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Sample records for high-power semiconductor lasers

  1. Advances in high power semiconductor diode lasers

    NASA Astrophysics Data System (ADS)

    Ma, Xiaoyu; Zhong, Li

    2008-03-01

    High power semiconductor lasers have broad applications in the fields of military and industry. Recent advances in high power semiconductor lasers are reviewed mainly in two aspects: improvements of diode lasers performance and optimization of packaging architectures of diode laser bars. Factors which determine the performance of diode lasers, such as power conversion efficiency, temperature of operation, reliability, wavelength stabilization etc., result from a combination of new semiconductor materials, new diode structures, careful material processing of bars. The latest progress of today's high-power diode lasers at home and abroad is briefly discussed and typical data are presented. The packaging process is of decisive importance for the applicability of high-power diode laser bars, not only technically but also economically. The packaging techniques include the material choosing and the structure optimizing of heat-sinks, the bonding between the array and the heat-sink, the cooling and the fiber coupling, etc. The status of packaging techniques is stressed. There are basically three different diode package architectural options according to the integration grade. Since the package design is dominated by the cooling aspect, different effective cooling techniques are promoted by different package architectures and specific demands. The benefit and utility of each package are strongly dependent upon the fundamental optoelectronic properties of the individual diode laser bars. Factors which influence these properties are outlined and comparisons of packaging approaches for these materials are made. Modularity of package for special application requirements is an important developing tendency for high power diode lasers.

  2. Reliability of high-power semiconductor laser arrays

    NASA Astrophysics Data System (ADS)

    Kung, Hsing H.; Craig, Richard R.; Zucker, Erik P.; Li, Benjamin; Scifres, Donald R.

    1992-10-01

    The reliability of continuously operating (cw) high power laser arrays is a critical factor for the acceptance of these devices in a wide range of applications. Extensive investigation into the reliability of semiconductor lasers has led to an improved understanding of failure mechanisms such as material defects, mirror damage and solder related failures as well as to methods which significantly suppress the occurrence of catastrophic failure. Furthermore, as a result of material quality improvements, laser arrays exhibit very low gradual degradation for high power operation up to 2 Watts cw. Long term lifetest data shows that the projected medium life at room temperature of such devices exceed 100,000 hours at 2 W cw.

  3. Laser apparatus for surgery and force therapy based on high-power semiconductor and fibre lasers

    SciTech Connect

    Minaev, V P

    2005-11-30

    High-power semiconductor lasers and diode-pumped lasers are considered whose development qualitatively improved the characteristics of laser apparatus for surgery and force therapy, extended the scope of their applications in clinical practice, and enhanced the efficiency of medical treatment based on the use of these lasers. The characteristics of domestic apparatus are presented and their properties related to the laser emission wavelength used in them are discussed. Examples of modern medical technologies based on these lasers are considered. (invited paper)

  4. High-power semiconductor lasers at eye-safe wavelengths

    NASA Astrophysics Data System (ADS)

    Osowski, Mark L.; Gewirtz, Yossi; Lammert, Robert M.; Oh, Se W.; Panja, Chameli; Elarde, Victor C.; Vaissie, Laurent; Patel, Falgun D.; Ungar, Jeffrey E.

    2009-05-01

    InP based diode lasers are required to realize the next generation of eyesafe applications, including direct rangefinding and HEL weapons systems. We report on the progress of high power eyesafe single spatial and longitudinal mode 1550nm MOPA devices, where we have achieved peak powers in excess of 10W with 50ns pulse widths. A conceptual model based on our recent MOPA results show the path towards scaling to high powers based on spatial beam combination with operating conditions suitable for direct rangefinding applications. We also report on the progress towards high power 14xx and 15xx nm pump lasers for eyesafe HEL systems.

  5. High power semiconductor lasers for deep space communications

    NASA Technical Reports Server (NTRS)

    Katz, J.

    1981-01-01

    The parameters of semiconductor lasers pertaining to their application as optical emitters are discussed. Several methods to overcome their basic disadvantage, which is the low level of powers they emit, are reviewed. Most of these methods are based on a coherent power combining of several lasers.

  6. Spatial and Spectral Brightness Enhancement of High Power Semiconductor Lasers

    NASA Astrophysics Data System (ADS)

    Leidner, Jordan Palmer

    The performance of high-power broad-area diode lasers is inhibited by beam filamentation induced by free-carrier-based self-focusing. The resulting beam degradation limits their usage in high-brightness, high-power applications such as pumping fiber lasers, and laser cutting, welding, or marking. Finite-difference propagation method simulations via RSoft's BeamPROP commercial simulation suite and a custom-built MATLAB code were used for the study and design of laser cavities that suppress or avoid filamentation. BeamPROP was used to design a tapered, passive, multi-mode interference cavity for the creation of a self-phase-locking laser array, which is comprised of many single-mode gain elements coupled to a wide output coupler to avoid damage from local high optical intensities. MATLAB simulations were used to study the effects of longitudinal and lateral cavity confinement on lateral beam quality in conventional broad-area lasers. This simulation was expanded to design a laser with lateral gain and index prescription that is predicted to operate at or above state-of-the-art powers while being efficiently coupled to conventional telecom single-mode optical fibers. Experimentally, a commercial broad-area laser was coupled in the far-field to a single-mode fiber Bragg grating to provide grating-stabilized single-mode laser feedback resulting in measured spectral narrowing for efficient pump absorption. Additionally a 19 GHz-span, spatially resolved, self-heterodyne measurement was made of a broad-area laser to study the evolution/devolution of the mode content of the emitted laser beam with increasing power levels.

  7. The next generation of high-power semiconductor diode lasers

    NASA Astrophysics Data System (ADS)

    Botez, Dan; Yang, Jane J.

    Progress made in both high-power coherent arrays for space communications and high-power incoherent arrays for efficient pumping of solid-state (Nd-YAG) laser is reviewed. It is concluded that parallel coupling in a strong index-guided structure makes it possible to increase the performance of resonant-optical-waveguide (ROW) arrays by orders of magnitude higher than that of other array types. Preliminary results from ROW arrays show greater than 2,000 h operation at 0.5-W output with little increase in drive current. Edge-emitting POW arrays are likely to reach 2-3 W continuous-wave diffraction limited power. Monolithic solid-state pumps are likely to deliver optical flux densities in excess of 1 kW/sq cm.

  8. High-power semiconductor laser array packaged on microchannel cooler using gold-tin soldering technology

    NASA Astrophysics Data System (ADS)

    Wang, Jingwei; Kang, Lijun; Zhang, Pu; Nie, Zhiqiang; Li, Xiaoning; Xiong, Lingling; Liu, Xingsheng

    2012-03-01

    High power semiconductor laser arrays have found increased applications in many fields. In this work, a hard soldering microchannel cooler (HSMCC) technology was developed for packaging high power diode laser array. Numerical simulations of the thermal behavior characteristics of hard solder and indium solder MCC-packaged diode lasers were conducted and analyzed. Based on the simulated results, a series of high power HSMCC packaged diode laser arrays were fabricated and characterized. The test and statistical results indicated that under the same output power the HSMCC packaged laser bar has lower smile and high reliability in comparison with the conventional copper MCC packaged laser bar using indium soldering technology.

  9. High power semiconductor laser source for space applications

    NASA Astrophysics Data System (ADS)

    Goodwin, A. R.; Whiteaway, J. E. A.; Collar, A. J.

    1986-07-01

    Semiconductor laser sources for optical communication links between geostationary and low Earth orbiting satellites were investigated. Phase locked arrays of coupled stripes or related devices offer single mode operation at much lower optical and current density than other techniques. The highest powers are expected using GaAlAs, the best reliability using InGaAsP. Use of very thin highly doped p-InP buffer layers in planar growth, wide mesas, long cavities, and facet coating for DCPBH lasers are suggested. Continuous output power values up to 340 mW can be generated by unoptimized multimode InGaAsP lasers emitting at 1.3 microns. It should be possible to generate continuous power levels greater than 1000 mW by optimizing facet reflectivity and thermal impedance. The Y-coupled array is the most promising concept. The addition of flared output guides, and the positioning of the couplers close to the facet with the larger number of emitters, should improve performance.

  10. High-power optically pumped semiconductor laser apllications

    NASA Astrophysics Data System (ADS)

    Morioka, S. Brandon

    2011-03-01

    OPS lasers have found applications in various industrial and scientific laser applications due to their power scaling capability, their wide range of emission wavelengths, physical size and their superior reliability. This paper provides an overview of commercially available OPS lasers and the applications in which they are used including biotechnology, medical, holography, Titanium-Sapphire laser pumping, non-lethal defense, forensics, and entertainment.

  11. Generation of high-power ultrashort optical pulses by semiconductor lasers

    NASA Astrophysics Data System (ADS)

    Dudelev, V. V.; Zazulin, S. V.; Kolykhalova, E. D.; Losev, S. N.; Deryagin, A. G.; Kuchinskii, V. I.; Efanov, M. V.; Sokolovskii, G. S.

    2016-12-01

    Fiber-coupled semiconductor lasers have been studied when pumped by high-power short electrical pulses of 5 ns width and leading front duration below 1 ns. In this pumping regime, it is possible to ensure significant sharpening of output pulses, the duration of which decreases below 80 ps for a single-mode laser and below 120 ps for a broad aperture multimode laser at an output peak optical power as high as 1.5 and 27 W, respectively.

  12. High-power high-brightness semiconductor lasers

    NASA Astrophysics Data System (ADS)

    Botez, D.

    2005-01-01

    Broad-stripe (greater than or equal to 100 microns) diode lasers have achieved CW powers as high as 15W, and wallplug efficiencies as high as 70%. For high coherent power photonic-crystal structures with modulated gain, that is active photonic crystals (APCs), of large index steps have been used, as early as 1988, for effective lateral-mode control range in large-aperture (100-200 microns) devices. Photonic-bandpass (PBP) structures relying on long-range resonant leaky-wave coupling, so called ROW arrays, have allowed stable, near-diffraction-limited beam operation to powers as high as 1.6W CW and 10W peak pulsed. Photonic-bandgap (PBG) structures with a built-in lattice defect, so called ARROW lasers, have provided up to 0.5W CW stable, single-mode power and hold the potential for 1W CW highly reliable single-mode operation. The solution for high-efficiency surface emission, from 2nd-order DFB/DBR lasers, in a single-lobe beam pattern was found in 2000. Single-lobe and single-mode operation in a diffraction-limited beam orthonormal to the chip surface was demonstrated, which opens the way for the realization of 2-D surface-emitting, 2nd-order APCs for the stable generation of watts of CW single-lobe, single-mode power from large 2-D apertures, as well as scalability of such devices at the wafer level.

  13. A study on the reliability of indium solder die bonding of high power semiconductor lasers

    NASA Astrophysics Data System (ADS)

    Liu, Xingsheng; Davis, Ronald W.; Hughes, Lawrence C.; Rasmussen, Michael H.; Bhat, Rajaram; Zah, Chung-En; Stradling, Jim

    2006-07-01

    High power semiconductor lasers have found increased applications. Indium solder is one of the most widely used solders in high power laser die bonding. Indium solder has some advantages in laser die bonding. It also has some concerns, however, especially in terms of reliability. In this paper, the reliability of indium solder die bonding of high power broad area semiconductor lasers was studied. It was found that indium solder bonded lasers have much shorter lifetime than AuSn solder bonded devices. Catastrophic degradation was observed in indium solder bonded lasers. Nondestructive optical and acoustic microscopy was conducted during the lifetime testing to monitor the failure process and destructive failure analysis was performed after the lasers failed. It was found that the sudden failure was caused by electromigration of indium solder at the high testing current of up to 7A. It was shown that voids were created and gradually enlarged by indium solder electromigration, which caused local heating near the facets of the laser. The local heating induced catastrophic optical mirror damage (COMD) of the lasers. It was discussed that current crowding, localized high temperature, and large temperature gradient contributed to the fast indium solder electromigration. It was observed that some bright pattern structures appeared on the front facet of the indium solder bonded lasers after the devices failed and the bright patterns grew and spread upon further testing. Failure analysis showed that the bright pattern structure apparent on the front facet was due to crystallization of the TiOx material of the front facet coating as a result of overheating during lifetime testing. It was concluded that indium solder is not suitable for high power laser applications due to electromigration at high current densities and high temperatures.

  14. High-power MIXSEL: an integrated ultrafast semiconductor laser with 6.4 W average power.

    PubMed

    Rudin, B; Wittwer, V J; Maas, D J H C; Hoffmann, M; Sieber, O D; Barbarin, Y; Golling, M; Südmeyer, T; Keller, U

    2010-12-20

    High-power ultrafast lasers are important for numerous industrial and scientific applications. Current multi-watt systems, however, are based on relatively complex laser concepts, for example using additional intracavity elements for pulse formation. Moving towards a higher level of integration would reduce complexity, packaging, and manufacturing cost, which are important requirements for mass production. Semiconductor lasers are well established for such applications, and optically-pumped vertical external cavity surface emitting lasers (VECSELs) are most promising for higher power applications, generating the highest power in fundamental transverse mode (>20 W) to date. Ultrashort pulses have been demonstrated using passive modelocking with a semiconductor saturable absorber mirror (SESAM), achieving for example 2.1-W average power, sub-100-fs pulse duration, and 50-GHz pulse repetition rate. Previously the integration of both the gain and absorber elements into a single wafer was demonstrated with the MIXSEL (modelocked integrated external-cavity surface emitting laser) but with limited average output power (<200 mW). We have demonstrated the power scaling concept of the MIXSEL using optimized quantum dot saturable absorbers in an antiresonant structure design combined with an improved thermal management by wafer removal and mounting of the 8-µm thick MIXSEL structure directly onto a CVD-diamond heat spreader. The simple straight cavity with only two components has generated 28-ps pulses at 2.5-GHz repetition rate and an average output power of 6.4 W, which is higher than for any other modelocked semiconductor laser.

  15. Lifetime of high-power GaAs photoconductive semiconductor switch triggered by laser of different power density

    NASA Astrophysics Data System (ADS)

    Liu, Yi; Wang, Wei; Shen, Yi; Shi, Jinshui; Zhang, Linwen; Xia, Liansheng

    2015-02-01

    Conduction modes of GaAs photoconductive semiconductor switch (PCSS) and their conditions are expounded. Laser diode and high-power picosecond Nd:YAG lasers are used as triggers for nonlinear mode and quasi-linear mode respectively in high-power conduction experiment. GaAs PCSS`s failure mechanisms and factors influencing lifetime in both modes are analyzed. It is found that the power density of laser at trigger time determines in which mode GaAs PCSS operates. Low-power laser triggers a nonlinear mode conduction in which GaAs PCSS`s lifetime is only 103, while high-power laser triggers a quasi-linear mode conduction in which GaAs PCSS`s lifetime is up to 105. According to the findings, the compact high-power pulsed power system based on mass of GaAs PCSSs demands for miniature high-power laser generators.

