. This weak signal level of the 837.5 nm transition line of chlorine can be attributed to some kind of self-absorption process taking place in the case of the concrete sample. PMID:21743558

  8. 1064-nm Nd:YAG laser nucleotomy

    NASA Astrophysics Data System (ADS)

    Vari, Sandor G.; Pergadia, Vani R.; Shi, Wei-Qiang; Snyder, Wendy J.; Fishbein, Michael C.; Grundfest, Warren S.

    1993-07-01

    The high incidence of patients with clinical and neurological symptoms of lumbar disc herniation has spurred the development of less invasive and more cost efficient methods to treat patients. In this study we evaluated pulsed and continuous wave (cw) 1064 nm Nd:YAG laser ablation and induced thermal damage in sheep intervertebral disc. We used the Heraeus LaserSonics Hercules 5040 (Nd:YAG) laser system and 400 micrometers bare and 600 micrometers ball-tipped fibers in cw and pulsed mode. For the laser parameters and fibers used in this study, ablation of the intervertebral disc was successful and thermal damage did not exceed 0.5 mm. Varying beam diameters and focusing abilities (i.e., bare and ball) did not produce any difference in the coagulation thermal effect.

  9. Detection of the level of fluoride in the commercially available toothpaste using laser induced breakdown spectroscopy with the marker atomic transition line of neutral fluorine at 731.1 nm

    NASA Astrophysics Data System (ADS)

    Gondal, M. A.; Maganda, Y. W.; Dastageer, M. A.; Al Adel, F. F.; Naqvi, A. A.; Qahtan, T. F.

    2014-04-01

    Fourth harmonic of a pulsed Nd:YAG laser (wavelength 266 nm) in combination with high resolution spectrograph equipped with Gated ICCD camera has been employed to design a high sensitive analytical system. This detection system is based on Laser Induced Breakdown Spectroscopy and has been tested first time for analysis of semi-fluid samples to detect fluoride content present in the commercially available toothpaste samples. The experimental parameters were optimized to achieve an optically thin and in local thermo dynamic equilibrium plasma. This improved the limits of detection of fluoride present in tooth paste samples. The strong atomic transition line of fluorine at 731.102 nm was used as the marker line to quantify the fluoride concentration levels. Our LIBS system was able to detect fluoride concentration levels in the range of 1300-1750 ppm with a detection limit of 156 ppm.

  10. 308-nm excimer laser in endodontics

    NASA Astrophysics Data System (ADS)

    Liesenhoff, Tim

    1992-06-01

    Root canal preparation was performed on 20 extracted human teeth. After opening the coronal pulp, the root canals were prepared by 308 nm excimer laser only. All root canals were investigated under SEM after separation in the axial direction. By sagittal separation of the mandibles of freshly slaughtered cows, it was possible to get access to the tissues and irradiate under optical control. Under irradiation of excimer laser light, tissue starts to fluoresce. It was possible to demonstrate that each tissue (dentin, enamel, bone, pulpal, and connective tissue) has a characteristic spectral pattern. The SEM analyses showed that it is well possible to prepare root canals safely. All organic soft tissue has been removed by excimer laser irradiation. There was no case of via falsa. The simultaneous spectroscopic identification of the irradiated tissue provides a safe protection from overinstrumentation. First clinical trials on 20 patients suffering of chronical apical parodontitis have been carried out successfully.

  11. Realization and characterization of single-frequency tunable 637.2 nm high-power laser

    NASA Astrophysics Data System (ADS)

    Wang, Jieying; Bai, Jiandong; He, Jun; Wang, Junmin

    2016-07-01

    We report the preparation of narrow-linewidth 637.2 nm laser device by single-pass sum-frequency generation (SFG) of two infrared lasers at 1560.5 nm and 1076.9 nm in PPMgO:LN crystal. Over 8.75 W of single-frequency continuously tunable 637.2 nm laser is realized, and corresponding optical-optical conversion efficiency is 38.0%. We study the behavior of crystals with different poling periods. The detailed experiments show that the output red lasers have very good power stability and beam quality. This high-performance 637.2 nm laser is significant for the realization of high power ultra-violet (UV) 318.6 nm laser via cavity-enhanced frequency doubling. Narrow-linewidth 318.6 nm laser is important for Rydberg excitation of cesium atoms via single-photon transition.

  12. 946 nm Diode Pumped Laser Produces 100mJ

    NASA Technical Reports Server (NTRS)

    Axenson, Theresa J.; Barnes, Norman P.; Reichle, Donald J., Jr.

    2000-01-01

    An innovative approach to obtaining high energy at 946 nm has yielded 101 mJ of laser energy with an optical-to-optical slope efficiency of 24.5%. A single gain module resonator was evaluated, yielding a maximum output energy of 50 mJ. In order to obtain higher energy a second gain module was incorporated into the resonator. This innovative approach produced un-surprised output energy of 101 mJ. This is of utmost importance since it demonstrates that the laser output energy scales directly with the number of gain modules. Therefore, higher energies can be realized by simply increasing the number of gain modules within the laser oscillator. The laser resonator incorporates two gain modules into a folded "M-shaped" resonator, allowing a quadruple pass gain within each rod. Each of these modules consists of a diode (stack of 30 microlensed 100 Watt diode array bars, each with its own fiber lens) end-pumping a Nd:YAG laser rod. The diode output is collected by a lens duct, which focuses the energy into a 2 mm diameter flat to flat octagonal pump area of the laser crystal. Special coatings have been developed to mitigate energy storage problems, including parasitic lasing and amplified spontaneous emission (ASE), and encourage the resonator to operate at the lower gain transition at 946 nm.

  13. Transcanalicular laser dacryocystorhinostomy using low energy 810 nm diode laser

    PubMed Central

    Gupta, Sanjiv K.; Kumar, Ajai; Agarwal, Swati; Pandey, Paritosh

    2012-01-01

    Background: Hypertrophic scarring may be a cause of failure after transcanalicular laser dacryocystorhinostomy (DCR) surgery. This hypertrophic scarring results from tissue charring and excessive coagulation, which may be caused by the high laser energy. We have evaluated the use of low energy settings to prevent hypertrophic scarring, for a successful outcome. Aims: To perform and evaluate transcanalicular laser DCR using low energy 810 nm diode laser. Design: Interventional, non-comparative, case series. Materials and Methods: Patients with nasolacrimal duct obstruction and chronic dacryocystitis, who needed DCR, and were fit for surgery under local anesthesia, were recruited to undergo transcanalicular laser DCR using a 810 nm diode laser. The outcome was measured by the patency of the lacrimal passage, as indicated by the relief in the symptoms and the patency on syringing at the last follow-up. The surgical time and surgical complications were noted. Statistical Analysis Used: Descriptive analysis. Results: The study included 94 patients. The average age was 30.1 years (range 15 - 69 years). Seventy (74.4%) patients were female. Eight patients had failed external DCR. Per-operative patency of the passage was obtained in all the patients. Average surgical time was seven minutes (5 – 18 minutes). At the end of the study period of one year, a successful outcome was seen in 85 patients (90.5%). There were eight patients of previous failed DCR surgeries, and six of them achieved a cure at the end of follow-up. Conclusions: Transcanalicular Laser DCR can be safely performed using a low power 810 nm diode laser. The surgery is elegant, minimally invasive, allows fast rehabilitation, and has an excellent success rate. PMID:23439888

  14. Comparison of 885 nm pumping and 808 nm pumping in Nd:CNGG laser operating at 1061 nm and 935 nm

    NASA Astrophysics Data System (ADS)

    Shi, Yuxian; Li, Qinan; Zhang, Dongxiang; Feng, Baohua; Zhang, Zhiguo; Zhang, Huaijin; Wang, Jiyang

    2010-07-01

    A Nd:CNGG laser operated at 935 nm and 1061 nm pumped at 885 nm and 808 nm, respectively, is demonstrated. The 885 nm direct pumping scheme shows some advantages over the 808 nm traditional pumping scheme. It includes higher slope efficiency, lower threshold, and better beam quality at high output power. With the direct pumping, the slope efficiency increases by 43% and the threshold decreases by 10% compared with traditional pumping in the Nd:CNGG laser operated at 935 nm. When the Nd:CNGG laser operates at 1061 nm, the direct pumping increases the slope efficiency by 14% with a 20% reduction in the oscillation threshold.

  15. Room-temperature, continuous-wave, 946-nm Nd:YAG laser pumped by laser-diode arrays and intracavity frequency doubling to 473 nm

    SciTech Connect

    Risk, W.P.; Lenth, W.

    1987-12-01

    We report the use of GaAlAs laser-diode arrays to pump a cw Nd:YAG laser operating on the 946-nm /sup 4/F/sub 3/2/..-->../sup 4/I/sub 9/2/ transition. At room temperature, the lasing threshold was reached with 58 mW of absorbed pump power, and, with 175 mW of absorbed pump power, 42 mW of output power at 946 nm was obtained in a TEM/sub 00/ mode by using 0.7% output coupling. In addition, pumping with an infrared dye laser operating in a pure TEM/sub 00/ mode was used to investigate the effects of reabsorption loss that are characteristic of the 946-nm laser transition. LiIO/sub 3/ was used as an intracavity doubling crystal, and 100 ..mu..W of blue light was generated by using diode-laser pumping in a nonoptimized cavity.

  16. Comparative study of Nd:KGW lasers pumped at 808 nm and 877 nm

    NASA Astrophysics Data System (ADS)

    Huang, Ke; Ge, Wen-Qi; Zhao, Tian-Zhuo; He, Jian-Guo; Feng, Chen-Yong; Fan, Zhong-Wei

    2015-10-01

    The laser performance and thermal analysis of Nd:KGW laser continuously pumped by 808 nm and 877 nm are comparatively investigated. Output power of 670 mW and 1587 mW, with nearly TEM00 mode, are achieved respectively at 808 nm pump and 877 nm pump. Meanwhile, a high-power passively Q-switched Nd:KGW/Cr4+:YAG laser pumped at 877 nm is demonstrated. An average output power of 1495 mW is obtained at pump power of 5.22 W while the laser is operating at repetition of 53.17 kHz. We demonstrate that 877 nm diode laser is a more potential pump source for Nd:KGW lasers.

  17. 1085 nm Nd:YVO4 laser intracavity pumped at 914 nm and sum-frequency mixing to reach cyan laser at 496 nm

    NASA Astrophysics Data System (ADS)

    Lü, Y. F.; Xia, J.; Yin, X. D.; Wang, D.; Zhang, X. H.

    2010-01-01

    We present for the first time a Nd:YVO4 laser at 1085 nm intracavity pumped at 914 nm by a Nd:YVO4 laser. We obtained intracavity powers of 57 W at 914 nm and 62 W at 1085 nm. Using type-I critical phase-matching LiB3O5 (LBO) crystal, a cyan laser at 496 nm is obtained by 914 and 1085 nm intracavity sum-frequency mixing. The maximum laser output power of 142 mW is obtained when an incident pump laser of 19.6 W is used.

  18. Laser Damage Growth in Fused Silica with Simultaneous 351 nm and 1053 nm irradiation

    SciTech Connect

    Norton, M A; Carr, A V; Carr, C W; Donohue, E E; Feit, M D; Hollingsworth, W G; Liao, Z; Negres, R A; Rubenchik, A M; Wegner, P J

    2008-10-24

    Laser-induced growth of optical damage often determines the useful lifetime of an optic in a high power laser system. We have extended our previous work on growth of laser damage in fused silica with simultaneous 351 nm and 1053 nm laser irradiation by measuring the threshold for growth with various ratios of 351 nm and 1053 nm fluence. Previously we reported that when growth occurs, the growth rate is determined by the total fluence. We now find that the threshold for growth is dependent on both the magnitude of the 351 nm fluence as well as the ratio of the 351 nm fluence to the 1053 nm fluence. Furthermore, the data suggests that under certain conditions the 1053 nm fluence does not contribute to the growth.

  19. The Double-ended 750 nm and 532 nm Laser Output from PPLN-FWM

    NASA Astrophysics Data System (ADS)

    Wang, Tao; Li, Yu-Xiang; Yao, Jian-Quan; Guo, Ling; Wang, Zhuo; Han, Sha-Sha; Zhang, Cui-Ying; Zhong, Kai

    2013-06-01

    We investigate 750 nm and 532 nm dual-wavelength laser for applications in the internet of things. A kind of optical maser is developed, in which the semiconductor module outputs the 808 nm pump light and then it goes into a double-clad Nd3+ :YAG monocrystal optical fiber through the intermediate coupler and forms a 1064 nm laser. The laser outputs come from both left and right terminals. In the right branch, the laser goes into the right cycle polarization LinNbO3 (PPLN) crystal through the right coupler, produces the optical parametric oscillation and forms the signal light λ1 (1500 nm), the idle frequency light λ2 (3660.55 nm), and the second-harmonic of the signal light λ3 (750 nm). These three kinds of light and the pump light λ4 together form the frequency matching and the quasi-phase matching, then the four-wave mixing occurs to create the high-gain light at wavelength 750 nm. Meanwhile, in the left branch, the laser goes into the left PPLN crystal through the left coupler, engenders frequency doubling and forms the light at wavelength 532 nm. That is to say, the optical maser provides 750 nm and 532 nm dual-wavelength laser outputting from two terminals, which is workable.

  20. All-fibre ytterbium laser tunable within 45 nm

    SciTech Connect

    Abdullina, S R; Babin, S A; Vlasov, A A; Kablukov, S I; Shelemba, I S; Kurkov, A S

    2007-12-31

    A tunable ytterbium-doped fibre laser is fabricated. The laser is tuned by using a tunable fibre Bragg grating (FBG) as a selecting intracavity element. The laser is tunable within 45 nm (from 1063 to 1108 nm) and emits {approx}6 W in the line of width {approx}0.15 nm, the output power and linewidth being virtually invariable within the tuning range. The method is proposed for synchronous tuning the highly reflecting and output FBGs, and a tunable ytterbium all-fibre laser is built. (lasers)

  1. Rb-stabilized laser at 1572 nm for CO2 monitoring

    NASA Astrophysics Data System (ADS)

    Matthey, R.; Moreno, W.; Gruet, F.; Brochard, P.; Schilt, S.; Mileti, G.

    2016-06-01

    We have developed a compact rubidium-stabilized laser system to serve as optical frequency reference in the 1.55-μm wavelength region, in particular for CO2 monitoring at 1572 nm. The light of a fiber-pigtailed distributed feedback (DFB) laser emitting at 1560 nm is frequency-doubled and locked to a sub-Doppler rubidium transition at 780 nm using a 2-cm long vapor glass cell. Part of the DFB laser light is modulated with an electro-optical modulator enclosed in a Fabry-Perot cavity, generating an optical frequency comb with spectral coverage extending from 1540 nm to 1580 nm. A second slave DFB laser emitting at 1572 nm and offset-locked to one line of the frequency comb shows a relative frequency stability of 1.10-11 at 1 s averaging time and <4.10-12 from 1 hour up to 3 days.

  2. Development of high coherence high power 193nm laser

    NASA Astrophysics Data System (ADS)

    Tanaka, Satoshi; Arakawa, Masaki; Fuchimukai, Atsushi; Sasaki, Yoichi; Onose, Takashi; Kamba, Yasuhiro; Igarashi, Hironori; Qu, Chen; Tamiya, Mitsuru; Oizumi, Hiroaki; Ito, Shinji; Kakizaki, Koji; Xuan, Hongwen; Zhao, Zhigang; Kobayashi, Yohei; Mizoguchi, Hakaru

    2016-03-01

    We have been developing a hybrid 193 nm ArF laser system that consists of a solid state seeding laser and an ArF excimer laser amplifier for power-boosting. The solid state laser consists of an Yb-fiber-solid hybrid laser system and an Er-fiber laser system as fundamentals, and one LBO and three CLBO crystals for frequency conversion. In an ArF power amplifier, the seed laser passes through the ArF gain media three times, and an average power of 110 W is obtained. As a demonstration of the potential applications of the laser, an interference exposure test is performed.

  3. 11 W narrow linewidth laser source at 780 nm for laser cooling and manipulation of Rubidium.

    PubMed

    Sané, S S; Bennetts, S; Debs, J E; Kuhn, C C N; McDonald, G D; Altin, P A; Close, J D; Robins, N P

    2012-04-01

    We present a narrow linewidth continuous laser source with over 11 W output power at 780 nm, based on single-pass frequency doubling of an amplified 1560 nm fibre laser with 36% efficiency. This source offers a combination of high power, simplicity, mode quality and stability. Without any active stabilization, the linewidth is measured to be below 10 kHz. The fibre seed is tunable over 60 GHz, which allows access to the D₂ transitions in ⁸⁷Rb and ⁸⁵Rb, providing a viable high-power source for laser cooling as well as for large-momentum-transfer beamsplitters in atom interferometry. Sources of this type will pave the way for a new generation of high flux, high duty-cycle degenerate quantum gas experiments. PMID:22513602

  4. Simultaneous three-wavelength continuous wave laser at 946 nm, 1319 nm and 1064 nm in Nd:YAG

    NASA Astrophysics Data System (ADS)

    Lü, Yanfei; Zhao, Lianshui; Zhai, Pei; Xia, Jing; Fu, Xihong; Li, Shutao

    2013-01-01

    A continuous-wave (cw) diode-end-pumped Nd:YAG laser that generates simultaneous laser at the wavelengths 946 nm, 1319 nm and 1064 nm is demonstrated. The optimum oscillation condition for the simultaneous three-wavelength operation has been derived. Using the separation of the three output couplers, we obtained the maximum output powers of 0.24 W at 946 nm, 1.07 W at 1319 nm and 1.88 W at 1064 nm at the absorbed pump power of 11.2 W. A total output power of 3.19 W for the three-wavelength was achieved at the absorbed pump power of 11.2 W with optical conversion efficiency of 28.5%.

  5. Comparison of 980-nm and 1070-nm in endovenous laser treatment (EVLT)

    NASA Astrophysics Data System (ADS)

    Topaloglu, Nermin; Tabakoglu, Ozgur; Ergenoglu, Mehmet U.; Gülsoy, Murat

    2009-07-01

    The use of endovenous laser treatment for varicose veins has been increasing in recent years. It is a safer technique than surgical vein stripping. Its complications (e.g. bruising, pain) are less than the complications of surgical vein stripping. But best parameters such as optimum wavelength, power, and application duration are still under investigation to clarify uncertainties about this technique. To prevent its complications and improve its clinical outcomes, the exact mechanism of it has to be known. The aim of this study is to investigate the effect of different laser wavelengths on endovenous laser therapy. In this study 980-nm diode laser and 1070-nm fiber laser were used. Human veins were irradiated with 980-nm and 1070-nm lasers at 8 W and 10 W to find the optimal power and wavelength. After laser application, remarkable shrinkage was observed. Inner and outer diameters of the veins also narrowed for both of the laser types. 10 W of 980-nm laser application led to better shrinkage results.

  6. Maskless pattern transfer using 355 nm laser

    NASA Astrophysics Data System (ADS)

    Gabran, S. R. I.; Mansour, R. R.; Salama, M. M. A.

    2012-05-01

    Low power near-ultraviolet laser can be employed in various pattern transfer techniques such as maskless lithography and organic film ablation. Laser maskless lithography allows rapid prototyping using thin as well as thick photoresist films. Non-photosensitive organic films can be patterned by laser ablation, and this technique is applied in creating micro-molds for metal deposition using electroplating and electroless deposition. This paper presents experimental results, a quantitative study and modeling of laser maskless processing using desktop Nd:YAG laser system using four different photoresists. Process variables were experimentally optimized to identify the appropriate laser parameters that would yield reliable and reproducible patterns. A finite element thermal model of the ablation process was created to investigate the effects of different substrate materials on the process quality.

  7. Absolute measurement of F2-laser power at 157 nm

    SciTech Connect

    Kueck, Stefan; Brandt, Friedhelm; Kremling, Hans-Albert; Gottwald, Alexander; Hoehl, Arne; Richter, Mathias

    2006-05-10

    We report a comparison of laser power measurements at the F2-laser wavelength oaf nm made at two facilities of the Physikalisch-Technische Bundesanstalt (PTB), the German national metrology institute. At the PTB laboratory at the electron storage ring BESSY II in Berlin, the scale for laser power was directly traced to a cryogenic radiometer operating at 157 nm, whereas at the PTB laser radiometry facility in Braunschweig the calibration of transfer detectors was performed with a newly developed standard for laser power at 157 nm, which is traceable in several steps to a cryogenic radiometer operating at 633 nm. The comparison was performed under vacuum conditions with laser pulse energies of?10 {mu}J, however with different average powers because different primary standard radiometers were used. The relative deviation for the responsivity of the transfer detector was 4.8% and thus within the combined standard uncertainty.

  8. Absolute frequency measurements and hyperfine structures of the molecular iodine transitions at 578 nm

    NASA Astrophysics Data System (ADS)

    Kobayashi, Takumi; Akamatsu, Daisuke; Hosaka, Kazumoto; Inaba, Hajime; Okubo, Sho; Tanabe, Takehiko; Yasuda, Masami; Onae, Atsushi; Hong, Feng-Lei

    2016-04-01

    We report absolute frequency measurements of 81 hyperfine components of the rovibrational transitions of molecular iodine at 578 nm using the second harmonic generation of an 1156-nm external-cavity diode laser and a fiber-based optical frequency comb. The relative uncertainties of the measured absolute frequencies are typically $1.4\\times10^{-11}$. Accurate hyperfine constants of four rovibrational transitions are obtained by fitting the measured hyperfine splittings to a four-term effective Hamiltonian including the electric quadrupole, spin-rotation, tensor spin-spin, and scalar spin-spin interactions. The observed transitions can be good frequency references at 578 nm, and are especially useful for research using atomic ytterbium since the transitions are close to the $^{1}S_{0}-^{3}P_{0}$ clock transition of ytterbium.

  9. High power diode lasers emitting from 639 nm to 690 nm

    NASA Astrophysics Data System (ADS)

    Bao, L.; Grimshaw, M.; DeVito, M.; Kanskar, M.; Dong, W.; Guan, X.; Zhang, S.; Patterson, J.; Dickerson, P.; Kennedy, K.; Li, S.; Haden, J.; Martinsen, R.

    2014-03-01

    There is increasing market demand for high power reliable red lasers for display and cinema applications. Due to the fundamental material system limit at this wavelength range, red diode lasers have lower efficiency and are more temperature sensitive, compared to 790-980 nm diode lasers. In terms of reliability, red lasers are also more sensitive to catastrophic optical mirror damage (COMD) due to the higher photon energy. Thus developing higher power-reliable red lasers is very challenging. This paper will present nLIGHT's released red products from 639 nm to 690nm, with established high performance and long-term reliability. These single emitter diode lasers can work as stand-alone singleemitter units or efficiently integrate into our compact, passively-cooled Pearl™ fiber-coupled module architectures for higher output power and improved reliability. In order to further improve power and reliability, new chip optimizations have been focused on improving epitaxial design/growth, chip configuration/processing and optical facet passivation. Initial optimization has demonstrated promising results for 639 nm diode lasers to be reliably rated at 1.5 W and 690nm diode lasers to be reliably rated at 4.0 W. Accelerated life-test has started and further design optimization are underway.

  10. 1064 nm laser emission of highly doped Nd: Yttrium aluminum garnet under 885 nm diode laser pumping

    NASA Astrophysics Data System (ADS)

    Lupei, V.; Pavel, N.; Taira, T.

    2002-06-01

    Highly efficient 1064 nm continuous-wave laser emission under 885 nm diode pumping in concentrated Nd: Yttrium aluminum garnet (YAG) crystals (up to 3.5 at. % Nd) and ceramics (up to 3.8 at. % Nd) is reported. A highly doped (2.4 at. %) Nd:YAG laser, passively Q switched by a Cr4+:YAG saturable absorber, is demonstrated.

  11. 40nm tunable multi-wavelength fiber laser

    NASA Astrophysics Data System (ADS)

    Jia, Qingsong; Wang, Tianshu; Zhang, Peng; Dong, Keyan; Jiang, Huilin

    2014-12-01

    A Brillouin-Erbium multi-wavelength tunable fiber laser at C-band is demostrated. A 10 km long singlemode fiber(SMF), a 6 m long Erbium-doped fiber, two couplers, a wavelength division multiplexer, a isolator, an optical circulator, a 980nm pump laser and a narrow linewidth tunable laser are included in the structure. A segment of 10 km-long single-mode fiber (SMF) between the two ports of a 1×2 coupler is used as Brillouin gain. Ebiumdoped fiber amplifier (EDFA) consists of a segment of 6m er-doped fiber pumped by 980nm laser dioder . A narrow linewidth tunable laser from 1527 to 1607 nm as Brillouin bump, At the Brillouin pump power of 8mW and the 980 nm pump power of 400 mw, 16 output channels with 0.08 nm spacing and tuning range of 40 nm from 1527 nm to 1567 nm are achieved. We realize the tunable output of wavelength by adjusting the 980 nm pump power and the Brillouin pump wavelength. Stability of the multiwavelength fiber laser is also observed.

  12. Upconverted luminescence under 800 nm laser diode excitation in Nd 3+-activated fluoroaluminate glass

    NASA Astrophysics Data System (ADS)

    Koepke, Cz.; Wisniewski, K.; Sikorski, L.; Piatkowski, D.; Kowalska, K.; Naftaly, M.

    2006-01-01

    We report on the upconverted luminescence in neodymium-activated fluoroaluminate glass obtained with 800 nm diode laser excitation. Several anti-Stokes emissions: at 588, 607, 720 and 750 nm are observed and appropriate transitions are assigned. For both latter emissions we observe strong dependence on temperature: the 720 nm emission intensity decreases with temperature, whereas the 750 nm emission increases. Interpretations are presented in terms of the influence of oxygen-affected sites on the radiationless transitions and multiphonon anti-Stokes excitation. The models provide reasonable fits to the experimental data.

  13. Scaling of laser-induced contamination growth at 266nm and 355nm

    NASA Astrophysics Data System (ADS)

    Ließmann, M.; Jensen, L.; Balasa, I.; Hunnekuhl, M.; Büttner, A.; Weßels, P.; Neumann, J.; Ristau, D.

    2015-11-01

    The growth of laser-induced contamination (LIC) on optical components in extraterrestrial missions is a known issue especially for the UV spectral region. The Laser Zentrum Hannover e.V. is responsible for the development of a pulsed laser-system operating at a wavelength of 266 nm for the ExoMars mission and for the qualification of used optics and materials regarding LIC. In this context, toluene was utilized which is an often used model contaminant in LIC studies. Test cycles based on the application of the two UV wavelengths 355 nm and 266 nm on fused silica substrates and ARcoated optics are conducted and the observed contamination effects are compared. This scaling allows for a rough estimate of the destructive influence of LIC on space optics degradation at 266 nm. Further tests will be performed with materials integrated into the ExoMars-laser-head under near-operation environmental conditions.