  16. The main factors that affect coupling efficiency of high-power semiconductor laser array and selfoc lens array

    NASA Astrophysics Data System (ADS)

    Jiang, Xiaoping; Liu, Desen

    2008-03-01

    The coupling technique of high-power semiconductor laser array is an advancing key project. A high power density collimated beam, which facula is much smaller, can be get by coupling high-power laser array with selfoc lens array. At the same time, the coupling efficiency is higher. The factors which affect the coupling efficiency mainly include NA, diameter, length and end surface fabricating of selfoc lens and coupling technique. In this paper, an 1×19 linear laser array which maximum continuous output power is 22W is coupled with a corresponding selfoc lens array. The maximum coupling efficiency is 58.2%.

  17. High power single-frequency continuously-tunable compact extended-cavity semiconductor laser.

    PubMed

    Laurain, A; Myara, M; Beaudoin, G; Sagnes, I; Garnache, A

    2009-06-08

    We demonstrate high power high efficiency (0:3 W) low noise single frequency operation of a compact extended-cavity surface-emitting-semiconductor-laser exhibiting a continuous tunability over 0:84 THz with high beam quality. We took advantage of thermal lens-based stability to develop a short (< 3 mm) plano-plano external cavity without any intracavity filter. The structure is optically pumped by a 1 W commercial 830 nm multimode diode laser. No heat management was required. We measured a low divergence circular TEM(00) beam at the diffraction limit (M(2) < 1:05) with a linear light polarization (> 37 dB). The side mode suppression ratio is 60 dB. The free running laser linewidth is 850 kHz limited by pump induced thermal fluctuations. Thanks to this high-Q external cavity approach, the frequency noise is low and the dynamics is in the relaxation-oscillation-free regime, exhibiting a low intensity noise, with a cutoff frequency approximately 250 MHz above which the shot noise level is reached. We show that pump properties define the cavity design and laser coherence.

  18. Reliability of single-mode and multi-mode high-power semiconductor lasers at eye-safe wavelengths

    NASA Astrophysics Data System (ADS)

    Stakelon, T.; Lucas, J.; Osowski, M.; Lammert, R.; Moon, S.; Panja, C.; Elarde, V.; Gallup, K.; Hu, W.; Ungar, J.

    2009-02-01

    High power semiconductor lasers with wavelengths in the eye-safer region have application to a variety of defense, medical and industrial applications. We report on the reliability of high power multimode and single mode InGaAsP/InP diode lasers with wavelengths in the range 1320 to 1550 nm in a variety of configurations, including single-chip, conduction-cooled arrays, arrays incorporating internal diffraction gratings, master-oscillator power amplifiers, and fiber-coupled modules of the above. In all cases we show very low rates of degradation in optical power and the absence of sudden failure from catastrophic optical damage or from laser-package interactions.

  19. Researching the 915 nm high-power and high-brightness semiconductor laser single chip coupling module

    NASA Astrophysics Data System (ADS)

    Wang, Xin; Wang, Cuiluan; Wu, Xia; Zhu, Lingni; Jing, Hongqi; Ma, Xiaoyu; Liu, Suping

    2017-02-01

    Based on the high-speed development of the fiber laser in recent years, the development of researching 915 nm semiconductor laser as main pumping sources of the fiber laser is at a high speed. Because the beam quality of the laser diode is very poor, the 915 nm laser diode is generally based on optical fiber coupling module to output the laser. Using the beam-shaping and fiber-coupling technology to improve the quality of output beam light, we present a kind of high-power and high-brightness semiconductor laser module, which can output 13.22 W through the optical fiber. Based on 915 nm GaAs semiconductor laser diode which has output power of 13.91 W, we describe a thoroughly detailed procedure for reshaping the beam output from the semiconductor laser diode and coupling the beam into the optical fiber of which the core diameter is 105 μm and the numerical aperture is 0.18. We get 13.22 W from the output fiber of the module at 14.5 A, the coupling efficiency of the whole module is 95.03% and the brightness is 1.5 MW/cm2 -str. The output power of the single chip semiconductor laser module achieves the advanced level in the domestic use.

  20. Pulse repetition rate scaling from 5 to 100 GHz with a high-power semiconductor disk laser.

    PubMed

    Mangold, Mario; Zaugg, Christian A; Link, Sandro M; Golling, Matthias; Tilma, Bauke W; Keller, Ursula

    2014-03-10

    The high-power semiconductor laser studied here is a modelocked integrated external-cavity surface emitting laser (MIXSEL), which combines the gain of vertical-external-cavity surface-emitting lasers (VECSELs) with the saturable absorber of a semiconductor saturable absorber mirror (SESAM) in a single semiconductor layer stack. The MIXSEL concept allows for stable and self-starting fundamental passive modelocking in a simple straight cavity and the average power scaling is based on the semiconductor disk laser concept. Previously record-high average output power from an optically pumped MIXSEL was demonstrated, however the long pulse duration of 17 ps prevented higher pulse repetition rates and many interesting applications such as supercontinuum generation and broadband frequency comb generation. With a novel MIXSEL structure, the first femtosecond operation was then demonstrated just recently. Here we show that such a MIXSEL can also support pulse repetition rate scaling from ≈5 GHz to >100 GHz with excellent beam quality and high average output power, by mechanically changing the cavity length of the linear straight cavity and the output coupler. Up to a pulse repetition rate of 15 GHz we obtained average output power >1 W and pulse durations <4 ps. Furthermore we have been able to demonstrate the highest pulse repetition rate from any fundamentally modelocked semiconductor disk laser with 101.2 GHz at an average output power of 127 mW and a pulse duration of 570 fs.

  1. Simulation of spectral stabilization of high-power broad-area edge emitting semiconductor lasers.

    PubMed

    Holly, Carlo; Hengesbach, Stefan; Traub, Martin; Hoffmann, Dieter

    2013-07-01

    The simulation of spectral stabilization of broad-area edge-emitting semiconductor diode lasers is presented in this paper. In the reported model light-, temperature- and charge carrier-distributions are solved iteratively in frequency domain for transverse slices along the semiconductor heterostructure using wide-angle finite-difference beam propagation. Depending on the operating current the laser characteristics are evaluated numerically, including near- and far-field patterns of the astigmatic laser beam, optical output power and the emission spectra, with central wavelength and spectral width. The focus of the model lies on the prediction of influences on the spectrum and power characteristics by frequency selective feedback from external optical resonators. Results for the free running and the spectrally stabilized diode are presented.

  2. Numerical study of high-power semiconductor lasers for operation at sub-zero temperatures

    NASA Astrophysics Data System (ADS)

    Hasler, K. H.; Frevert, C.; Crump, P.; Erbert, G.; Wenzel, H.

    2017-04-01

    We present results on the impact of the Al-content in the waveguide structure on the electro-optical characteristics of 9xx nm, GaAs-based high-power lasers operated at room (300 K) and at sub-zero (200 K) heat sink temperatures. Experimentally a strong improvement of conversion efficiency and output power has been found if the lasers are cooled down. Numerical simulations using a software tool which solves the thermo-dynamic based drift-diffusion equations are able to reproduce the experimental findings. The reasons for the improved performance at lower temperatures are the enhancement of the modal gain and the reduced accumulation of electrons in the p-confinement layers resulting in a reduction of the leakage current. The latter allows the realization of lasers with a reduced Al content having a smaller series resistance and thus further enlarged conversion efficiency at sub-zero temperatures.

  3. High-order diffraction gratings for high-power semiconductor lasers

    SciTech Connect

    Vasil'eva, V. V.; Vinokurov, D. A.; Zolotarev, V. V.; Leshko, A. Yu.; Petrunov, A. N.; Pikhtin, N. A.; Rastegaeva, M. G.; Sokolova, Z. N. Shashkin, I. S.; Tarasov, I. S.

    2012-02-15

    A deep diffraction grating with a large period ({approx}2 {mu}m) within one of the cladding layers is proposed for the implementation of selective feedback in a semiconductor laser. Frequency dependences of reflectance in the 12th diffraction order for rectangular, triangular, and trapezoidal diffraction gratings are calculated. It is shown that the maximum reflectance of the waveguide mode is attained using a rectangular or trapezoidal grating {approx}2 {mu}m deep in the laser structure. Deep trapezoidal diffraction gratings with large periods are fabricated in the Al{sub 0.3}Ga{sub 0.7}As cladding layer of a GaAs/AlGaAs laser structure using photolithography and reactive ion etching.

  4. High-power single spatial mode AlGaAs channeled-substrate-planar semiconductor diode lasers for spaceborne communications

    NASA Technical Reports Server (NTRS)

    Connolly, J. C.; Carlin, D. B.; Ettenberg, M.

    1989-01-01

    A high power single spatial mode channeled substrate planar AlGaAs semiconductor diode laser was developed. The emission wavelength was optimized at 860 to 880 nm. The operating characteristics (power current, single spatial mode behavior, far field radiation patterns, and spectral behavior) and results of computer modeling studies on the performance of the laser are discussed. Reliability assessment at high output levels is included. Performance results on a new type of channeled substrate planar diode laser incorporating current blocking layers, grown by metalorganic chemical vapor deposition, to more effectively focus the operational current to the lasing region was demonstrated. The optoelectronic behavior and fabrication procedures for this new diode laser are discussed. The highlights include single spatial mode devices with up to 160 mW output at 8600 A, and quantum efficiencies of 70 percent (1 W/amp) with demonstrated operating lifetimes of 10,000 h at 50 mW.

  5. Far field and wavefront characterization of a high-power semiconductor laser for free space optical communications

    NASA Technical Reports Server (NTRS)

    Cornwell, Donald M., Jr.; Saif, Babak N.

    1991-01-01

    The spatial pointing angle and far field beamwidth of a high-power semiconductor laser are characterized as a function of CW power and also as a function of temperature. The time-averaged spatial pointing angle and spatial lobe width were measured under intensity-modulated conditions. The measured pointing deviations are determined to be well within the pointing requirements of the NASA Laser Communications Transceiver (LCT) program. A computer-controlled Mach-Zehnder phase-shifter interferometer is used to characterize the wavefront quality of the laser. The rms phase error over the entire pupil was measured as a function of CW output power. Time-averaged measurements of the wavefront quality are also made under intensity-modulated conditions. The measured rms phase errors are determined to be well within the wavefront quality requirements of the LCT program.

  6. Toward realizing high power semiconductor terahertz laser sources at room temperature

    NASA Astrophysics Data System (ADS)

    Razeghi, Manijeh

    2011-05-01

    The terahertz (THz) spectral range offers promising applications in science, industry, and military. THz penetration through nonconductors (fabrics, wood, plastic) enables a more efficient way of performing security checks (for example at airports), as illegal drugs and explosives could be detected. Being a non-ionizing radiation, THz radiation is environment-friendly enabling a safer analysis environment than conventional X-ray based techniques. However, the lack of a compact room temperature THz laser source greatly hinders mass deployment of THz systems in security check points and medical centers. In the past decade, tremendous development has been made in GaAs/AlGaAs based THz Quantum Cascade Laser (QCLs), with maximum operating temperatures close to 200 K (without magnetic field). However, higher temperature operation is severely limited by a small LO-phonon energy (~ 36 meV) in this material system. With a much larger LO-phonon energy of ~ 90 meV, III-Nitrides are promising candidates for room temperature THz lasers. However, realizing high quality material for GaN-based intersubband devices presents a significant challenge. Advances with this approach will be presented. Alternatively, recent demonstration of InP based mid-infrared QCLs with extremely high peak power of 120 W at room temperature opens up the possibility of producing high power THz emission with difference frequency generation through two mid-infrared wavelengths.

  7. Three-dimensional failure analysis of high power semiconductor laser diodes operated in vacuum

    NASA Astrophysics Data System (ADS)

    Yeoh, Terence S.; Chaney, John A.; Leung, Martin S.; Ives, Neil A.; Feinberg, Z. D.; Ho, James G.; Wen, Jianguo

    2007-12-01

    The damaged region of a semiconductor laser diode that failed in a vacuum environment was analyzed using focused ion beam (FIB) serial sectioning, time-of-flight secondary ion mass spectrometry (ToF-SIMS), high resolution transmission electron microscopy (TEM), electron energy loss spectroscopy (EELS), energy dispersive x-ray spectroscopy (EDS), and nanodiffraction. The FIB nanotomography models and the TEM cross sections show a damage structure extending deep into the core and originating at the diode/antireflective (AR) coating interface. Nanocrystalline gold was detected at this interface using both TEM diffraction and EDS, and the localization of gold along the core at the diode/AR interface was corroborated using 3D ToF-SIMS. A thinning of the AR coating above the failure site was observed by TEM with a corresponding increase in carbon content on the AR surface detected with EELS. It is suggested that failure proceeded by pyrolysis of adsorbed hydrocarbons on the AR coating, which, in the presence of a high optical flux, contributed to carbothermal reduction of the AR coating. As the optical flux increased, thermal gradients facilitate metal migration, leading to larger gold clusters. These clusters are sites for deep level traps and may promote catalytic reactions.

  8. Tunable high-power narrow-linewidth semiconductor laser based on an external-cavity tapered amplifier.

    PubMed

    Chi, Mingjun; Jensen, Ole Bjarlin; Holm, Jesper; Pedersen, Christian; Andersen, Peter Eskil; Erbert, Götz; Sumpf, Bernd; Petersen, Paul Michael

    2005-12-26

    A high-power narrow-linewidth laser system based on a tapered semiconductor optical amplifier in external cavity is demonstrated. The external cavity laser system uses a new tapered amplifier with a super-large optical-cavity (SLOC) design that leads to improved performance of the external cavity diode lasers. The laser system is tunable over a 29 nm range centered at 802 nm. As high as 1.95 W output power is obtained at 803.84 nm, and an output power above 1.5 W is achieved from 793 to 812 nm at operating current of 3.0 A. The emission linewidth is below 0.004 nm and the beam quality factor M2 is below 1.3 over the 29 nm tunable range. As an example of application, the laser system is used as a pump source for the generation of 405 nm blue light by single-pass frequency doubling in a periodically poled KTiOPO4. An output power of 24 mW at 405 nm, corresponding to a conversion efficiency of 0.83%/W is attained.

  9. Merged beam laser design for reduction of gain-saturation and two-photon absorption in high power single mode semiconductor lasers.

    PubMed

    Lysevych, M; Tan, H H; Karouta, F; Fu, L; Jagadish, C

    2013-04-08

    In this paper we report a method to overcome the limitations of gain-saturation and two-photon absorption faced by developers of high power single mode InP-based lasers and semiconductor optical amplifiers (SOA) including those based on wide-waveguide or slab-coupled optical waveguide laser (SCOWL) technology. The method is based on Y-coupling design of the laser cavity. The reduction in gain-saturation and two-photon absorption in the merged beam laser structures (MBL) are obtained by reducing the intensity of electromagnetic field in the laser cavity. Standard ridge-waveguide lasers and MBLs were fabricated, tested and compared. Despite a slightly higher threshold current, the reduced gain-saturation in MBLs results in higher output power. The MBLs also produced a single spatial mode, as well as a strongly dominating single spectral mode which is the inherent feature of MBL-type cavity.

  10. Simulation of power – current characteristics of high-power semiconductor lasers emitting in the range 1.5 – 1.55 μm

    SciTech Connect

    Gorlachuk, P V; Ivanov, A V; Kurnosov, V D; Kurnosov, K V; Romantsevich, V I; Simakov, V A; Chernov, R V

    2014-02-28

    We report the simulation of power – current characteristics of high-power semiconductor lasers emitting in the range 1.5 – 1.55 μm. A technique is described which allows one to determine the thermal resistance and characteristic temperatures of a laser diode. The radiative and nonradiative carrier recombination rates are evaluated. Simulation results are shown to agree well with experimental data. (lasers)

  11. Nonlinear optical compression of high-power 10-μm CO2 laser pulses in gases and semiconductors

    NASA Astrophysics Data System (ADS)

    Pigeon, Jeremy; Tochitsky, Sergei; Joshi, Chan

    2017-03-01

    We review a series of experiments on nonlinear optical compression of high-power, picosecond, 10-µm CO2 laser pulses. Presented schemes include self-phase modulation in a Xe-filled hollow glass waveguide, self-phase modulation in GaAs followed by compression, and multiple four-wave mixing compression of a laser beat-wave in GaAs. The novel nonlinear optics and technical challenges uncovered through these experiments are discussed.

  12. High-power 880-nm diode-directly-pumped passively mode-locked Nd:YVO₄ laser at 1342 nm with a semiconductor saturable absorber mirror.

    PubMed

    Li, Fang-Qin; Liu, Ke; Han, Lin; Zong, Nan; Bo, Yong; Zhang, Jing-Yuan; Peng, Qin-Jun; Cui, Da-Fu; Xu, Zu-Yan

    2011-04-15

    A high-power 880-nm diode-directly-pumped passively mode-locked 1342 nm Nd:YVO₄ laser was demonstrated with a semiconductor saturable absorber mirror (SESAM). The laser mode radii in the laser crystal and on the SESAM were optimized carefully using the ABCD matrix formalism. An average output power of 2.3 W was obtained with a repetition rate of 76 MHz and a pulse width of 29.2 ps under an absorbed pump power of 12.1 W, corresponding to an optical-optical efficiency of 19.0% and a slope efficiency of 23.9%, respectively.

  13. High power solid state lasers

    SciTech Connect

    Weber, H.

    1988-01-01

    These proceedings discuss the following subjects: trends in materials processing with laser radiation; slabs and high power systems; glasses and new crystals; solid state lasers at HOYA Corp.; lamps, resonators and transmission; glasses as active materials for high average power solid state lasers; flashlamp pumped GGG-crystals; alexandrite lasers; designing telescope resonators; mode operation of neodymium: YAG lasers; intracavity frequency doubling with KTP crystal and thermal effects in cylinder lasers.

  14. High-power pulsed lasers

    SciTech Connect

    Holzrichter, J.F.

    1980-04-02

    The ideas that led to the successful construction and operation of large multibeam fusion lasers at the Lawrence Livermore Laboratory are reviewed. These lasers are based on the use of Nd:glass laser materials. However, most of the concepts are applicable to any laser being designed for fusion experimentation. This report is a summary of lectures given by the author at the 20th Scottish University Summer School in Physics, on Laser Plasma Interaction. This report includes basic concepts of the laser plasma system, a discussion of lasers that are useful for short-pulse, high-power operation, laser design constraints, optical diagnostics, and system organization.

  15. Theory of direct and indirect effect of two-photon absorption on nonlinear optical losses in high power semiconductor lasers

    NASA Astrophysics Data System (ADS)

    Avrutin, E. A.; Ryvkin, B. S.

    2017-01-01

    The effect of the transverse laser structure on two-photon absorption (TPA) related effects in high-power diode lasers is analysed theoretically. The direct effect of TPA is found to depend significantly on the transverse waveguide structure, and predicted to be weaker in broad and asymmetric waveguide designs. The indirect effect of TPA, via carrier generation in the waveguide and free-carrier absorption, is analysed for the case of a symmetric laser waveguide and shown to be strongly dependent on the active layer position. With the active layer near the mode peak, the indirect effect is weaker than the direct effect due to the population of TPA-created carriers being efficiently depleted by their diffusion and capture into the active layer, whereas for the active layer position strongly shifted towards the p-cladding, the indirect effect can become the dominant power limitation at very high currents. It is shown that for optimizing a laser design for pulsed high power operation, both TPA related effects and the inhomogeneous carrier accumulation in the waveguide caused by diffusive current need to be taken into account.

  16. High power DUV lasers for material processing

    NASA Astrophysics Data System (ADS)

    Mimura, Toshio; Kakizaki, Kouji; Oizumi, Hiroaki; Kobayashi, Masakazu; Fujimoto, Junichi; Matsunaga, Takashi; Mizoguchi, Hakaru

    2016-11-01

    A frontier in laser machining has been required by material processing in DUV region because it is hard to get high power solid-state lasers in this spectral region. DUV excimer lasers are the only solution, and now the time has come to examine the new applications of material processing with DUV excimer lasers. The excimer lasers at 193nm and 248nm have been used in the semiconductor manufacturing for long years, and have field-proven stability and reliability. The high photon energy of 6.4 eV at 193nm is expected to interact directly with the chemical bond of hard-machining materials, such as CFRP, diamond and tempered glasses. We report the latest results of material processing by 193nm high power DUV laser.

  17. Optical-cell model based on the lasing competition of mode structures with different Q-factors in high-power semiconductor lasers

    SciTech Connect

    Podoskin, A. A. Shashkin, I. S.; Slipchenko, S. O.; Pikhtin, N. A.; Tarasov, I. S.

    2015-08-15

    A model describing the operation of a completely optical cell, based on the competition of lasing of Fabry-Perot cavity modes and the high-Q closed mode in high-power semiconductor lasers is proposed. Based on rate equations, the conditions of lasing switching between Fabry-Perot modes for ground and excited lasing levels and the closed mode are considered in the case of increasing internal optical loss under conditions of high current pump levels. The optical-cell operation conditions in the mode of a high-power laser radiation switch (reversible mode-structure switching) and in the mode of a memory cell with bistable irreversible lasing switching between mode structures with various Q-factors are considered.

  18. INTERNATIONAL CONFERENCE ON SEMICONDUCTOR INJECTION LASERS SELCO-87: Behavior of gain-guided lasers generating high-power nanosecond pulses

    NASA Astrophysics Data System (ADS)

    Erbert, G.

    1988-11-01

    Computer-controlled apparatus was used in an investigation of gain-guided narrow-stripe AlGaAs double heterostructure lasers. These lasers were excited with current pulses of 10 ns duration and amplitudes up to 3 A. The watt-ampere characteristics together with near- and far-field radiation patterns were considered using an analytic model of the lasers. The results showed that the values of the gain under a stripe contact or of the absorption outside this region varied with the output power.

  19. Surface activated bonding of GaAs and SiC wafers at room temperature for improved heat dissipation in high-power semiconductor lasers

    NASA Astrophysics Data System (ADS)

    Higurashi, Eiji; Okumura, Ken; Nakasuji, Kaori; Suga, Tadatomo

    2015-03-01

    Thermal management of high-power semiconductor lasers is of great importance since the output power and beam quality are affected by the temperature rise of the gain region. Thermal simulations of a vertical-external-cavity surface-emitting laser by a finite-element method showed that the solder layer between the semiconductor thin film consisting of the gain region and a heat sink has a strong influence on the thermal resistance and direct bonding is preferred to achieve effective heat dissipation. To realize thin-film semiconductor lasers directly bonded on a high-thermal-conductivity substrate, surface-activated bonding using an argon fast atom beam was applied to the bonding of gallium arsenide (GaAs) and silicon carbide (SiC) wafers. The GaAs/SiC structure was demonstrated in the wafer scale (2 in. in diameter) at room temperature. The cross-sectional transmission electron microscopy observations showed that void-free bonding interfaces were achieved.

  20. High power gas laser amplifier

    DOEpatents

    Leland, Wallace T.; Stratton, Thomas F.

    1981-01-01

    A high power output CO.sub.2 gas laser amplifier having a number of sections, each comprising a plurality of annular pumping chambers spaced around the circumference of a vacuum chamber containing a cold cathode, gridded electron gun. The electron beam from the electron gun ionizes the gas lasing medium in the sections. An input laser beam is split into a plurality of annular beams, each passing through the sections comprising one pumping chamber.

  1. Optics assembly for high power laser tools

    DOEpatents

    Fraze, Jason D.; Faircloth, Brian O.; Zediker, Mark S.

    2016-06-07

    There is provided a high power laser rotational optical assembly for use with, or in high power laser tools for performing high power laser operations. In particular, the optical assembly finds applications in performing high power laser operations on, and in, remote and difficult to access locations. The optical assembly has rotational seals and bearing configurations to avoid contamination of the laser beam path and optics.

  2. Characterization of a Low-phase-noise, High-power (370 mW), External-Cavity Semiconductor Laser

    DTIC Science & Technology

    2010-07-21

    Integrated Circuits: John Wiley & Sons, Inc. [21] A. Dandridge, " Fiber Optic Sensors Based on the Mach-Zehnder and Michelson Interferometers ," in Fiber ...Foam (Formerly E.N. Murray)] with two encased MZIs inside [see for example Optiphase MFI Michelson Fiber Interferometer ]. (b) Close-up of the high... Interferometer Detector* LASER Fiber ‐wrapped PZT coil Output ‐ V 3 dB Coupler ΔL = LS ‐ LR Differential Optical Phase 2 n L f c πφ Δ ΔΔ =

  3. High power laser perforating tools and systems

    SciTech Connect

    Zediker, Mark S; Rinzler, Charles C; Faircloth, Brian O; Koblick, Yeshaya; Moxley, Joel F

    2014-04-22

    ystems devices and methods for the transmission of 1 kW or more of laser energy deep into the earth and for the suppression of associated nonlinear phenomena. Systems, devices and methods for the laser perforation of a borehole in the earth. These systems can deliver high power laser energy down a deep borehole, while maintaining the high power to perforate such boreholes.

  4. Transmission electron microscopy characterization of Au/Pt/Ti/Pt/GaAs ohmic contacts for high power GaAs/InGaAs semiconductor lasers.

    PubMed

    Łaszcz, A; Czerwinski, A; Ratajczak, J; Szerling, A; Phillipp, F; Van Aken, P A; Katcki, J

    2010-03-01

    We report on transmission electron microscopy studies of Au/Pt/Ti/Pt(10-30 nm) contact structures for high power GaAs/InGaAs semiconductor lasers. The studies showed that annealing at 450 degrees C of contact structures causes the reaction of whole Pt with substrate components (Ga and As) and the formation of Pt-GaAs interlayers with smooth interfaces as required for such structures. Annealing of the structures at 470 and 490 degrees C unfavourably affects the contact structure. At this condition, the strong downward diffusion of Au and Pt from the top layers causes a formation of Au-Pt pits, which break the Ti barrier. Transmission electron microscopy observation revealed that Au/Pt/Ti/Pt(10-30 nm) system annealed at 450 degrees C is appropriate for practical applications. The EDS technique used to identify the phase composition in the Pt(30 nm)/GaAs structure (specially produced for the EDS analysis) annealed at 450 degrees C showed that two layers were formed as a result of the reaction of the whole Pt layer with GaAs, and they consist of Ga, Pt and As. The top layer has the highest concentration of Ga. However, the bottom layer, which is close to the substrate, has the highest concentration of As.

  5. Continuous high-power gas lasers

    NASA Technical Reports Server (NTRS)

    Hertzberg, A.

    1979-01-01

    High power gas laser concepts are discussed with emphasis on the role that fluid mechanics has played in their development. Consideration is given to three types of systems: gasdynamic lasers, HF supersonic diffusion lasers, and electric discharge lasers. Flow effects and aerodynamic windows in such lasers are briefly described. Future directions of research are outlined.

  6. High power, high reliability laser diodes

    NASA Astrophysics Data System (ADS)

    Scifres, D. R.; Welch, D. F.; Craig, R. R.; Zucker, E.; Major, J. S.; Harnagel, G. L.; Sakamoto, M.; Haden, J. M.; Endriz, J. G.; Kung, H.

    1992-06-01

    Results are presented on catastrophic damage limits and life-test measurements for four types of high-power laser diodes operating at wavelengths between 980 nm and 690 nm. The laser diodes under consideration are CW multimode lasers, CW laser bars, quasi-CW bars/2D stacked arrays, and single transverse mode lasers.

  7. High power laser apparatus and system

    NASA Technical Reports Server (NTRS)

    Evans, J. C., Jr.; Brandhorst, H. W., Jr. (Inventor)

    1975-01-01

    A high-power, continuous-wave laser was designed for use in power transmission and energy-collecting systems, and for producing incoherent light for pumping a laser material. The laser has a high repetitive pulsing rate per unit time, resulting in a high-power density beam. The laser is composed of xenon flash tubes powered by fast-charging capacitors flashed in succession by a high-speed motor connected to an automobile-type distributor.

  8. Fabrication and optimization of 1.55-μm InGaAsP/InP high-power semiconductor diode laser

    NASA Astrophysics Data System (ADS)

    Qing, Ke; Shaoyang, Tan; Songtao, Liu; Dan, Lu; Ruikang, Zhang; Wei, Wang; Chen, Ji

    2015-09-01

    A comprehensive design optimization of 1.55-μm high power InGaAsP/InP board area lasers is performed aiming at increasing the internal quantum efficiency (ηi) while maintaining the low internal loss (αi) of the device, thereby achieving high power operation. Four different waveguide structures of broad area lasers were fabricated and characterized in depth. Through theoretical analysis and experiment verifications, we show that laser structures with stepped waveguide and thin upper separate confinement layer will result in high ηi and overall slope efficiency. A continuous wave (CW) single side output power of 160 mW was obtained for an uncoated laser with a 50-μm active area width and 1 mm cavity length. Project supported by the National Natural Science Foundation of China (Nos. 61274046, 61201103) and the National High Technology Research and Development Program of China (No. 2013AA014202).

  9. High power ultrashort pulse lasers

    SciTech Connect

    Perry, M.D.

    1994-10-07

    Small scale terawatt and soon even petawatt (1000 terawatt) class laser systems are made possible by application of the chirped-pulse amplification technique to solid-state lasers combined with the availability of broad bandwidth materials. These lasers make possible a new class of high gradient accelerators based on the large electric fields associated with intense laser-plasma interactions or from the intense laser field directly. Here, we concentrate on the laser technology to produce these intense pulses. Application of the smallest of these systems to the production of high brightness electron sources is also introduced.

  10. High power laser diodes for the NASA direct detection laser transceiver experiment

    NASA Technical Reports Server (NTRS)

    Seery, Bernard D.; Holcomb, Terry L.

    1988-01-01

    High-power semiconductor laser diodes selected for use in the NASA space laser communications experiments are discussed. The diode selection rationale is reviewed, and the laser structure is shown. The theory and design of the third mirror lasers used in the experiments are addressed.

  11. A High Power Frequency Doubled Fiber Laser

    NASA Technical Reports Server (NTRS)

    Thompson, Robert J.; Tu, Meirong; Aveline, Dave; Lundblad, Nathan; Maleki, Lute

    2003-01-01

    This viewgraph presentation reports on the development of a high power 780 nm laser suitable for space applications of laser cooling. A possible solution is to use frequency doubling of high power 1560 nm telecom lasers. The presentation shows a diagram of the frequency conversion, and a graph of the second harmonic generation in one crystal, and the use of the cascading crystals. Graphs show the second harmonic power as a function of distance between crystals, second harmonic power vs. pump power, tunability of laser systems.