  14. Applications of combination wavelength (1060-nm and 530-nm) and pulsed Nd:YAG laser for contact laser surgery.

    PubMed

    Liu, K R; Peyman, G A; Myers, J D; Hamlin, S A; Katoh, N

    1989-01-01

    Two pulsed neodimium yittrium aluminum garnet (Nd:YAG) laser systems were evaluated for contact surgery through a fiberoptic system with a sapphire tip. Pulsed Nd:YAG laser at 1060 nm was as effective as continuous-wave Nd:YAG laser in producing tissue incisions. A combination of 1060-nm and 530-nm wavelengths achieved smooth cutting at lower energy levels. Corneal endothelial cell damage occurred at the high power level (7 watts) required for smooth underwater incisions with both continuous wave and pulsed lasers. PMID:2733255

  15. Bismuth-doped germanosilicate fibre laser with 20-W output power at 1460 nm

    SciTech Connect

    Firstov, Sergei V; Shubin, Aleksei V; Khopin, V F; Mel'kumov, Mikhail A; Bufetov, Igor' A; Medvedkov, O I; Gur'yanov, Aleksei N; Dianov, Evgenii M

    2011-07-31

    We report the first cw bismuth - germanium codoped silica fibre laser with an output power above 20 W at 1460 nm and 50% optical efficiency. The laser operates on a transition between energy levels of bismuth-related active centres associated with silicon. The incorporation of a small amount ({approx}5 mol %) of germanium into the core of bismuth-doped silica fibre has little effect on its luminescence spectrum but reduces optical losses, which limit the laser efficiency. (letters)

  16. Applications of the 308-nm excimer laser in dermatology

    NASA Astrophysics Data System (ADS)

    Farkas, A.; Kemeny, L.

    2006-05-01

    Excimer lasers contain a mixture of a noble inert gas and a halogen, which form excited dimers only in the activated state. High-energy current is used to produce these dimers, which have a very short lifetime, and after their fast dissociation they release the excitation energy through ultraviolet photons. The application of these lasers proved to be successful in medicine, including the field of ophthalmology, cardiology, angiology, dentistry, orthopaedics, and, in recent years, dermatology. For medical purposes, the 193-nm argon fluoride, the 248-nm krypton fluoride, the 351-nm xenon fluoride, and the 308-nm xenon chloride lasers are used. Recently, the 308-nm xenon chloride laser has gained much attention as a very effective treatment modality in dermatological disorders. It was successfully utilized in psoriasis; later, it proved to be useful in handling other lightsensitive skin disorders and even in the treatment of allergic rhinitis. This review summarizes the possible applications of this promising tool in dermatology.

  17. Evaluation of the Diode laser (810nm,980nm) on dentin tubule diameter following internal bleaching

    PubMed Central

    Kiomarsi, Nazanin; Salim, Soheil; Sarraf, Pegah; Javad-Kharazifard, Mohammad

    2016-01-01

    Background The aim of this study was to evaluate the effect of diode laser irradiation and bleaching materials on the dentinal tubule diameter after laser bleaching. Material and Methods The dentin discs of 40 extracted third molar were used in this experiment. Each disc surface was divided into two halves by grooving. Half of samples were laser bleached at different wavelengths with two different concentrations of hydrogen peroxide. Other half of each disc with no laser bleaching remained as a negative control. Dentin discs were assigned randomly into four groups (n=10) with following hydrogen peroxide and diode laser wavelength specifications; Group 1 (30% - 810 nm), group 2 (30% - 980 nm), group 3 (46% - 810 nm) and group 4 (46% - 980 nm). All specimens were sent for scanning electron microscopic (SEM) analysis in order to measure tubular diameter in laser treated and control halves. Data were analyzed by ANOVA and Tukey test (p<0.05). Results A significant reduction in dentin tubule diameter was observed in groups 1, 2 and 4. There was no significant difference between groups 1 and 2 and between groups 3 and 4 after bleaching. Conclusions The SEM results showed that diode laser was able to reduce dentin tubule diameter and its effect on dentin was dependent on chemical action of bleaching material. Key words:Laser, diode, dentin, tubule, diameter. PMID:27398172

  18. Generation and use of high power 213 nm and 266 nm laser radiation and tunable 210-400 nm laser radiation with BBO crystal matrix array

    DOEpatents

    Gruen, Dieter M.

    2000-01-01

    A 213 nm laser beam is capable of single photon ablative photodecomposition for the removal of a polymer or biological material substrate. Breaking the molecular bonds and displacing the molecules away from the substrate in a very short time period results in most of the laser photon energy being carried away by the displaced molecules, thus minimizing thermal damage to the substrate. The incident laser beam may be unfocussed and is preferably produced by quintupling the 1064 nm radiation from a Nd:YAG solid state laser, i.e., at 213 nm. In one application, the 213 nm laser beam is expanded in cross section and directed through a plurality of small beta barium borate (BBO) crystals for increasing the energy per photon of the laser radiation directed onto the substrate. The BBO crystals are arranged in a crystal matrix array to provide a large laser beam transmission area capable of accommodating high energy laser radiation without damaging the BBO crystals. The BBO crystal matrix array may also be used with 266 nm laser radiation for carrying out single or multi photon ablative photodecomposition. The BBO crystal matrix array may also be used in an optical parametric oscillator mode to generate high power tunable laser radiation in the range of 210-400 nm.

  19. Effects of 946-nm thermal shift and broadening on Nd3+:YAG laser performance

    NASA Astrophysics Data System (ADS)

    Seyed Ebrahim, Pourmand; Ghasem, Rezaei

    2015-12-01

    Spectroscopic properties of flashlamp pumped Nd3+:YAG laser are studied as a function of temperature in a range from -30 °C to 60 °C. The spectral width and shift of quasi three-level 946.0-nm inter-Stark emission within the respective intermanifold transitions of 4F3/2 → 4I9/2 are investigated. The 946.0-nm line shifts toward the shorter wavelength and broadens. In addition, the threshold power and slope efficiency of the 946.0-nm laser line are quantified with temperature. The lower the temperature, the lower the threshold power is and the higher the slope efficiency of the 946.0-nm laser line is, thus the higher the laser output is. This phenomenon is attributed to the ion-phonon interaction and the thermal population in the ground state. Project supported by Estahban Branch, Islamic Azad University.

  20. Injection locking of a diode-pumped Nd:YAG laser at 946 nm

    SciTech Connect

    Hollemann, G.; Peik, E.; Rusch, A.; Walther, H.

    1995-09-15

    Injection locking in the quasi-three-level laser system Nd:YAG {sup 4}{ital F}{sub 3/2}--{sup 4}{ital I}{sub 9/2} at 946 nm is reported. The master and slave oscillators are pumped by laser diodes. The master oscillator is frequency stabilized to a high-finesse cavity, resulting in a laser linewidth of less than 10 Hz. Using intracavity frequency doubling of the slave oscillator, we achieve a single-mode output power of 60 mW at 473 nm. The laser radiation was frequency quadrupled, resulting in an UV power of 0.55 mW at 236.5 nm. The laser system was used to excite a strongly forbidden In{sup +} transition, proposed as a new optical frequency standard. {copyright} 1995 Optical Society of America

  1. Extended tunability of Nd-doped fiber lasers operating at 872-936  nm.

    PubMed

    Leconte, B; Cadier, B; Gilles, H; Girard, S; Robin, T; Laroche, M

    2015-09-01

    Efficient operation of an Nd-doped fiber laser operating in a wavelength-tunable configuration using a volume Bragg grating (VBG) is reported in this Letter. A high-power operation on the 4F3/2-4I9/2 transition of Nd3+ at short wavelengths below 900 nm is demonstrated for the first time in silica fibers. A high-efficiency (47% laser conversion) output power up to 22 W and a narrow linewidth of 0.035 nm are achieved. This configuration is compared with a more conventional fiber laser setup using a bandpass filter and a highly reflective dichroic mirror. PMID:26368721

  2. Diode-pumped Nd:YAG laser emitting at 884 nm Diode-pumped Nd:YAG laser emitting at 884 nm

    NASA Astrophysics Data System (ADS)

    Chen, X.; Shao, Y.; Yuan, J. L.; Zhang, D.; Li, Y. L.

    2012-07-01

    We present what is, to the best of our knowledge, the first diode-pumped Nd-doped Y3Al5O12 (Nd:YAG) laser emitting at 884 nm, based on the 4F3/2 → 4I9/2 transition, generally used for a 946 nm emission. The use of a pump module with 16 passes through the crystal allowed the realization of a Nd:YAG thin-disk laser with 1.14 W of continuous wave (CW) output power at 884 nm. Moreover, intracavity second-harmonic generation (SHG) in CW mode has also been demonstrated with a power of 151 mW at 442 nm by using a BiB3O6 (BiBO) nonlinear crystal.

  3. Highly efficient CW intracavity frequency-doubled Yb:YAG-LBO laser at 515 nm under 968 nm diode laser pumping

    NASA Astrophysics Data System (ADS)

    Sun, G. C.; Li, Y. D.; Zhao, M.; Chen, X. Y.; Wang, J. B.; Chen, G. B.

    2011-05-01

    We describe the output performances of the 1030 nm transition in Yb:YAG under in-band pumping with diode laser at the 968 nm wavelength. An end-pumped Yb:YAG crystal yielded 1.93 W of continuous-wave (CW) output power for 9.1 W of absorbed pump power. The slope efficiency with respect to the absorbed pump power was 23.6%. Furthermore, 205 mW 515 nm green light was acquired by frequency doubling, resulting in an optical-to-optical efficiency with respect to the absorbed pump power of 2.7%. Comparative results obtained for the pump with diode laser at 940 nm are given in order to prove the advantages of the in-band pumping.

  4. Measurement of Laser Damage Threshold of 355-nm Antireflection Coating

    NASA Astrophysics Data System (ADS)

    Tamura, Shigeharu; Kimura, Saburo; Sato, Yoshiyuki; Otani, Minoru; Yoshida, Hidetsugu; Yoshida, Kunio

    1989-06-01

    The laser damage thresholds of various types of antireflection (AR) coatings for an UV (355-nm) laser system were measured. Among them, the coatings consisting of two low-index materials, SiO2 and MgF2, had the highest average thresholds: 2.1 J/cm2 on fused silica substrates and 2.6 J/cm2 on sapphire substrates. The SiO2/MgF2 coating is hopeful for UV laser component.

  5. 80 nm tunable DBR-free semiconductor disk laser

    NASA Astrophysics Data System (ADS)

    Yang, Z.; Albrecht, A. R.; Cederberg, J. G.; Sheik-Bahae, M.

    2016-07-01

    We report a widely tunable optically pumped distributed Bragg reflector (DBR)-free semiconductor disk laser with 6 W continuous wave output power near 1055 nm when using a 2% output coupler. Using only high reflecting mirrors, the lasing wavelength is centered at 1034 nm and can be tuned up to a record 80 nm by using a birefringent filter. We attribute such wide tunability to the unique broad effective gain bandwidth of DBR-free semiconductor disk lasers achieved by eliminating the active mirror geometry.

  6. Porcine dermal lesions produced by 1540-nm laser radiation pulses

    NASA Astrophysics Data System (ADS)

    Roach, William P.; Johnson, Thomas E.

    2001-07-01

    Completion of recent studies within our group indicates a breed-based difference in dermal response to 1540 nm 0.8 millisecond laser pulses. Laser exposure to Yucatan Mini- Pigs (highly pigmented skin) and Yorkshire pigs (lightly pigmented skin) demonstrate statistical differences between the ED50's of the two breeds. Laser delivery is accomplished using an Er:Glass system producing 1540 nm of light at millisecond exposure times and in the range of 5 to 95 J/cm2. Dermal lesion development was evaluated for acute, 1 hour, and 24-hour post exposure presentation. Our data contradicts the theory that water absorption is the sole mechanism of dermal tissue damage observed from 1540 nm laser exposures, as skin chromophores appear to play a role in lesion development.

  7. Compact frequency-quadrupled pulsed 1030nm fiber laser

    NASA Astrophysics Data System (ADS)

    McIntosh, Chris; Goldberg, Lew; Cole, Brian; DiLazaro, Tom; Hays, Alan D.

    2016-03-01

    A compact 1030nm fiber laser for ultraviolet generation at 257.5nm is presented. The laser employs a short length of highly-doped, large core (20μm), coiled polarization-maintaining ytterbium-doped double-clad fiber pumped by a wavelength-stabilized 975nm diode. It is passively Q-switched via a Cr4+:YAG saturable absorber and generates 2.4W at 1030nm in a 110μJ pulse train. Lithium triborate (LBO) and beta-barium borate (BBO) are used to achieve 325mW average power at the fourth harmonic. The laser's small form factor, narrow linewidth and modest power consumption are suitable for use in a man-portable ultraviolet Raman explosives detection system.

  8. TUNABLE DIODE LASER MEASUREMENTS OF NO2 NEAR 670 NM AND 395 NM. (R823933)

    EPA Science Inventory

    Two single-mode diode lasers were used to record high-resolution absorption spectra of NO2 (dilute in Ar) near 670.2 and 394.5 nm over a range of temperatures (296 to 774 K) and total pressures (2.4 x 10(-2) to 1 atm). A commercial InGaAsP laser was tuned 1.3 cm(-1) at a repetiti...

  9. All-solid-state low noise Yb:YAG/LBO green laser at 515 nm

    NASA Astrophysics Data System (ADS)

    Liu, Qianqian; Yang, Min; Yao, Yi; Zhao, Ling; Li, Bin; Qu, Dapeng; Zheng, Quan

    2013-07-01

    We report the efficient compact green laser at 515 nm generation by intracavity frequency doubling of a continuous wave (CW) laser operation of a diode-pumped Yb:YAG laser on the transition at 1030 nm. An LBO crystal, cut for critical type I phase matching at room temperature is used for second harmonic generation (SHG) of the laser. With the incident pump power of 10 W, 270 mW of CW output power at 515 nm is achieved with 15-mm-long LBO. The optical-to-optical conversion efficiency is 2.7%, and the power stability in 8 h is better than 2.36% with low noise.

  10. High power eye-safe Er3+:YVO4 laser diode-pumped at 976 nm and emitting at 1603 nm

    NASA Astrophysics Data System (ADS)

    Newburgh, G. A.; Dubinskii, M.

    2016-02-01

    We report on the performance of an eye-safe laser based on a Er:YVO4 single crystal, diode-pumped at 976 nm (4I15/2-->4I11/2 transition) and operating at 1603 nm (4I13/2-->4I15/2 transition) with good beam quality. A 10 mm long Er3+:YVO4 slab, cut with its c-axis perpendicular to the laser cavity axis, was pumped in σ-polarization and lased in π-polarization. The laser operated in a quasi-continuous wave (Q-CW) regime with nearly 9 W output power, and with a slope efficiency of about 39% with respect to absorbed power. This is believed to be the highest efficiency and highest power achieved from an Er3+:YVO4 laser pumped in the 970-980 nm absorption band.

  11. YSGG 2790-nm superficial ablative and fractional ablative laser treatment.

    PubMed

    Smith, Kevin C; Schachter, G Daniel

    2011-05-01

    The 2790-nm wavelength YSGG laser was introduced for aesthetic purposes under the trade name Pearl by Cutera in 2007. In clinical use, the Pearl superficial resurfacing laser has proved effective and well tolerated for the correction of superficial brown epidermal dyschromia and superficial fine lines and scars, and the Pearl Fractional laser produces excellent improvement in both dyschromia and improvement of deeper lines and moderately deep acne scarring. The two laser treatments can be combined in a single treatment session on different parts of the face or on the entire face, depending on patient needs and priorities. PMID:21763987

  12. 100 W average power femtosecond laser at 343 nm.

    PubMed

    Rothhardt, Jan; Rothhardt, Carolin; Müller, Michael; Klenke, Arno; Kienel, Marco; Demmler, Stefan; Elsmann, Tino; Rothhardt, Manfred; Limpert, Jens; Tünnermann, Andreas

    2016-04-15

    We present a femtosecond laser system delivering up to 100 W of average power at 343 nm. The laser system employs a Yb-based femtosecond fiber laser and subsequent second- and third-harmonic generation in beta barium borate (BBO) crystals. Thermal gradients within these BBO crystals are mitigated by sapphire heat spreaders directly bonded to the front and back surface of the crystals. Thus, a nearly diffraction-limited beam quality (M2 < 1.4) is achieved, despite the high thermal load to the nonlinear crystals. This laser source is expected to push many industrial and scientific applications in the future. PMID:27082370

  13. Ocular safety limits for 1030nm femtosecond laser cataract surgery

    NASA Astrophysics Data System (ADS)

    Wang, Jenny; Sramek, Christopher; Paulus, Yannis M.; Lavinsky, Daniel; Schuele, Georg; Anderson, Dan; Dewey, David; Palanker, Daniel V.

    2013-03-01

    Application of femtosecond lasers to cataract surgery has added unprecedented precision and reproducibility but ocular safety limits for the procedure are not well-quantified. We present an analysis of safety during laser cataract surgery considering scanned patterns, reduced blood perfusion, and light scattering on residual bubbles formed during laser cutting. Experimental results for continuous-wave 1030 nm irradiation of the retina in rabbits are used to calibrate damage threshold temperatures and perfusion rate for our computational model of ocular heating. Using conservative estimates for each safety factor, we compute the limits of the laser settings for cataract surgery that optimize procedure speed within the limits of retinal safety.

  14. Determination of transition probability for the 655-nm Tl line.

    NASA Astrophysics Data System (ADS)

    Karabourniotis, D.; Couris, S.; Damelincourt, J. J.

    Studies of high-pressure Hg-Tl I a.c. (50 Hz) arc plasmas have been used to verify the validity of Boltzmann statistics at the moment of maximum electron density (5 ms) by applying LTE criteria. For a known plasma temperature, the transition probability of the optically-thin 655-nm line of Tl was derived from emission measurements by using the self-reversed 535-nm line of Tl as reference [A655 = (3.74±0.37)×106s-1].

  15. Brain lesion induced by 1319nm laser radiation

    NASA Astrophysics Data System (ADS)

    Yang, Zaifu; Chen, Hongxia; Wang, Jiarui; Chen, Peng; Ma, Ping; Qian, Huanwen

    2010-11-01

    The laser-tissue interaction has not been well defined at the 1319 nm wavelength for brain exposure. The goal of this research effort was to identify the behavioral and histological changes of brain lesion induced by 1319 nm laser. The experiment was performed on China Kunming mice. Unilateral brain lesions were created with a continuous-wave Nd:YAG laser (1319nm). The brain lesions were identified through behavioral observation and histological haematoxylin and eosin (H&E) staining method. The behavior change was observed for a radiant exposure range of 97~773 J/cm2. The histology of the recovery process was identified for radiant exposure of 580 J/cm2. Subjects were sacrificed 1 hour, 1 week, 2 weeks, 3 months, 7 months and 13 months after laser irradiation. Results showed that after laser exposure, behavioral deficits, including kyphosis, tail entasia, or whole body paralysis could be noted right after the animals recovered from anesthesia while gradually disappeared within several days and never recurred again. Histologically, the laser lesion showed a typical architecture dependent on the interval following laser treatment. The central zone of coagulation necrosis is not apparent right after exposure but becomes obvious within several days. The nerotic tissue though may persist for a long time, will finally be completely resorbed. No carbonization granules formed under our exposure condition.

  16. Advances in 193 nm excimer lasers for mass spectrometry applications

    NASA Astrophysics Data System (ADS)

    Delmdahl, Ralph; Esser, Hans-Gerd; Bonati, Guido

    2016-03-01

    Ongoing progress in mass analysis applications such as laser ablation inductively coupled mass spectrometry of solid samples and ultraviolet photoionization mediated sequencing of peptides and proteins is to a large extent driven by ultrashort wavelength excimer lasers at 193 nm. This paper will introduce the latest improvements achieved in the development of compact high repetition rate excimer lasers and elaborate on the impact on mass spectrometry instrumentation. Various performance and lifetime measurements obtained in a long-term endurance test over the course of 18 months will be shown and discussed in view of the laser source requirements of different mass spectrometry tasks. These sampling type applications are served by excimer lasers delivering pulsed 193 nm output of several mJ as well as fast repetition rates which are already approaching one Kilohertz. In order to open up the pathway from the laboratory to broader market industrial use, sufficient component lifetimes and long-term stable performance behavior have to be ensured. The obtained long-term results which will be presented are based on diverse 193 nm excimer laser tube improvements aiming at e.g. optimizing the gas flow dynamics and have extended the operational life the laser tube for the first time over several billion pulses even under high duty-cycle conditions.

  17. 1064 nm Nd:YAG laser intracavity pumped at 946 nm and sum-frequency mixing for an emission at 501 nm

    NASA Astrophysics Data System (ADS)

    Lü, Y. F.; Zhang, X. H.; Xia, J.; Jin, G. Y.; Wang, J. G.; Yin, X. D.; Zhang, A. F.

    2010-05-01

    We present for the first time a Nd:YAG laser emitting at 1064 nm intracavity pumped by a 946 nm diode-pumped Nd:YAG laser. A 809 nm laser diode is used to pump the first Nd:YAG crystal emitting at 946 nm, and the second Nd:YAG laser emitting at 1064 nm intracavity pumped at 946 nm. Intracavity sum-frequency mixing at 946 and 1064 nm was then realized in a LBO crystal to reach the cyan range. We obtained a continuous-wave output power of 485 mW at 501 nm with a pump laser diode emitting 25.4 W at 809 nm.

  18. Quantity change in collagen following 830-nm diode laser welding

    NASA Astrophysics Data System (ADS)

    Tang, Jing; O'Callaghan, David; Rouy, Simone; Godlewski, Guilhem; Prudhomme, Michel

    1996-12-01

    The actual mechanism for production of laser welding of tissue is presently unknown, but collagen plays an important role is tissue welded after laser irradiance. The quantity change in collagen extracted from the abdominal aorta of Wistar rats after tissue welding using an 830 nm diode laser was investigated. The collagen contents following repeated pepsin digestion after acetic acid extraction were determined with Sircol collagen assay. Compared with untreated aorta, the collagen content of the treated vessel was obvious decreased immediately after laser irradiation and following an initial increase on day 3, there was a peak at day 10. The results suggest that a part of collagen molecules is denatured by the heat of laser. There is an effect of stimulating collagen synthesis after laser welding with parameters used in this study.

  19. High-efficiency direct-pumped Nd:YVO 4-LBO laser operating at 671 nm

    NASA Astrophysics Data System (ADS)

    Lü, Yan-Fei; Zhang, Xi-He; Xia, Jing; Yin, Xiao-Dong; Zhang, An-Feng; Bao, Lin; Lü, Wang

    2010-04-01

    The continuous-wave high-efficiency laser emission from Nd:YVO 4 at the fundamental wavelength of 1342 nm and its 671 nm second harmonic obtained by intra-cavity frequency doubling in an LBO nonlinear crystal are investigated under pumping by diode laser at 880 nm (on the 4F 3/2→ 4I 13/2 transition). The end-pumped Nd:YVO 4 crystal yielded a continuous-wave output power of 9.6 W at 1342 nm for 18.9 W of absorbed pump power. The slope efficiency measured with respect to the absorbed pump power is 60%. An output of 5.5 W at 671 nm was obtained by frequency doubling, resulting in an optical-to-optical efficiency with respect to the absorbed pump power of 29%. Comparative results obtained for the pump with a diode laser at 808 nm (on the 4F 5/2→ 4I 13/2 transition) are given in order to prove the advantages of the 880 nm wavelength pumping.

  20. Enhancement of 800 nm upconversion emission in a thulium doped tellurite microstructured fiber pumped by a 1560 nm femtosecond fiber laser

    NASA Astrophysics Data System (ADS)

    Jia, Zhixu; Yao, Chuanfei; Wang, Shunbin; Zheng, Kezhi; Xiong, Liangming; Luo, Jie; Lv, Dajuan; Qin, Guanshi; Ohishi, Yasutake; Qin, Weiping

    2016-04-01

    We report enhanced upconversion (UC) fluorescence in Tm3+ doped tellurite microstructured fibers (TDTMFs) fabricated by using a rod-in-tube method. Under the pumping of a 1560 nm femtosecond fiber laser, ultrabroadband supercontinuum light expanding from ˜1050 to ˜2700 nm was generated in a 4 cm long TDTMF. Simultaneously, intense 800 nm UC emission from the 3H4 → 3H6 transition of Tm3+ was observed in the same TDTMF. Compared to that pumped by a 1560 nm continuous wave fiber laser, the UC emission intensity was enhanced by ˜4.1 times. The enhancement was due to the spectral broadening in the TDTMF under the pumping of the 1560 nm femtosecond fiber laser.

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

  2. A compact efficient deep ultraviolet laser at 266 nm

    NASA Astrophysics Data System (ADS)

    Zhai, S. Y.; Wang, X. L.; Wei, Y.; Chen, W. D.; Zhuang, F. J.; Xu, S.; Li, B. X.; Fu, J. J.; Chen, Z. Q.; Wang, H. W.; Huang, C. H.; Zhang, G.

    2013-04-01

    We present a highly efficient and cost-effective watt-level deep-ultraviolet laser operating at 266 nm. Type-I phase-matching LBO crystals and type-I phase-matching BBO crystals were used for frequency doubling and fourth-harmonic generation, respectively. The highest 1.82 W average power of the 266 nm laser was obtained from nonlinear frequency conversion at a repetition rate of 30 kHz and a pump power of 18.8 W. The conversion efficiency from the diode to the deep-ultraviolet laser scales up to 10.7%. This is, to our knowledge, the highest efficiency ever reported generated from a laser diode single-end-pumped acousto-optic Q-switched system.

  3. Raman spectroscopy using 1550 nm (retina-safe) laser excitation.

    PubMed

    Brouillette, Carl; Huang, Hermes; Smith, Wayne; Farquharson, Stuart

    2011-05-01

    During the past decade, the use of portable Raman analyzers for field measurements has grown dramatically. However, most analyzers use 785 nm excitation lasers that can cause permanent eye damage. To overcome this safety concern, we have built a portable Fourier transform (FT) Raman analyzer using a 1550 nm retina-safe excitation laser and have compared its performance to our 1064 nm FT-Raman analyzer, which uses the same optical design. Raman theory predicts approximately five times lower peak intensities at 1550 nm. Although we found that intensities were as much as 20 times less intense, the analyzer is still capable of measuring spectra of sufficient quality to identify and differentiate chemicals. PMID:21513601

  4. 810nm, 980nm, 1470nm and 1950nm diode laser comparison: a preliminary "ex vivo" study on oral soft tissues

    NASA Astrophysics Data System (ADS)

    Fornaini, Carlo; Merigo, Elisabetta; Sozzi, Michele; Selleri, Stefano; Vescovi, Paolo; Cucinotta, Annamaria

    2015-02-01

    The introduction of diode lasers in dentistry has several advantages, mainly consisting on the reduced size, reduced cost and possibility to beam delivering by optical fibers. At the moment the two diode wavelengths normally utilized in the dental field are 810 and 980 nm for soft tissues treatments. The aim of this study was to compare the efficacy of four different diode wavelengths: 810, 980, 1470 and 1950 nm diode laser for the ablation of soft tissues. Several samples of veal tongue were exposed to the four different wavelengths, at different fluences. The internal temperature of the soft tissues, in the area close to the beam, was monitored with thermocouple during the experiment. The excision quality of the exposed samples have been characterized by means of an optical microscope. Tissue damages and the cut regularity have been evaluated on the base of established criteria. The lowest thermal increase was recorded for 1950 nm laser. Best quality and speed of incision were obtained by the same wavelength. By evaluating epithelial, stromal and vascular damages for all the used wavelengths, the best result, in terms of "tissue respect", have been obtained for 1470 and 1950 nm exposures. From the obtained results 1470 and 1950 nm diode laser showed to be the best performer wavelengths among these used in this "ex vivo" study, probably due to their greatest affinity to water.

  5. Laser diode and pumped Cr:Yag passively Q-switched yellow-green laser at 543 nm

    NASA Astrophysics Data System (ADS)

    Yao, Y.; Ling, Zhao; Li, B.; Qu, D. P.; Zhou, K.; Zhang, Y. B.; Zhao, Y.; Zheng, Q.