  12. High Power Free Electron Lasers

    SciTech Connect

    George Neil

    2004-04-12

    FEL Oscillators have been around since 1977 providing not only a test bed for the physics of Free Electron Lasers and electron/photon interactions but as a workhorse of scientific research. The characteristics that have driven the development of these sources are the desire for high peak and average power, high pulse energies, wavelength tunability, timing flexibility, and wavelengths that are unavailable from more conventional laser sources. User programs have been performed using such sources encompassing medicine, biology, solid state research, atomic and molecular physics, effects of non-linear fields, surface science, polymer science, pulsed laser vapor deposition, to name just a few. Recently the incorporation of energy recovery systems has permitted extension of the average power capabilities to the kW level and beyond. Development of substantially higher power systems with applications in defense and security is believed feasible with modest R&D efforts applied to a few technology areas. This paper will discuss at a summary level the physics of such devices, survey existing and planned facilities, and touch on the applications that have driven the development of these popular light sources.

  13. High power diode lasers reliability experiment

    NASA Astrophysics Data System (ADS)

    Lu, Guoguang; Xie, Shaofeng; Hao, Mingming; Huang, Yun; En, Yunfei

    2013-12-01

    In order to evaluate and obtain the actual lifetime data of high power laser diodes, an automated high power laser diodes reliability experiment was developed and reported in this paper. This computer controlled setup operates the laser diodes 24 hours a day, the parameters such as output power, wavelength were test once in one hour. The experiment has 60 work stations, the temperature control range is from 25°C to 70°C, and the output power of the aging device is beyond 20W.

  14. High Power Short Wavelength Laser Development

    DTIC Science & Technology

    1977-11-01

    Unlimited güä^äsjäsiiiüüü X NRTC-77-43R P I High Power Short Wavelength Laser Development November 1977 D. B. Cohn and W. B. Lacina...NO NRTC-77-43R, «. TITLE fana »uetjjitj BEFORE COMPLETING FORM CIPIENT’S CATALOO NUMBER KIGH.POWER SHORT WAVELENGTH LASER DEVELOPMENT , 7...fWhtn Data Enterte NRTC-77-43R HIGH POWER SHORT WAVELENGTH LASER DEVELOPMENT ARPA Order Number: Program Code Number: Contract Number: Principal

  15. High-Power Amplifier Free Electron Lasers

    DTIC Science & Technology

    2006-06-01

    society, including laser pointers , printers, compact-disc players, DVD players, product scanners and even as instruments in medical procedures. With...FREE ELECTRON LASERS by Tyrone Y. Voughs June 2006 Thesis Advisor: William B. Colson Co-Advisor: Robert L. Armstead...2006 3. REPORT TYPE AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE High-Power Amplifier Free Electron Lasers 6. AUTHOR(S) LT Tyrone Y

  16. High power regenerative laser amplifier

    DOEpatents

    Miller, J.L.; Hackel, L.A.; Dane, C.B.; Zapata, L.E.

    1994-02-08

    A regenerative amplifier design capable of operating at high energy per pulse, for instance, from 20-100 Joules, at moderate repetition rates, for instance from 5-20 Hertz is provided. The laser amplifier comprises a gain medium and source of pump energy coupled with the gain medium; a Pockels cell, which rotates an incident beam in response to application of a control signal; an optical relay system defining a first relay plane near the gain medium and a second relay plane near the rotator; and a plurality of reflectors configured to define an optical path through the gain medium, optical relay and Pockels cell, such that each transit of the optical path includes at least one pass through the gain medium and only one pass through the Pockels cell. An input coupler, and an output coupler are provided, implemented by a single polarizer. A control circuit coupled to the Pockels cell generates the control signal in timed relationship with the input pulse so that the input pulse is captured by the input coupler and proceeds through at least one transit of the optical path, and then the control signal is applied to cause rotation of the pulse to a polarization reflected by the polarizer, after which the captured pulse passes through the gain medium at least once more and is reflected out of the optical path by the polarizer before passing through the rotator again to provide an amplified pulse. 7 figures.

  17. High power regenerative laser amplifier

    DOEpatents

    Miller, John L.; Hackel, Lloyd A.; Dane, Clifford B.; Zapata, Luis E.

    1994-01-01

    A regenerative amplifier design capable of operating at high energy per pulse, for instance, from 20-100 Joules, at moderate repetition rates, for instance from 5-20 Hertz is provided. The laser amplifier comprises a gain medium and source of pump energy coupled with the gain medium; a Pockels cell, which rotates an incident beam in response to application of a control signal; an optical relay system defining a first relay plane near the gain medium and a second relay plane near the rotator; and a plurality of reflectors configured to define an optical path through the gain medium, optical relay and Pockels cell, such that each transit of the optical path includes at least one pass through the gain medium and only one pass through the Pockels cell. An input coupler, and an output coupler are provided, implemented by a single polarizer. A control circuit coupled to the Pockels cell generates the control signal in timed relationship with the input pulse so that the input pulse is captured by the input coupler and proceeds through at least one transit of the optical path, and then the control signal is applied to cause rotation of the pulse to a polarization reflected by the polarizer, after which the captured pulse passes through the gain medium at least once more and is reflected out of the optical path by the polarizer before passing through the rotator again to provide an amplified pulse.

  18. Generation of high-power laser light with Gigahertz splitting.

    PubMed

    Unks, B E; Proite, N A; Yavuz, D D

    2007-08-01

    We demonstrate the generation of two high-power laser beams whose frequencies are separated by the ground state hyperfine transition frequency in (87)Rb. The system uses a single master diode laser appropriately shifted by high frequency acousto-optic modulators and amplified by semiconductor tapered amplifiers. This produces two 1 W laser beams with a frequency spacing of 6.834 GHz and a relative frequency stability of 1 Hz. We discuss possible applications of this apparatus, including electromagnetically induced transparency-like effects and ultrafast qubit rotations.

  19. Lifetest on a high-power laser diode array transmitter

    NASA Astrophysics Data System (ADS)

    Greulich, P.; Hespeler, B.; Spatscheck, Th.

    1991-05-01

    The optical transmiter component of a free space optical communication system is critical, in that it impacts on the mechanical configuration, power requirements, mass, reliability, and transmission bit-rate of the entire system. Attention is presently given to the transmitter output power and beam quality, as well as its electrical-to-optical power conversion efficiency, in view of state-of-the-art high power transmitters for intensity modulation/direct detection and semiconductor laser transmitter systems.

  20. Early history of high-power lasers

    NASA Astrophysics Data System (ADS)

    Sutton, George W.

    2002-02-01

    This paper gives the history of the invention and development of early high power lasers, to which the author contributed and had personal knowledge. The earliest hint that a high power laser could be built came from the electric CO2-N2-He laser of Javan. It happened that the director of the Avco-Everett Research Laboratory had written his Ph.D. dissertation on the deactivation of the vibrational excitation of N2 in an expanding flow under Edward Teller, then at Columbia Univ. The director then started an in-house project to determine if gain could be achieved in a mixture similar to Javan's by means of a shock tunnel where a shock heated mixture of N2, CO2, and He gas was expanded through a supersonic nozzle into a cavity. This concept was named by the author as the gasdynamic laser (GDL). The paper traces the history of the initial gain measurements, the Mark II laser, the RASTA laser, the Tri-Service laser, its troubles and solutions, the United Technology's XLD gasdynamic laser, and their ALL laser. The history of the coastal Crusader will also be mentioned. Also discussed are the early experiments on a combustion-driven chemical laser, and its subsequent rejection by the director.

  1. Scaling blackbody laser to high powers

    NASA Technical Reports Server (NTRS)

    Deyoung, R. J.

    1985-01-01

    Lasers pumped by solar heated blackbody cavities have potential for multimegawatt power beaming in space. There are two basic types of blackbody lasers; cavity pumped and transfer system. The transfer system is judged to be more readily scalable to high power. In this system, either N2 or CO is heated by the blackbody cavity then transferred into the laser cavity where CO2 is injected. The N2-CO2 system was demonstrated, but probably has lower efficiency than the CO-CO system. The characteristics of potential transfer laser systems are outlined.

  2. High power diode pumped alkali vapor lasers

    NASA Astrophysics Data System (ADS)

    Zweiback, J.; Krupke, B.

    2008-05-01

    Diode pumped alkali lasers have developed rapidly since their first demonstration. These lasers offer a path to convert highly efficient, but relatively low brightness, laser diodes into a single high power, high brightness beam. General Atomics has been engaged in the development of DPALs with scalable architectures. We have examined different species and pump characteristics. We show that high absorption can be achieved even when the pump source bandwidth is several times the absorption bandwidth. In addition, we present experimental results for both potassium and rubidium systems pumped with a 0.2 nm bandwidth alexandrite laser. These data show slope efficiencies of 67% and 72% respectively.

  3. The future of high power laser techniques

    NASA Astrophysics Data System (ADS)

    Poprawe, Reinhart; Loosen, Peter; Hoffmann, Hans-Dieter

    2007-05-01

    High Power Lasers have been used for years in corresponding applications. Constantly new areas and new processes have been demonstrated, developed and transferred to fruitful use in industry. With the advent of diode pumped solid state lasers in the multi-kW-power regime at beam qualities not far away from the diffraction limit, a new area of applicability has opened. In welding applications speeds could be increased and systems could be developed with higher efficiently leading also to new perspectives for increased productivity, e.g. in combined processing. Quality control is increasingly demanded by the applying industries, however applications still are rare. Higher resolution of coaxial process control systems in time and space combined with new strategies in signal processing could give rise to new applications. The general approach described in this paper emphasizes the fact, that laser applications can be developed more efficiently, more precisely and with higher quality, if the laser radiation is tailored properly to the corresponding application. In applying laser sources, the parameter ranges applicable are by far wider and more flexible compared to heat, mechanical or even electrical energy. The time frame ranges from several fs to continuous wave and this spans approximately 15 orders of magnitude. Spacewise, the foci range from several µm to cm and the resulting intensities suitable for materials processing span eight orders of magnitude from 10 3 to 10 11 W/cm2. In addition to space (power, intensity) and time (pulse) the wavelength can be chosen as a further parameter of optimization. As a consequence, the resulting new applications are vast and can be utilized in almost every market segment of our global economy (Fig. 1). In the past and only partly today, however, this flexibility of laser technology is not exploited in full in materials processing, basically because in the high power regime the lasers with tailored beam properties are not

  4. High-power laser applications in Nippon Steel Corporation

    NASA Astrophysics Data System (ADS)

    Minamida, Katsuhiro

    2000-02-01

    The laser, which was invented in 1960, has been developed using various substances of solids, liquids, gases and semiconductors as laser active media. Applications of laser utilizing the coherent properties of laser light and the high power density light abound in many industries and in heavy industries respectively. The full-scale use of lasers in the steel industry began nearly 23 years ago with their applications as controllable light sources. Its contribution to the increase in efficiency and quality of the steel making process has been important and brought us the saving of the energy, the resource and the labor. Laser applications in the steel making process generally require high input energy, so it is essential to consider the interaction between the laser beam and the irradiated material. In particular, the reflectivity of the laser beam on the surface of material and the quantity of the laser-induced plasma are critical parameters for high efficient processes with low energy losses. We have developed plenty of new laser systems for the steel making process with their considerations in mind. A review of the following high-power-laser applications is given in the present paper: (1) Use of plasma as a secondary heat source in CO2 laser welding for connecting steel sheets of various grades. (2) Laser-assisted electric resistance welding of pipes. (3) New type all-laser-welded honeycomb panels for high-speed transport. (4) Laser flying welder for continuous hot rolling mill using two 45 kW CO2 lasers.

  5. Catastrophic Optical Damage in High-Power, Broad-Area Laser Diodes

    NASA Astrophysics Data System (ADS)

    Chin, Aland K.; Bertaska, Rick K.

    Catastrophic optical damage (COD) is semiconductor material within the optical cavity of laser diodes that is thermally damaged by the laser light. COD results in the failure of laser diodes. The phenomena of COD in high-power, broad-area laser diodes are described along with methods to eliminate it.

  6. High-power picosecond laser pulse recirculation.

    PubMed

    Shverdin, M Y; Jovanovic, I; Semenov, V A; Betts, S M; Brown, C; Gibson, D J; Shuttlesworth, R M; Hartemann, F V; Siders, C W; Barty, C P J

    2010-07-01

    We demonstrate a nonlinear crystal-based short pulse recirculation cavity for trapping the second harmonic of an incident high-power laser pulse. This scheme aims to increase the efficiency and flux of Compton-scattering-based light sources. We demonstrate up to 40x average power enhancement of frequency-doubled submillijoule picosecond pulses, and 17x average power enhancement of 177 mJ, 10 ps, 10 Hz pulses.

  7. High Power Picosecond Laser Pulse Recirculation

    SciTech Connect

    Shverdin, M Y; Jovanovic, I; Semenov, V A; Betts, S M; Brown, C; Gibson, D J; Shuttlesworth, R M; Hartemann, F V; Siders, C W; Barty, C P

    2010-04-12

    We demonstrate a nonlinear crystal-based short pulse recirculation cavity for trapping the second harmonic of an incident high power laser pulse. This scheme aims to increase the efficiency and flux of Compton-scattering based light sources. We demonstrate up to 36x average power enhancement of frequency doubled sub-millijoule picosecond pulses, and 17x average power enhancement of 177 mJ, 10 ps, 10 Hz pulses.

  8. Modulation instability in high power laser amplifiers.

    PubMed

    Rubenchik, Alexander M; Turitsyn, Sergey K; Fedoruk, Michail P

    2010-01-18

    The modulation instability (MI) is one of the main factors responsible for the degradation of beam quality in high-power laser systems. The so-called B-integral restriction is commonly used as the criteria for MI control in passive optics devices. For amplifiers the adiabatic model, assuming locally the Bespalov-Talanov expression for MI growth, is commonly used to estimate the destructive impact of the instability. We present here the exact solution of MI development in amplifiers. We determine the parameters which control the effect of MI in amplifiers and calculate the MI growth rate as a function of those parameters. The safety range of operational parameters is presented. The results of the exact calculations are compared with the adiabatic model, and the range of validity of the latest is determined. We demonstrate that for practical situations the adiabatic approximation noticeably overestimates MI. The additional margin of laser system design is quantified.

  9. High power coherent polarization locked laser diode.

    PubMed

    Purnawirman; Phua, P B

    2011-03-14

    We have coherently combined a broad area laser diode array to obtain high power single-lobed output by using coherent polarization locking. The single-lobed coherent beam is achieved by spatially combining four diode emitters using walk-off crystals and waveplates while their phases are passively locked via polarization discrimination. While our previous work focused on coherent polarization locking of diode in Gaussian beams, we demonstrate in this paper, the feasibility of the same polarization discrimination for locking multimode beams from broad area diode lasers. The resonator is designed to mitigate the loss from smile effect by using retro-reflection feedback in the cavity. In a 980 nm diode array, we produced 7.2 W coherent output with M2 of 1.5x11.5. The brightness of the diode is improved by more than an order of magnitude.

  10. Apparatus for advancing a wellbore using high power laser energy

    DOEpatents

    Zediker, Mark S.; Land, Mark S.; Rinzler, Charles C.; Faircloth, Brian O.; Koblick, Yeshaya; Moxley, Joel F.