    2013-03-01

    Efficient and compact yellow green pulsed laser output at 543 nm is generated by frequency doubling of a passively Q-switched end diode-pumped Nd:YVO4 laser at 1086 nm under the condition of sup-pressing the higher gain transition near 1064 nm. With 15 W of diode pump power and the frequency doubling crystal LBO, as high as 1.58 W output power at 543 nm is achieved. The optical to optical conversion efficiency from the corresponding Q-switched fundamental output to the yellow green output is 49%. The peak power of the Q-switched yellow green pulse laser is up to 30 kW with 5 ns pulse duration. The output power stability over 8 hours is better than 2.56% at the maximum output power. To the best of our knowledge, this is the highest watt-level laser at 543 nm generated by frequency doubling of a passively Q-switched end diode pumped Nd:YVO4 laser at 1086 nm.

  6. An 885-nm Direct Pumped Nd:CNGG 1061 nm Q-Switched Laser

    NASA Astrophysics Data System (ADS)

    Li, Qi-Nan; Zhang, Tao; Feng, Bao-Hua; Zhang, Zhi-Guo; Zhang, Huai-Jin; Wang, Ji-Yang

    2014-07-01

    The 885 nm direct pumping method, directly into the 4F3/2 emitting level of Nd3+ ion, is used to a Nd:CNGG crystal to product passive Q-switched 1061 nm laser pulses, for the first time to the best of our knowledge. A maximum average output power of 1.16 W for 1061 nm Q-switched pulses and a repetition rate of 12.54 kHz are obtained. The pulse width is measured to be 24 ns and the peak power is 3.843 kW. A high-quality fundamental transverse mode can be observed owing to the reduction of the thermal effect for Nd:CNGG crystal by 885 nm direct pumping.

  7. Interaction between high power 532nm laser and prostatic tissue: in vivo evaluation for laser prostatectomy

    NASA Astrophysics Data System (ADS)

    Malek, Reza; Kang, Hyun Wook; Peng, Steven Yihlih; Stinson, Douglas; Beck, Michael; Koullick, Ed

    2011-03-01

    A previous in vitro study demonstrated that 180W was the optimal power to reduce photoselective vaporization of the prostate (PVP) time for larger prostate glands. In this study, we investigated anatomic and histologic outcomes and ablation parameters of 180W laser performed with a new 750-μm side-firing fiber in a survival study of living canines. Eight male canines underwent anterograde PVP with the 180W 532-nm laser. Four each animals were euthanized 3 hours or 8 weeks postoperatively. Prostates were measured and histologically analyzed after hematoxylin and eosin (H&E), triphenyltetrazolium chloride (TTC), or Gomori trichrome (GT) staining. Compared to the previous 120W laser, PVP with the 180W laser bloodlessly created a 76% larger cavity (mean 11.8 vs. 6.7 cm3; p=0.014) and ablated tissue at a 77% higher rate (mean 2.3 vs. 1.3 cm3/min; p=0.03) while H&E- and TTC-staining demonstrated its 33% thicker mean coagulation zone (2.0+/-0.4 vs. 1.5+/-0.3 mm). H&E-stained cross-sectional prostatic tissue specimens from the 3-hour (acute) group showed histologic evolution of concentric non-viable coagulation zone, partially viable hyperemic transition zone of repair, and viable non-treated zone. H&E- and GT-stained specimens from the 8-week (chronic) group revealed healed circumferentially epithelialized, non-edematous, prostatic urethral channels with no increase in collagen in the subjacent prostatic tissue vis-á-vis the normal control. Our canine study demonstrates that 180W 532-nm laser PVP with its new fiber has a significantly higher ablation rate with a more hemostatic coagulation zone, but equally favorable tissue interaction and healing, compared with our previous 120W canine study.

  8. High power operation of a flashlamp-pumped Nd:YAG laser at 1123 nm

    NASA Astrophysics Data System (ADS)

    Lee, Hee Chul; Kim, Yong Pyung

    2010-04-01

    A high power flashlamp-pumped Nd:YAG laser at 1123 nm with a repetition rate of 40 Hz is investigated. Simple but specially coated resonator mirrors are adopted to suppress the parasitic oscillation at gain transition lines higher than 1123 nm. A maximum average output power of 40 W with an electrical pumping energy of 45.7 J and pumping pulse duration of 150 μs is achieved. To the best of our knowledge, the output power of 40 W at a wavelength of 1123 nm is the highest record up to now.

  9. High average power, narrow band 248 nm alexandrite laser system

    SciTech Connect

    Kuper, J.W.; Chin, T.C.; Papanestor, P.A.

    1994-12-31

    A compact line-narrowed 248 nm solid state laser source operating at 15 mJ {at} 100 Hz PRF was demonstrated. Constraints due to thermal loading of components were addressed. Tradeoffs between pulse energy and repetition rate were investigated. A method for overcoming thermal dephasing in the THG material was achieved by scanning a slab shaped crystal.

  10. 635nm diode laser biostimulation on cutaneous wounds

    NASA Astrophysics Data System (ADS)

    Solmaz, Hakan; Gülsoy, Murat; Ülgen, Yekta

    2014-05-01

    Biostimulation is still a controversial subject in wound healing studies. The effect of laser depends of not only laser parameters applied but also the physiological state of the target tissue. The aim of this project is to investigate the biostimulation effects of 635nm laser irradiation on the healing processes of cutaneous wounds by means of morphological and histological examinations. 3-4 months old male Wistar Albino rats weighing 330 to 350 gr were used throughout this study. Low-level laser therapy was applied through local irradiation of red light on open skin excision wounds of 5mm in diameter prepared via punch biopsy. Each animal had three identical wounds on their right dorsal part, at which two of them were irradiated with continuous diode laser of 635nm in wavelength, 30mW of power output and two different energy densities of 1 J/cm2 and 3 J/cm2. The third wound was kept as control group and had no irradiation. In order to find out the biostimulation consequences during each step of wound healing, which are inflammation, proliferation and remodeling, wound tissues removed at days 3, 7, 10 and 14 following the laser irradiation are morphologically examined and than prepared for histological examination. Fragments of skin including the margin and neighboring healthy tissue were embedded in paraffin and 6 to 9 um thick sections cut are stained with hematoxylin and eosin. Histological examinations show that 635nm laser irradiation accelerated the healing process of cutaneous wounds while considering the changes of tissue morphology, inflammatory reaction, proliferation of newly formed fibroblasts and formation and deposition of collagen fibers. The data obtained gives rise to examine the effects of two distinct power densities of low-level laser irradiation and compare both with the non-treatment groups at different stages of healing process.

  11. Power scaling of laser diode pumped Pr3+:LiYF4 cw lasers: efficient laser operation at 522.6 nm, 545.9 nm, 607.2 nm, and 639.5 nm.

    PubMed

    Gün, Teoman; Metz, Philip; Huber, Günter

    2011-03-15

    We report efficient cw laser operation of laser diode pumped Pr(3+)-doped LiYF4 crystals in the visible spectral region. Using two InGaN laser diodes emitting at λ(P)=443.9 nm with maximum output power of 1 W each and a 2.9-mm-long crystal with a doping concentration of 0.5%, output powers of 938 mW, 418 mW, 384 mW, and 773 mW were achieved for the laser wavelengths 639.5 nm, 607.2 nm, 545.9 nm, and 522.6 nm, respectively. The maximum absorbed pump powers were approximately 1.5 W, resulting in slope efficiencies of 63.6%, 32.0%, 52.1%, and 61.5%, as well as electro-optical efficiencies of 9.4%, 4.2%, 3.8%, and 7.7%, respectively. Within these experiments, laser diode-pumped laser action at 545.9 nm was demonstrated for what is believed to be the first time. PMID:21403756

  12. Ultraviolet continuous-wave laser source at 205 nm for hydrogen spectroscopy

    NASA Astrophysics Data System (ADS)

    Galtier, Sandrine; Nez, François; Julien, Lucile; Biraben, François

    This paper reports on the generation of 15 mW of continuous narrow-band laser source at 205 nm. The infra-red light source provided by a Titanium-Sapphire (TiSa) laser is mixed with the fourth harmonic of a Nd:YVO4 laser by the use of a β-barium borate (BBO) non-linear crystal. This highly reliable and powerful ultraviolet (UV) source is an ideal tool for the 1S-3S hydrogen spectroscopy. Moreover, the wide tunability of the TiSa laser combined with this experimental set up makes the generation of bright deep ultra-violet (D-UV) sources possible. In particular, we plan to produce a 194 nm continuous light beam which is necessary to perform the 1S-4S transition in hydrogen.

  13. High power narrowband 589 nm frequency doubled fibre laser source.

    PubMed

    Taylor, Luke; Feng, Yan; Calia, Domenico Bonaccini

    2009-08-17

    We demonstrate high-power high-efficiency cavity-enhanced second harmonic generation of an in-house built ultra-high spectral density (SBS-suppressed) 1178 nm narrowband Raman fibre amplifier. Up to 14.5 W 589 nm CW emission is achieved with linewidth Delta nu(589) < 7 MHz in a diffraction-limited beam, with peak external conversion efficiency of 86%. The inherently high spectral and spatial qualities of the 589 nm source are particularly suited to both spectroscopic and Laser Guide Star applications, given the seed laser can be easily frequency-locked to the Na D(2a) emission line. Further, we expect the technology to be extendable, at similar or higher powers, to wavelengths limited only by the seed-pump-pair availability. PMID:19687946

  14. Ar-ion-laser-pumped infrared dye laser at 875-1084 nm

    SciTech Connect

    Kato, K.

    1984-12-01

    High-efficiency high-power cw dye-laser operation has been acheived from 875 to 1084 nm by pumping two styryl derivatives with an Ar-ion laser. Peak output powers as high as 900 and 750 mW were obtained around 925 and 980 nm, respectively.

  15. High-brightness 800nm fiber-coupled laser diodes

    NASA Astrophysics Data System (ADS)

    Berk, Yuri; Levy, Moshe; Rappaport, Noam; Tessler, Renana; Peleg, Ophir; Shamay, Moshe; Yanson, Dan; Klumel, Genadi; Dahan, Nir; Baskin, Ilya; Shkedi, Lior

    2014-03-01

    Fiber-coupled laser diodes have become essential sources for fiber laser pumping and direct energy applications. Single emitters offer reliable multi-watt output power from a 100 m lateral emission aperture. By their combination and fiber coupling, pump powers up to 100 W can be achieved from a low-NA fiber pigtail. Whilst in the 9xx nm spectral range the single emitter technology is very mature with <10W output per chip, at 800nm the reliable output power from a single emitter is limited to 4 W - 5 W. Consequently, commercially available fiber coupled modules only deliver 5W - 15W at around 800nm, almost an order of magnitude down from the 9xx range pumps. To bridge this gap, we report our advancement in the brightness and reliability of 800nm single emitters. By optimizing the wafer structure, laser cavity and facet passivation process we have demonstrated QCW device operation up to 19W limited by catastrophic optical damage to the 100 μm aperture. In CW operation, the devices reach 14 W output followed by a reversible thermal rollover and a complete device shutdown at high currents, with the performance fully rebounded after cooling. We also report the beam properties of our 800nm single emitters and provide a comparative analysis with the 9xx nm single emitter family. Pump modules integrating several of these emitters with a 105 μm / 0.15 NA delivery fiber reach 35W in CW at 808 nm. We discuss the key opto-mechanical parameters that will enable further brightness scaling of multi-emitter pump modules.

  16. Demonstration of miniaturized 20mW CW 280nm and 266nm solid-state UV laser sources

    NASA Astrophysics Data System (ADS)

    Landru, Nicolas; Georges, Thierry; Beaurepaire, Julien; Le Guen, Bruno; Le Bail, Guy

    2015-02-01

    Visible 561 nm and 532 nm laser emissions from 14-mm long DPSS monolithic cavities are frequency converted to deep UV 280 nm and 266 nm in 16-mm long monolithic external cavities. Wavelength conversion is fully insensitive to mechanical vibrations and the whole UV laser sources fit in a miniaturized housing. More than 20 mW deep UV laser emission is demonstrated with high power stability, low noise and good beam quality. Aging tests are in progress but long lifetimes are expected thanks to the cavity design. Protein detection and deep UV resonant Raman spectroscopy are applications that could benefit from these laser sources.

  17. Spectroscopy of the 199Hg Optical Clock Transition at 265.5 nm

    NASA Astrophysics Data System (ADS)

    Lytle, Christian; Paul, Justin; Jones, R.

    2013-05-01

    Neutral Hg is an excellent candidate for a stable and accurate atomic clock. The doubly-forbidden clock transition at 265.5 nm can provide an extremely high-quality resonance factor (Q) when confined in an optical lattice at the Stark-shift free ``magic'' wavelength. A key feature of the Hg system is the expected reduced uncertainty of black-body radiation induced Stark shifts compared to other optically-based neutral atom clocks. We demonstrate precision spectroscopy of the 1S0 - 3P0 clock transition in 199Hg in a MOT. The MOT population of 106 atoms was depleted by over 70% using 3 mW from a cavity-stabilized probe laser tuned to the clock transition. We present our characterization of the transition and efforts to implement a stable Hg clock system.

  18. 551 nm Generation by sum-frequency mixing of intracavity pumped Nd:YAG laser

    NASA Astrophysics Data System (ADS)

    Dong, Y.; Li, S. T.; Zhang, X. H.

    2012-02-01

    We present for the first time a Nd:YAG laser emitting at 1319 nm intracavity pumped by a 946 nm diode-pumped Nd:YAG laser. A 809 nm laser diode is used to pump the first Nd:YAG crystal emitting at 946 nm, and the second Nd:YAG laser emitting at 1319 nm intracavity pumped at 946 nm. Intracavity sumfrequency mixing at 946 and 1319 nm was then realized in a LBO crystal to reach the yellow range. We obtained a continuous-wave output power of 158 mW at 551 nm with a pump laser diode emitting 18.7 W at 809 nm.

  19. 980 nm narrow linewidth Yb-doped phosphate fiber laser

    NASA Astrophysics Data System (ADS)

    Li, Pingxue; Yao, Yifei; Hu, Haowei; Chi, Junjie; Yang, Chun; Zhao, Ziqiang; Zhang, Guangju

    2014-12-01

    A narrow-linewidth ytterbium (Yb)-doped phosphate fiber laser based on fiber Bragg grating (FBG) operating around 980 nm is reported. Two different kinds of cavity are applied to obtain the 980 nm narrow-linewidth output. One kind of the cavity consists of a 0.35 nm broadband lindwidth high-reflection FBG and the Yb-doped phosphate fiber end with 0° angle, which generates a maximum output power of 25 mW. The other kind of resonator is composed of a single mode Yb-doped phosphate fiber and a pair of FBGs. Over 10.7 mW stable continuous wave are obtained with two longitudinal modes at 980 nm. We have given a detailed analysis and discussion for the results.

  20. Laser enhancements for Lunar Laser Ranging at 532 nm

    NASA Astrophysics Data System (ADS)

    Martinot-Lagarde, G.; Aimar, M.; Albanèse, D.; Courde, C.; Exertier, P.; Fienga, A.; Mariey, H.; Métris, G.; Rigard-Cerison, R.; Samain, E.; Torre, J.-M.; Viot, H.

    This article exposes how we improved (by more than a factor of four) the green Lunar Laser Ranging instrumental sensitivity of the French telemetric station of the "Observatoire de la Côte d'Azur" in 2012. The primary reason for this success is the doubling of the pulse energy of our green Nd:YAG laser, reaching now 200 mJ at 10 Hz. This first gain is due to the replacement (inside our oscillator cavity) of the dye cell with a CR4+:YAG crystal saturable absorber. Complementary spatial beam profile improvements are also described, regarding polarisation, flashlamp geometry and specific lens arrangements (to exclude ghosts from focusing on the 8 m long amplification chain). Those combined laser enhancements pave the way to future science breakthrough linked to quasi-millimetric determination of the Earth-Moon dynamics (Murphy, 2013). Jointly, we propose an empirical thermal lensing model, varying with the cycle ratio of the flashlamps. Our model connects Koechner's (1970) continuous pumping to our intermittent pumping case, with a "normalised heating coefficient" equalling 0.05 only if the electrical lamp input power is equal to 6 kW and scaling as this [electrical input power into the lamps] to the power of [half the pumping cycle ratio].

  1. Efficient and compact intracavity-frequency-doubled Nd:LuVO4/LBO laser at 538 nm end-pumped by a fiber-coupled laser diode

    NASA Astrophysics Data System (ADS)

    Liu, B.; Li, Y. L.; Jiang, H. L.

    2011-10-01

    We report a diode-pumped Nd:LuVO4 laser emitting at 1076 nm, based on the 4 F 3/2-4 I 11/2 transition, generally used for a 1066 nm emission. A power of 689 mW at 1076 nm has been achieved in continuous-wave (CW) operation with a fiber-coupled laser diode emitting 17.8 W at 809 nm. Intracavity second-harmonic generation (SHG) in CW mode has also been demonstrated with a power of 105 mW at 538 nm by using a LiB3O5 (LBO) nonlinear crystal.

  2. Flash-lamp pumped Pr:YAP laser operated at wavelengths of 747 nm and 662 nm

    NASA Astrophysics Data System (ADS)

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

    2009-02-01

    Successful room-temperature generation of Pr:YAP laser radiation at wavelengths of 747 nm and 662 nm was demonstrated. A flash-lamp pumped Pr:YAP laser was operated in free-running pulsed regime at room temperature. Permanent laser action was reached by means of a special UV color glass plate filter placed directly into the laser cavity. The maximum output energy and pulse length reached at wavelengths of 747 nm and 662 nm were 102 mJ, 92 μs and 6.1 mJ, 47.5 μs, respectively. The laser beam parameter M2 ~ 1.5 was measured when the 662 nm wavelength was generated. In the case of 747 nm wavelength generation, M2 ~ 1.2 was reached with a diaphragm inside the resonator. For different pumped energy values, the line shape and linewidth remained stable for both cases.

  3. Laser-Matter Interactions with a 527 nm Drive

    SciTech Connect

    Glenzer, S; Niemann, C; Witman, P; Wegner, P; Mason, D; Haynam, C; Parham, T; Datte, P

    2007-02-16

    The primary goal of this Exploratory Research is to develop an understanding of laser-matter interactions with 527-nm light (2{omega}) for studies of interest to numerous Laboratory programs including inertial confinement fusion (ICF), material strength, radiation transport, and hydrodynamics. In addition, during the course of this work we will develop the enabling technology and prototype instrumentation to diagnose a high fluence laser beam for energy, power, and near field intensity profile at 2{omega}. Through this Exploratory Research we have established an extensive experimental and modeling data base on laser-matter interaction with 527 nm laser light (2{omega}) in plasma conditions of interest to numerous Laboratory programs. The experiments and the laser-plasma interaction modeling using the code pF3D have shown intensity limits and laser beam conditioning requirements for future 2{omega} laser operations and target physics experiments on the National Ignition Facility (NIF). These findings have set requirements for which present radiation-hydrodynamic simulations indicate the successful generation of relevant pressure regimes in future 2{omega} experiments. To allow these experiments on the NIF, optics and optical mounts were prepared for the 18mm Second Harmonic Generation Crystal (SHG crystal) that would provide the desired high conversion efficiency from 1{omega} to 2{omega}. Supporting experimental activities on NIF included high-energy 1{omega} shots at up to 22kJ/beamline (4MJ full NIF 1{omega} equivalent energy) that demonstrated, in excess, the 1{omega} drive capability of the main laser that is required for 2{omega} operations. Also, a very extensive 3{omega} campaign was completed (see ''The National Ignition Facility Laser Performance Status'' UCRL-JRNL-226553) that demonstrated that not only doubling the laser, but also tripling the laser (a much more difficult and sensitive combination) met our model predictions over a wide range of laser

  4. Efficient 750-nm LED-pumped Nd:YAG laser.

    PubMed

    Huang, Kuan-Yan; Su, Cheng-Kuo; Lin, Meng-Wei; Chiu, Yu-Chung; Huang, Yen-Chieh

    2016-05-30

    We report an Nd:YAG laser pumped by light emission diodes (LEDs) at 750 nm. With 1% output coupling from a linear cavity containing a 2-cm long Nd:YAG crystal, the laser generated 37.5 μJ pulse energy at 1064 nm with M2 = 1.1 when pumped by 2.73-mJ LED energy in a 1-ms pulse at a 10 Hz rate. The measured optical and slope efficiencies for this linear-cavity laser are 1.36, and 9%, respectively. With 1 and 5% output couplings from a Z-cavity containing the same laser crystal, the lasers generated 346 and 288 μJ pulse energy with an optical efficiency of 3.4 and 2.8% and slope efficiency of 6.6 and 14%, respectively, for the same 1-ms pump pulse repeating at a 10 Hz rate. At the highest output from the Z-cavity, the measured M2 for the beam is 3.6. PMID:27410125

  5. High-efficiency high-brightness diode lasers at 1470 nm/1550 nm for medical and defense applications

    NASA Astrophysics Data System (ADS)

    Gallup, Kendra; Ungar, Jeff; Vaissie, Laurent; Lammert, Rob; Hu, Wentao

    2012-03-01

    Diode lasers in the 1400 nm to 1600 nm regime are used in a variety of applications including pumping Er:YAG lasers, range finding, materials processing, aesthetic medical treatments and surgery. In addition to the compact size, efficiency, and low cost advantages of traditional diode lasers, high power semiconductor lasers in the eye-safe regime are becoming widely used in an effort to minimize the unintended impact of potentially hazardous scattered optical radiation from the laser source, the optical delivery system, or the target itself. In this article we describe the performance of high efficiency high brightness InP laser bars at 1470nm and 1550nm developed at QPC Lasers for applications ranging from surgery to rangefinding.

  6. Pseudomorphic Single-Quantum-Well Lasers Emit At 980 Nm

    NASA Technical Reports Server (NTRS)

    Larsson, Anders; Forouhar, Siamak; Cody, Jeffrey G.; Lang, Robert J.; Andrekson, Peter A.

    1992-01-01

    Narrow-stripe semiconductor lasers emitting at 980 nm include pseudomorphic In0.2Ga0.8As/GaAs/AlxGa1-xAs graded-index-of-refraction, separate-confinement-heterostructure single quantum well(GRINSCH SQW) with overlaid ridge waveguide. 980 nm chosen as one that yields most efficient pumping because there is no absorption in excited states at this wavelength. Suitable for pumping Er(Sup3+)-doped optical-fiber amplifiers in optical-fiber communication systems and optical phased-array ranging systems.

  7. All solid-state continuous-wave Nd:YAG laser at 1319 and 659.5 nm under direct 885 nm pumping

    NASA Astrophysics Data System (ADS)

    Lü, Y. F.; Zhang, X. H.; Xia, J.; Yin, X. D.; Bao, L.; Quan, H.

    2010-01-01

    The continuous-wave high efficiency laser emission of Nd:YAG at the fundamental wavelength of 1319 nm and its 659.5-nm second harmonic obtained by intracavity frequency doubling with an LBO nonlinear crystal is investigated under pumping by diode laser at 885 nm (on the 4 F 3/2 → 4 I 13/2 transition). An end-pumped Nd:YAG crystal yielded 9.1 W at 1319 nm of continuous-wave output power for 18.2 W of absorbed pump power. The slope efficiency with respect to the absorbed pump power is 0.55. Furthermore, 5.2 W 659.5 nm red light is acquired by frequency doubling, resulting in an optical-to-optical efficiency with respect to the absorbed pump power of 0.286. Comparative results obtained for the pump with diode laser at 808 nm (on the 4 F 5/2 → 4 I 13/2 transition) are given in order to prove the advantages of the 885 nm wavelength pumping.

  8. Next generation 8xx nm laser bars and single emitters

    NASA Astrophysics Data System (ADS)

    Strauss, Uwe; Müller, Martin; Swietlik, Tomasz; Fehse, Robin; Lauer, Christian; Grönninger, Günther; König, Harald; Keidler, Markus; Fillardet, Thierry; Kohl, Andreas; Stoiber, Michael; Scholl, Iris; Biesenbach, Jens; Baeumler, Martina; Konstanzer, Helmer

    2011-03-01

    Semiconductor lasers with emission in the range 790 - 880 nm are in use for a variety of application resulting in different laser designs to fulfill requirements in output power, operation temperature and lifetimes. The output power is limited by self heating and catastrophic optical mirror damage at the laser facet (COMD). Now we present data on bars fabricated with our new facet technology, which enables us to double the maximum facet load. We present q-cw laser bar with 80% fill factor with increased power level to 350W in long term operation at 200μs and 100Hz. The COMD limit of the bar is as high as 680W. Using Quantel's optimized packaging stacks with 11 bars of 5mm widths are tested at up to 120A resulting over 66% power conversion efficiency at 1600W output power. Laser bars for continuous wave operation like 50% fill factor bars had an COMD limit of approx. 250W with conventional facet technology, the value is equivalent to 10W per 200μm emitter (conditions: 200μs). The new facet technology pushes the facet stability to 24W/emitter. The new process and an improved design enable us to shift continuous wave operation at 808nm from 100W to 150W/bar with lifetimes of several thousand hours at 30°C using DILAS mounting technology. Higher power is possible depending on lifetime requirements. The power conversion efficiency of the improved devices is as high as 62% at 200W cw. The next limitation of 8xxnm lasers is high temperature operation: Values of 60-80°C are common for consumer applications of single emitters. Therefore Osram developed a new epitaxial design which reduced the generation of bulk defects. The corresponding Osram single emitters operate at junction temperatures up to 95°C, a value which corresponds to 80°C heat sink temperature for lasers soldered on C-mount or 65°C case temperature for lasers mounted in TO can. Current densities of the single emitter broad area lasers are as high as 1.4kA/cm2 at 850nm emission wavelength.

  9. Laser-induced damage measurements with 266-nm pulses

    NASA Astrophysics Data System (ADS)

    Deaton, T. F.; Smith, W. L.

    1980-07-01

    Results of a survey of laser-induced damage thresholds for optical components at 266-nm are reported. The thresholds were measured at two pulse durations; 0.150 ns and 1.0 ns. The 30 samples tested include four commercial dielectric reflectors, three metallic reflectors, two anti-reflection films, a series of eight half-wave oxide and fluoride films, and twelve bare surfaces (fluoride crystals, silica, sapphire, BK-7 glass, cesium dideuterium arsenate and potassium dihydrogen phosphate). The 266-nm pulses were obtained by frequency-quadrupling a Nd:YAG, glass laser. Equivalent plane imagery and calorimetry were used to measure the peak fluence of each of the UV pulses with an accuracy of + or - of 15%; the uncertainty in the threshold determinations is typically + or - 30%.

  10. induced by 1,540-nm laser excitation

    NASA Astrophysics Data System (ADS)

    Zheng, J.; Wang, X. F.; He, W. Y.; Bu, Y. Y.; Yan, X. H.

    2014-06-01

    The multi-photon ultraviolet upconversion emission properties and synergistic effect are investigated in BaSr2Y6O12:Er3+ phosphor. The deep-ultraviolet emissions centered at 274, 297 and 324-nm are observed under the 1,540-nm excitation, which results from a seven-, six- and six-photon upconversion process, respectively. A synergistic effect is found, which shows that the red emission intensity under 351- and 1,540-nm dual excitation is 4.7 % time stronger than the sum of red emission intensities under the 351 and 1,540-nm single excitation. This phenomenon is attributed to the 4I13/2 and 4I11/2 levels of Er3+ from non-radiative transition process under the 351-nm excitation are excited again to 4F9/2 level by absorbing 1,540-nm photon in the 351- and 1,540-nm dual-excitation process.

  11. 308-nm Excimer laser treatment of palmoplantar psoriasis.

    PubMed

    Goldberg, David J; Chwalek, Jennifer; Hussain, Mussarrat

    2011-04-01

    Psoriasis is a chronic inflammatory condition affecting 1-3% of the population. The incidence of palmoplantar involvement has been estimated to be between 2.8% and 40.9%. Significant psychosocial distress and difficulty performing activities of daily living can result. Treatment is often challenging. Traditional treatments include topical steroids, anthralin, calcipotriene, PUVA, methotrexate, cyclosporine, retinoids and biologics. In this case series, we report our success with the 308-nm excimer laser in the treatment of palmoplantar psoriasis. PMID:21401376

  12. 494 nm blue laser based on sum-frequency mixing of diode pumped Nd3+ lasers

    NASA Astrophysics Data System (ADS)

    Zou, J.; Wang, L. R.

    2012-02-01

    We report for the first time a continuous-wave (CW) blue radiation at 494 nm by intracavity sumfrequency generation of 912 nm Nd:GdVO4 laser and 1079 nm Nd:YAlO3 (Nd:YAP) laser. Using type-I critical phase matching LiB3O5 (LBO) crystal, 494 nm blue laser was obtained by 912 and 1079 nm intra-cavity sum-frequency mixing, and output power of 179 mW was demonstrated. At the output power level of 179 mW, the output power stability is better than 3.5% and laser beam quality M 2 factor is 1.21.

  13. 980nm diode laser pump modules operating at high temperature

    NASA Astrophysics Data System (ADS)

    Campbell, Jenna; Semenic, Tadej; Leisher, Paul; Bhunia, Avijit; Mashanovitch, Milan; Renner, Daniel

    2016-03-01

    Existing thermal management technologies for diode laser pumps place a significant load on the size, weight and power consumption of High Power Solid State and Fiber Laser systems, thus making current laser systems very large, heavy, and inefficient in many important practical applications. This problem is being addressed by the team formed by Freedom Photonics and Teledyne Scientific through the development of novel high power laser chip array architectures that can operate with high efficiency when cooled with coolants at temperatures higher than 50 degrees Celsius and also the development of an advanced thermal management system for efficient heat extraction from the laser chip array. This paper will present experimental results for the optical, electrical and thermal characteristics of 980 nm diode laser pump modules operating effectively with liquid coolant at temperatures above 50 degrees Celsius, showing a very small change in performance as the operating temperature increases from 20 to 50 degrees Celsius. These pump modules can achieve output power of many Watts per array lasing element with an operating Wall-Plug-Efficiency (WPE) of >55% at elevated coolant temperatures. The paper will also discuss the technical approach that has enabled this high level of pump module performance and opportunities for further improvement.

  14. Femtosecond-pulse-driven 10-Hz 41.8-nm laser in Xe IX

    NASA Astrophysics Data System (ADS)

    Lemoff, B. E.; Yin, G. Y.; Gordon, C. L., III; Barty, C. P. J.; Harris, S. E.

    1996-01-01

    We report the observation of extreme UV lasing at 41.81 nm on the 4d95d1S0 - 4d95p1P1 transition in Xe IX, as proposed by Lemoff et al. [Opt. Lett. 19, 569 (1994)]. A 10-Hz circularly polarized 800-nm laser pulse with an energy of \\similar 70 mJ and a duration of \\similar 40 fs is longitudinally focused to a peak intensity of >3 \\times 1016 W / cm2 over a length of 8.4 nm in a differentially pumped cell containing 12 Torr of Xe gas. Laser amplification was observed with an estimated gain coefficient of 13 cm-1 and a total gain of exp(11).

  15. Picosecond laser texturization of mc-silicon for photovoltaics: A comparison between 1064 nm, 532 nm and 355 nm radiation wavelengths

    NASA Astrophysics Data System (ADS)

    Binetti, Simona; Le Donne, Alessia; Rolfi, Andrea; Jäggi, Beat; Neuenschwander, Beat; Busto, Chiara; Frigeri, Cesare; Scorticati, Davide; Longoni, Luca; Pellegrino, Sergio

    2016-05-01

    Self-organized surface structures were produced by picosecond laser pulses on multi-crystalline silicon for photovoltaic applications. Three different laser wavelengths were employed (i.e. 1064 nm, 532 nm and 355 nm) and the resulting morphologies were observed to effectively reduce the reflectivity of the samples after laser irradiation. Besides, a comparative study of the laser induced subsurface damage generated by the three different wavelengths was performed by confocal micro-Raman, photoluminescence and transmission electron microscopy. The results of both the structural and optical characterization showed that the mc-Si texturing performed with the laser at 355 nm provides surface reflectivity between 11% and 8% over the spectral range from 400 nm to 1 μm, while inducing the lowest subsurface damage, located above the depletion region of the p-n junction.

  16. Spectroscopic and laser properties of Tm3+ optical centers in CaF2 crystal under 795 nm diode laser excitation

    NASA Astrophysics Data System (ADS)

    Doroshenko, M. E.; Alimov, O. K.; Papashvili, A. G.; Martynova, K. A.; Konyushkin, V. A.; Nakladov, A. N.; Osiko, V. V.

    2015-12-01

    The dynamics of Tm3+ optical center formation with increasing thulium concentration and the influence of different optical centers on the fluorescence and laser properties of the 2 μm 3F4-3H6 transition under ~795 nm laser diode excitation is studied.

  17. All-solid-state continuous-wave frequency doubling Nd:YAG/LBO laser with 8.2 W output power at 660 nm

    NASA Astrophysics Data System (ADS)

    Zhu, P. F.; Li, B.; Liu, W. Q.; Liu, T. H.; Fang, C. X.; Zhao, Y.; Zheng, Q.

    2012-11-01

    An efficient and compact red laser at 660 nm is generated by intracavity frequency doubling of continuous wave (CW) laser operation of a diode pumped Nd:YAG laser at 1319 nm under the condition of suppression the higher gain transition near 1064 and 1319 nm under the condition of suppression the higher gain transition near 1064 and 1338 nm. With 40 W diode pump power and a frequency doubling crystal LBO, as high as 8.6 W of CW output power at 660 nm is achieved, corresponding to an optical-to-optical conversion efficiency of 21.5% and the output power stability in 8 h is better than 2.73%. To the best of our knowledge, this it the highest conversion efficiency of watt-level laser at 660 nm generated by intracavity frequency doubling of a diode end pumped Nd:YAG laser at 1319 nm.

  18. Ageing of optical components under laser irradiation at 532nm

    NASA Astrophysics Data System (ADS)

    Becker, S.; Delrive, L.; Bouchut, P.; Andre, B.; Geffraye, F.

    2005-09-01

    The pulsed Laser Induced Damage Threshold (LIDT) of optical components usually reaches several hundreds of MW/cm2. When exposed to laser power several order of magnitude below their LIDT, the optical component lifetime is, by default, considered infinite. Under specific conditions, the accumulation of laser pulses may lead to a contamination of the surface and a degradation of its optical properties and LIDT. In the first order, these phenomena depend on the experimental conditions such as the irradiation time, the laser power, and the environment. In order to better understand the physics emphasizing this degradation, we developed an experimental cell with an in-situ spectroscopic ellipsometry diagnostic. The dry-pumped cell sheltering the sample is associated with a mass spectrometer that enables us to follow the environmental conditions in which we experiment the ageing. Anti-reflection coatings on fused silica were tested under 10 kHz-532 nm laser ageing. We present first results of degradation obtained in these conditions.

  19. Efficiency intracavity frequency-doubled Nd:CNGG-LBO green laser at 530.5 nm under direct 885 nm pumping into the emitting level

    NASA Astrophysics Data System (ADS)

    Liu, W. M.; Zhang, X.

    2011-10-01

    We report an efficient laser emission on the 1061 nm 4 F 3/2 to 4 I 11/2 transition in Nd:CNGG under the pump with diode laser at 885 nm. Continuous wave (CW) 5.4 W output power at 1061 nm is obtained under 17.4 W of incident pump power; the slope efficiency with respect to the incident pump power was 36.2%. Moreover, intracavity frequency doubling with LiB3O5 (LBO) nonlinear crystal yielded 1.75 W of green light at 530.5 nm. An optical-to-optical efficiency with respect to the incident pump power was 10.1%.

  20. Highly efficient intracavity frequency-doubled Nd:GdVO4-LBO red laser at 670 nm under direct 880 nm pumping

    NASA Astrophysics Data System (ADS)

    Lü, Y. F.; Zhang, X. H.; Xia, J.; Yin, X. D.; Zhang, A. F.; Bao, L.; Wang, D.; Quan, H.

    2009-12-01

    We report the efficient compact red laser at 670 nm generation by intracavity frequency doubling of a continuous wave laser operation of a diode direct pumped Nd:GdVO4 laser on the 4 F 3/2 → 4 I 13/2 transition at 1340 nm. An LBO crystal, cut for critical type I phase matching at room temperature is used for second harmonic generation of the laser. At an absorbed pump power of 16.2 W, as high as 5.1 W of continuous wave output power at 670 nm is achieved with 15-mm-long LBO. The optical-to-optical conversion efficiency is up to 0.31, and the fluctuation of the red output power was better than 3.0% in the given 30 min. Comparative results obtained for the pump with diode laser at 808 nm, into the highly-absorbing 4 F 5/2 level, are given in order to prove the advantages of the 880 nm wavelength pumping.

  1. Drilling rate of five metals with picosecond laser pulses at 355, 532, and 1064 nm

    NASA Astrophysics Data System (ADS)

    Spiro, Alex; Lowe, Mary; Pasmanik, Guerman

    2012-06-01

    Experimental results on picosecond laser processing of aluminum, nickel, stainless steel, molybdenum, and tungsten are described. Hole drilling is employed for comparative analysis of processing rates in an air environment. Drilling rates are measured over a wide range of laser fluences (0.05-20 J/cm2). Experiments with picosecond pulses at 355 nm are carried out for all five metals and in addition at 532 nm, and 1064 nm for nickel. A comparison of drilling rate with 6-ps and 6-ns pulses at 355 nm is performed. The dependence of drilling rate on laser fluence measured with picosecond pulses demonstrates two logarithmic regimes for all five metals. To determine the transition from one regime to another, a critical fluence is measured and correlated with the thermal properties of the metals. The logarithmic regime at high-fluence range with UV picosecond pulses is reported for the first time. The energy efficiency of material removal for the different regimes is evaluated. The results demonstrate that UV picosecond pulses can provide comparable quality and higher processing rate compared with literature data on ablation with near-IR femtosecond lasers. A significant contribution of two-photon absorption to the ablation process is suggested to explain high processing rate with powerful UV picosecond pulses.

  2. Preliminary report: comparison of 980-nm, 808-nm diode laser enhanced with indocyanine green to the Nd:YAG laser applied to equine respiratory tissue

    NASA Astrophysics Data System (ADS)

    Tate, Lloyd P.; Blikslager, Anthony T.; Campbell, Nigel B.

    2001-05-01

    The Neodynium: Yttrium Aluminum Garnet (Nd:YAG) laser has been the mainstay of performing upper respiratory laser surgery in the equine since 1984. The 808-nm diode laser has also been applied transendoscopically as well as the 980-nm diode laser over recent years. It has been shown that Indocyanine Green (ICG) enhances the performance of the 808- nm laser because it is absorbed at 810 nm of light. The 808- nm laser's tissue interaction combined with ICG is equivalent to or greater than the Nd:YAG laser's cutting ability. The 980-nm diode laser performance was similar to that of the Nd:YAG as determined by the parameters of this study. This study compared the depths and widths of penetration achieved with the 808-nm diode laser after intravenous injection of ICG on equine respiratory tissue. It also compared depths and widths of penetration achieved by the non-contact application of the 980-nm diode laser delivering the same energy of 200 joules. The depths and widths of penetration of both diode lasers were compared to themselves and to the Nd:YAG laser with all factors remaining constant.

  3. Analysis of Cervical Supernatant Samples Luminescence Using 355 nm Laser

    NASA Astrophysics Data System (ADS)

    Vaitkuviene, A.; Gegzna, V.; Kurtinaitiene, R.; Stanikunas, R.; Rimiene, J.; Vaitkus, J.

    2010-05-01

    The biomarker discovery for accurate detection and diagnosis of cervical carcinoma and its malignant precursors represents one of the current challenges in clinical medicine. Laser induced autofluorescence spectra in cervical smear content were fitted to predict the cervical epithelium diagnosis as a lab off "optical biopsy" method. Liquid PAP supernatant sediment dried on Quartz plate spectroscopy was performed by 355 nm Nd YAG microlaser STA-1 (Standa, Ltd). For comparison a liquid supernatant spectroscopy was formed by laboratory "Perkin Elmer LS 50B spetrometer at 290, 300, 310 nm excitations. Analysis of spectrum was performed by approximation using the multi-peaks program with Lorentz functions for the liquid samples and with Gaussian functions for the dry samples. Ratio of spectral components area to the area under whole experimental curve (SPP) was calculated. The spectral components were compared by averages of SPP using Mann-Whitney U-test in histology groups. Results. Differentiation of Normal and HSIL/CIN2+ cases in whole supernatant could be performed by stationary laboratory lamp spectroscopy at excitation 290 nm and emission >379 nm with accuracy AUC 0,69, Sens 0,72, Spec 0,65. Differentiation Normal versus HSIL/CIN2+ groups in dried enriched supernatant could be performed by 355 nm microlaser excitation at emission 405-424 nm with accuracy (AUC 0,96, Sens 0,91, Spec 1.00). Diagnostic algorithm could be created for all histology groups differentiation under 355 nm excitation. Microlaser induced "optical biopsy "looks promising method for cervical screening at the point of care.

  4. A simplified 461-nm laser system using blue laser diodes and a hollow cathode lamp for laser cooling of Sr

    PubMed Central

    Shimada, Yosuke; Chida, Yuko; Ohtsubo, Nozomi; Aoki, Takatoshi; Takeuchi, Makoto; Kuga, Takahiro; Torii, Yoshio

    2013-01-01

    We develop a simplified light source at 461 nm for laser cooling of Sr without frequency-doubling crystals but with blue laser diodes. An anti-reflection coated blue laser diode in an external cavity (Littrow) configuration provides an output power of 40 mW at 461 nm. Another blue laser diode is used to amplify the laser power up to 110 mW by injection locking. For frequency stabilization, we demonstrate modulation-free polarization spectroscopy of Sr in a hollow cathode lamp. The simplification of the laser system achieved in this work is of great importance for the construction of transportable optical lattice clocks. PMID:23822327

  5. Study of a Tm:Ho:YLF laser pumped by a Raman shifted erbium-doped fibre laser at 1678 nm

    SciTech Connect

    Kalachev, Yu L; Mikhailov, Viktor A; Podreshetnikov, V V; Shcherbakov, Ivan A

    2010-06-23

    The lasing, spectral, and luminescent characteristics of a Tm:Ho:YLF laser pumped by a Raman shifted erbium-doped fibre laser ({lambda} = 1678 nm) into the 1682-nm absorption line of the {sup 3}H{sub 6}-{sup 3}F{sub 4} transition of the Tm{sup 3+} ion are studied. It is shown that the total (with respect to the absorbed power) and slope laser efficiencies upon pulsed pumping reach 46% and 50%, respectively. The output radiation power in the cw regime is 400 mW. The comparative measurements showed that pumping by a fibre laser at 1678 nm is more efficient than diode pumping at 792 nm. (lasers)

  6. Wavelength dependence on the forensic analysis of glass by nanosecond 266 nm and 1064 nm laser induced breakdown spectroscopy

    SciTech Connect

    Cahoon, Erica M.; Almirall, Jose R.

    2010-05-01

    Laser induced breakdown spectroscopy can be used for the chemical characterization of glass to provide evidence of an association between a fragment found at a crime scene to a source of glass of known origin. Two different laser irradiances, 266 nm and 1064 nm, were used to conduct qualitative and quantitative analysis of glass standards. Single-pulse and double-pulse configurations and lens-to-sample-distance settings were optimized to yield the best laser-glass coupling. Laser energy and acquisition timing delays were also optimized to result in the highest signal-to-noise ratio corresponding to the highest precision and accuracy. The crater morphology was examined and the mass removed was calculated for both the 266 nm and 1064 nm irradiations. The analytical figures of merit suggest that the 266 nm and 1064 nm wavelengths are capable of good performance for the forensic chemical characterization of glass. The results presented here suggest that the 266 nm laser produces a better laser-glass matrix coupling, resulting in a better stoichiometric representation of the glass sample. The 266 nm irradiance is therefore recommended for the forensic analysis and comparison of glass samples.

  7. Viability and Regeneration of Chondrocytes after Laser Cartilage Reshaping Using 1,460 nm Diode Laser

    PubMed Central

    Mo, Ji-Hun; Kim, Ji-Sun; Lee, Jae-Wook; Chung, Phil-Sang

    2013-01-01

    Objectives Cartilage reshaping by laser irradiation is used to correct septal and auricular cartilage deformities. Chondrocyte viability following laser irradiation and reshaping has been well established. However, the regeneration process of chondrocyte after laser irradiation has not been revealed yet. The aims of this study were to determine the mechanism of cartilaginous thermal injury and the regenerative process of damaged cartilage following laser irradiation. Methods Laser irradiation was performed on human septal cartilage and rabbit auricular cartilage using a 1,460-nm diode laser. We observed change in the shape of cartilage and evaluated the extent of cartilage injury using live/dead cell assay via confocal microscopy. Hoechst and propidium iodide (PI) staining was used to evaluate the mechanism of chondrocyte injury after laser irradiation. To evaluate the regeneration of cartilage, laser irradiated cartilages were reimplanted into a subperichondrial pocket and were harvested at 1, 2, and 4 weeks after reimplantation for viability assessment and histologic examination. Results Laser irradiation using a 1,460-nm diode laser produced a marked shape change in both human septal and rabbit auricular cartilages. Thermal damage on cartilage was correlated with the exposure time and the laser power. Hoechst and PI staining showed that chondrocyte death by laser irradiation was due to mainly necrosis, rather than apoptosis. In lower power treatment group (0.3 W and 0.5 W), all the chondrocytes regenerated within 4 weeks, however, in 1 W treatment group, chondrocytes could not regenerate until 4 weeks. Conclusion Reshaping of cartilage using 1,460 nm diode laser was attained concurrently with the thermal injury to the chondrocytes. The extent of thermal damage on chondrocytes was dependent on the exposure time and the laser power and the damaged chondrocytes irradiated with lower level of laser power could be regenerated after reimplantation into

  8. Evaluation of dental pulp repair using low level laser therapy (688 nm and 785 nm) morphologic study in capuchin monkeys

    NASA Astrophysics Data System (ADS)

    Pretel, H.; Oliveira, J. A.; Lizarelli, R. F. Z.; Ramalho, L. T. O.

    2009-02-01

    The aim of this study was to evaluate the hypothesis that low-level laser therapy (LLLT) 688 nm and 785 nm accelerate dentin barrier formation and repair process after traumatic pulp exposure. The sample consisted of 45 premolars of capuchin monkeys (Cebus apella) with pulp exposure Class V cavities. All premolars were treated with calcium hydroxide (Ca(OH)2), divided in groups of 15 teeth each, and analyzed on 7th, 25th, and 60th day. Group GI - only Ca(OH)2, GII - laser 688 nm, and GIII - laser 785 nm. Laser beam was used in single and punctual dose with the parameters: continuous, 688 nm and 785 nm wavelength, tip's area of 0.00785 cm2, power 50 mW, application time 20 s, dose 255 J/cm2, energy 2 J. Teeth were capped with Ca(OH)2, Ca(OH)2 cement and restored with amalgam. All groups presented pulp repair. On 25th day the thickness of the formed dentin barrier was different between the groups GI and GII (p < 0.05) and between groups GI and GIII (p < 0.01). On 60th day there was difference between GI and GIII (p < 0.01). It may be concluded that, LLLT 688 nm and 785 nm accelerated dentin barrier formation and consequently pulp repair process, with best results using infrared laser 785 nm.

  9. 1047 nm laser diode master oscillator Nd:YLF power amplifier laser system

    NASA Technical Reports Server (NTRS)

    Yu, A. W.; Krainak, M. A.; Unger, G. L.

    1993-01-01

    A master oscillator power amplifier (MOPA) laser transmitter system at 1047 nm wavelength using a semiconductor laser diode and a diode pumped solid state (Nd:YLF) laser (DPSSL) amplifier is described. A small signal gain of 23 dB, a near diffraction limited beam, 1 Gbit/s modulation rates and greater than 0.6 W average power are achieved. This MOPA laser has the advantage of amplifying the modulation signal from the laser diode master oscillator (MO) with no signal degradation.

  10. Subpicosecond 41.8-nm X-ray laser in the plasma produced by femtosecond laser irradiation of a xenon cluster jet

    SciTech Connect

    Ivanova, E P

    2012-12-31

    Model calculations are performed of the radiation gain for the 4d5d (J = 0) - 4d5p (J = 1) transition with a wavelength of 41.8 nm in Pd-like xenon ions in the plasma produced by femtosecond laser irradiation of a xenon cluster jet. Conditions for the excitation of an ultrashort-pulse ({approx}1 ps) X-ray laser are discussed. (lasers)

  11. 25 W Raman-fiber-amplifier-based 589 nm laser for laser guide star.

    PubMed

    Feng, Yan; Taylor, Luke R; Calia, Domenico Bonaccini

    2009-10-12

    We report on a 25 W continuous wave narrow linewidth (< 2.3 MHz) 589 nm laser by efficient (> 95%) coherent beam combination of two narrow linewidth (< 1.5 MHz) Raman fiber amplifiers with a Mach-Zehnder interferometer scheme and frequency doubling in an external resonant cavity with an efficiency of 86%. The results demonstrate the narrow linewidth Raman fiber amplifier technology as a promising solution for developing laser for sodium laser guide star adaptive optics. PMID:20372636

  12. Laser induced fluorescence (LIF) of Hg2 and Hg3 via dissociation of HgBr2 at 157 nm

    NASA Astrophysics Data System (ADS)

    Skordoulis, C.; Sarantopoulou, E.; Spyrou, S. M.; Kosmidis, C.; Cefalas, A. C.

    1991-06-01

    Laser induced fluorescence of the mercury clusters Hg2 and Hg3 in the spectral range between 300 nm to 510 nm has been obtained from the dissociation of HgBr2 at 7.88 eV (157.5 nm) with an F2 molecular laser, together with fluorescence from mercury atomic transitions from highly excited states. The excitation process involves two photon absorption which dissociates the molecule at 15.76 eV total photon energy with the subsequent formation of the metallic clusters.

  13. Fiber-laser pumped actively Q-switched Er:LuYAG laser at 1648 nm

    NASA Astrophysics Data System (ADS)

    Yang, X. F.; Wang, Y.; Zhao, T.; Zhu, H. Y.; Shen, D. Y.

    2016-02-01

    We demonstrated an acousto-optic Q-switched 1648 nm Er:LuYAG laser resonantly pumped by a cladding-pumped Er,Yb fiber laser at 1532 nm. Stable Q-switching operation was obtained with the pulse repetition rate (PRR) varying from 200 Hz to 10 kHz. At PRR of 200 Hz, the laser yielded Q-switched pulses with 3.3 mJ pulse energy and 65 ns pulse duration, corresponding to a peak power of 50.7 kW for 10.4 W of incident pump power.

  14. Study on the Pr:KYF ultraviolet laser at 305 nm pumped by blue laser

    NASA Astrophysics Data System (ADS)

    Ni, Tian-yi; Li, Yong-liang; Zhang, Tian-yi; Ruan, Ren-qiu

    2012-09-01

    An all-solid-state Pr:KY3F10 (Pr:KYF) laser pumped by blue laser (471 nm) has been demonstrated. With the incident pump power of 2.6 W, the maximum output power at 610 nm is 213 mW. Moreover, the intracavity second-harmonic generation (SHG) is also achieved with the maximum ultraviolet (UV) power at 305 nm of 11 mW by using a β-BaB2O4 (BBO) nonlinear crystal.

  15. Optical trapping and cooling of 87Rb with a 1550 nm fiber laser

    NASA Astrophysics Data System (ADS)

    Olson, Abraham; Wang, Ping; Niffenegger, Robert; Ma, Qianli; Chen, Yong P.

    2011-05-01

    We have investigated optical trapping and cooling of 87Rb with a 1550nm single-frequency, fiber laser. We present a technique to map out the 3D spatial intensity profile of an optical dipole trap by imaging a background, untrapped cold atomic cloud. The 1550 nm laser causes a strong AC Stark shift [1] of the excited state (5P3/2) of 87Rb which we image by driving the D2 transition. Such Stark tomography allows us to use an untrapped cloud of 87Rb to characterize the potential trap depth, beam waist, trapping frequency, beam quality factor (M2), and astigmatism of the trap beam. We also investigated schemes for all-optical evaporative cooling of trapped atoms to quantum degeneracy.

  16. Next-generation 193-nm laser for sub-100-nm lithography

    NASA Astrophysics Data System (ADS)

    Duffey, Thomas P.; Blumenstock, Gerry M.; Fleurov, Vladimir B.; Pan, Xiaojiang; Newman, Peter C.; Glatzel, Holger; Watson, Tom A.; Erxmeyer, J.; Kuschnereit, Ralf; Weigl, Bernhard

    2001-09-01

    The next generation 193 nm (ArF) laser has been designed and developed for high-volume production lithography. The NanoLithTM 7000, offering 20 Watts average output power at 4 kHz repetition rates is designed to support the highest exposure tool scan speeds for maximum productivity and wafer throughput. Fundamental design changes made to the laser core technologies are described. These advancements in core technology support the delivery of highly line-narrowed light with

  17. 650 nm Laser stimulated dating from Side Antique Theatre, Turkey

    NASA Astrophysics Data System (ADS)

    Doğan, M.; Meriç, N.

    2014-03-01

    Samples were taken from the archeological excavation site, which was at the backs of the Side Antique Theatre. Samples were taken from under the base rock in this area. Polymineral fine grains were examined to determine the ages of the sediments. Samples gathered from the Side Antique Theatre were investigated through using the SAR method. Firstly, one part of the samples were evaluated by using conventional IRSL reading head model of (ELSEC-9010) which is infrared (880±80 nm) stimulation source with Schott BG39 filter. The IRSL age dating with feldspar minerals, gives a number of overestimated or underestimated age values as a result. A new reading head was proposed with the following configuration attachments for overestimation of equivalent dose rates. Measurements were done with this newly designed red laser stimulating reading head which works with Elsec 9010 OSL age dating system. SAR measurements were performed by (650±10 nm) red laser light source with two Schott BG3 filters. With usage of the new designed reading head; closer results were obtained in comparision with the Antique Theatre's expected age range. Fading rates were taken into consideration and these corrections were also handled for true age results.

  18. The study of laser beam riding guided system based on 980nm diode laser

    NASA Astrophysics Data System (ADS)

    Qu, Zhou; Xu, Haifeng; Sui, Xin; Yang, Kun

    2015-10-01

    With the development of science and technology, precision-strike weapons has been considered to be important for winning victory in military field. Laser guidance is a major method to execute precision-strike in modern warfare. At present, the problems of primary stage of Laser guidance has been solved with endeavors of countries. Several technical aspects of laser-beam riding guided system have been mature, such as atmosphere penetration of laser beam, clutter inhibition on ground, laser irradiator, encoding and decoding of laser beam. Further, laser beam quality, equal output power and atmospheric transmission properties are qualified for warfare situation. Riding guidance instrument is a crucial element of Laser-beam riding guided system, and is also a vital element of airborne, vehicle-mounted and individual weapon. The optical system mainly consist of sighting module and laser-beam guided module. Photoelectric detector is the most important sensing device of seeker, and also the key to acquire the coordinate information of target space. Currently, in consideration of the 1.06 u m of wavelength applied in all the semi-active laser guided weapons systems, lithium drifting silicon photodiode which is sensitive to 1.06 u m of wavelength is used in photoelectric detector. Compared to Solid and gas laser, diode laser has many merits such as small volume, simple construction, light weight, long life, low lost and easy modulation. This article introduced the composition and operating principle of Laser-beam riding guided system based on 980 nm diode laser, and made a analysis of key technology; for instance, laser irradiator, modulating disk of component, laser zooming system. Through the use of laser diode, Laser-beam riding guided system is likely to have smaller shape and very light.