    2014-09-02

    Delivering high power laser energy to form a borehole deep into the earth using laser energy. Down hole laser tools, laser systems and laser delivery techniques for advancement, workover and completion activities. A laser bottom hole assembly (LBHA) for the delivery of high power laser energy to the surfaces of a borehole, which assembly may have laser optics, a fluid path for debris removal and a mechanical means to remove earth.

  11. Two photon absorption in high power broad area laser diodes

    NASA Astrophysics Data System (ADS)

    Dogan, Mehmet; Michael, Christopher P.; Zheng, Yan; Zhu, Lin; Jacob, Jonah H.

    2014-03-01

    Recent advances in thermal management and improvements in fabrication and facet passivation enabled extracting unprecedented optical powers from laser diodes (LDs). However, even in the absence of thermal roll-over or catastrophic optical damage (COD), the maximum achievable power is limited by optical non-linear effects. Due to its non-linear nature, two-photon absorption (TPA) becomes one of the dominant factors that limit efficient extraction of laser power from LDs. In this paper, theoretical and experimental analysis of TPA in high-power broad area laser diodes (BALD) is presented. A phenomenological optical extraction model that incorporates TPA explains the reduction in optical extraction efficiency at high intensities in BALD bars with 100μm-wide emitters. The model includes two contributions associated with TPA: the straightforward absorption of laser photons and the subsequent single photon absorption by the holes and electrons generated by the TPA process. TPA is a fundamental limitation since it is inherent to the LD semiconductor material. Therefore scaling the LDs to high power requires designs that reduce the optical intensity by increasing the mode size.

  12. 157 W all-fiber high-power picosecond laser.

    PubMed

    Song, Rui; Hou, Jing; Chen, Shengping; Yang, Weiqiang; Lu, Qisheng

    2012-05-01

    An all-fiber high-power picosecond laser is constructed in a master oscillator power amplifier configuration. The self-constructed fiber laser seed is passively mode locked by a semiconductor saturable absorber mirror. Average output power of 157 W is obtained after three stages of amplification at a fundamental repetition rate of 60 MHz. A short length of ytterbium double-clad fiber with a high doping level is used to suppress nonlinear effects. However, a stimulated Raman scattering (SRS) effect occurs owing to the 78 kW high peak power. A self-made all-fiber repetition rate increasing system is used to octuple the repetition rate and decrease the high peak power. Average output power of 156.6 W is obtained without SRS under the same pump power at a 480 MHz repetition rate with 0.6 nm line width.

  13. High power gas laser - Applications and future developments

    NASA Technical Reports Server (NTRS)

    Hertzberg, A.

    1977-01-01

    Fast flow can be used to create the population inversion required for lasing action, or can be used to improve laser operation, for example by the removal of waste heat. It is pointed out that at the present time all lasers which are capable of continuous high-average power employ flow as an indispensable aspect of operation. High power laser systems are discussed, taking into account the gasdynamic laser, the HF supersonic diffusion laser, and electric discharge lasers. Aerodynamics and high power lasers are considered, giving attention to flow effects in high-power gas lasers, aerodynamic windows and beam manipulation, and the Venus machine. Applications of high-power laser technology reported are related to laser material working, the employment of the laser in controlled fusion machines, laser isotope separation and photochemistry, and laser power transmission.

  14. Hybrid high power femtosecond laser system

    NASA Astrophysics Data System (ADS)

    Trunov, V. I.; Petrov, V. V.; Pestryakov, E. V.; Kirpichnikov, A. V.

    2006-01-01

    Design of a high-power femtosecond laser system based on hybrid chirped pulse amplification (CPA) technique developed by us is presented. The goal of the hybrid principle is the use of the parametric and laser amplification methods in chirped pulse amplifiers. It makes it possible to amplify the low-cycle pulses with a duration of <= fs to terawatt power with a high contrast and high conversion efficiency of the pump radiation. In a created system the Ti:Sapphire laser with 10 fs pulses at 810 nm and output energy about 1-3 nJ will be used like seed source. The oscillator pulses were stretched to duration of about 500 ps by an all-reflective grating stretcher. Then the stretched pulses are injected into a nondegenerate noncollinear optical parametric amplifier (NOPA) on the two BBO crystals. After amplification in NOPA the residual pump was used in a bow-tie four pass amplifier with hybrid active medium (based on Al II0 3:Ti 3+ and BeAl IIO 4:Ti 3+ crystals). The final stage of the amplification system consists of two channels, namely NIR (820 nm) and short-VIS (410 nm). Numerical simulation has shown that the terawatt level of output power can be achieved also in a short-VIS channel at the pumping of the double-crystal BBO NOPA by the radiation of the fourth harmonic of the Nd:YAG laser at 266 nm. Experimentally parametric amplification in BBO crystals of 30-50 fs pulses were investigated and optimized using SPIDER technique and single-shot autocomelator for the realization of shortest duration 40 fs.

  15. Effect of high-power laser radiation on characteristics of thin silicon nitride films

    SciTech Connect

    Roizin, Y.O.; Khuan, K.S.

    1986-09-01

    High-power laser radiation is used in microelectronic technology for purposes such as annealing radiation defects in MOS structures after ion implantation. This paper considers accumulated changes in electrical characteristics of metal-nitride-oxide-semiconductor (MNOS) structures under the action of neodymium laser pulses with an energy density below the visible damage threshold. The experimental results obtained are interpreted.

  16. Semiconductor microcavity lasers

    SciTech Connect

    Gourley, P.L.; Wendt, J.R.; Vawter, G.A.; Warren, M.E.; Brennan, T.M.; Hammons, B.E.

    1994-02-01

    New kinds of semiconductor microcavity lasers are being created by modern semiconductor technologies like molecular beam epitaxy and electron beam lithography. These new microcavities exploit 3-dimensional architectures possible with epitaxial layering and surface patterning. The physical properties of these microcavities are intimately related to the geometry imposed on the semiconductor materials. Among these microcavities are surface-emitting structures which have many useful properties for commercial purposes. This paper reviews the basic physics of these microstructured lasers.

  17. Atmospheric propagation and combining of high power lasers: comment.

    PubMed

    Goodno, Gregory D; Rothenberg, Joshua E

    2016-10-10

    Nelson et al. [Appl. Opt.55, 1757 (2016)APOPAI0003-693510.1364/AO.55.001757] recently concluded that coherent beam combining and remote phase locking of high-power lasers are fundamentally limited by the laser source linewidth. These conclusions are incorrect and not relevant to practical high-power coherently combined laser architectures.

  18. Atmospheric Propagation and Combining of High-Power Lasers

    DTIC Science & Technology

    2015-09-08

    Naval Research Laboratory Washington, DC 20375-5320 NRL/MR/6703--15-9646 Atmospheric Propagation and Combining of High - Power Lasers W. NelsoN...ABSTRACT c. THIS PAGE 18. NUMBER OF PAGES 17. LIMITATION OF ABSTRACT Atmospheric Propagation and Combining of High - Power Lasers W. Nelson,* P. Sprangle...Turbulence Beam combining In this paper we analyze the beam combining and atmospheric propagation of high - power lasers for directed-energy (DE

  19. Flow lasers. [fluid mechanics of high power continuous output operations

    NASA Technical Reports Server (NTRS)

    Christiansen, W. H.; Russell, D. A.; Hertzberg, A.

    1975-01-01

    The present work reviews the fluid-mechanical aspects of high-power continuous-wave (CW) lasers. The flow characteristics of these devices appear as classical fluid-mechanical phenomena recast in a complicated interactive environment. The fundamentals of high-power lasers are reviewed, followed by a discussion of the N2-CO2 gas dynamic laser. Next, the HF/DF supersonic diffusion laser is described, and finally the CO electrical-discharge laser is discussed.

  20. High power diode lasers for solid-state laser pumps

    NASA Technical Reports Server (NTRS)

    Linden, Kurt J.; Mcdonnell, Patrick N.

    1994-01-01

    The development and commercial application of high power diode laser arrays for use as solid-state laser pumps is described. Such solid-state laser pumps are significantly more efficient and reliable than conventional flash-lamps. This paper describes the design and fabrication of diode lasers emitting in the 780 - 900 nm spectral region, and discusses their performance and reliability. Typical measured performance parameters include electrical-to-optical power conversion efficiencies of 50 percent, narrow-band spectral emission of 2 to 3 nm FWHM, pulsed output power levels of 50 watts/bar with reliability values of over 2 billion shots to date (tests to be terminated after 10 billion shots), and reliable operation to pulse lengths of 1 ms. Pulse lengths up to 5 ms have been demonstrated at derated power levels, and CW performance at various power levels has been evaluated in a 'bar-in-groove' laser package. These high-power 1-cm stacked-bar arrays are now being manufactured for OEM use. Individual diode laser bars, ready for package-mounting by OEM customers, are being sold as commodity items. Commercial and medical applications of these laser arrays include solid-state laser pumping for metal-working, cutting, industrial measurement and control, ranging, wind-shear/atmospheric turbulence detection, X-ray generation, materials surface cleaning, microsurgery, ophthalmology, dermatology, and dental procedures.

  1. High power diode lasers for solid-state laser pumps

    NASA Astrophysics Data System (ADS)

    Linden, Kurt J.; McDonnell, Patrick N.

    1994-02-01

    The development and commercial application of high power diode laser arrays for use as solid-state laser pumps is described. Such solid-state laser pumps are significantly more efficient and reliable than conventional flash-lamps. This paper describes the design and fabrication of diode lasers emitting in the 780 - 900 nm spectral region, and discusses their performance and reliability. Typical measured performance parameters include electrical-to-optical power conversion efficiencies of 50 percent, narrow-band spectral emission of 2 to 3 nm FWHM, pulsed output power levels of 50 watts/bar with reliability values of over 2 billion shots to date (tests to be terminated after 10 billion shots), and reliable operation to pulse lengths of 1 ms. Pulse lengths up to 5 ms have been demonstrated at derated power levels, and CW performance at various power levels has been evaluated in a 'bar-in-groove' laser package. These high-power 1-cm stacked-bar arrays are now being manufactured for OEM use. Individual diode laser bars, ready for package-mounting by OEM customers, are being sold as commodity items. Commercial and medical applications of these laser arrays include solid-state laser pumping for metal-working, cutting, industrial measurement and control, ranging, wind-shear/atmospheric turbulence detection, X-ray generation, materials surface cleaning, microsurgery, ophthalmology, dermatology, and dental procedures.

  2. A High Power Frequency Doubled Fiber Laser

    NASA Technical Reports Server (NTRS)

    Thompson, Rob; Tu, Meirong; Aveline, Dave; Lundblad, Nathan; Maleki, Lute

    2003-01-01

    This slide presentation reviews the power frequencies for the doubled fiber laser. It includes information on the 780 nm laser, second harmonic generation in one crystal, cascading crystals, the tenability of laser systems, laser cooling, and directions for future work.

  3. Laser welding of polymers using high-power diode lasers

    NASA Astrophysics Data System (ADS)

    Bachmann, Friedrich G.; Russek, Ulrich A.

    2002-06-01

    Laser welding of polymers using high power diode lasers offers specific process advantages over conventional technologies, such as short process times while providing optically and qualitatively valuable weld seams, contactless yielding of the joining energy, absence of process induced vibrations, imposing minimal thermal stress and avoiding particle generation. Furthermore, this method exhibits high integration capabilities and automatization potential. Moreover, because of the current favorable cost development within the high power diode laser market laser welding of polymers has become more and more an industrially accepted joining method. This novel technology permits both, reliable high quality joining of mechanically and electronically highly sensitive micro components and hermetic sealing of macro components. There are different welding strategies available, which are adaptable to the current application. Within the frame of this discourse scientific and also application oriented result concerning laser transmission welding of polymers using preferably diode lasers are presented. Besides the sue laser system the fundamental process strategies as well as decisive process parameters are illustrated. The importance of optical, thermal and mechanical properties is discussed. Applications at real technical components will be presented, demonstrating the industrial implementation capability and the advantages of a novel technology.

  4. Laser welding of polymers using high-power diode lasers

    NASA Astrophysics Data System (ADS)

    Bachmann, Friedrich G.; Russek, Ulrich A.

    2003-09-01

    Laser welding of polymers using high power diode lasers offers specific process advantages over conventional technologies, such as short process times while providing optically and qualitatively valuable weld seams, contactless yielding of the joining energy, absence of process induced vibrations, imposing minimal thermal stress and avoiding particle generation. Furthermore this method exhibits high integration capabilities and automatization potential. Moreover, because of the current favorable cost development within the high power diode laser market laser welding of polymers has become more and more an industrially accepted joining method. This novel technology permits both, reliable high quality joining of mechanically and electronically highly sensitive micro components and hermetic sealing of macro components. There are different welding strategies available, which are adaptable to the current application. Within the frame of this discourse scientific and also application oriented results concerning laser transmission welding of polymers using preferably diode lasers are presented. Besides the used laser systems the fundamental process strategies as well as decisive process parameters are illustrated. The importance of optical, thermal and mechanical properties is discussed. Applications at real technical components will be presented, demonstrating the industrial implementation capability and the advantages of a novel technology.

  5. High power laser workover and completion tools and systems

    SciTech Connect

    Zediker, Mark S; Rinzler, Charles C; Faircloth, Brian O; Koblick, Yeshaya; Moxley, Joel F

    2014-10-28

    Workover and completion systems, devices and methods for utilizing 10 kW or more laser energy transmitted deep into the earth with the suppression of associated nonlinear phenomena. Systems and devices for the laser workover and completion of a borehole in the earth. These systems and devices can deliver high power laser energy down a deep borehole, while maintaining the high power to perform laser workover and completion operations in such boreholes deep within the earth.

  6. Industrial high-power diode lasers: reliability, power, and brightness

    NASA Astrophysics Data System (ADS)

    Strohmaier, Stephan; An, Haiyan; Vethake, Thilo

    2012-03-01

    High power semiconductor lasers, single emitters and bars are developing fast. During the last decade key parameters of diode lasers, such as beam quality, power, spatial and spectral brightness, efficiency as well as reliability have been greatly improved. However, often only individual parameters have been optimized, accepting an adverse effect in the other key parameters. For demanding industrial applications in most cases it is not sufficient to achieve a record value in one of the parameters, on the contrary it is necessary to optimize all the mentioned parameters simultaneously. To be able to achieve this objective it is highly advantageous to have insight in the whole process chain, from epitaxial device structure design and growth, wafer processing, mounting, heat sink design, product development and finally the customer needs your final product has to fulfill. In this publication an overview of recent advances in industrial diode lasers at TRUMPF will be highlighted enabling advanced applications for both high end pump sources as well as highest brightness direct diode.

  7. Tunable semiconductor lasers

    NASA Technical Reports Server (NTRS)

    Taghavi-Larigani, Shervin (Inventor); Vanzyl, Jakob J. (Inventor); Yariv, Amnon (Inventor)

    2006-01-01

    Tunable semiconductor lasers are disclosed requiring minimized coupling regions. Multiple laser embodiments employ ring resonators or ring resonator pairs using only a single coupling region with the gain medium are detailed. Tuning can be performed by changing the phase of the coupling coefficient between the gain medium and a ring resonator of the laser. Another embodiment provides a tunable laser including two Mach-Zehnder interferometers in series and a reflector coupled to a gain medium.