  19. 1 W of 261 nm cw generation in a Pr 3+:LiYF 4 laser pumped by an optically pumped semiconductor laser at 479 nm

    NASA Astrophysics Data System (ADS)

    Ostroumov, Vasiliy; Seelert, Wolf

    2008-02-01

    The lack of blue pump sources for Pr-doped materials has been overcome with the recent progress in optically pumped semiconductor lasers (OPS) operating at 479 nm. The availability of reliable high power OPS pump lasers, makes Pr 3+-doped crystals ideal gain media for compact and efficient ultraviolet solid-state lasers with output power in the Watt range. We report on the scalability of a 522/261 nm Pr:YLF cw laser that is dual-end-pumped by two OPS lasers at 479 nm. At 9.6 W of incident pump power more than 4 W were obtained at 522 nm with a slope efficiency of 45%. Intracavity frequency doubling of 522 nm resulted in 1 Watt of cw UV output at 261 nm.

  20. Laser stabilization at 1536 nm using regenerative spectral hole burning

    NASA Astrophysics Data System (ADS)

    Sellin, P. B.; Strickland, N. M.; Böttger, T.; Carlsten, J. L.; Cone, R. L.

    2001-04-01

    Laser frequency stabilization giving a 500-Hz Allan deviation for a 2-ms integration time with drift reduced to 7 kHz/min over several minutes was achieved at 1536 nm in the optical communication band. A continuously regenerated spectral hole in the inhomogeneously broadened 4I15/2(1)-->4I13/2(1) optical absorption of an Er3+:Y2SiO5 crystal was used as the short-term frequency reference, while a variation on the locking technique allowed simultaneous use of the inhomogeneously broadened absorption line as a long-term reference. The reported frequency stability was achieved without vibration isolation. Spectral hole burning frequency stabilization provides ideal laser sources for high-resolution spectroscopy, real-time optical signal processing, and a range of applications requiring ultra-narrow-band light sources or coherent detection; the time scale for stability and the compatibility with spectral hole burning devices make this technique complementary to other frequency references for laser stabilization.

  1. Effects of 810 nm laser on mouse primary cortical neurons

    NASA Astrophysics Data System (ADS)

    Kharkwal, Gitika B.; Sharma, Sulbha K.; Huang, Ying-Ying; De Taboada, Luis; McCarthy, Thomas; Hamblin, Michael R.

    2011-03-01

    In the past four decades numerous studies have reported the efficacy of low level light (laser) therapy (LLLT) as a treatment for diverse diseases and injuries. Recent studies have shown that LLLT can biomodulate processes in the central nervous system and has been extensively studied as a stroke treatment. However there is still a lack of knowledge on the effects of LLLT at the cellular level in neurons. The present study aimed to study the effect of 810 nm laser on several cellular processes in primary cortical neurons cultured from mouse embryonic brains. Neurons were irradiated with light dose of 0.03, 0.3, 3, 10 and 30 J/cm2 and intracellular levels of reactive oxygen species, nitric oxide and calcium were measured. The changes in mitochondrial function in response to light were studied in terms of adenosine triphosphate (ATP) and mitochondrial membrane potential (MMP). Light induced a significant increase in calcium, ATP and MMP at lower fluences and a decrease at higher fluence. ROS was induced significantly by light at all light doses. Nitric oxide levels also showed an increase on treatment with light. The results of the present study suggest that LLLT at lower fluences is capable of inducing mediators of cell signaling process which in turn may be responsible for the biomodulatory effects of the low level laser. At higher fluences beneficial mediators are reduced but potentially harmful mediators are increased thus offering an explanation for the biphasic dose response.

  2. Magnetoelastically induced magnetic anisotropy transition in [CoO5nm/CoPt7nm]5 multilayer films

    NASA Astrophysics Data System (ADS)

    Guo, Lei; Harumoto, Takashi; Sannomiya, Takumi; Muraishi, Shinji; Nakamura, Yoshio; Shi, Ji

    2016-06-01

    The magnetic anisotropy transition of [CoO5nm/CoPt7nm]5 multilayer film with respect to post-annealing has been studied systematically. It undergoes a smooth transition from longitudinal magnetic anisotropy (LMA) to perpendicular magnetic anisotropy (PMA) upon annealing and returns backward to LMA at high temperature of 550 °C. The strongest PMA of [CoO5nm/CoPt7nm]5 is achieved after post-annealing at 300 °C and the tolerable post-annealing temperature with strong PMA is up to 400 °C, which indicates this multilayer film could be a potential candidate for the PMA application at middle-high-temperature-region between 300 °C and 400 °C. The mechanism responsible for the transition of magnetic anisotropy has been investigated by analyzing CoO/CoPt interface and CoPt layer internal stress. It is found the effective PMA energy is proportional to the in-plane tensile stress of CoPt layer but is inversely proportional to the roughness of CoO/CoPt interface. Finally, by means of low temperature experiment we demonstrate the magnetic anisotropy transition observed in [CoO5nm/CoPt7nm]5 multilayer film is mainly attributed to the change of CoPt layer in-plane tensile stress.

  3. A 1.5-W frequency doubled semiconductor disk laser tunable over 40 nm at around 745 nm

    NASA Astrophysics Data System (ADS)

    Saarinen, Esa J.; Lyytikäinen, Jari; Ranta, Sanna; Rantamäki, Antti; Saarela, Antti; Sirbu, Alexei; Iakovlev, Vladimir; Kapon, Eli; Okhotnikov, Oleg G.

    2016-03-01

    We report on a semiconductor disk laser emitting 1.5 W of output power at the wavelength of 745 nm via intracavity frequency doubling. The high power level and the < 40 nm tuning range make the laser a promising tool for medical treatments that rely on photosensitizing agents and biomarkers in the transmission window of tissue between 700 and 800 nm. The InP-based gain structure of the laser was wafer-fused with a GaAs-based bottom mirror and thermally managed with an intracavity diamond heat spreader. The structure was pumped with commercial low-cost 980 nm laser diode modules. Laser emission at 1490 nm was frequency-doubled with a bismuth borate crystal that was cut for type I critical phase matching. At the maximum output power, we achieved an optical-to-optical efficiency of 8.3% with beam quality parameter M2 below 1.5. The laser wavelength could be tuned with an intracavity birefringent plate from 720 to 764 nm.

  4. Coherence measurements of a transient 14.7-nm x-ray laser

    NASA Astrophysics Data System (ADS)

    Dunn, James; Smith, Raymond F.; Hubert, Sebastian; Fajardo, Marta; Zeitoun, Philippe; Hunter, James R.; Remond, Christian; Vanbostal, Laurent; Jacquemot, Sylvie; Nilsen, Joseph; Lewis, Ciaran L. S.; Marmoret, Remy; Shlyaptsev, Vyacheslav N.; Ravet, Marie-Francoise; Delmotte, Franck

    2003-12-01

    We present the longitudinal coherence measurement of the transient inversion collisional x-ray laser for the first time. The Ni-like Pd x-ray laser at 14.68 nm is generated by the LLNL COMET laser facility and is operating in the gain-saturated regime. Interference fringes are produced using a Michelson interferometer setup in which a thin multilayer-coated membrane is used as a beam splitter. The longitudinal coherence length for the picosecond duration 4d1S0 --> 4p1P1 lasing transition is determined to be ~400 µm (1/e HW) by adjusting the length of one interferometer arm and measuring the resultant variation in fringe visibility. This is four times improved coherence than previous measurements on quasi-steady state schemes largely as a result of the narrower line profile in the lower temperature plasma. The inferred gain-narrowed linewidth of ~0.29 pm is also substantially narrower than previous measurements on quasi-steady state x-ray laser schemes. This study shows that the coherence of the x-ray laser beam can be improved by changing the laser pumping conditions. The x-ray laser is operating at 4 5 times the transform-limited pulse.

  5. Continuous wave laser generation at 1064 nm in femtosecond laser inscribed Nd:YVO4 channel waveguides

    NASA Astrophysics Data System (ADS)

    Tan, Yang; Chen, Feng; Vázquez de Aldana, J. R.; Torchia, G. A.; Benayas, A.; Jaque, D.

    2010-07-01

    We report on continuous wave 1064 nm laser generation from an ultrafast laser inscribed neodymium-doped yttrium orthovanadate channel waveguide with pumping at 808 nm. Single-mode stable laser operations have been observed with pump powers at threshold as low as 14 mW and with laser slope efficiencies as high as 38.7%.

  6. Comparison of 1470nm laser and 1470nm laser heat head for ex-vivo kidney tissue cutting: a preliminary study

    NASA Astrophysics Data System (ADS)

    Zhou, Zhentian; Zhang, Lupeng; Liu, Jiafeng; Shun, Zhi; Li, Wenzhi; Liu, Zhuwen; Liang, Zhiyuan

    2014-11-01

    Purpose: Compare of the efficiency of 1470nm laser and 1470nm laser heat head for tissue cutting in vitro porcine kidney tissue . Method: We designed a laser heat head that convert laser energy into thermal energy by the absorbing materials. Fresh kidney tissue was harvested from a porcine and then placed on a turntable with constant speed . The same power of 1470nm laser and 1470nm laser heat head was used to cutting tissue, respectively .The cutting results and the range of thermal damage was compared after cutting . Result: Compared with 1470nm laser, 1470nm laser heat head's cutting traces is more smooth and the thermal damage area is very regular ,so it has smaller damage to deep tissue . Conclusion: The efficiency of laser heat head for tissue cutting was better. This study indicate that we might be able to make laser which the tissue have a low absorption coefficient about it to obtain good results for tissue cutting through the laser point heat source.

  7. Temperature dependence of quasi-three level laser transition for long pulse Nd:YAG laser

    NASA Astrophysics Data System (ADS)

    Bidin, Noriah; Pourmand, Seyed Ebrahim; Sidi Ahmad, Muhamad Fakaruddin; Khrisnan, Ganesan; Mohd Taib, Nur Athirah; Nadia Adnan, Nurul; Bakhtiar, Hazri

    2013-02-01

    The influence of temperature and pumping energy on stimulated emission cross section and the laser output of quasi-three level laser transition are reported. Flashlamp is used to pump Nd:YAG laser rod. Distilled water is mixed with ethylene glycol to vary the temperature of the cooling system between -30 and 60 °C. The capacitor voltage of flashlamp driver is verified to manipulate the input energy within the range of 10-70 J. The line of interest in quasi-three level laser comprised of 938.5 and 946 nm. The stimulated emission cross section of both lines is found to be inversely proportional to the temperature but directly proportional to the input energy. This is attributed from thermal broadening effect. The changes of stimulated emission cross section and the output laser with respect to the temperature and input energy on line 946 nm are realized to be more dominant in comparison to 938.5 nm.

  8. Diode-laser-pumped tunable 896-939.5-nm neodymium-doped fiber laser with 43-mW output power.

    PubMed

    Cook, A L; Hendricks, H D

    1998-05-20

    A diode-laser-pumped neodymium-doped fiber laser is presented. For a launched pump power of 85 mW, the fiber laser had a cw output power of 43 mW, which is approximately an order of magnitude greater output power than any previously reported diode-pumped neodymium fiber laser operating on the 4F(3/2)-4I(9/2) transition, which covers the 900-950-nm region. The fiber laser had a threshold power of 10 mW and a slope efficiency of 58% with respect to launched pump power. Tuning with a diffraction grating was obtained from 896 to 937 nm with narrow-band output powers as high as 32 mW. Emission was also obtained at 939.5 nm with use of a fiber Bragg grating as the output reflector. PMID:18273282

  9. Diode laser pumped blue-light source at 473 nm using intracavity frequency doubling of a 946 nm Nd:YAG laser

    SciTech Connect

    Risk, W.P.; Pon, R.; Lenth, W.

    1989-04-24

    Using intracavity frequency doubling of a diode laser pumped 946 nm Nd:YAG laser, 3.1 mW of blue output power at 473 nm was obtained. Angle-tuned, type-I frequency doubling in potassium niobate was employed, and both the KNbO/sub 3/ and Nd:YAG crystals were used at room temperature.

  10. Laser Direct Writing of Long Period Fiber Grating by 800 NM Femtosecond Laser Pulses

    NASA Astrophysics Data System (ADS)

    Ruan, Shuangchen; Huang, Yi; Du, Chenlin; Yu, Yongqin

    Femtosecond laser pulses with ultrashort time duration and ultrahigh peak power can cause the refractive index change in transparent materials and micron scale machining precision. Long period fiber gratings (LPFGs) with different periods and different grating lengths in the standard single mode fiber were fabricated, using laser direct writing method, by femtosecond laser pulses with pulse width of 200 fs at a center wavelength of 800 nm in air. The transmission spectra were studied in the range of 1510 nm to 1610 nm. Two LPFGs with period of 400 μm, and 550 μm, respectively fabricated with same irradiation power of 275 mW, were shown. The loss peak of 1552 nm, the transmission loss of 16 dB and the FWHM of 20 nm were obtained when the period of LPFG was 400 μm, while the loss peak of 1588 nm, the transmission loss of 20 dB and the FWHM of 25 nm were achieved when the period of LPFG was 550 μm. According to the theory of mode field coupling for long period grating, it was indicated that the modulation of refractive index Δn was in the level of 10-2.

  11. Al-free active region laser diodes at 894 nm for compact Cesium atomic clocks

    NASA Astrophysics Data System (ADS)

    Von Bandel, N.; Bébé Manga Lobé, J.; Garcia, M.; Larrue, A.; Robert, Y.; Vinet, E.; Lecomte, M.; Drisse, O.; Parillaud, O.; Krakowski, M.

    2015-03-01

    Time-frequency applications are in need of high accuracy and high stability clocks. Compact industrial Cesium atomic clocks optically pumped is a promising area that could satisfy these demands. However, the stability of these clocks relies, among others, on the performances of laser diodes that are used for atomic pumping. This issue has led the III-V Lab to commit to the European Euripides-LAMA project that aims to provide competitive compact optical Cesium clocks for earth applications. This work will provide key experience for further space technology qualification. We are in charge of the design, fabrication and reliability of Distributed-Feedback diodes (DFB) at 894nm (D1 line of Cesium) and 852nm (D2 line). The use of D1 line for pumping will provide simplified clock architecture compared to D2 line pumping thanks to simpler atomic transitions and larger spectral separation between lines in the 894nm case. Also, D1 line pumping overcomes the issue of unpumped "dark states" that occur with D2 line. The modules should provide narrow linewidth (<1MHz), very good reliability in time and, crucially, be insensitive to optical feedback. The development of the 894nm wavelength is grounded on our previous results for 852nm DFB. Thus, we show our first results from Al-free active region with InGaAsP quantum well broad-area lasers (100μm width, with lengths ranging from 2mm to 4mm), for further DFB operation at 894nm. We obtained low internal losses below 2cm-1, the external differential efficiency is 0.49W/A with uncoated facets and a low threshold current density of 190A/cm², for 2mm lasers at 20°C.

  12. Diode pumped Nd:Lu0.5Y0.5VO4-LBO red laser at 671 nm

    NASA Astrophysics Data System (ADS)

    Li, Y. L.; Liu, J. Y.; Zhang, Y. C.

    2012-03-01

    We report a efficient compact red laser at 671 nm generation by intracavity frequency doubling of a continuous wave laser operation of a diode pumped Nd:Lu0.5Y0.5VO4 laser on the 4 F 3/2-4 I 13/2 transition at 1342 nm. An LBO crystal, cut for critical type I phase matching at room temperature is used for second harmonic generation of the laser. At an absorbed pump power of 17.8 W, as high as 2.25 W of continuous wave output power at 671 nm is achieved with 10-mm-long LBO. The optical-to-optical conversion efficiency is up to 12.6%, and the fluctuation of the red output power was better than 3.6% in the given 30 min.

  13. 8.3 W diode-end-pumped continuous-wave Nd:YAG laser operating at 946-nm.

    PubMed

    Zhou, Rui; Zhang, Tieli; Li, Enbang; Ding, Xin; Cai, Zhiqiang; Zhang, Baigang; Wen, Wuqi; Wang, Peng; Yao, Jianquan

    2005-12-12

    This paper reports a diode-end-pumped continuous-wave (CW) Nd:YAG laser operating at 946-nm by utilizing the 4F3/2-4I9/2 transition. We demonstrated that at an incident pump power of 27.7 W, an output power of 8.3-W could be achieved with a slope efficiency of 33.5%. To the best of our knowledge, this is the highest CW output power at 946 nm generated by LD end-pumped Nd:YAG lasers. By using intracavity frequency doubling with an LBO crystal, we further obtained a 473-nm blue laser with an output power of 1.2 W, achieving an optical-to-optical conversion efficiency of 7.1% at a pump power of 16.9 W. The short-term power instability of the blue laser was less than 1 %. PMID:19503225

  14. 750 nm 1.5 W frequency-doubled semiconductor disk laser with a 44 nm tuning range.

    PubMed

    Saarinen, Esa J; Lyytikäinen, Jari; Ranta, Sanna; Rantamäki, Antti; Sirbu, Alexei; Iakovlev, Vladimir; Kapon, Eli; Okhotnikov, Oleg G

    2015-10-01

    We demonstrate 1.5 W of output power at the wavelength of 750 nm by intracavity frequency doubling a wafer-fused semiconductor disk laser diode-pumped at 980 nm. An optical-to-optical efficiency of 8.3% was achieved using a bismuth borate crystal. The wavelength of the doubled emission could be tuned from 720 to 764 nm with an intracavity birefringent plate. The beam quality parameter M2 of the laser output was measured to be below 1.5 at all pump powers. The laser is a promising tool for biomedical applications that can take advantage of the large penetration depth of light in tissue in the 700-800 nm spectral range. PMID:26421536

  15. 954 nm Raman fiber laser with multimode laser diode pumping

    NASA Astrophysics Data System (ADS)

    Zlobina, E. A.; Kablukov, S. I.; Skvortsov, M. I.; Nemov, I. N.; Babin, S. A.

    2016-03-01

    CW Raman fiber laser emitting at 954 nm under direct pumping by a high-power multimode laser diode at 915 nm is demonstrated. A cavity of the laser is formed with 2.5 km-long multimode graded-index fiber and two mirrors: highly reflective fiber Bragg grating (FBG) at one side and normally cleaved fiber end at the other side. The laser generates low-index transverse modes at the Stokes wavelength with output power above 4 W at a slope efficiency above 40%. It is shown that utilization of a narrowband FBG mirror with low reflectivity instead of the cleaved fiber end with Fresnel reflection leads to stronger spectral mode selection, but the generated power is reduced in this case.

  16. Demonstration of a 100 Hz Repetition Rate Soft X-Ray Laser and Gain-Saturated Sub-10 nm Table-Top Lasers

    NASA Astrophysics Data System (ADS)

    Rocca, J. J.; Reagan, B. A.; Wang, Y.; Alessi, D.; Wernsing, K.; Luther, B. M.; Curtis, M. A.; Berrill, M.; Martz, D.; Wang, S.; Yin, L.; Furch, F.; Woolston, M.; Patel, D.; Shlyaptsev, V. N.; Menoni, C. S.

    We report the first operation of a table-top soft x-ray laser at 100 Hz repetition rate. This gain saturated laser produces 0.15 mW average power in the 18.9 nm line of nickel-like molybdenum in the form of 1.5 μJ pulses. This is the highest average power reported to date from a compact coherent soft x-ray laser source operating at wavelengths shorter than 20 nm. The soft x-ray laser is excited by a diode-pumped chirped pulse amplification Yb:YAG laser that produces 1 J pulses of 5 ps duration. We have also demonstrated the efficient generation of sub-9 nm wavelength laser pulses of microjoule energy at 1 Hz repetition rate with a table-top laser. Gain-saturated lasing was obtained at 8.85 nm in nickel-like lanthanum ions. Isoelectronic scaling along the lanthanide series resulted in lasing at wavelengths as short as 7.36 nm. Simulations show that the collisionally broadened atomic transitions in these dense plasmas can support the amplification of sub-picosecond soft x-ray laser pulses.

  17. Analysis of laser produced plasmas of gold in the 1-7 nm region

    NASA Astrophysics Data System (ADS)

    Li, Bowen; Higashiguchi, Takeshi; Otsuka, Takamitsu; Yugami, Noboru; Dunne, Padraig; Kilbane, Deirdre; Sokell, Emma; O'Sullivan, Gerry

    2014-04-01

    Extreme ultraviolet (EUV) spectra from gold laser produced plasmas were recorded in the 1-7 nm region using two Nd:YAG lasers with pulse lengths of 150 ps and 10 ns, respectively, operating at a range of power densities. The maximum focused peak power density was 9.5 × 1013 W cm-2 for the former and 5.3 × 1012 W cm-2 for the latter. Two intense quasicontinuous intensity bands resulting from n = 4-n = 4 and n = 4-n = 5 unresolved transition arrays dominate the 4-5.5 and 1.5-3.6 nm regions of both spectra. Comparison with atomic structure calculations performed with the Cowan suite of atomic structure codes as well as consideration of previous experimental and theoretical results aided identification of the most prominent features in the spectra. For the ns spectrum, the highest ion stage that could be identified from the n = 4-n = 5 arrays was Au28+ while for the ps plasma the presence of significantly higher stages was deduced and lines due to 4d104f-4d94f2 transitions in Ag-like Au32+ give rise to the strongest observed features within the n = 4-n = 4 array while in the n = 4-n = 5 array it was possible to identify a number of previously unidentified spectral features as resulting from 4f-5g transitions in the spectra of Au XX to Au XXXIII.

  18. Room-temperature diode-bar-pumped Nd:YAG laser at 946 nm

    SciTech Connect

    Clarkson, W.A.; Koch, R.; Hanna, D.C.

    1996-05-01

    Efficient, high-power operation of a diode-bar-pumped Nd:YAG laser on the quasi-three-level transition at 946 nm is reported. Longitudinal pumping of a simple folded cavity by a 20-W diode bar, with a two-mirror beam shaper used to reformat the bar{close_quote}s output, yields a continuous-wave output power at room temperature of {approximately}3W in a 1.5-times diffraction-limited beam for 13.6 W of incident pump power. The corresponding optical slope efficiency was approximately 33{percent}. {copyright} {ital 1996 Optical Society of America.}

  19. Stable, high-power, single-frequency generation at 532 nm from a diode-bar-pumped Nd:YAG ring laser with an intracavity LBO frequency doubler.

    PubMed

    Martin, K I; Clarkson, W A; Hanna, D C

    1997-06-20

    We obtained 2.5 W of single-frequency TEM(00) output at 532 nm using a Brewster-angled LBO crystal for intracavity second-harmonic generation in a diode-bar-pumped Nd:YAG laser. By inserting a thin uncoated étalon, the 1061.4-nm laser transition can be selected, generating 1.6 W of output at 530.7 nm. PMID:18253441

  20. 32.8-nm X-ray laser produced in a krypton cluster jet

    SciTech Connect

    Ivanova, E P; Vinokhodov, A Yu

    2013-12-31

    We have interpreted the well-known experimental quantum yield data for a 32.8-nm X-ray laser operating at the 3d{sup 9}4d (J = 0) – 3d{sup 9}4p (J = 1) transition of Kr{sup 8+} with the use of gaseous krypton or a krypton cluster jet. Proceeding from our model we propose a novel scheme for the 32.8-nm laser produced in a krypton cluster jet. The quantum yield is shown to saturate for a plasma length of ∼300 μm, a krypton ion density n{sub Kr} ∼ (4 – 9) × 10{sup 19} cm{sup -3}, and an electron temperature Te ∼ 5000 eV. In this case, the energy conversion coefficient amounts to ∼5 × 10{sup -3} of the pump pulse energy. We propose the experimental setup for producing a highefficiency subpicosecond X-ray laser in a krypton cluster jet. (lasers)

  1. Q -switched laser at 912 nm using ground-state-depleted neodymium in yttrium orthosilicate

    SciTech Connect

    Beach, R.; Albrecht, G.; Solarz, R.; Krupke, W.; Comaskey, B.; Mitchell, S. ); Brandle, C.; Berkstresser, G. )

    1990-09-15

    A ground-state-depleted laser is demonstrated in the form of a {ital Q}-switched oscillator operating at 912 nm. By using Nd{sup 3+} as the active ion and Y{sub 2}SiO{sub 5} as the host material, the laser transition is from the lowest-lying Stark level of the Nd{sup 3+} {sup 4}{ital F}{sub 3/2} level to a Stark level 355 cm{sup {minus}1} above the lowest-lying one in the {sup 4}{ital I}{sub 9/2} manifold. The necessity of depleting the ground {sup 4}{ital I}{sub 9/2} manifold is evident for this level scheme as transparency requires a 10% inversion. To achieve the high excitation levels required for the efficient operation of this laser, bleach-wave pumping using an alexandrite laser at 745 nm has been employed. With KNbO{sub 3}, noncritical phase matching is possible at 140{degree} C using {ital d}{sub 32} and is demonstrated.

  2. 1319 nm and 1356 nm dual-wavelength operation of diode-side-pumped Nd:YAG laser

    NASA Astrophysics Data System (ADS)

    Chen, Ming; Wang, Zhi-chao; Zhang, Shen-jin; Yang, Feng; Zhang, Feng-feng; Yuan, Lei; He, Miao; Li, Jia-jia; Zhang, Xiao-wen; Zong, Nan; Wang, Zhi-min; Bo, Yong; Peng, Qin-jun; Cui, Da-fu; Xu, Zu-yan

    2016-05-01

    We report the first demonstration on a diode-side-pumped quasi continuous wave (QCW) dual-wavelength Nd:YAG laser operating at 1319 nm and 1356 nm. The resonator adopts symmetrical L-shaped flat-flat structure working in a thermally near unstable cavity. By precise coating on the cavity mirrors, the simultaneous oscillation at 1319 nm and 1356 nm is delivered. A maximum dual-wavelength output power of 9.4 W is obtained. The beam quality factor M2 is measured to be 1.9.

  3. Electro-optically Q-switched dual-wavelength Nd:YLF laser emitting at 1047 nm and 1053 nm

    NASA Astrophysics Data System (ADS)

    Men, Shaojie; Liu, Zhaojun; Cong, Zhenhua; Li, Yongfu; Zhang, Xingyu

    2015-05-01

    A flash-lamp pumped electro-optically Q-switched dual-wavelength Nd:YLF laser is demonstrated. Two Nd:YLF crystals placed in two cavities are employed to generate orthogonally polarized 1047 nm and 1053 nm radiations, respectively. The two cavities are jointed together by a polarizer and share the same electro-optical Q-switch. Two narrow-band pass filters are used to block unexpected oscillations at the hold-off state of the electro-optical Q-switch. In this case, electro-optical Q-switching is able to operate successfully. With pulse synchronization realized, the maximum output energy of 66.2 mJ and 83.9 mJ are obtained for 1047 nm and 1053 nm lasers, respectively. Correspondingly, the minimum pulse width is both 17 ns for 1047 nm and 1053 nm lasers. Sum frequency generation is realized. This demonstrates the potential of this laser in difference-frequency generations to obtain terahertz wave.

  4. All-solid-state continuous-wave frequency doubling Nd:LuVO4/LBO laser with 9.6 W output power at 672 nm

    NASA Astrophysics Data System (ADS)

    Li, B.; Zhao, L.; Zhang, Y. B.; Zheng, Q.; Zhao, Y.; Yao, Y.

    2012-12-01

    An efficient and compact red laser at 672 nm is generated by intracavity frequency doubling of a continuous wave (CW) laser operation of a diode pumped Nd:LuVO4 laser at 1344 nm under the condition of suppression the higher gain transition near 1064 nm. With 38 W diode pump power and a frequency doubling crystal LBO, as high as 9.6 W of CW output power at 672 nm is achieved, corresponding to an optical-to-optical conversion efficiency of 25.3% and the output power stability in 8 h is better than 2.38%. To the best of our knowledge, this it the highest conversion efficiency of watt-level laser at 672 nm generated by intracavity frequency doubling of a diode pumped Nd:LuVO4 laser at 1344 nm.

  5. All-solid-state continuous-wave frequency doubling Nd:LuVO4/LBO laser with 9.6 W output power at 458 nm

    NASA Astrophysics Data System (ADS)

    Li, B.; Zhao, L.; Zhang, Y. B.; Zheng, Q.; Zhao, Y.; Yao, Y.

    2013-02-01

    An efficient and compact red laser at 458 nm is generated by intracavity frequency doubling of a continuous wave (CW) laser operation of a diode pumped Nd:LuVO4 laser at 916 nm under the condition of suppression the higher gain transition near 1064 nm. With 30 W diode pump power and a frequency doubling crystal LBO, as high as 9.6 W of CW output power at 458 nm is achieved, corresponding to an optical-to-optical conversion efficiency of 32.0% and the output power stability in 8 hours is better than 2.35%. To the best of our knowledge, this it the highest conversion efficiency of watt-level laser at 458 nm generated by intracavity frequency doubling of a diode pumped Nd:LuVO4 laser at 916 nm.

  6. High power 1018 nm monolithic Yb3+-doped fiber laser and amplifier High power 1018 nm monolithic Yb3+-doped fiber laser and amplifier

    NASA Astrophysics Data System (ADS)

    Xiao, H.; Zhou, P.; Wang, X. L.; Guo, S. F.; Xu, X. J.

    2012-10-01

    In this letter high power monolithic 1018 nm fiber laser and amplifier are presented. The output characteristics of 1018 nm laser with amplified spontaneous emission (ASE) feedback, fiber Bragg gratings (FBG) reflectivity, gain fiber length and other parameters are experimentally investigated. The difference between 1018 and 1064 nm amplification are also compared in experiment. Based on these experimental results, we find viable approaches to improve the laser and amplifier's performances. 85 W 1018 nm fiber laser with a slope efficiency of 71% and 110 W 1018 nm fiber amplifier with the slope efficiency of 77% are achieved, both of which we believe are the highest output at this wavelength that ever reported in open detail.

  7. A diode-pumped Nd3+-doped gadolinium gallium garnet quasi-three-level laser at 933 nm

    NASA Astrophysics Data System (ADS)

    Liu, J. H.; Han, Y. H.; Zhao, Y. D.

    2013-11-01

    We report for the first time a Nd3+-doped gadolinium gallium garnet (Nd:GGG) laser operating on a quasi-three-level laser at 933 nm, based on the 4F3/2-4I9/2 transition. Continuous wave 691 mW output power at 933 nm is obtained under 10.2 W of incident pump power. Moreover, intracavity second-harmonic generation has also been achieved with a blue power of 89 mW by using a LiB3O5 (LBO) nonlinear crystal.

  8. 980-nm 14-pin butterfly module dual-channel CW QW semiconductor laser for pumping

    NASA Astrophysics Data System (ADS)

    Deng, Yun; Yan, Changling; Qu, Yi; Li, Hui; Wang, Yuxia; Gao, Xin; Qiao, Zhongliang; Li, Mei; Qu, Bowen; Lu, Peng; Bo, Baoxue

    2010-10-01

    Nowadays, with its mature progress, the 790 nm - 1000 nm wavelength semiconductor laser is widely used in the fields of laser machining, laser ranging, laser radar, laser imaging, laser anti-counterfeit, biomedical and etc. Best of all, the 980 nm wavelength laser has its widespread application in the pumping source of Er3+ -doped fiber amplifier, optic fiber gyroscopes and other devices. The output wavelength of the fiber amplifier which takes the 980 nm wavelength laser as its pumping source is between 1060 nm and 1550 nm. This type of laser has its extremely wide range of applications in optical communication and other fields. Moreover, some new application domains keep constantly being developed. The semiconductor laser with the dual-channel ridge wave guide and the 980 nm emission wavelength is presented in this paper. In our work, we fabricated Lasers with the using of multi-quantum well (MQW) wafer grew by MBE, and the PL-wavelength of the MQW was 970 nm. The standard photofabrication method and the inductively coupled plasma (ICP) etching technology are adopted in the process of making dual-channel ridge wave guide with the width of 4 μm and height of 830 nm. In the state of continuous work at room temperature, the laser could output the single mode beam of 70 mW stably under the current of 100 mA. The threshold current of the laser diode is 17 mA and the slope efficiency is 0.89 W/A. The 3 dB spectrum bandwidth of the laser beam is 0.2 nm. This laser outputs its beam by a pigtail fiber on which Bragg grating for frequency stabilization is carved. The laser diode, the tail fiber, and the built-in refrigeration and monitoring modules are sealed in a 14-pin butterfly packaging. It can be used directly as the pumping source of Er3+ - doped fiber amplifier or optic fiber gyroscopes.

  9. Phase transitions in femtosecond laser ablation

    NASA Astrophysics Data System (ADS)

    Povarnitsyn, Mikhail E.; Khishchenko, Konstantin V.; Levashov, Pavel R.

    2009-03-01

    In this study we simulate an interaction of femtosecond laser pulses (100 fs, 800 nm, 0.1-10 J/cm 2) with metal targets of Al, Au, Cu, and Ni. For analysis of laser-induced phase transitions, melting and shock waves propagation as well as material decomposition we use an Eulerian hydrocode in conjunction with a thermodynamically complete two-temperature equation of state with stable and metastable phases. Isochoric heating, material evaporation from the free surface of the target and fast propagation of the melting and shock waves are observed. On rarefaction the liquid phase becomes metastable and its lifetime is estimated using the theory of homogeneous nucleation. Mechanical spallation of the target material at high strain rates is also possible as a result of void growth and confluence. In our simulation several ablation mechanisms are taken into account but the main issue of the material is found to originate from the metastable liquid state. It can be decomposed either into a liquid-gas mixture in the vicinity of the critical point, or into droplets at high strain rates and negative pressure. The simulation results are in agreement with available experimental findings.

  10. Laser transit anemometer experiences in supersonic flow

    NASA Technical Reports Server (NTRS)

    Hunter, William W., Jr.; Humphreys, William M., Jr.

    1988-01-01

    The purpose of this paper is to present examples of velocity measurements obtained in supersonic flow fields with the laser transit anemometer system. Velocity measurements of a supersonic jet exhausting in a transonic flow field, a cone boundary survey in a Mach 4 flow field, and a determination of the periodic disturbance frequencies of a sonic nozzle flow field are presented. Each of the above three cases also serves to illustrate different modes of laser transit anemometer operation. A brief description of the laser transit anemometer system is also presented.

  11. Recent developments in Fourier domain mode locked lasers for optical coherence tomography: imaging at 1310 nm vs. 1550 nm wavelength.

    PubMed

    Biedermann, Benjamin R; Wieser, Wolfgang; Eigenwillig, Christoph M; Huber, Robert

    2009-07-01

    We report on recent progress in Fourier domain mode-locking (FDML) technology. The paper focuses on developments beyond pushing the speed of these laser sources. After an overview of improvements to FDML over the last three years, a brief analysis of OCT imaging using FDML lasers with different wavelengths is presented. For the first time, high speed, high quality FDML imaging at 1550 nm is presented and compared to a system at 1310 nm. The imaging results of human skin for both wavelengths are compared and analyzed. Sample arm optics, power on the sample, heterodyne gain, detection bandwidth, colour cut levels and sample location have been identical to identify the influence of difference in scattering and water absorption. The imaging performance at 1310 nm in human skin is only slightly better and the results suggest that water absorption only marginally affects the penetration depth in human skin at 1550 nm. For several applications this wavelength may be preferred. PMID:19565537

  12. Diode-pumped CW frequency-doubled Nd:GSAG-LBO blue laser at 471 nm

    NASA Astrophysics Data System (ADS)

    Li, Y. L.; Jiang, H. L.; Ni, T. Y.; Zhang, T. Y.; Tao, Z. H.; Zeng, Y. H.

    2011-04-01

    We describe the output performances of the 942 nm 4F3/2 → 4I9/2 transition in Nd:GSAG under diode-laser pumping. An end-pumped Nd:GSAG crystal yielded 3.7 W of continuous-wave output power for 17.8 W of absorbed pump power. The slope efficiency with respect to the absorbed pump power was 23.4%. Furthermore, with 17.8 W of diode pump power and the frequency-doubling crystal LiB3O5 (LBO), a maximum output power of 572 mW in the blue spectral range at 471 nm has been achieved, corresponding to an optical-to-optical conversion efficiency of 3.2%; the output power stability over 4 h is better than 4.1%.

  13. Diode-pumped quasi-three-level Nd:CLNGG laser at 928 nm

    NASA Astrophysics Data System (ADS)

    Li, Y. L.; Jiang, H. L.; Ni, T. Y.; Zhang, T. Y.; Tao, Z. H.; Zeng, Y. H.

    2011-04-01

    We describe the output performances of the 928 nm 4 F 3/2 → 4 I 9/2 transition in Nd:CLNGG under diode-laser pumping. An end-pumped Nd:CLNGG crystal yielded 1.3 W of continuous-wave output power for 17.8 W of absorbed pump power. The slope efficiency with respect to the absorbed pump power was 11.2%. Furthermore, with 17.8 W of diode pump power and the frequency-doubling crystal LiB3O5 (LBO), a maximum output power of 260 mW in the blue spectral range at 464 nm has been achieved. The blue output power stability over 4 h is better than 3.2%.

  14. Microdrilling of metals using femtosecond laser pulses and high average powers at 515 nm and 1030 nm

    NASA Astrophysics Data System (ADS)

    Döring, S.; Ancona, A.; Hädrich, S.; Limpert, J.; Nolte, S.; Tünnermann, A.

    2010-07-01

    We investigate the microdrilling of metals (stainless steel, copper and tungsten) for two different wavelengths, 1030 nm and 515 nm, in the regime of femtosecond laser pulses. An ytterbium-doped fibre CPA system provides high pulse energies (up to 70 μJ) and high repetition rates (up to 800 kHz), corresponding to high average powers of about 50 W, for this experimental study.

  15. Properties of continuous-wave 1123 nm laser with diode-side-pumped Nd:YAG

    NASA Astrophysics Data System (ADS)

    Bai, F.; Wang, Q. P.; Liu, Z. J.; Zhang, X. Y.; Sun, W. J.

    2010-11-01

    Laser properties of diode-side-pumped Nd:YAG laser operating at 1123 nm are demonstrated. A 1.0 at % Nd-doped Nd:YAG rod with a size of Ø3 × 63 mm2 is used as the active medium. Both radial and tangential thermal focal lengths of this side-pumped Nd:YAG rod are determined under lasing condition. The results show that the bifocusing strength of 1123 nm laser is larger than that of 1164 nm laser, and 1123-nm thermal focal lengths are shorter than those of 1064-nm laser due to higher quantum defect. Laser output performances of 1123 nm in terms of stability, output power and beam quality influenced by pump power at different cavity lengths are also discussed with a convex-piano cavity.

  16. Feasibility of a 486 nm Fraunhofer laser source based on a 4F(sub 3/2) yields 4I(sub 9/2) neodymium laser

    NASA Astrophysics Data System (ADS)

    Hanson, F. E.; Katz, D. L.; Poirier, P.

    1992-03-01

    The objective of this research was to investigate the potential of a laser source based on the neodymium (4)F(sub 3/2) (yields) (4)I(sub 9/2) transition for operation at 486.1 nm, the H(sub beta) Fraunhofer wavelength. We characterized this transition in Nd:YAG. Also, we identified stimulated rotational Raman conversion in H2, D2, and HD as a critical step in such a system.

  17. Nanobumps on silicon created with polystyrene spheres and 248 or 308 nm laser pulses

    SciTech Connect

    Piparia, Reema; Rothe, Erhard W.; Baird, R. J.

    2006-11-27

    Huang et al. [Appl. Phys. Lett. 86, 161911 (2005)] formed arrays of nanobumps on a silicon substrate. They applied a 248 nm laser pulse to a surface monolayer of 1-{mu}m-diameter polystyrene spheres. The authors first replicated their experiment with 248 nm light. But when 308 nm pulses were applied instead, the nanobumps had a different shape and composition. At 248 nm, much of the laser light is absorbed in the polystyrene, which serves to quickly distort, melt, and ablate the sphere. At 308 nm, very little light is absorbed. The nanobumps from 248 nm radiation are organic polymers, while those formed with 308 nm pulses are silicon based.

  18. Optically pumped gas laser using electronic transitions in the NaRb molecule

    SciTech Connect

    Kaslin, V.M.; Yakushev, O.F.

    1983-12-01

    Laser superradiance was achieved for the first time as a result of an electronic transition in a diatomic heteronuclear molecule as a result of direct optical pumping. This superradiance was observed in the region of 670 nm due to a transition to the ground state X/sup 1/..sigma../sup +/ of the intermetallic alkali molecule NaRb pumped by radiation from a pulsed copper vapor laser (lambda = 510.6 nm).

  19. Laser Ablation of Dental Calculus Around 400 nm Using a Ti:Sapphire Laser

    SciTech Connect

    Schoenly, J.; Seka, W.; Rechmann, P.

    2009-10-19

    A Nd:YAG laser-pumped, frequency-doubled Ti:sapphire laser is used for selective ablation of calculus. The laser provides ≤25 mJ at 400 nm (60-ns pulse width, 10-Hz repetition rate). The laser is coupled into an optical multimode fiber coiled around a 4-in.-diam drum to generate a top-hat output intensity profile. With coaxial water cooling, this is ideal for efficient, selective calculus removal. This is in stark contrast with tightly focused Gaussian beams that are energetically inefficient and lead to irreproducible results. Calculus is well ablated at high fluences ≥2 J/cm^2; stalling occurs below this fluence because of photobleaching. Healthy hard tissue is not removed at fluences ≤3 J/cm^2.

  20. Diode-pumped Yb:GSO-LBO laser at 544 nm

    NASA Astrophysics Data System (ADS)

    Wang, J. G.; Dong, Y.

    2011-12-01

    We report a green laser at 544 nm generation by intracavity frequency doubling of a continuous wave (CW) laser operation of a 1088 nm Yb:GSO laser under in-band diode pumping at 940 nm. An LiB3O5 (LBO) crystal, cut for critical type I phase matching at room temperature is used for second harmonic generation of the laser. At an incident pump power of 17.8 W, as high as 444 mW of CW output power at 544 nm is achieved. The fluctuation of the green output power was better than 4.6% in the given 4 h.

  1. Diode-pumped Nd:GAGG-LBO laser at 531 nm

    NASA Astrophysics Data System (ADS)

    Zou, J.; Chu, H.; Wang, L. R.

    2012-03-01

    We report a green laser at 531 nm generation by intracavity frequency doubling of a continuous wave (cw) laser operation of a 1062 nm Nd:GAGG laser under in-band diode pumping at 808 nm. A LiB3O5 (LBO) crystal, cut for critical type I phase matching at room temperature is used for second harmonic generation of the laser. At an incident pump power of 18.5 W, as high as 933 mW of cw output power at 531 nm is achieved. The fluctuation of the green output power was better than 3.5% in the given 4 h.

  2. Simultaneous Dual-Wavelength Operation of Nd-Doped Yttrium Orthovanadate Self-Raman Laser at 1175 nm and Undoped Gadolinium Orthovanadate Raman Laser at 1174 nm

    NASA Astrophysics Data System (ADS)

    Shen, Hongbin; Wang, Qingpu; Zhang, Xingyu; Zhang, Lei; Zhang, Chu; Chen, Xiaohan; Cong, Zhenhua; Bai, Fen; Liu, Zhaojun

    2013-04-01

    A diode-pumped actively Q-switched Nd-doped yttrium orthovanadate self-Raman emission at 1175 nm and undoped gadolinium orthovanadate Raman emission at 1174 nm dual-wavelength laser is demonstrated. With the pump power of 20.5 W and pulse repetition frequency of 20 kHz, the maximum dual-wavelength output power of 1.52 W was obtained, which contained a 0.71 W 1174 nm Raman laser component and a 0.81 W 1175 nm self-Raman laser component. The corresponding dual-wavelength Raman pulse width was 14.8 ns. Experimental results indicated that the dual-wavelength Raman laser with a small wavelength separation was effectively realized through simultaneous self-Raman and Raman shift.

  3. 83 W yellow—green laser at 556 nm from frequency-doubling of a Q-switched Nd:YAG laser at 1112 nm in LBO

    NASA Astrophysics Data System (ADS)

    Wang, Z. C.; Xu, J. L.; Bo, Y.; Peng, Q. J.; Xie, S. Y.; Xu, Y. T.; Yang, F.; Zhang, J. Y.; Cui, D. F.; Xu, Z. Y.

    2011-11-01

    We demonstrate a high power 556 nm yellow-green laser by intracavity frequency doubled of the diode-pumped 1112 nm Nd:YAG laser in a symmetrical L-shaped flat-flat cavity. The coatings of the resonator mirrors were carefully designed to achieve efficient operation of fundamental wavelength of the laser at 1112 nm. By using a type-II phase matching LBO nonlinear crystal as the frequency-doubler, the maximum output power of the 556 nm laser was measured to be as high as 83 W with a pulse repetition frequency (PRF) of 10 kHz under incident pump power of 1150 W, corresponding to an optical-to-optical conversion efficiency of about 7.2%. The fluctuation of output power was less than 2% over 30 min.

  4. Comparison of the photothermal effects of 808nm gold nanorod and indocyanine green solutions using an 805nm diode laser

    NASA Astrophysics Data System (ADS)

    Hasanjee, Aamr M.; Zhou, Feifan; West, Connor; Silk, Kegan; Doughty, Austin; Bahavar, Cody F.; Chen, Wei R.

    2016-03-01

    Non-invasive laser immunotherapy (NLIT) is a treatment method for metastatic cancer which combines noninvasive laser irradiation with immunologically modified nanostructures to ablate a primary tumor and induce a systemic anti-tumor response. To further expand the development of NLIT, two different photosensitizing agents were compared: gold nanorods (GNR) with an optical absorption peak of 808 nm and indocyanine green (ICG) with an optical absorption peak of ~800 nm. Various concentrations of GNR and ICG solutions were irradiated at different power densities using an 805 nm diode laser, and the temperature of the solutions was monitored during irradiation using a thermal camera. For comparison, dye balls made up of a 1:1 volume ratio of gel solution to GNR or ICG solution were placed in phantom gels and were then irradiated using the 805 nm diode laser to imitate the effect of laser irradiation on in vivo tumors. Non-invasive laser irradiation of GNR solution for 2 minutes resulted in a maximum increase in temperature by 31.8 °C. Additionally, similar irradiation of GNR solution dye ball within phantom gel for 10 minutes resulted in a maximum temperature increase of 8.2 °C. Comparatively, non-invasive laser irradiation of ICG solution for 2 minutes resulted in a maximum increase in temperature by 28.0 °C. Similar irradiation of ICG solution dye ball within phantom gel for 10 minutes yielded a maximum temperature increase of only 3.4 °C. Qualitatively, these studies showed that GNR solutions are more effective photosensitizing agents than ICG solution.

  5. Coagulative and ablative characteristics of a novel diode laser system (1470nm) for endonasal applications

    NASA Astrophysics Data System (ADS)

    Betz, C. S.; Havel, M.; Janda, P.; Leunig, A.; Sroka, R.

    2008-02-01

    Introduction: Being practical, efficient and inexpensive, fibre guided diode laser systems are preferable over others for endonasal applications. A new medical 1470 nm diode laser system is expected to offer good ablative and coagulative tissue effects. Methods: The new 1470 nm diode laser system was compared to a conventional 940 nm system with regards to laser tissue effects (ablation, coagulation, carbonization zones) in an ex vivo setup using fresh liver and muscle tissue. The laser fibres were fixed to a computer controlled stepper motor, and the light was applied using comparable power settings and a reproducible procedure under constant conditions. Clinical efficacy and postoperative morbidity was evaluated in two groups of 10 patients undergoing laser coagulation therapy of hyperplastic nasal turbinates. Results: In the experimental setup, the 1470 nm laser diode system proved to be more efficient in inducing tissue effects with an energy factor of 2-3 for highly perfused hepatic tissue to 30 for muscular tissue. In the clinical case series, the higher efficacy of the 1470 nm diode laser system led to reduced energy settings as compared to the conventional system with comparable clinical results. Postoperative crusting was less pronounced in the 1470 nm laser group. Conclusion: The 1470 nm diode laser system offers a highly efficient alternative to conventional diode laser systems for the coagulation of hyperplastic nasal turbinates. According to the experimental results it can be furthermore expected that it disposes of an excellent surgical potential with regards to its cutting abilities.

  6. All solid-state continuous-wave intracavity frequency-doubled Nd:LuVO4-LBO red laser at 671.5 nm

    NASA Astrophysics Data System (ADS)

    Jiang, Z. M.; Liang, W.; Chen, D. R.; Zhang, X. H.

    2011-01-01

    We report for the first time a efficient compact red laser at 671.5 nm generation by intracavity frequency doubling of a continuous wave laser operation of a diode direct pumped Nd:LuVO4 laser on the 4 F 3/2 → 4 I 13/2 transition at 1343 nm. An LBO crystal, cut for critical type I phase matching at room temperature is used for second harmonic generation of the laser. At an absorbed pump power of 16.2 W, as high as 4.3 W of continuous wave output power at 671.5 nm is achieved with 10-mm-long LBO. Comparative results obtained for the pump with diode laser at 808 nm, into the highly-absorbing 4 F 5/2 level, are given in order to prove the advantages of the 880 nm wavelength pumping.

  7. All-solid-state continuous-wave frequency doubling Nd:LuVO4/LBO laser with 2.17 W output power at 543 nm

    NASA Astrophysics Data System (ADS)

    Li, B.; Zhao, L.; Zhang, Y. B.; Zheng, Q.; Zhao, Y.; Yao, Y.

    2013-03-01

    Efficient and compact green-yellow laser output at 543 nm is generated by intracavity frequency doubling of a CW diode-pumped Nd:LuVO4 laser at 1086 nm under the condition of suppressing the higher gain transition near 1064 nm. With 16 W of diode pump power and the frequency-doubling crystal LBO, as high as 2.17 W of CW output power at 543 nm is achieved, corresponding to an optical-to-optical conversion efficiency of 13.6% and the output power stability over 8 hours is better than 2.86%. To the best of our knowledge, this is the highest watt-level laser at 543 nm generated by intracavity frequency doubling of a diode pumped Nd:LuVO4 laser at 1086 nm.

  8. All-solid-state continuous-wave frequency-doubling Nd:YVO(4)/LBO laser with 2.35 W output power at 543 nm.

    PubMed

    Yao, Yi; Zheng, Quan; Qu, Dapeng; Gong, Xiangyu; Zhou, Kai; Liu, Yang; Zhao, Ling

    2009-12-01

    Efficient and compact green-yellow laser output at 543 nm is generated by intracavity frequency doubling of a cw diode-pumped Nd:YVO(4) laser at 1086 nm under the condition of suppressing the higher gain transition near 1064 nm. With 14.5 W of diode pump power and the frequency-doubling crystal LiB(3)O(5), as high as 2.35 W of cw output power at 543 nm is achieved, corresponding to an optical-to-optical conversion efficiency of 15.7%; the output power stability over 5 h is better than 2.56%. To the best of our knowledge, this is the highest watt-level laser at 543 nm generated by intracavity frequency doubling of a diode pumped Nd:YVO(4) laser at 1086 nm. PMID:19953186

  9. Wavelength stabilizer based on dual fiber Bragg gratings for 980nm Mini-uncooled pump laser

    NASA Astrophysics Data System (ADS)

    Hu, Shuangshuang; Li, Yi; Jiang, Qunjie; Wu, Bin; Yu, Xiaojing; Wang, Haifang

    2008-12-01

    High power 980nm pump lasers are the key components in optical fiber amplifier. Wavelength stability for 980nm Miniuncooled pump laser is required to maintain the amplifier's efficiency throughout its lifetime. In this paper, a new type of wavelength stabilizer for uncooled pump laser which utilizes two fiber Bragg gratings (FBGs) matched in wavelength, bandwidth, and reflectivity is presented. The characteristics of transmissivity and reflectivity for the dual FBGs stabilized 980nm pump laser are theoretically modeled and experimentally studied. The results show that the output spectral characteristics of the uncooled pump laser with the dual FBGs have been greatly improved. The laser module can work steadily over a wide temperature range from 0°C to 70°C, with 0.2nm wavelength shift, along with more than 45dB side mode suppression ratio, and less than 1.57nm spectral bandwidth.

  10. Low threshold CW Nc laser oscillator at 1060 nm study

    NASA Technical Reports Server (NTRS)

    Birnbaum, M.; Deshazer, L. G.

    1976-01-01

    A broad range of characteristics of neodymium/yag lasers were investigated. With Nd:YVO4 crystals, CW 1.06 mu lasers were operated with thresholds a factor of 2 lower than Nd:YAG and with greater slope efficiencies. Thus, the first step in the development of new oscillators suitable for application in high data rate laser communication systems which surpass the present performance of the Nd:YAG laser has been successfully demonstrated.

  11. Megahertz FDML laser with up to 143nm sweep range for ultrahigh resolution OCT at 1050nm

    NASA Astrophysics Data System (ADS)

    Kolb, Jan Philip; Klein, Thomas; Eibl, Matthias; Pfeiffer, Tom; Wieser, Wolfgang; Huber, Robert

    2016-03-01

    We present a new design of a Fourier Domain Mode Locked laser (FDML laser), which provides a new record in sweep range at ~1μm center wavelength: At the fundamental sweep rate of 2x417 kHz we reach 143nm bandwidth and 120nm with 4x buffering at 1.67MHz sweep rate. The latter configuration of our system is characterized: The FWHM of the point spread function (PSF) of a mirror is 5.6μm (in tissue). Human in vivo retinal imaging is performed with the MHz laser showing more details in vascular structures. Here we could measure an axial resolution of 6.0μm by determining the FWHM of specular reflex in the image. Additionally, challenges related to such a high sweep bandwidth such as water absorption are investigated.

  12. Study on the laser crystal thermal compensation of LD end-pumped Nd:YAG 1319 nm/1338 nm dual-wavelength laser

    NASA Astrophysics Data System (ADS)

    Sun, R.; Wu, C. T.; Yu, M.; Yu, K.; Wang, C.; Jin, G. Y.

    2015-12-01

    The thermal model of laser diode (LD) end-pumped Nd: YAG was established. We analyzed the thermal effect of the crystal during the generation of 1319 nm/1338 nm dual-wavelength laser. Together with the bonded and non-bonded Nd:YAG crystal characteristics, we proposed to consider the bonded crystal’s internal temperature distribution of the three axes abc for the first time. The results showed that, compared with the non-bonded crystals, the bonded crystals could effectively reduce the crystal temperature. It provided a theoretical basis to solve the problem related to the thermal effect of the laser crystal and improve the laser output performance. The Nd:YAG laser crystal thermal model in this article could be widely applicable to similar laser crystals. The results provide a method to analyze and evaluate bonding crystal thermal compensation effectiveness by establishing the Nd:YAG crystal’s temperature distribution.