  8. High power diode and solid state lasers

    NASA Astrophysics Data System (ADS)

    Eichler, H. J.; Fritsche, H.; Lux, O.; Strohmaier, S. G.

    2017-01-01

    Diode lasers are now basic pump sources of crystal, glass fiber and other solid state lasers. Progress in the performance of all these lasers is related. Examples of recently developed diode pumped lasers and Raman frequency converters are described for applications in materials processing, Lidar and medical surgery.

  9. High-power, high-intensity laser propagation and interactions

    SciTech Connect

    Sprangle, Phillip; Hafizi, Bahman

    2014-05-15

    This paper presents overviews of a number of processes and applications associated with high-power, high-intensity lasers, and their interactions. These processes and applications include: free electron lasers, backward Raman amplification, atmospheric propagation of laser pulses, laser driven acceleration, atmospheric lasing, and remote detection of radioactivity. The interrelated physical mechanisms in the various processes are discussed.

  10. High-Power COIL and YAG Laser Welding

    DTIC Science & Technology

    2002-01-24

    UNCLASSIFIED Defense Technical Information Center Compilation Part Notice ADP012387 TITLE: High-Power COIL and YAG Laser Welding DISTRIBUTION...ADP012376 thru ADP012405 UNCLASSIFIED High-power COIL and YAG laser welding Fumio Wani, Tokuhiro Nakabayashi, Akiyoshi Hayakawa, Sachio Suzuki, and...is worse, but it has the function of pulse modulation which the COIL dose not have. As a result of the welding test with the 6 kW Nd:YAG laser, it

  11. High power laser downhole cutting tools and systems

    DOEpatents

    Zediker, Mark S; Rinzler, Charles C; Faircloth, Brian O; Koblick, Yeshaya; Moxley, Joel F

    2015-01-20

    Downhole cutting systems, devices and methods for utilizing 10 kW or more laser energy transmitted deep into the earth with the suppression of associated nonlinear phenomena. Systems and devices for the laser cutting operations within a borehole in the earth. These systems and devices can deliver high power laser energy down a deep borehole, while maintaining the high power to perform cutting operations in such boreholes deep within the earth.

  12. High Power Fiber Lasers and Applications to Manufacturing

    NASA Astrophysics Data System (ADS)

    Richardson, Martin; McComb, Timothy; Sudesh, Vikas

    2008-09-01

    We summarize recent developments in high power fiber laser technologies and discuss future trends, particularly in their current and future use in manufacturing technologies. We will also describe our current research programs in fiber laser development, ultra-fast and new lasers, and will mention the expectations in these areas for the new Townes Laser Institute. It will focus on new core laser technologies and their applications in medical technologies, advanced manufacturing technologies and defense applications. We will describe a program on large mode area fiber development that includes results with the new gain-guiding approach, as well as high power infra-red fiber lasers. We will review the opportunities for high power fiber lasers in various manufacturing technologies and illustrate this with applications we are pursuing in the areas of femtosecond laser applications, advanced lithographies, and mid-IR technologies.

  13. Robotics For High Power Laser Beam Manipulation

    NASA Astrophysics Data System (ADS)

    Watson, Henry E.

    1989-03-01

    The research and development programs in manufacturing science at The Pennsylvania State University have a major emphasis on laser materials processing technology development. A major thrust of this program is the development of an intelligent robotic system which can manipulate a laser beam in three dimension with the precision required for welding. The robot is called LARS for Laser Articulated Robotic System. A gantry based robot was selected as the foundation for LARS and the system is divided into five major subsystems: robot, electronic control, vision, workhead, beam transport, and software. An overview of the Laser Robotics program including laser materials processing research programs will be provided.

  14. Frequency stable high power lasers in space

    NASA Technical Reports Server (NTRS)

    Byer, Robert L.

    1989-01-01

    The concept of a laser heterodyne gravity wave antenna that would operate in solar orbit with a one million kilometer path length is discussed. Laser technology that would be appropriate for operation of this space-based gravity wave detector is also discussed. The rapid progress in diode laser coupled with the energy storage and potentially sub-Hertz linewidths of solid state lasers, and the possibility of efficient frequency conversion by nonlinear optical techniques defines a technology that is appropriate for laser interferometry in space. The present status of diode-laser-pumped, solid state lasers is summarized and future progress is projected in areas of linewidth control, high average power, operating efficiency, and operational lifetimes that are essential for space-based applications.

  15. Propagation and focusing properties of high-power laser beams

    NASA Astrophysics Data System (ADS)

    Lu, Baida; Bin, Zhang

    1996-11-01

    In This paper, on the basis of the generalized Huygens- Fresnel diffraction integral and by using the statistical- optics model of high-power lasers presented by Manes and Simmons at LLNL, the propagation and focusing properties of high-power lasers with amplitude modulations (AMs) and phase fluctuations (PFs) have been studied in detail. Numerical calculations for the apertured case have been performed, showing the dependence of focused field characteristics on the truncation parameter, Fresnel number of the system, phase fluctuations and amplitude modulations of high-power laser beams.

  16. Lifetime estimation of high power lasers

    NASA Astrophysics Data System (ADS)

    Lu, Guoguang; Huang, Yun; En, Yunfei

    2010-11-01

    We have set up a computer automated controlled diode array reliability experiment which can take up 10 to 20 high power cm-bars. Subsequent 25°C and 50°C lifetime tests were completed. According to the method of least squares, the degradation model of cm-bars is obtained. Using the model and weibull++7 software, the extrapolated lifetime of cmbars at 25°C is 7950 hours (2.86×109 shots). We also obtain an acceleration factor 1.88 of resulting in a thermal activation energy of Ea=0.21eV using Arrhenius function. Finally, failure analysis was carried on the gradually degraded devices, the results show that it is the facet degradation which made high power cm-bars degrade during the long time lifetime test.

  17. 120 Mbit/s QPPM high power semiconductor transmitter performance and reliability

    NASA Astrophysics Data System (ADS)

    Greulich, P.; Hespeler, B.; Spatscheck, Th.

    1991-06-01

    Optical and electrical performance of a high power semiconductor laser transmitter (HPST) and of the related driver electronics are presented. Stable single-lobed operation of the HPST is accomplished by retroreflection of one lobe of the dual-lobed far field using a GRIN lens and stripe mirror. The envisaged peak-power output power of 1 W is achieved and 120 Mbit/s data transmission applying QPPM is demonstrated. Preliminary results after 2400 h of a lifetest performed on a laser array without a stripe mirror yield a bias current increase of about 2.1 x 10 exp -5/h and an efficiency decrease of 1 x 10 exp -5 hr.

  18. High power femtosecond lasers at ELI-NP

    SciTech Connect

    Dabu, Razvan

    2015-02-24

    Specifications of the high power laser system (HPLS) designed for nuclear physics experiments are presented. Configuration of the 2 × 10 PW femtosecond laser system is described. In order to reach the required laser beam parameters, advanced laser techniques are proposed for the HPLS: parametric amplification and cross-polarized wave generation for the intensity contrast improvement and spectral broadening, acousto-optic programmable filters to compensate for spectral phase dispersion, optical filters for spectrum management, combined methods for transversal laser suppression.

  19. Rapid heating of matter using high power lasers

    SciTech Connect

    Bang, Woosuk

    2016-04-08

    This slide presentation describes motivation (uniform and rapid heating of a target, opportunity to study warm dense matter, study of nuclear fusion reactions), rapid heating of matter with intense laser-driven ion beams, visualization of the expanding warm dense gold and diamond, and nuclear fusion experiments using high power lasers (direct heating of deuterium spheres (radius ~ 10nm) with an intense laser pulse.

  20. Overview on the high power excimer laser technology

    NASA Astrophysics Data System (ADS)

    Liu, Jingru

    2013-05-01

    High power excimer laser has essential applications in the fields of high energy density physics, inertial fusion energy and industry owing to its advantages such as short wavelength, high gain, wide bandwidth, energy scalable and repetition operating ability. This overview is aimed at an introduction and evaluation of enormous endeavor of the international high power excimer laser community in the last 30 years. The main technologies of high power excimer laser are reviewed, which include the pumping source technology, angular multiplexing and pulse compressing, beam-smoothing and homogenous irradiation, high efficiency and repetitive operation et al. A high power XeCl laser system developed in NINT of China is described in detail.

  1. High-power disk and fiber lasers: a performance comparison

    NASA Astrophysics Data System (ADS)

    Ruppik, Stefan; Becker, Frank; Grundmann, Frank-Peter; Rath, Wolfram; Hefter, Ulrich

    2012-03-01

    The Performance of High Power Disk Lasers and Fiber Lasers along with their rapid development to the high power cw regime have been of great interest throughout the last decade. Both technologies are still in the focus of several conferences, workshops, and papers and represent the "state-of-the-art" of industrial high power solid state lasers for material processing. As both laser concepts are considered to be the leading 1 μm light-source, this presentation presents an objective and fair comparison of the two different technologies from a manufacturer who pursued both. From the geometry of the active material, through the resonator design, cooling regime, and pumping method to the point of beam quality and power scaling, the different approaches associated with the advantages, challenge and limits of each technology will be discussed. Based on ROFIN's substantial industrial experience with both laser concepts, an outlook into future trends and chances, especially linked to fiber laser, will be given.

  2. High-power lasers for directed-energy applications.

    PubMed

    Sprangle, Phillip; Hafizi, Bahman; Ting, Antonio; Fischer, Richard

    2015-11-01

    In this article, we review and discuss the research programs at the Naval Research Laboratory (NRL) on high-power lasers for directed-energy (DE) applications in the atmosphere. Physical processes affecting propagation include absorption/scattering, turbulence, and thermal blooming. The power levels needed for DE applications require combining a number of lasers. In atmospheric turbulence, there is a maximum intensity that can be placed on a target that is independent of the initial beam spot size and laser beam quality. By combining a number of kW-class fiber lasers, scientists at the NRL have successfully demonstrated high-power laser propagation in a turbulent atmosphere and wireless recharging. In the NRL experiments, four incoherently combined fiber lasers having a total power of 5 kW were propagated to a target 3.2 km away. These successful high-power experiments in a realistic atmosphere formed the basis of the Navy's Laser Weapon System. We compare the propagation characteristics of coherently and incoherently combined beams without adaptive optics. There is little difference in the energy on target between coherently and incoherently combined laser beams for multi-km propagation ranges and moderate to high levels of turbulence. Unlike incoherent combining, coherent combining places severe constraints on the individual lasers. These include the requirement of narrow power spectral linewidths in order to have long coherence times as well as polarization alignment of all the lasers. These requirements are extremely difficult for high-power lasers.

  3. Beam Stop For High-Power Lasers

    NASA Technical Reports Server (NTRS)

    Mcdermid, Iain S.; Williamson, William B.

    1990-01-01

    Graphite/aluminum plate absorbs most of light. Beam stop fits on standard optical mounting fixture. Graphite plate thick enough to absorb incident laser beam but thin enough to transfer heat quickly to heat sink. Device used for variety of blocking purposes. For example, blocks laser beam after it passes through experimental setup, or at each stage of setup so stages checked and tested in sequence. Negligible reflectance of device is valuable safety feature, protecting both users and equipment from reflections.

  4. High power, electrically tunable quantum cascade lasers

    NASA Astrophysics Data System (ADS)

    Slivken, Steven; Razeghi, Manijeh

    2016-02-01

    Mid-infrared laser sources (3-14 μm wavelengths) which have wide spectral coverage and high output power are attractive for many applications. This spectral range contains unique absorption fingerprints of most molecules, including toxins, explosives, and nerve agents. Infrared spectroscopy can also be used to detect important biomarkers, which can be used for medical diagnostics by means of breath analysis. The challenge is to produce a broadband midinfrared source which is small, lightweight, robust, and inexpensive. We are currently investigating monolithic solutions using quantum cascade lasers. A wide gain bandwidth is not sufficient to make an ideal spectroscopy source. Single mode output with rapid tuning is desirable. For dynamic wavelength selection, our group is developing multi-section laser geometries with wide electrical tuning (hundreds of cm-1). These devices are roughly the same size as a traditional quantum cascade lasers, but tuning is accomplished without any external optical components. When combined with suitable amplifiers, these lasers are capable of multi-Watt single mode output powers. This manuscript will describe our current research efforts and the potential for high performance, broadband electrical tuning with the quantum cascade laser.

  5. Freeform beam shaping for high-power multimode lasers

    NASA Astrophysics Data System (ADS)

    Laskin, Alexander; Laskin, Vadim

    2014-03-01

    Widening of using high power multimode lasers in industrial laser material processing is accompanied by special requirements to irradiance profiles in such technologies like metal or plastics welding, cladding, hardening, brazing, annealing, laser pumping and amplification in MOPA lasers. Typical irradiance distribution of high power multimode lasers: free space solid state, fiber-coupled solid state and diodes lasers, fiber lasers, is similar to Gaussian. Laser technologies can be essentially improved when irradiance distribution on a workpiece is uniform (flattop) or inverse-Gauss; when building high-power pulsed lasers it is possible to enhance efficiency of pumping and amplification by applying super-Gauss irradiance distribution with controlled convexity. Therefore, "freeform" beam shaping of multimode laser beams is an important task. A proved solution is refractive field mapping beam shaper like Shaper capable to control resulting irradiance profile - with the same unit it is possible to get various beam profiles and choose optimum one for a particular application. Operational principle of these devices implies transformation of laser irradiance distribution by conserving beam consistency, high transmittance, providing collimated low divergent output beam. Using additional optics makes it possible to create resulting laser spots of necessary size and round, elliptical or linear shape. Operation out of focal plane and, hence, in field of lower wavefront curvature, allows extending depth of field. The refractive beam shapers are implemented as telescopes and collimating systems, which can be connected directly to fiber-coupled lasers or fiber lasers, thus combining functions of beam collimation and irradiance transformation.

  6. Commercial applications of high-powered laser diodes

    NASA Astrophysics Data System (ADS)

    Cunningham, David L.; Jacobs, Richard D.

    1995-04-01

    The development of high power laser diodes using surface emitting distributed feedback (SEDFB) techniques has matured to the point where serious marketing analyses have been conducted. While development of the base technology continues, the initiation of systems applications and manufacturing engineering has begun. This effort, in direct response to growing market demand, is the critical bridge between research and the development of viable products for commercial applications. This paper addresses the history of laser technology development, the current status of high powered laser diode development, the forces defining current and future markets and the role of `conventional wisdom' in laser technology and market development.

  7. Industrial applications of high power diode lasers in materials processing

    NASA Astrophysics Data System (ADS)

    Bachmann, Friedrich

    2003-03-01

    Diode lasers are widely used in communication, computer and consumer electronics technology. These applications are based on systems, which provide power in the milliwatt range. However, in the mean time high power diode lasers have reached the kilowatt power range. This became possible by special cooling and mounting as well as beam combination and beam forming technologies. Such units are nowadays used as a direct source for materials processing. High power diode lasers have entered the industrial manufacturing area [Proceedings of the Advanced Laser Technologies Conference 2001, Proc. SPIE, Constanta, Romania, 11-14 September 2001].