  13. 21nm x-ray laser Thomson scattering of laser-heated exploding foil plasmas

    SciTech Connect

    Dunn, J; Rus, B; Mocek, T; Nelson, A J; Foord, M E; Rozmus, W; Baldis, H A; Shepherd, R L; Kozlova, M; Polan, J; Homer, P; Stupka, M

    2007-09-26

    Recent experiments were carried out on the Prague Asterix Laser System (PALS) towards the demonstration of a soft x-ray laser Thomson scattering diagnostic for a laser-produced exploding foil. The Thomson probe utilized the Ne-like zinc x-ray laser which was double-passed to deliver {approx}1 mJ of focused energy at 21.2 nm wavelength and lasting {approx}100 ps. The plasma under study was heated single-sided using a Gaussian 300-ps pulse of 438-nm light (3{omega} of the PALS iodine laser) at laser irradiances of 10{sup 13}-10{sup 14} W cm{sup -2}. Electron densities of 10{sup 20}-10{sup 22} cm{sup -3} and electron temperatures from 200 to 500 eV were probed at 0.5 or 1 ns after the peak of the heating pulse during the foil plasma expansion. A flat-field 1200 line mm{sup -1} variable-spaced grating spectrometer with a cooled charge-coupled device readout viewed the plasma in the forward direction at 30{sup o} with respect to the x-ray laser probe. We show results from plasmas generated from {approx}1 {micro}m thick targets of Al and polypropylene (C{sub 3}H{sub 6}). Numerical simulations of the Thomson scattering cross-sections will be presented. These simulations show electron peaks in addition to a narrow ion feature due to collective (incoherent) Thomson scattering. The electron features are shifted from the frequency of the scattered radiation approximately by the electron plasma frequency {+-}{omega}{sub pe} and scale as n{sub e}{sup 1/2}.

  14. Efficient 1061 and 1329 nm laser emission of Nd:CNGG lasers under 885 nm diode pumping into the emitting level

    NASA Astrophysics Data System (ADS)

    Li, Y. L.; Jiang, H. L.; Ni, T. Y.; Zhang, T. Y.; Tao, Z. H.; Zeng, Y. H.

    2011-03-01

    We report an efficiency Nd:CNGG laser operating at 1061 and 1329 nm, respectively, direct pumped by a diode laser at 885 nm for the first time to our knowledge. The maximum outputs of 4.5 and 2.9 W, at 1061 and 1329 nm, respectively, are obtained in a 6-mm-thick 0.5 at % Nd:CNGG crystal with 13.5 W of absorbed pump power at 885 nm, leading to a high slope efficiency with respect to the absorbed pump power of 32.2 and 22.1%. Under traditional pumping at 808 nm, the maximum outputs of 3.9 and 2.7 W, at 1061 and 1329 nm, respectively, are obtained with 15.4 W of absorbed pump power, corresponding to the slope efficiency with respect to the absorbed pump power of 25.2 and 17.9%.

  15. 456-nm deep-blue laser generation by intracavity frequency doubling of Nd:GdVO4 under 879-nm diode pumping

    NASA Astrophysics Data System (ADS)

    Gao, J.; Yu, X.; Li, X. D.; Chen, F.; Zhang, K.; Yan, R. P.; Yu, J. H.; Wang, Y. Z.

    2009-01-01

    We report on a simple, compact continuous-wave 456-nm laser by intracavity frequency doubling of an end-pumped Nd:GdVO4 laser on the 4 F 3/2 → 4 I 9/2 transition. A 5-mm-long, 0.2-at % Nd:GdVO4 bulk crystal is employed as the gain medium and the Nd3+ ion is directly pumped into the emitting level (4 F 3/2) by a novel 879-nm laser diode. Intracavity frequency doubling with a 15-mm-long LBO crystal and a 10-mm-long BiBO crystal in a linear cavity yield 56- and 118-mW single-ended blue outputs at the absorbed pump power of 11.9 W, respectively. The corresponding values are scaled to 286 and 391 mW, respectively, in a V-type cavity, with optical conversion efficiencies of 2.4 and 3.3% versus the absorbed pump power. The fluctuations of the 456-nm output power for both cases are less than 3% at the maximum output level.

  16. High-average-power, 100-Hz-repetition-rate, tabletop soft-x-ray lasers at sub-15-nm wavelengths

    NASA Astrophysics Data System (ADS)

    Reagan, Brendan A.; Berrill, Mark; Wernsing, Keith A.; Baumgarten, Cory; Woolston, Mark; Rocca, Jorge J.

    2014-05-01

    Efficient excitation of dense plasma columns at 100-Hz repetition rate using a tailored pump pulse profile produced a tabletop soft-x-ray laser average power of 0.1 mW at λ = 13.9 nm and 20 μW at λ = 11.9 nm from transitions of Ni-like Ag and Ni-like Sn, respectively. Lasing on several other transitions with wavelengths between 10.9 and 14.7 nm was also obtained using 0.9-J pump pulses of 5-ps duration from a compact diode-pumped chirped pulse amplification Yb:YAG laser. Hydrodynamic and atomic plasma simulations show that the pump pulse profile, consisting of a nanosecond ramp followed by two peaks of picosecond duration, creates a plasma with an increased density of Ni-like ions at the time of peak temperature that results in a larger gain coefficient over a temporally and spatially enlarged space leading to a threefold increase in the soft-x-ray laser output pulse energy. The high average power of these compact soft-x-ray lasers will enable applications requiring high photon flux. These results open the path to milliwatt-average-power tabletop soft-x-ray lasers.

  17. All-solid-state cw frequency-doubling Nd:YLiF4/LBO blue laser with 4.33 W output power at 454 nm under in-band diode pumping at 880 nm.

    PubMed

    Lü, Yanfei; Zhang, Xihe; Cheng, Weibo; Xia, Jing

    2010-07-20

    We generated efficient blue laser output at 454 nm by intracavity frequency doubling of a continuous-wave (cw) diode-pumped Nd:YLiF(4) (Nd:YLF) laser at 908 nm based on the (4)F(3/2)-(4)I(9/2) transition. With 32.8 W of incident pump power at 880 nm and the frequency-doubling crystal LiB(3)O(5), a level as high as 4.33 W of cw output power at 454 nm is achieved, corresponding to an optical conversion efficiency of 13.2% with respect to the incident pump power. To the best of our knowledge, this is the first blue laser at 454 nm generated by intracavity frequency doubling of a diode-pumped Nd:YLF. PMID:20648194

  18. Femtosecond laser-written lithium niobate waveguide laser operating at 1085 nm

    NASA Astrophysics Data System (ADS)

    Tan, Yang; de Aldana, Javier R. Vázquez; Chen, Feng

    2014-10-01

    We report on the channel waveguide lasers at 1085 nm in femtosecond laser written Type II waveguides in an Nd:MgO:LiNbO3 crystal. The waveguide was constructed in a typical dual-line approach. In the geometry, we found that four vicinal regions of the track pair could guide light propagation. In addition, these guiding cores support polarization-dependent-guided modes. The propagation losses of the waveguides were measured to be as low as 1 dB/cm. Under an optical pump at 808 nm, the continuous-wave waveguide lasing at 1085 nm was generated, reaching a slope efficiency of 27% and maximum output power of 8 mW. The lasing threshold was 71 mW. Our results show that with the femtosecond laser written Nd:MgO:LiNbO3 waveguide as the miniature light source, it was possible to construct all-LiNbO3-based integrated devices for diverse photonic applications.

  19. CW, single-frequency 229nm laser source for Cd-cooling by harmonic conversion

    NASA Astrophysics Data System (ADS)

    Kaneda, Yushi; Yarborough, J. M.; Merzlyak, Yevgeny

    2015-02-01

    More than 200mW of CW 229nm for Cd atom cooling application was generated by the 4th harmonic of a single frequency optically pumped semiconductor laser using a 10-mm long, Brewster-cut BBO crystal in an external cavity. With 650mW of 458nm input, 216mW of 229nm power was observed. Conversion efficiency from 458nm to 229nm was more than 33%.

  20. A tunable, Nd-doped lithium niobate laser at 1084 nm

    SciTech Connect

    Schearer, L.D. ); Leduc, M.

    1988-10-01

    Over 250 mW of CW laser emission at 1084 nm is obtained from Nd:LiNbO{sub 3} when the rod is end-pumped along the crystalline {open quote}{ital y}{close quote} axis by 1 W from a Kr{sup +} laser at 752 nm. The laser can be tuned over 3 nm at the 1084 nm peak with a thin, uncoated etalon in the cavity. Thresholds of 30 mW of absorbed pump power were obtained with a weak output coupler, rising to 220 mW with a 35% transmitting output mirror. No pump-induced photorefractive effects were observed.

  1. Efficient laser action on the 342-nm band of molecular iodine using ArF laser pumping

    NASA Astrophysics Data System (ADS)

    Shaw, M. J.; Edwards, C. B.; Oneill, F.; Fotakis, C.; Donovan, R. J.

    1980-08-01

    Strong laser action on the 342-nm band of I2 has been obtained by transverse pumping I2/SF6 mixtures at 193 nm with an ArF laser. The highest output energy obtained was 230 mJ at an intrinsic energy conversion efficiency of approximately 30% equivalent to a photon efficiency of greater than 50%.

  2. High power single-longitudinal-mode cyan laser at 500.8 nm

    NASA Astrophysics Data System (ADS)

    Hao, E. J.; Li, T.; Wang, Z. D.

    2012-05-01

    An all-solid-state single-longitudinal-mode (SLM) laser at 500.8 nm with 830 mW output power has been demonstrated for the first time. By using a new resonator for doubly resonant, Nd:GdVO4 and Nd:YAG were pumped by two laser diode arrays coupled by optical fiber, respectively. In the two sub-cavities, SLM wavelengths of 1064 and 946 nm were induced by using the twisted-mode technique and then mixed into SLM 500.8 nm laser with sum-frequency technology. The SLM 500.8 nm laser output of 830 mW was obtained at the incident pump power of 20 W for Nd:GdVO4 and 23 W for Nd:YAG. The experimental results showed that the intracavity sum-frequency mixing by twisted-mode technique is an effective method for SLM 500.8 nm laser.

  3. High-Efficiency 894-nm Laser Emission of Laser-Diode-Bar-Pumped Cesium-Vapor Laser

    NASA Astrophysics Data System (ADS)

    Zheng, Yujin; Niigaki, Minoru; Miyajima, Hirofumi; Hiruma, Teruo; Kan, Hirofumi

    2009-03-01

    We report a high-efficiency cesium-vapor laser with a high-gas-pressure (˜3-atm helium and 0.49-atm ethane) cell pumped by a high-power external-cavity laser-diode bar. Peak laser power of 12.1 W at 894 nm was obtained, when the absorbed peak pump power was 23.1 W. The achieved slope efficiencies with the incident pump power and the absorbed pump power were 33 and 81.7%, respectively.

  4. 1,450-nm diode laser in combination with the 1550-nm fractionated erbium-doped fiber laser for the treatment of steatocystoma multiplex: a case report.

    PubMed

    Moody, Megan N; Landau, Jennifer M; Goldberg, Leonard H; Friedman, Paul M

    2012-07-01

    Steatocystoma multiplex (SM) is a rare condition characterized by multiple, small, asymptomatic dermal cysts. Treatment options are limited, with varying degrees of success; these include oral isotretinoin, surgical excision or drainage, and liquid nitrogen cryotherapy. The most effective method is excision, but cosmetic considerations, time, overall cost, and pain must be considered, because patients tend to have multiple cysts. Lasers, especially nonablative devices, have not frequently been used to treat SM. Herein, we present the case of a patient with isolated steatocystoma multiplex on the abdomen and lower chest with substantial clearance after two laser treatment sessions using two complementary lasers: a 1,450-nm diode laser to target the abnormal sebaceous glands and a 1,550-nm fractionated erbium-doped fiber laser to target the dermal cysts. PMID:22487444

  5. 7-W single-mode thulium-doped fibre laser pumped at 1230 nm

    SciTech Connect

    Kravtsov, K S; Bufetov, Igor' A; Medvedkov, O I; Dianov, Evgenii M; Yashkov, M V; Gur'yanov, A N

    2005-07-31

    An efficient thulium-doped fibre laser emitting at {approx}2 {mu}m upon pumping into the long-wavelength {sup 3}H{sub 6} {yields} {sup 3}H{sub 5} absorption band of Tm{sup 3+} ions is developed. The maximum output power of the single-mode thulium laser pumped at 1230 nm was 7 W at 1956 nm for a pump conversion efficiency of 35%. (lasers)

  6. Tunable millisecond narrow-band Nd:GSGG laser around 1336.6 nm for 27Al+ optical clock

    NASA Astrophysics Data System (ADS)

    Wang, M.-Q.; Zhang, F.-F.; Li, J.-J.; Wang, Z.-M.; Zong, N.; Zhang, S.-J.; Yang, F.; Yuan, L.; Bo, Y.; Cui, D.-F.; Peng, Q.-J.; Xu, Z.-Y.

    2016-05-01

    We developed a narrow-band, Nd:GSGG ring laser tunable around 1336.6 nm with a tuning range more than 24 pm. The maximum output energy is 0.26 J per pulse with a pulse width of 900 μs and a pulse repetition rate of 10 Hz. The root-mean-square of wavelength stability in 1 h is 0.27 pm, and M2 factor is 1.06 at the output energy of 0.16 J per pulse. It can be a good candidate of the fundamental laser, of which the eighth-harmonic generation at 167.0787 nm can be used to induce the 27Al+ ion by the 1S0↔1P1 transition for laser cooling when it is used as the medium for optical clock.

  7. Implications of the temperature dependence of Nd:YAG spectroscopic values for low temperature laser operation at 946 nm

    NASA Astrophysics Data System (ADS)

    Yoon, S. J.; Mackenzie, J. I.

    2014-05-01

    We present our measurements of the key spectroscopic properties over the temperature range of 77 K to 450 K for Nd3+ ions doped in Y3Al5O12 (YAG). From room to liquid nitrogen temperature (LNT), the peak absorption cross section around 808 nm increased by almost 3 times, in conjunction the bandwidth of this absorption line reduced by the same factor. At LNT the peak of the absorption line was blue shifted by 0.25 nm with respect to that at 300 K. The fluorescence spectrum between 850 nm - 1450 nm was measured, from which the emission cross sections for the three main transitions were calculated. One note of particular interest for the dominant emission wavelengths around 1064nm and 1061nm (4F3/2 --> 4I11/2) was the switch in their relative strength below 170K, and at LNT the 1061 nm line has almost twice the cross section as at 1064nm.. The fluorescence and lifetime of the upper laser level (4F3/2) was measured and the effective emission cross section determined by the Fuchtbauer-Ladenburg (F-L) method. The effective emission cross section for 946 nm (R1 --> Z5) increased by more than two times over the 300 K to 77 K range. A numerical fit for the temperature dependent emission cross section at 946 nm and 1064 nm and also calculated absorption coefficient at 808 nm pump diode laser have also obtained from the measured spectroscopic data.

  8. Generation of 369.4 nm Radiation by Efficient Doubling of a Diode Laser

    NASA Technical Reports Server (NTRS)

    Williams, A.; Seidel, D. J.; Maleki, J.

    1993-01-01

    A resonant cavity second harmonic generation system has been developed to produce 369.4 nm radiation from a 738.8 nm diode laser with 10 mW nominal output power. This system utilizes a polarization technique to lock the cavity to the laser frequency. In this paper we report on an evaluation of the system using a Titanium:Sapphire laser as the input source, and preliminary results with a diode laser source. To our knowledge, this is the deepest uv light ever produced by frequency-doubling a diode laser.

  9. Single-frequency distributed Bragg reflector Nd doped silica fiber laser at 930 nm.

    PubMed

    Fang, Qiang; Xu, Yang; Fu, Shijie; Shi, Wei

    2016-04-15

    We report a single-frequency distributed Bragg reflector (DBR) fiber laser at 930 nm for the first time, to the best of our knowledge. A ∼2.5 cm long commercial highly neodymium-doped silica fiber was utilized as the gain medium to achieve ∼1.9 mW laser output. The single longitudinal mode operation of this laser was verified by a scanning Fabry-Perot interferometer. This fiber laser is suited for seeding high-power 930 nm narrow-linewidth laser amplifiers, which can be used to generate coherent single-frequency pure blue light through frequency doubling. PMID:27082356

  10. 1 W at 785 nm from a frequency-doubled wafer-fused semiconductor disk laser.

    PubMed

    Rantamäki, Antti; Rautiainen, Jussi; Lyytikäinen, Jari; Sirbu, Alexei; Mereuta, Alexandru; Kapon, Eli; Okhotnikov, Oleg G

    2012-04-01

    We demonstrate an optically pumped semiconductor disk laser operating at 1580 nm with 4.6 W of output power, which represents the highest output power reported from this type of laser. 1 W of output power at 785 nm with nearly diffraction-limited beam has been achieved from this laser through intracavity frequency doubling, which offers an attractive alternative to Ti:sapphire lasers and laser diodes in a number of applications, e.g., in spectroscopy, atomic cooling and biophotonics. PMID:22513615

  11. Isotope shifts and hyperfine structure of the laser-cooling Fe I 358-nm line

    NASA Astrophysics Data System (ADS)

    Huet, N.; Pettens, M.; Bastin, T.

    2015-11-01

    We report on the measurement of the isotope shifts of the 3 d74 s a 5F5-3 d74 p z 5G6o Fe i line at 358 nm between all four stable isotopes ,Fe56Fe54,Fe57 , and Fe58 , as well as the hyperfine structure of that line for Fe57 , the only stable isotope having a nonzero nuclear spin. This line is of primary importance for laser-cooling applications. In addition, an experimental value of the field and specific mass shift coefficients of the transition is reported as well as the hyperfine structure magnetic dipole coupling constant A of the transition excited state in Fe57 , namely A (3 d74 p z 5G6o) =31.241 (48 ) MHz. The measurements were carried out by means of laser-induced fluorescence spectroscopy performed on an isotope-enriched iron atomic beam. All measured frequency shifts are reported with relative uncertainties below one third percent.

  12. Efficient emission at 1908 nm in a diode-pumped Tm:YLF laser

    SciTech Connect

    Zakharov, N G; Antipov, Oleg L; Savikin, A P; Sharkov, V V; Eremeikin, O N; Frolov, Yu N; Mishchenko, G M; Velikanov, S D

    2009-05-31

    Emission parameters at 1908 nm in a longitudinally-diode-pumped Tm:YLF laser are studied. The laser parameters are optimised to obtain the maximal power of high-quality cw radiation. The output power of {approx}27 W is obtained at the slope efficiency of {approx}50% and total optical pump conversion efficiency of {approx}41%. (lasers and amplifiers)

  13. Bi-doped fiber lasers and amplifiers for a spectral region of 1300-1470 nm.

    PubMed

    Bufetov, Igor A; Firstov, Sergey V; Khopin, Vladimir F; Medvedkov, Oleg I; Guryanov, Alexey N; Dianov, Evgeny M

    2008-10-01

    Bismuth-doped fiber lasers operating in the range 1300-1470 nm have been demonstrated for the first time, to our knowledge. It has been shown that Bi-doped alumina-free phosphogermanosilicate fibers reveal optical gain in a wavelength range of 1240-1485 nm with pumping at 1205, 1230, or 808 nm. PMID:18830360

  14. Stimulated scattering effects in gold-nanorod-water samples pumped by 532 nm laser pulses

    PubMed Central

    Shi, Jiulin; Wu, Haopeng; Liu, Juan; Li, Shujing; He, Xingdao

    2015-01-01

    Stimulated scattering in gold-nanorod-water samples has been investigated experimentally. The scattering centers are impurity particles rather than the atoms or molecules of conventional homogeneous scattering media. The pump source for exciting stimulated scattering is a pulsed and narrow linewidth second-harmonic Nd: YAG laser, with 532 nm wavelength, ~8 ns pulse duration, and 10 Hz repetition rate. Experimental results indicate that SMBS, SBS and STRS can be generated in gold-nanorod-water samples under appropriate pump and absorption conditions. The incident pump energy has to be larger than a certain threshold value before stimulated scattering can be detected. The absorption coefficient of samples at 532 nm wavelength depends on the one of characteristic absorption bands of gold nanorods located around 530 nm. A critical absorption coefficient can be determined for the transition from SBS to STRS. Also, the spectral-line-broadening effects of STRS have been observed, the line-shape presents a pseudo-Voigt profile due to the random thermal motion of molecules and strong particle collision. PMID:26173804

  15. An Optical Clock/Frequency Standard at 657 nm Based On Laser-Cooled Neutral Calcium

    NASA Astrophysics Data System (ADS)

    Oates, Chris

    2002-05-01

    Optical atomic clocks are receiving increased attention due to their enormous potential for high stability and accuracy, and because of the revolution in optical metrology that resulted from the development of fs-laser-based optical clockwork.(S. A. Diddams, T. Üdem, J. C. Bergquist, E. A. Curtis, R. E. Drullinger, L. Hollberg, W. M. Itano, W. D. Lee, C. W. Oates, K. R. Vogel, and D. J. Wineland, Science 293, 825 (2001).) We have constructed a high performance diode-laser-based optical frequency reference that uses an intercombination line (400 Hz natural linewidth) in laser-cooled neutral Ca at 657 nm. Absolute frequency measurements against the Cs-based NIST time ensemble via fs-laser metrology have led to a determination of the clock frequency (456 THz) with 26 Hz uncertainty.(T. Üdem, S. A. Diddams, K. R. Vogel, C. W. Oates, E. A. Curtis, W. D. Lee, W. M. Itano, R. E. Drullinger, J. C. Bergquist, and L. Hollberg, Phys. Rev. Lett. 86, 4996 (2001).) Measurements of the short-term fractional frequency instability against a Hg^+ ion optical clock system (again via the fs-laser comb) yielded an upper limit of 6x10-15 @ 1 s. In order to improve these results by an order of magnitude or more, we are currently developing a second-stage cooling scheme for Ca. This approach uses quenched cooling with the narrow clock transition and can reduce the atomic temperature by nearly three orders of magnitude. Recent cooling results in one and three dimensions will be presented.

  16. Power and radiance scaling of a 946 nm Nd:YAG planar waveguide laser

    NASA Astrophysics Data System (ADS)

    Ng, S. P.; Mackenzie, J. I.

    2012-03-01

    We present a diode-end-pumped Nd:YAG planar waveguide laser operating on neodymium's quasi-four-level transition at a wavelength of 946 nm. Two modes of operation are described: a high-power multi-mode monolithic cavity generating 105 for 210 W of incident pump power with a slope efficiency of ˜54%, and secondly, a high-radiance configuration employing an external stable resonator producing a maximum output power of 29.2 for 86.5 W of incident pump-power, with a slope efficiency of 33%. The output beam quality values of the external cavity were M2 of 3.2 by 2.4, leading to a maximum radiance of 0.43 GW cm-2 sr-1.

  17. Proposed SLR Optical Bench Required to Track Debris Using 1550 nm Lasers

    NASA Technical Reports Server (NTRS)

    Shappirio, M.; Coyle, D. B.; McGarry, J. F.; Bufton, J.; Cheek, J. W.; Clarke, G.; Hull, S. M.; Skillman, D. R.; Stysley, P. R.; Sun, X.; Young, R. P.; Zagwodzki, T.

    2015-01-01

    A previous study has indicated that by using approx.1550 nm wavelengths a laser ranging system can track debris objects in an "eye safe" manner, while increasing the expected return rate by a factor of approx. 2/unit area of the telescope. In this presentation we develop the optical bench required to use approx.1550nm lasers, and integration with a 532nm system. We will use the optical bench configuration for NGSLR as the baseline, and indicate a possible injection point for the 1550 nm laser. The presentation will include what elements may need to be changed for transmitting the required power on the approx.1550nm wavelength, supporting the alignment of the laser to the telescope, and possible concerns for the telescope optics.

  18. Spectroscopy and laser cooling on the - line in Yb via an injection-locked diode laser at 1,111.6 nm

    NASA Astrophysics Data System (ADS)

    Kostylev, N.; Locke, C. R.; Tobar, M. E.; McFerran, J. J.

    2015-03-01

    We generate 555.8-nm light with sub-MHz linewidth through the use of laser injection locking of a semiconductor diode at 1,111.6 nm, followed by frequency doubling in a resonant cavity. The integrity of the injection lock is investigated by studying an offset beat signal between slave and master lasers, by performing spectroscopy on the transition in magneto-optically trapped ytterbium, and by demonstrating additional laser cooling of with the 555.8-nm light in a dual-wavelength magneto-optical trap (MOT). For the - spectroscopy, we confirm the linear dependence between ground-state linewidth and the intensity of an off-resonant laser, namely that used to cool Yb atoms in a - magneto-optical trap. A temperature of 60 μK is produced for in the dual-wavelength MOT. Our results demonstrate the suitability of injection-locked 1,100-1,130-nm laser diodes as a source for sub-MHz linewidth radiation in the yellow-green spectrum.

  19. High-average-power narrow-line-width sum frequency generation 589 nm laser

    NASA Astrophysics Data System (ADS)

    Lu, Yanhua; Fan, Guobin; Ren, Huaijin; Zhang, Lei; Xu, Xiafei; Zhang, Wei; Wan, Min

    2015-10-01

    An 81 W average-power all-solid-state sodium beacon laser at 589 nm with a repetition rate of 250 Hz is introduced, which is based on a novel sum frequency generation idea between two high-energy, different line widths, different beam quality infrared lasers (a 1064 nm laser and a 1319 nm laser). The 1064 nm laser, which features an external modulated CW single frequency seed source and two stages of amplifiers, can provide average-power of 150 W, beam quality M2 of ~1.8 with ultra-narrow line width (< 100 kHz). The 1319 nm laser can deliver average-power of 100 W, beam quality M2 of ~3.0 with a narrow line width of ~0.3 GHz. By sum frequency mixing in a LBO slab crystal (3 mm x 12 mm x 50 mm), pulse energy of 325 mJ is achieved at 589 nm with a conversion efficiency of 32.5 %. Tuning the center wavelength of 1064 nm laser by a PZT PID controller, the target beam's central wavelength is accurately locked to 589.15910 nm with a line width of ~0.3 GHz, which is dominated mainly by the 1319 nm laser. The beam quality is measured to be M2 < 1.3. The pulse duration is measured to be 150 μs in full-width. To the best of our knowledge, this represents the highest average-power for all-solid-state sodium beacon laser ever reported.

  20. Sum frequency generation of UV laser radiation at 266  nm in LBO crystal.

    PubMed

    Nikitin, D G; Byalkovskiy, O A; Vershinin, O I; Puyu, P V; Tyrtyshnyy, V A

    2016-04-01

    We report experimental results of generation at 266 nm in LBO crystal by frequency mixing of the fundamental (1064 nm) and third harmonic (355 nm) of ytterbium pulsed fiber laser radiation. Deep ultraviolet (DUV) output power of 3.3 W at 266 nm was achieved with 14% IR-to-DUV conversion efficiency. UV-induced bulk degradation of LBO crystals was observed and visualized by the dark field method. PMID:27192312

  1. 500.5-nm blue-green laser based on sum-frequency mixing of diode pumped neodymium lasers

    NASA Astrophysics Data System (ADS)

    Wang, S. F.; Na, Y. X.

    2011-07-01

    We report for the first time a continuous-wave (CW) coherent radiation at 500.5 nm by intracavity sum-frequency generation of 1063 nm Nd:GdVO4 laser and 946 nm Nd:YAG laser. Blue-green laser is obtained by using a doubly cavity, type-II critical phase matching KTiOPO4 (KTP) crystal sum-frequency mixing. With total pump power of 27.8 W, TEM00 mode blue-green laser at 500.5 nm of 421 mW is obtained. At the output power level of 421 mW, the blue-green power stability is better than 2.8% and laser beam quality M 2 factor is 1.37.

  2. 504 nm blue-green laser based on sum-frequency mixing of diode pumped Nd3+ lasers

    NASA Astrophysics Data System (ADS)

    Wu, Y.; Jin, G. Y.; Dong, Y.

    2011-08-01

    We report for the first time a continuous-wave (CW) blue-green radiation at 504 nm by intracavity sum-frequency generation of 946 nm Nd:YAG laser and 1080 nm Nd:YAlO3 (Nd:YAP) laser. Using type-I critical phase matching LiB3O5 (LBO) crystal, 504 nm blue-green laser was obtained by 946 and 1080 nm intra-cavity sum-frequency mixing, and output power of 215 mW was demonstrated. At the output power level of 215 mW, the output power stability is better than 4.7% and laser beam quality M2 factor is 1.21.

  3. High-power output of ytterbium-doped oxyorthosilicate lasers at 1018 nm

    NASA Astrophysics Data System (ADS)

    Lin, Niannian; Li, Wenxue; Zhou, Yuan; Shi, Yi; Yan, Ming; Yang, Kangwen; Zhao, Jian; Yang, Xianghui; Zeng, Heping

    2013-01-01

    A high-power laser system at 1018 nm was realized with an ytterbium-doped oxyorthosilicate solid-state master oscillator and ytterbium-doped double-clad fiber amplifier. In the Yb:LSO (Yb:Lu2SiO5) and Yb:LYSO (Yb:LuYSiO5) master laser oscillator, we attained the broadest tunable wavelength range from 994.50 to 1094.22 nm. In the power amplifier, we achieved an output power up to 4.14 W at 1018 nm by amplifying the Yb:LSO laser under a pump power of 15.8 W.

  4. Comparing 1470- and 980-nm diode lasers for endovenous ablation treatments.

    PubMed

    Aktas, Aykut Recep; Celik, Orhan; Ozkan, Ugur; Cetin, Mustafa; Koroglu, Mert; Yilmaz, Sevda; Daphan, Birsen U; Oguzkurt, Levent

    2015-07-01

    The purpose of this study was to compare the effectiveness of 1470- and 980-nm lasers with regard to power output, complications, recanalization rates, and treatment response. We prospectively evaluated the effectiveness of endovenous laser ablation (EVLA) in a total of 152 great and small saphenous veins from 96 patients. Lasers were randomly used based on the availability of the units. Patients were clinically evaluated for Clinical Etiologic Anatomic Pathophysiologic (CEAP) stage and examined with Doppler ultrasound. Treatment response was determined anatomically by occlusion of the vein and clinically by the change in the venous clinical severity score (VCSS). Seventy-eight of the saphenous veins underwent EVLA with a 980-nm laser and 74 underwent EVLA with a 1470-nm laser. Treatment response was (68) 87.2 % in the 980-nm group and (74) 100 % in the 1470-nm group (p = 0.004). The median VCSS decreased from 4 to 2 in the 980-nm group (p < 0.001) and from 8 to 2 (p < 0.001) in the 1470-nm group. At 1-year follow-up, seven veins treated with 980 nm and two veins treated with 1470 nm were recanalized (p = 0.16); the average linear endovenous energy density (LEED) was 83.9 (r, 55-100) J/cm and 58.5 (r, 45-115) J/cm, respectively (p < 0.001). Postoperative minor complications occurred in 23 (29.4 %) limbs in the 980-nm group and in 19 (25.6 %) limbs of the 1470-nm group (p = 0.73). EVLA with the 1470-nm laser have less energy deposition for occlusion and better treatment response. PMID:25990260

  5. Elimination of photon quenching by a transition layer to fabricate a quenching-shield sandwich structure for 800 nm excited upconversion luminescence of Nd3+-sensitized nanoparticles.

    PubMed

    Zhong, Yeteng; Tian, Gan; Gu, Zhanjun; Yang, Yijun; Gu, Lin; Zhao, Yuliang; Ma, Ying; Yao, Jiannian

    2014-05-01

    Nd3+-sensitized quenching-shield sandwich-structured upconversion nanoparticles are reported, which exhibit highly efficient upconversion photoluminescence under excitation by an 800 nm continuous-wave laser. The transition-layer structure is essential to bridge energy transfer from the sensitizer to the activator and simultaneously block energy back-transfer from the activator to the sensitizer. These 800 nm-excited upconversion nanoparticles are a key step toward the development of upconversion nanophosphors for biological applications. PMID:24338994

  6. 11 W single gain-chip dilute nitride disk laser emitting around 1180 nm.

    PubMed

    Korpijärvi, Ville-Markus; Leinonen, Tomi; Puustinen, Janne; Härkönen, Antti; Guina, Mircea D

    2010-12-01

    We report power scaling experiments of a GaInNAs/GaAs-based semiconductor disk laser operating at ~1180 nm. Using a single gain chip cooled to mount temperature of ~10 °C we obtained 11 W of output power. For efficient thermal management we used a water-cooled microchannel mount and an intracavity diamond heat spreader. Laser performance was studied using different spot sizes of the pump beam on the gain chip and different output couplers. Intracavity frequency-doubling experiments led to generation of ~6.2 W of laser radiation at ~590 nm, a wavelength relevant for the development of sodium laser guide stars. PMID:21164909

  7. Monolithic 626 nm single-mode AlGaInP DBR diode laser.

    PubMed

    Blume, G; Nedow, O; Feise, D; Pohl, J; Paschke, K

    2013-09-01

    Single-mode lasers below 630 nm are still realized using complex laser systems. We present distributed Bragg reflector (DBR) ridge waveguide lasers (RWL) based on AlGaInP. When packaged into sealed TO-3 housings and cooled internally to about 0°C the DBR-RWL emit more than 50 mW at a wavelength of 626.0 nm into a nearly diffraction-limited single longitudinal mode with a spectral width below 1 MHz. These new monolithic diode lasers have the potential to drastically miniaturize existing set-ups e.g. for quantum information processing. PMID:24104041

  8. 1016nm all fiber picosecond MOPA laser with 50W output.

    PubMed

    Qi, Xue; Chen, Sheng-Ping; Sun, Hai-Yue; Yang, Bing-Ke; Hou, Jing

    2016-07-25

    This paper presents an all fiber high power picosecond laser at 1016 nm in master oscillator power amplifier (MOPA) configuration. A direct amplification of this seed source encounters obvious gain competition with amplified spontaneous emission (ASE) at ~1030 nm, leading to a seriously reduced amplification efficiency. To suppress the ASE and improve the amplification efficiency, we experimentally investigate the influence of the gain fiber length and the residual ASE on the perforemance of the 1016 nm amplifier. The optimized 1016 nm MOPA laser exhibits an average power of 50 W and an optical conversion efficiency of 53%. PMID:27464139

  9. Dual-wavelength laser operation at 1061 and 942 nm in Nd:GSAG

    NASA Astrophysics Data System (ADS)

    Fu, X. H.; Che, Y.; Li, Y. L.

    2011-06-01

    A dual-wavelength continuous-wave (CW) diode end-pumped gadolinium scandium aluminum garnet (Nd:GSAG) laser that generates simultaneous laser action at the wavelengths 1061 and 942 nm is demonstrated. A total output power of 589 mW (476 mW at 1061 nm and 113 mW at 942 nm) for the dual-wave-length was achieved at the incident pump power of 18.2 W. The M 2 values for 942 and 1061 nm lights were found to be around 1.18 and 1.37, respectively.

  10. High power frequency doubled GaInNAs semiconductor disk laser emitting at 615 nm.

    PubMed

    Härkönen, Antti; Rautiainen, Jussi; Guina, Mircea; Konttinen, Janne; Tuomisto, Pietari; Orsila, Lasse; Pessa, Markus; Okhotnikov, Oleg G

    2007-03-19

    We report on an optically-pumped intracavity frequency doubled GaInNAs/GaAs -based semiconductor disk laser emitting around 615 nm. The laser operates at fundamental wavelength of 1230 nm and incorporates a BBO crystal for light conversion to the red wavelength. Maximum output power of 172 mW at 615 nm was achieved from a single output. Combined power from two outputs was 320 mW. The wavelength of visible emission could be tuned by 4.5 nm using a thin glass etalon inside the cavity. PMID:19532562

  11. Research on 9xx nm diode laser for direct and pumping applications

    NASA Astrophysics Data System (ADS)

    Sebastian, J.; Hülsewede, R.; Pietrzak, A.; Zorn, M.; Wölz, M.; Meusel, J.; Schröder, M.; Wittschirk, Th.

    2015-02-01

    High-power laser bars and single emitters have proven as attractive light sources for many industrial applications such as direct material processing or as pump sources for solid state and fiber-lasers. There is also a great interest in quasi-CW laser bars for high-energy projects. These applications require a continuous improvement of laser diodes for reliable optical output powers, high electrical-to-optical efficiencies, brightness and costs. In this paper JENOPTIK presents an overview of recent research for highly efficient CW and quasi-CW laser devices emitting in a wide wavelength range between 880 nm and 1020 nm. The last research results concern the 9xx single emitters and laser arrays. The 9xx nm 12 W single emitters and 976 nm 55 W laser arrays have efficiencies above 65%. New life time tests for single emitter devices currently exceed 1300 hours of reliable operation at room temperature and over 1500 hours at 45°C. Because of the small far field distribution of the optical power, the high output power and the small near field the 55 W arrays show a brightness of 75 MW x cm-2sr-1 with 95% power content. The technology for new generation 940 nm high fill-factor bars has been currently extended to emission wavelengths of 976 nm and 1020 nm with excellent results: 200 W output power with 63% efficiency using passive cooling. The innovative design of the laser structure enables, moreover, the realization of 500 W 880 nm quasi-CW laser bars with wall-plug efficiencies of 55% and a narrow fast-axis divergence angle of 40° (95% power content).

  12. Generation of continuous-wave 194 nm laser for mercury ion optical frequency standard

    NASA Astrophysics Data System (ADS)

    Zou, Hongxin; Wu, Yue; Chen, Guozhu; Shen, Yong; Liu, Qu; Precision measurement; atomic clock Team

    2015-05-01

    194 nm continuous-wave (CW) laser is an essential part in mercury ion optical frequency standard. The continuous-wave tunable radiation sources in the deep ultraviolet (DUV) region of the spectrum is also serviceable in high-resolution spectroscopy with many atomic and molecular lines. We introduce a scheme to generate continuous-wave 194 nm radiation with SFM in a Beta Barium Borate (BBO) crystal here. The two source beams are at 718 nm and 266 nm, respectively. Due to the property of BBO, critical phase matching (CPM) is implemented. One bow-tie cavity is used to resonantly enhance the 718 nm beam while the 266 nm makes a single pass, which makes the configuration easy to implement. Considering the walk-off effect in CPM, the cavity mode is designed to be elliptical so that the conversion efficiency can be promoted. Since the 266 nm radiation is generated by a 532 nm laser through SHG in a BBO crystal with a large walk-off angle, the output mode is quite non-Gaussian. To improve mode matching, we shaped the 266 nm beam into Gaussian modes with a cylindrical lens and iris diaphragm. As a result, 2.05 mW 194 nm radiation can be generated. As we know, this is the highest power for 194 nm CW laser using SFM in BBO with just single resonance. The work is supported by the National Natural Science Foundation of China (Grant No. 91436103 and No. 11204374).

  13. Efficient continuous-wave intracavity frequency-doubled Nd:YAG-LBO blue laser at 473 nm under diode pumping directly into the emitting level

    NASA Astrophysics Data System (ADS)

    Lü, Y. F.; Yin, X. D.; Xia, J.; Wang, R. G.; Wang, D.

    2010-01-01

    We report the efficient blue laser at 473 nm generation by intracavity frequency doubling of a continuous wave laser operation of a 885 nm diode direct pumped Nd:YAG laser on the 4F3/2 → 4I9/2 transition at 946 nm. A LiB3O5 (LBO) crystal, cut for critical type I phase matching at room temperature is used for second harmonic generation of the laser. At the absorbed pump power of 18.7 W, as high as 4.3 W of continuous wave output power at 473 nm is achieved with 15 mm long LBO. The optical-to-optical conversion efficiency with respect to the absorbed power is up to 0.23, and the beam quality M2 value is 1.2.

  14. Note: Deep ultraviolet Raman spectrograph with the laser excitation line down to 177.3 nm and its application

    SciTech Connect

    Jin, Shaoqing; Fan, Fengtao; Guo, Meiling; Zhang, Ying; Feng, Zhaochi E-mail: canli@dicp.ac.cn; Li, Can E-mail: canli@dicp.ac.cn

    2014-04-15

    Deep UV Raman spectrograph with the laser excitation line down to 177.3 nm was developed in this laboratory. An ellipsoidal mirror and a dispersed-subtractive triple monochromator were used to collect and disperse Raman light, respectively. The triple monochromator was arranged in a triangular configuration with only six mirrors used. 177.3 nm laser excited Raman spectrum with cut-off wavenumber down to 200 cm{sup −1} and spectral resolution of 8.0 cm{sup −1} can be obtained under the condition of high purity N{sub 2} purging. With the C–C σ bond in Teflon selectively excited by the 177.3 nm laser, resonance Raman spectrum of Teflon with good quality was recorded on the home-built instrument and the σ-σ{sup *} transition of C–C bond was studied. The result demonstrates that deep UV Raman spectrograph is powerful for studying the systems with electronic transition located in the deep UV region.

  15. Continuous wave Nd:YAG-BiBO blue laser under direct 869 nm pumping

    NASA Astrophysics Data System (ADS)

    Zou, J.; Chu, H.; Wang, L. R.

    2012-03-01

    We report a blue laser at 473 nm generation by intracavity frequency doubling of a continuous wave (CW) laser operation of a 946 nm Nd:YAG laser under in-band diode pumping at 869 nm. An BiBO crystal, cut for critical type I phase matching at room temperature is used for second harmonic generation of the laser. At an incident pump power of 8.6 W, as high as 721 mW of CW output power at 473 nm is achieved. The optical-to-optical conversion efficiency is up to 8.4%, and the fluctuation of the blue output power was better than 3.5% in the given 30 min.

  16. Combination of 595-nm pulsed dye laser, long-pulsed 755-nm alexandrite laser, and microdermabrasion treatment for keratosis pilaris: retrospective analysis of 26 Korean patients.

    PubMed

    Lee, Sang Ju; Choi, Min Ju; Zheng, Zhenlong; Chung, Won Soon; Kim, Young Koo; Cho, Sung Bin

    2013-06-01

    Keratosis pilaris (KP) has beenpresented as small keratotic follicular papules with or without surrounding erythema. Various treatments with laser or light therapy have been used for the management of KP with various clinical outcomes. In the present study, we investigated the efficacy and safety of a combination therapy for KP. A total of 29 anatomical sites with KP in 26 patients were treated using a 595-nm pulsed dye laser (PDL) with nonpurpuragenic fluences, a long-pulsed 755-nm alexandrite laser, and microdermabrasion. Clinical improvement was assessed by comparing preand posttreatment clinical photographs and patient satisfaction rates. Evaluation of the clinical results three months after the treatments showed that 12 of the 29 anatomical sites (41.4%) demonstrated Grade 3 clinical improvement, ten (34.5%) had Grade 2 clinical improvement, four (13.8%) showed Grade 1 improvement, and three (10.3%) showed Grade 4 improvement. We observed that KP lesions improved not only in erythema and skin texture, but also in brownish dyschromias. Potential adverse events were not observed, except prolonged posttherapy scaling. Our observations demonstrate that combination therapy using a 595-nm PDL, a long-pulsed 755-nm alexandrite laser, and microdermabrasion can have a positive therapeutic effect on KP. PMID:23464682

  17. 885-nm Pumped Ceramic Nd:YAG Master Oscillator Power Amplifier Laser System

    NASA Technical Reports Server (NTRS)

    Yu, Anthony

    2012-01-01

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

  18. Watt-level continuous-wave diode lasers at 1180 nm with high spectral brightness

    NASA Astrophysics Data System (ADS)

    Paschke, K.; Blume, G.; Brox, O.; Bugge, F.; Fricke, J.; Feise, D.; Hofmann, J.; Wenzel, H.; Erbert, G.

    2015-03-01

    Distributed Bragg reflector (DBR) tapered lasers emitting near 1180 nm were developed. The integration of DBR surface gratings in an edge-emitting laser structure with a highly strained quantum well and a tapered laser geometry allows nearly diffraction limited emission into a single longitudinal mode with an optical output power of more than 2 W. The laser will allow direct second harmonic generation (SHG) in a single pass configuration and hence will enable the manufacturing of miniaturized laser modules near 590 nm for out-of-the-lab applications. An integration of a heater element at the DBR grating allows the tuning of the emission wavelength of more than 2 nm without the mechanical movement of gratings. This easy tuning simplifies the phase matching to a SHG crystal.

  19. 1120nm highly brilliant laser sources for SHG-modules in bio-analytics and spectroscopy

    NASA Astrophysics Data System (ADS)

    Paschke, Katrin; Fiebig, Christian; Blume, Gunnar; Bugge, Frank; Fricke, Jörg; Erbert, Götz

    2013-03-01

    Highly brilliant diode lasers at 1120nm with a high optical output power, nearly diffraction limited beam and narrow spectral line width are increasingly important for non-linear frequency conversion to 560 nm. We present experimental results about edge-emitting distributed Bragg reflector (DBR) tapered diode lasers emitting at 1120 nm. The investigated lasers show an output power of up to 8W with a conversion efficiency of about 40%, and a lifetime of more than 5000 h at 5 W. The lasers also exhibit a small vertical divergence <15° full width at half maximum (FWHM), a nearly diffraction limited beam quality, and a narrow spectral line width with FWHM smaller than 10pm. These properties allow the lasers to be used for future second harmonic (SH) generation.

  20. Characterization, diagnosis and ablation of human teeth using blue laser at 457 nm

    NASA Astrophysics Data System (ADS)

    El-Sherif, Ashraf F.; Gomaa, Walid; El-Sharkawy, Yasser H.

    2014-02-01

    The light interaction with tissue is governed by the specific wavelength of the laser used and the optical properties of target tissue. Absorption, scattering and fluorescence together can probably be used as the basis of quantitative diagnostic methods for teeth caries. The absorption coefficient of human teeth was determined from detached wet teeth (incisors and premolars). Laser absorption of these teeth was measured using compact blue laser source at wavelength of 457 nm and a high resolution spectrometer equipped with an integrating sphere. The average absorption coefficient of abnormal caries tissue of human teeth is observed to be higher than the normal ones. Detection and diagnosis of caries tissues were monitored by high resolution translational scanning of human teeth. We have a powerful tool to diagnosis a caries region of human teeth using blue laser at 457 nm. Ablations of caries region are investigated using higher power of blue laser at 457 nm.

  1. Theoretical and experimental research on the ˜980-nm Yb-doped fiber laser

    NASA Astrophysics Data System (ADS)

    Wang, Yanshan; Ke, Weiwei; Ma, Yi; Sun, Yinhong; Feng, Yujun

    2016-07-01

    The output properties of the ˜980-nm Yb-doped fiber laser versus pump power and core-cladding ratio of gain fiber, also the amplified spontaneous emission (ASE) at different wavelengths of seed laser, are investigated theoretically. An all-fiber amplifier based on different wavelengths of seed laser at 974.4, 977, and 981.7 nm brings the studies on parasitic oscillation and ASE in the ˜980-nm Yb-doped fiber amplifier. Through the theoretical and experimental research, we found that the controlling of three-level ASE around ˜980-nm is pivotal for obtaining a high-power 980-nm Yb-doped fiber amplifier.

  2. Efficient laser performance of a cryogenic Yb:YAG laser pumped by fiber coupled 940 and 969 nm laser diodes

    NASA Astrophysics Data System (ADS)

    Jambunathan, V.; Miura, T.; Těsnohlídková, L.; Lucianetti, A.; Mocek, T.

    2015-01-01

    Laser performance of Yb:YAG at different cryogenic temperatures pumped by a fiber coupled diode laser emitting at 940 and 969 nm were presented. The pump laser diode bandwidth, absorption bandwidth as well as absorption of the laser material at cryogenic temperatures play a vital role on laser performance. The laser threshold decreases and the output power and slope efficiency increase when cooled to cryogenic temperatures.

  3. 1579 NM Fiber Laser Source for Spaceborne Monitoring of Carbon Dioxide

    NASA Astrophysics Data System (ADS)

    Cézard, Nicolas; Lombard, Laurent; Le Gouët, Julien; Goular, Didier; Bresson, Alexandre; Dolfi-Bouteyre, Agnès; Canat, Guillaume

    2016-06-01

    We report on the development of a 1579 nm pulsed fiber laser source with high peak-power, intended to be used as a lidar source for CO2 monitoring from space. We first discuss water-vapor sensitivity of spaceborne CO2 measurements by lidar and point the interest of the 1579 nm wavelength with that respect. Then we detail the current development status of the pulsed fiber laser source.

  4. Dual-wavelength waveguide lasers at 1064 and 1079 nm in Nd:YAP crystal by direct femtosecond laser writing.

    PubMed

    Nie, Weijie; Cheng, Chen; Jia, Yuechen; Romero, Carolina; Vázquez de Aldana, Javier R; Chen, Feng

    2015-05-15

    Low-loss depressed cladding waveguides have been produced in Nd:YAP laser crystal by using direct femtosecond laser writing. Under optical pump at 812 nm at room temperature, continuous-wave simultaneous dual-wavelength laser oscillations at 1064 and 1079 nm, both along TM polarization, have been realized in the waveguiding structures. It has been found that, with the variation of pump polarization, the intensity ratio of 1064 and 1079 nm emissions varies periodically, while the polarization of output dual-wavelength laser remains unchanged. The maximum output power achieved for the Nd:YAP waveguide lasers is ∼200  mW with a slope efficiency of 33.4%. PMID:26393759

  5. Compact high power barium nitrite crystal-based Raman laser at 1197 nm for photoacoustic imaging of fat.

    PubMed

    Li, Rui; Slipchenko, Mikhail N; Wang, Pu; Cheng, Ji-Xin

    2013-04-01

    Photoacoustic imaging employing molecular overtone vibration as a contrast mechanism opens a new avenue for bond-selective imaging of deep tissues. Broad use of this modality is, however, hampered by the extremely low conversion efficiency of optical parametric oscillators at the overtone transition wavelengths. To overcome such a barrier, we demonstrate the construction and use of a compact, barium nitrite crystal-based Raman laser for photoacoustic imaging of C-H overtone vibrations. Using a 5-ns Nd∶YAG laser as the pumping source, up to 21.4 mJ pulse energy at 1197 nm was generated, corresponding to a conversion efficiency of 34.8%. Using the 1197 nm pulses, three-dimensional photoacoustic imaging of intramuscular fat was demonstrated. PMID:23536057

  6. Compact high power barium nitrite crystal-based Raman laser at 1197 nm for photoacoustic imaging of fat

    NASA Astrophysics Data System (ADS)

    Li, Rui; Slipchenko, Mikhail N.; Wang, Pu; Cheng, Ji-Xin

    2013-04-01

    Photoacoustic imaging employing molecular overtone vibration as a contrast mechanism opens a new avenue for bond-selective imaging of deep tissues. Broad use of this modality is, however, hampered by the extremely low conversion efficiency of optical parametric oscillators at the overtone transition wavelengths. To overcome such a barrier, we demonstrate the construction and use of a compact, barium nitrite crystal-based Raman laser for photoacoustic imaging of C-H overtone vibrations. Using a 5-ns Nd∶YAG laser as the pumping source, up to 21.4 mJ pulse energy at 1197 nm was generated, corresponding to a conversion efficiency of 34.8%. Using the 1197 nm pulses, three-dimensional photoacoustic imaging of intramuscular fat was demonstrated.

  7. Compact high power barium nitrite crystal-based Raman laser at 1197 nm for photoacoustic imaging of fat

    PubMed Central

    Li, Rui; Slipchenko, Mikhail N.; Wang, Pu

    2013-01-01

    Abstract. Photoacoustic imaging employing molecular overtone vibration as a contrast mechanism opens a new avenue for bond-selective imaging of deep tissues. Broad use of this modality is, however, hampered by the extremely low conversion efficiency of optical parametric oscillators at the overtone transition wavelengths. To overcome such a barrier, we demonstrate the construction and use of a compact, barium nitrite crystal-based Raman laser for photoacoustic imaging of C–H overtone vibrations. Using a 5-ns Nd∶YAG laser as the pumping source, up to 21.4 mJ pulse energy at 1197 nm was generated, corresponding to a conversion efficiency of 34.8%. Using the 1197 nm pulses, three-dimensional photoacoustic imaging of intramuscular fat was demonstrated. PMID:23536057

  8. Single-frequency tunable 447.3 nm laser by frequency doubling of tapered amplified diode laser at cesium D1 line.

    PubMed

    Zhang, Yan; Liu, Jinhong; Wu, Jinze; Ma, Rong; Wang, Dan; Zhang, Junxiang

    2016-08-22

    A continuous single-frequency tunable blue laser at 447.3 nm is developed by external-cavity frequency doubling of a tapered amplifier-boosted continuous-wave diode laser at cesium (Cs) D1 line. A maximum blue power of 178 mW with 50.8% conversion efficiency is obtained. It can be continuously tuned over a range around 1.6 GHz as the diode laser frequency is scanned across the F=4→F'=3 transition of 133Cs D1 line. The generated tunable and stable blue laser source has potential applications in constructing quantum light-atom interfaces in quantum networks. PMID:27557253

  9. Atomic force microscopy analysis of human cornea surface after UV (λ=266 nm) laser irradiation

    NASA Astrophysics Data System (ADS)

    Spyratou, E.; Makropoulou, M.; Moutsouris, K.; Bacharis, C.; Serafetinides, A. A.

    2009-07-01

    Efficient cornea reshaping by laser irradiation for correcting refractive errors is still a major issue of interest and study. Although the excimer laser wavelength of 193 nm is generally recognized as successful in ablating corneal tissue for myopia correction, complications in excimer refractive surgery leads to alternative laser sources and methods for efficient cornea treatment. In this work, ablation experiments of human donor cornea flaps were conducted with the 4th harmonic of an Nd:YAG laser, with different laser pulses. AFM analysis was performed for examination of the ablated cornea flap morphology and surface roughness.

  10. Corneal thermal damage threshold dependence on the exposure duration for near-infrared laser radiation at 1319 nm

    NASA Astrophysics Data System (ADS)

    Wang, Jiarui; Jiao, Luguang; Chen, Hongxia; Yang, Zaifu; Hu, Xiangjun

    2016-01-01

    The corneal damage effects induced by 1319-nm transitional near-infrared laser have been investigated for years. However, the damage threshold dependence on exposure duration has not been revealed. The in vivo corneal damage thresholds (ED50s) were determined in New Zealand rabbits for 1319-nm laser radiation for exposure durations from 75 ms to 10 s. An additional corneal ED50 was determined at 1338 nm for a 5-ms exposure. The incident corneal irradiance diameter was fixed at 2 mm for all exposure conditions to avoid the influence of spot size on threshold. The ED50s given in terms of the corneal radiant exposure for exposure durations of 5 ms, 75 ms, 0.35 s, 2 s, and 10 s were 39.4, 51.5, 87.2, 156.3, and 311.1 J/cm2, respectively. The 39.4 J/cm2 was derived from the ED50 for 1338 nm (27.0 J/cm2). The ED50s for exposure durations of 75 ms to 10 s were correlated by a power law equation, ED50=128.9t0.36 in J/cm2, where t was the input in the unit of second, with correlation coefficient (R) of 0.997. Enough safe margins existed between the ED50s and the maximum permitted exposures from current laser safety standard.