  8. Scaling brilliance of high power laser diodes

    NASA Astrophysics Data System (ADS)

    König, Harald; Grönninger, Guenther; Lauer, Christian; Reill, Wolfgang; Arzberger, Markus; Strauß, Uwe; Kissel, Heiko; Biesenbach, Jens; Kösters, Arnd; Malchus, Joerg; Krause, Volker K.

    2010-02-01

    New direct diode laser systems and fiber lasers require brilliant fiber coupled laser diodes for efficient operation. In the German funded project HEMILAS different laser bar designs are investigated with tailored beam parameter products adapted for efficient fiber coupling. In this paper we demonstrate results on 9xx and 1020nm bars suitable for coupling into 200μm fibers. With special facet technology and optimised epitaxial structure COD-free laser bars were fabricated with maximum efficiency above 66%. For short bars consisting of five 100μm wide emitters 75W CW maximum output power was reached. In QCW-mode up to 140W are demonstrated. The 10% fill factor bars with 4mm cavity are mounted with hard solder. Lifetime tests in long pulse mode with 35W output power exceed 5000 hours of testing without degradation or spontaneous failures. Slow axis divergence stays below 7° up to power levels of 40W and is suitable for simple fiber coupling into 200μm NA 0.22 fibers with SAC and FAC lenses. For fiber coupling based on beam rearrangement with step mirrors, bars with higher fill factor of 50% were fabricated and tested. The 4mm cavity short bars reach efficiencies above 60%. Lifetime tests at accelerated powers were performed. Finally fiber coupling results with output powers of up to 2.4 kW and beam quality of 30 mm mrad are demonstrated.

  9. High power parallel ultrashort pulse laser processing

    NASA Astrophysics Data System (ADS)

    Gillner, Arnold; Gretzki, Patrick; Büsing, Lasse

    2016-03-01

    The class of ultra-short-pulse (USP) laser sources are used, whenever high precession and high quality material processing is demanded. These laser sources deliver pulse duration in the range of ps to fs and are characterized with high peak intensities leading to a direct vaporization of the material with a minimum thermal damage. With the availability of industrial laser source with an average power of up to 1000W, the main challenge consist of the effective energy distribution and disposition. Using lasers with high repetition rates in the MHz region can cause thermal issues like overheating, melt production and low ablation quality. In this paper, we will discuss different approaches for multibeam processing for utilization of high pulse energies. The combination of diffractive optics and conventional galvometer scanner can be used for high throughput laser ablation, but are limited in the optical qualities. We will show which applications can benefit from this hybrid optic and which improvements in productivity are expected. In addition, the optical limitations of the system will be compiled, in order to evaluate the suitability of this approach for any given application.

  10. High power laser and cathode structure thereof

    SciTech Connect

    Nam, K. H.; Seguin, H. J.; Tulip, J.

    1981-09-08

    A cathode structure for gas lasers is disclosed that is comprised of a flat plate of non-conducting material positioned in the laser in spaced relation to the laser anode to define a discharge region therebetween, a two-dimensional array of metal sub-electrode rods passing through the plate and having their upper ends lying flush with the surface of the plate, a block of dielectric material positioned below the plate and containing a series of transverse channels therein, electric current conductors lying in the channels and adapted for connection to a power supply, the lower ends of the said rods passing through openings in the block into the channels to define a predetermined uniform gap between the ends of the rods and the electrical conductor, and a liquid electrolyte solution filling the channels and electrically connecting the sub-electrode rods and the conductors.

  11. Semiconductor nanowire lasers

    NASA Astrophysics Data System (ADS)

    Eaton, Samuel W.; Fu, Anthony; Wong, Andrew B.; Ning, Cun-Zheng; Yang, Peidong

    2016-06-01

    The discovery and continued development of the laser has revolutionized both science and industry. The advent of miniaturized, semiconductor lasers has made this technology an integral part of everyday life. Exciting research continues with a new focus on nanowire lasers because of their great potential in the field of optoelectronics. In this Review, we explore the latest advancements in the development of nanowire lasers and offer our perspective on future improvements and trends. We discuss fundamental material considerations and the latest, most effective materials for nanowire lasers. A discussion of novel cavity designs and amplification methods is followed by some of the latest work on surface plasmon polariton nanowire lasers. Finally, exciting new reports of electrically pumped nanowire lasers with the potential for integrated optoelectronic applications are described.

  12. Atmospheric propagation and combining of high-power lasers.

    PubMed

    Nelson, W; Sprangle, P; Davis, C C

    2016-03-01

    In this paper, we analyze beam combining and atmospheric propagation of high-power lasers for directed-energy (DE) applications. The large linewidths inherent in high-power fiber and slab lasers cause random phase and intensity fluctuations that occur on subnanosecond time scales. Coherently combining these high-power lasers would involve instruments capable of precise phase control and operation at rates greater than ∼10  GHz. To the best of our knowledge, this technology does not currently exist. This presents a challenging problem when attempting to phase lock high-power lasers that is not encountered when phase locking low-power lasers, for example, at milliwatt power levels. Regardless, we demonstrate that even if instruments are developed that can precisely control the phase of high-power lasers, coherent combining is problematic for DE applications. The dephasing effects of atmospheric turbulence typically encountered in DE applications will degrade the coherent properties of the beam before it reaches the target. Through simulations, we find that coherent beam combining in moderate turbulence and over multikilometer propagation distances has little advantage over incoherent combining. Additionally, in cases of strong turbulence and multikilometer propagation ranges, we find nearly indistinguishable intensity profiles and virtually no difference in the energy on the target between coherently and incoherently combined laser beams. Consequently, we find that coherent beam combining at the transmitter plane is ineffective under typical atmospheric conditions.

  13. Method and apparatus for tuning high power lasers

    DOEpatents

    Hutchinson, Donald P.; Vandersluis, Kenneth L.

    1977-04-19

    This invention relates to high power gas lasers that are adapted to be tuned to a desired lasing wavelength through the use of a gas cell to lower the gain at a natural lasing wavelength and "seeding" the laser with a beam from a low power laser which is lasing at the desired wavelength. This tuning is accomplished with no loss of power and produces a pulse with an altered pulse shape. It is potentially applicable to all gas lasers.

  14. Simulation of High Power Lasers (Preprint)

    DTIC Science & Technology

    2010-06-01

    product of laser power. 5. References 1 Wilcox, D. C, Turbulence Modeling for CFD, DCW Industries, Inc. pp. 185-193, July 1998. 2 Menter, F. L...Modeling for CFD, DCW Industries, Inc. pp. 294-296, July 1998. 4 Perram, G. P, .Int. J. Chem. Kinet. 27, 817-28 (1995). 5 Madden, T. J. and Solomon

  15. High-power laser source evaluation

    SciTech Connect

    Back, C.A.; Decker, C.D.; Dipeso, G.J.; Gerassimenko, M.; Managan, R.A.; Serduke, F.J.D.; Simonson, G.F.; Suter, L.J.

    1997-07-01

    This document reports progress in these areas: EXPERIMENTAL RESULTS FROM NOVA: TAMPED XENON UNDERDENSE X-RAY EMITTERS; MODELING MULTI-KEV RADIATION PRODUCTION OF XENON-FILLED BERYLLIUM CANS; MAPPING A CALCULATION FROM LASNEX TO CALE; HOT X RAYS FROM SEEDED NIF CAPSULES; HOHLRAUM DEBRIS MEASUREMENTS AT NOVA; FOAM AND STRUCTURAL RESPONSE CALCULATIONS FOR NIF NEUTRON EXPOSURE SAMPLE CASE ASSEMBLY DESIGN; NON-IGNITION X-RAY SOURCE FLUENCE-AREA PRODUCTS FOR NUCLEAR EFFECTS TESTING ON NIF. Also appended are reprints of two papers. The first is on the subject of ``X-Ray Production in Laser-Heated Xe Gas Targets.`` The second is on ``Efficient Production and Applications of 2- to 10-keV X Rays by Laser-Heated Underdense Radiators.``

  16. Irradiance analyzer for high power lasers

    SciTech Connect

    Conrad, R.W.

    1981-04-07

    An irradiance analysis system which includes an array of square rods that are joined together and have a flat entrance end and a polished flat exit end through which visible light is transmitted to a fresnel lens and focused to a particular area where the image focused is photographed so that when the various frames are developed they can be analyzed in a conventional film densitometer to yield quantative data on the temporal variation of laser beam irradiance distributions.

  17. Germanate Glass Fiber Lasers for High Power

    DTIC Science & Technology

    2016-01-04

    germanate based glasses with a specific focus on glass stability during thermal- cycling which is representative of the steps required to fabricate a doped...evidence of crystallisation after thermal cycling , and is of a low enough loss to realize a fiber laser. The glass stability is demonstrated by...specific focus on glass stability during thermal- cycling which is representative of the steps required to fabricate a doped micro-structured germanate

  18. Improved Spatial Filter for high power Lasers

    SciTech Connect

    Estabrook, Kent G.; Celliers, Peter M.; Murray, James E.; DaSilva, Luiz; MacGowan, Brian J.; Rubenchik, Alexander M.; Manes, Kenneth R.; Drake, Robert P.; Afeyan, Bedros

    1998-06-01

    A new pinhole architecture incorporates features intended to reduce the rate of plasma generation in a spatial filter for high-energy laser pulse beams. An elongated pinhole aperture is provided in an apertured body for rejecting off-axis rays of the laser pulse beam. The internal surface of the elongated aperture has a diameter which progressively tapers from a larger entrance cross-sectional area at an inlet to a smaller output cross-sectional area at an outlet. The tapered internal surface causes off-axis rays to be refracted in a low density plasma layer that forms on the internal surface or specularly reflected at grazing incidence from the internal surface. Off-axis rays of the high-energy pulse beam are rejected by this design. The external surface of the apertured body adjacent to the larger entrance cross-sectional area at the inlet to the elongated aperture is angled obliquely with respect to the to direction of the path of the high-energy laser pulse beam to backscatter off-axis rays away from the high-energy pulse beam. The aperture is formed as a truncated cone or alternatively with a tapered square cross-section. The internal surface of the aperture is coated with an ablative material, preferably high-density material which can be deposited with an exploding wire.

  19. MM&T Program for the Establishment of Production Techniques for High Power Bulk Semiconductor Limiters.

    DTIC Science & Technology

    1979-07-01

    F. Jellison, ’"-Band, High Power Solid State Receiv6:. IProtector Employing a Bulk Semiconductor Limiter", 1979 IEEE, MTT-S- INTERNATIONAL , Orlando...Techniques for High-Power Bulk Semiconductor Limiters", First Quaterly Report for Contract DAAB07-76-C-0039, ECOM, U.S. Army Electronics Research and...Electronics Supply Ctr Palo Alto, CA 94304 Directorate of Engineering & Standardization Rockwell International ATTN: (DESC-ECS) Mr. N.A. Hauck Science

  20. CHRONICLE: International forum on advanced high-power lasers and applications (AHPLA '99)

    NASA Astrophysics Data System (ADS)

    Afanas'ev, Yurii V.; Zavestovskaya, I. N.; Zvorykin, V. D.; Ionin, Andrei A.; Senatsky, Yu V.; Starodub, Aleksandr N.

    2000-05-01

    A review of reports made on the International Forum on Advanced High-Power Lasers and Applications, which was held at the beginning of November 1999 in Osaka (Japan), is presented. Five conferences were held during the forum on High-Power Laser Ablation, High-Power Lasers in Energy Engineering, High-Power Lasers in Civil Engineering and Architecture, High-Power Lasers in Manufacturing, and Advanced High-Power Lasers. The following trends in the field of high-power lasers and their applications were presented: laser fusion, laser applications in space, laser-triggered lightning, laser ablation of materials by short and ultrashort pulses, application of high-power lasers in manufacturing, application of high-power lasers in mining, laser decommissioning and decontamination of nuclear reactors, high-power solid-state and gas lasers, x-ray and free-electron lasers. One can find complete information on the forum in SPIE, vols. 3885-3889.

  1. Overview of the NASA high power laser program

    NASA Technical Reports Server (NTRS)

    Lundholm, J. G.

    1976-01-01

    The overall objectives of the NASA High Power Laser Program are reviewed along with their structure and center responsibilities. Present and future funding, laser power transmission in space, selected program highlights, the research and technology schedule, and the expected pace of the program are briefly considered.

  2. Device for wavefront correction in an ultra high power laser

    DOEpatents

    Ault, Earl R.; Comaskey, Brian J.; Kuklo, Thomas C.

    2002-01-01

    A system for wavefront correction in an ultra high power laser. As the laser medium flows past the optical excitation source and the fluid warms its index of refraction changes creating an optical wedge. A system is provided for correcting the thermally induced optical phase errors.

  3. High-Power Laser Source Evaluation

    DTIC Science & Technology

    1998-07-01

    uniform:«»! had been:taped. A sample beam profile at the receiver Zerodur Au-coated mirror 20 cm diameter f/6 Diode laser Diode bars 1 21 m beam...amplifiers and mirrors . This is of concern to the NIF Project and the use of unconverted 1.06 p.m light to produce these x-ray sources might require...they may result in DSWA Final Report - 34 NWET ANNUAL REPORT - QDV-99-0001 undesirable conditions at the turning mirrors or ghosts in the up-beam

  4. Stretchers and compressors for ultra-high power laser systems

    SciTech Connect

    Yakovlev, I V

    2014-05-30

    This review is concerned with pulse stretchers and compressors as key components of ultra-high power laser facilities that take advantage of chirped-pulse amplification. The potentialities, characteristics, configurations and methods for the matching and alignment of these devices are examined, with particular attention to the history of the optics of ultra-short, ultra-intense pulses before and after 1985, when the chirped-pulse amplification method was proposed, which drastically changed the view of the feasibility of creating ultra-high power laser sources. The review is intended primarily for young scientists and experts who begin to address the amplification and compression of chirped pulses, experts in laser optics and all who are interested in scientific achievements in the field of ultra-high power laser systems. (review)

  5. High-power laser source evaluation

    SciTech Connect

    Back, C. A.; Decker, C. D.; Davis, J. F.; Dixit, S.; Grun, J.; Managan, R. A.; Serduke, F. J. D.; Simonson, G. F.; Suter, L. J.; Wuest, C. R.; Ze, F.

    1998-07-01

    Robust Nuclear-Weapons-Effects Testing (NWET) capability will be needed for the foreseeable future to ensure the performance and reliability, in nuclear environments, of the evolving U.S. stockpile of weapons and other assets. Ongoing research on the use of high-energy lasers to generate environments of utility in nuclear weapon radiation effects simulations is addressed in the work described in this report. Laser-driven hohlraums and a variety of other targets have been considered in an effort to develop NWET capability of the highest possible fidelity in above-ground experiments. The envelope of large-system test needs is shown as the gray region in fig. 1. It does not represent the spectrum of any device; it is just the envelope of the spectral region of outputs from a number of possible devices. It is a goal of our laser-only and ignition-capsule source development work to generate x rays that fall somewhere in this envelope. One of the earlier appearances of this envelope is in ref. 1. The Defense Special Weapons Agency provided important support for the work described herein. A total of $520K was provided in the 1997 IACROs 97-3022 for Source Development and 97-3048 for Facilitization. The period of performance specified in the Statement of Work ran from 28 February 1997 until 30 November 1997. This period was extended, by agreement with DSWA, for two reasons: 1) despite the stated period of performance, funds were not available at LLNL to begin this work until somewhat later in the fiscal year, and 2) we agreed to stretch the current resources until follow-on funds were in hand, to minimize effects of ramping down and up again. The tasks addressed in this report are the following: 1) Non-ignition-source model benchmarking and design. This involves analysis of existing and new data on laser-only sources to benchmark LASNEX predictions 2) Non-ignition-source development experiments 3) Ignition capsule design to improve total x-ray output and simplify target

  6. High power solid state laser modulator

    DOEpatents

    Birx, Daniel L.; Ball, Don G.; Cook, Edward G.

    2004-04-27

    A multi-stage magnetic modulator provides a pulse train of .+-.40 kV electrical pulses at a 5-7 kHz repetition rate to a metal vapor laser. A fractional turn transformer steps up the voltage by a factor of 80 to 1 and magnetic pulse compression is used to reduce the pulse width of the pulse train. The transformer is fabricated utilizing a rod and plate stack type of construction to achieve a high packing factor. The pulses are controlled by an SCR stack where a plurality of SCRs are electrically connected in parallel, each SCR electrically connected to a saturable inductor, all saturable inductors being wound on the same core of magnetic material for enhanced power handling characteristics.

  7. Diode pumped alkali vapor lasers for high power applications

    NASA Astrophysics Data System (ADS)

    Zweiback, J.; Krupke, B.; Komashko, A.

    2008-02-01

    General Atomics has been engaged in the development of diode pumped alkali vapor lasers. We have been examining the design space looking for designs that are both efficient and easily scalable to high powers. Computationally, we have looked at the effect of pump bandwidth on laser performance. We have also looked at different lasing species. We have used an alexandrite laser to study the relative merits of different designs. We report on the results of our experimental and computational studies.

  8. Phosphate glass useful in high power lasers

    DOEpatents

    Hayden, Joseph S.; Sapak, David L.; Ward, Julia M.

    1990-01-01

    A low- or no-silica phosphate glass useful as a laser medium and having a high thermal conductivity, K.sub.90.degree. C. >0.8 W/mK, and a low coefficient of thermal expansion, .alpha..sub.20.degree.-40.degree. C. <80.times.10.sup.-7 /.degree.C., consists essentially of (on a batch composition basis): the amounts of Li.sub.2 O and Na.sub.2 O providing an average alkali metal ionic radius sufficiently low whereby said glass has K.sub.90.degree. C. >0.8 W/mK and .alpha..sub.20.degree.-40.degree. C. <80.times.10.sup.-7 /.degree.C., and wherein, when the batch composition is melted in contact with a silica-containing surface, the final glass composition contains at most about 3.5 mole % of additional silica derived from such contact during melting. The Nd.sub.2 O.sub.3 can be replaced by other lasing species.

  9. High power induction free electron laser

    NASA Astrophysics Data System (ADS)

    Miller, John L.

    1988-12-01

    Free electron laser (FEL) amplifiers driven by linear induction accelerators have considerable potential for scaling to high average powers. The high electron beam current produces large single pass gain and extraction efficiency, resulting in high peak power. The pulse repetition frequency scaling is limited primarily by accelerator and pulsed power technology. Two FEL experiments have been performed by the Beam Research Program at the Lawrence Livermore National Laboratory (LLNL): The ELF experiment used the 3.5-MeV beam from the Experimental Test Accelerator (ETA) and operated at a wavelength of 8.6 mm. This device achieved an overall single-pass gain of 45 dB, an output power of 1.5 GW, and an extraction efficiency of 35 percent. The microwave beam was confined in a waveguide in the 4-m-long wiggler. The PALADIN experiment uses the 45-MeV beam from the Advanced Test Accelerator and operates at a wavelength of 10.6 micrometers. Using a 15-m long wiggler a single pass gain of 27 dB was produced. Gain guiding was observed to confine the amplified beam within a beam tube that had a Fresnel number less than 1. The results of these experiments have been successfully modeled using a three dimensional particle simulation code. The Program also has ongoing efforts to develop wiggler, pulsed power and induction linac technology. A focus of much of this work is the ETA-II accelerator, which incorporates magnetic pulse compression drivers. One application of ETA-II will be to drive a 1 mm wavelength FEL. The microwave output will be used for a plasma heating experiment.

  10. High Power Induction Free Electron Laser

    NASA Astrophysics Data System (ADS)

    Miller, John L.

    1989-07-01

    Free electron laser (FEL) amplifiers driven by linear induction accelerators have considerable potential for scaling to high average powers. The high electron beam current produces large single pass gain and extraction efficiency, resulting in high peak power. The pulse repetition frequency scaling is limited primarily by accelerator and pulsed power technology. Two FEL experiments have been performed by the Beam Research Program at the Lawrence Livermore National Laboratory (LLNL): The ELF experiment used the 3.5-MeV beam from the Experimental Test Accelerator (ETA) and operated at a wavelength of 8.6 mm. This device achieved an overall single-pass gain of 45 dB, an output power of 1.5 GW, and an extraction efficiency of 35%. The microwave beam was confined in a waveguide in the 4-m-long wiggler. The PALADIN experiment uses the 45-MeV beam from the Advanced Test Accelerator and operates at a wavelength of 10.6 IA. Using a 15-m long wiggler a single pass gain of 27 dB was produced. Gain guiding was observed to confine the amplified beam within a beam tube that had a Fresnel number less than 1. The results of these expriments have been successfully modeled using a three dimensional particle simulation code. The Program also has ongoing efforts to develop wiggler, pulsed power and induction linac technology. A focus of much of this work is the ETA-II accelerator, which incorporates magnetic pulse compression drivers. One application of ETA-II will be to drive a 1 mm wavelength FEL. The microwave output will be used for a plasma heating experiment.

  11. Phosphate glass useful in high power lasers

    DOEpatents

    Hayden, J.S.; Sapak, D.L.; Ward, J.M.

    1990-05-29

    A low- or no-silica phosphate glass useful as a laser medium and having a high thermal conductivity, K[sub 90 C] > 0.8 W/mK, and a low coefficient of thermal expansion, [alpha][sub 20--40 C] < 80[times]10[sup [minus]7]/C, consists essentially of (on a batch composition basis Mole %): P[sub 2]O[sub 5], 45-70; Li[sub 2]O, 15-35; Na[sub 2]O, 0-10; Al[sub 2]O[sub 3], 10-15; Nd[sub 2]O[sub 3], 0.01-6; La[sub 2]O[sub 3], 0-6; SiO[sub 2], 0-8; B[sub 2]O[sub 3], 0-8; MgO, 0-18; CaO, 0-15; SrO, 0-9; BaO, 0-9; ZnO, 0-15; the amounts of Li[sub 2]O and Na[sub 2]O providing an average alkali metal ionic radius sufficiently low whereby said glass has K[sub 90 C] > 0.8 W/mK and [alpha][sub 20--40 C] < 80[times]10[sup [minus]7]/C, and wherein, when the batch composition is melted in contact with a silica-containing surface, the final glass composition contains at most about 3.5 mole % of additional silica derived from such contact during melting. The Nd[sub 2]O[sub 3] can be replaced by other lasing species. 3 figs.

  12. Modeling of high power laser interaction with metals

    NASA Astrophysics Data System (ADS)

    Mustafa, Kurt; Zahide, Demircioǧlu

    2017-02-01

    Laser matter interaction has been very popular subject from the first recognition of lasers. Laser application in industry or laboratory applications are based on definite interactions of the laser beam with the workpiece. In this paper, an effective model related with high power radiation interaction with metals is presented. In metals, Lorentz-Drude model is used calculate permeability theoretically. The plasma frequency was calculated at various temperatures and using the obtained results the refractive index of the metal (Ag) was investigated. The calculation result revealed that the effect of the temperature need to be considered at reflection and transmission of the laser beam.

  13. Transient Plasma Photonic Crystals for High-Power Lasers.

    PubMed

    Lehmann, G; Spatschek, K H

    2016-06-03

    A new type of transient photonic crystals for high-power lasers is presented. The crystal is produced by counterpropagating laser beams in plasma. Trapped electrons and electrically forced ions generate a strong density grating. The lifetime of the transient photonic crystal is determined by the ballistic motion of ions. The robustness of the photonic crystal allows one to manipulate high-intensity laser pulses. The scheme of the crystal is analyzed here by 1D Vlasov simulations. Reflection or transmission of high-power laser pulses are predicted by particle-in-cell simulations. It is shown that a transient plasma photonic crystal may act as a tunable mirror for intense laser pulses. Generalizations to 2D and 3D configurations are possible.

  14. High power repetitive TEA CO2 pulsed laser

    NASA Astrophysics Data System (ADS)

    Yang, Guilong; Li, Dianjun; Xie, Jijiang; Zhang, Laiming; Chen, Fei; Guo, Jin; Guo, Lihong

    2012-07-01

    A high power repetitive spark-pin UV-preionized TEA CO2 laser system is presented. The discharge for generating laser pulses is controlled by a rotary spark switch and a high voltage pulsed trigger. Uniform glow discharge between two symmetrical Chang-electrodes is realized by using an auto-inversion circuit. A couple of high power axial-flow fans with the maximum wind speed of 80 m/s are used for gas exchange between the electrodes. At a repetitive operation, the maximum average output laser power of 10.4 kW 10.6 μm laser is obtained at 300 Hz, with an electro-optical conversion efficiency of 15.6%. At single pulsed operation, more pumping energy and higher gases pressures can be injected, and the maximum output laser energy of 53 J is achieved.

  15. Trends in high power laser applications in civil engineering

    NASA Astrophysics Data System (ADS)

    Wignarajah, Sivakumaran; Sugimoto, Kenji; Nagai, Kaori

    2005-03-01

    This paper reviews the research and development efforts made on the use of lasers for material processing in the civil engineering industry. Initial investigations regarding the possibility of using lasers in civil engineering were made in the 1960s and '70s, the target being rock excavation. At that time however, the laser powers available were too small for any practical application utilization. In the 1980's, the technology of laser surface cleaning of historically important structures was developed in Europe. In the early 1990s, techniques of laser surface modification, including glazing and coloring of concrete, roughening of granite stones, carbonization of wood were pursued, mainly in Japan. In the latter part of the decade, techniques of laser decontamination of concrete surfaces in nuclear facilities were developed in many countries, and field tests were caried out in Japan. The rapid advances in development of diode lasers and YAG lasers with high power outputs and efficiencies since the late 1990's have led to a revival of worldwide interest in the use of lasers for material processing in civil engineering. The authors believe that, in the next 10 years or so, the advent of compact high power lasers is likely to lead to increased use of lasers of material processing in the field of civil engineering.

  16. Transparent ceramic photo-optical semiconductor high power switches

    DOEpatents

    Werne, Roger W.; Sullivan, James S.; Landingham, Richard L.

    2016-01-19

    A photoconductive semiconductor switch according to one embodiment includes a structure of sintered nanoparticles of a high band gap material exhibiting a lower electrical resistance when excited by light relative to an electrical resistance thereof when not exposed to the light. A method according to one embodiment includes creating a mixture comprising particles, at least one dopant, and at least one solvent; adding the mixture to a mold; forming a green structure in the mold; and sintering the green structure to form a transparent ceramic. Additional system, methods and products are also presented.

  17. In-volume heating using high-power laser diodes

    NASA Astrophysics Data System (ADS)

    Denisenkov, Valentin S.; Kiyko, Vadim V.; Vdovin, Gleb V.

    2015-03-01

    High-power lasers are useful instruments suitable for applications in various fields; the most common industrial applications include cutting and welding. We propose a new application of high-power laser diodes as in-bulk heating source for food industry. Current heating processes use surface heating with different approaches to make the heat distribution more uniform and the process more efficient. High-power lasers can in theory provide in-bulk heating which can sufficiently increase the uniformity of heat distribution thus making the process more efficient. We chose two media (vegetable fat and glucose) for feasibility experiments. First, we checked if the media have necessary absorption coefficients on the wavelengths of commercially available laser diodes (940-980 nm). This was done using spectrophotometer at 700-1100 nm which provided the dependences of transmission from the wavelength. The results indicate that vegetable fat has noticeable transmission dip around 925 nm and glucose has sufficient dip at 990 nm. Then, after the feasibility check, we did numerical simulation of the heat distribution in bulk using finite elements method. Based on the results, optimal laser wavelength and illuminator configuration were selected. Finally, we carried out several pilot experiments with high-power diodes heating the chosen media.

  18. High-power diode-pumped Tm:YLF laser

    NASA Astrophysics Data System (ADS)

    Schellhorn, M.

    2008-04-01

    A high-power, continuous-wave 3.5% Tm3+ doped LiYF4 (Tm:YLF) laser has been developed. Using two Tm:YLF rods in a single cavity, 55 W of laser output at 1910 nm was obtained with a slope efficiency of 49%. The M2 factor was found to be <3. With a single Tm:YLF rod, a maximum laser power of 30 W was obtained with a slope efficiency of 50%. The laser was tuned to the peak absorption wavelength of Ho:YAG of 1907.5 nm by an intracavity quartz etalon with an output power loss < 1 W.

  19. Welding with High-power Lasers: Trends and Developments

    NASA Astrophysics Data System (ADS)

    Bachmann, M.; Gumenyuk, A.; Rethmeier, M.

    High-power laser beam welding became new stimuli within the last 10 years due to the availability of a new generation of high brightness multi kilowatt solid state lasers. In the welding research new approaches have been developed to establish reliable and praxis oriented welding processes meeting the demands of modern industrial applications during this time. The paper focuses on some of the current scientific and technological aspects in this research field like hybrid laser arc welding, simulation techniques, utilization of electromagnetic fields or reduced pressure environment for laser beam welding processes, which contributed to the further development of this technology or will play a crucial role in its further industrial implementation.

  20. High-Power Fiber Lasers for Directed-Energy Applications

    DTIC Science & Technology

    2008-01-01

    demonstrated in a moder- ately turbulent environment. HIgH-PowEr FIbEr LAsErs Although a number of companies manufacture high-power fiber lasers , IPG ...in approximately one year. Multi- kilowatt , single-mode fiber lasers are robust, compact, and have high wall- plug efficiency, random polarization...and large band- width (~0.1%). A 1 kW, single-mode IPG fiber laser module, operating at wavelength l = 1.075 μm, exclud- ing power supply, measures w

  1. High-power synchronously pumped femtosecond Raman fiber laser.

    PubMed

    Churin, D; Olson, J; Norwood, R A; Peyghambarian, N; Kieu, K

    2015-06-01

    We report a high-power synchronously pumped femtosecond Raman fiber laser operating in the normal dispersion regime. The Raman laser is pumped by a picosecond Yb(3+)-doped fiber laser. It produces highly chirped pulses with energy up to 18 nJ, average power of 0.76 W and 88% efficiency. The pulse duration is measured to be 147 fs after external compression. We observed two different regimes of operation of the laser: coherent and noise-like regime. Both regimes were experimentally characterized. Numerical simulations are in a good agreement with experimental results.

  2. Diamond optical components for high-power and high-energy laser applications

    NASA Astrophysics Data System (ADS)

    Anoikin, Eugene; Muhr, Alexander; Bennett, Andrew; Twitchen, Daniel; de Wit, Henk

    2015-02-01

    High-power and high-energy laser systems have firmly established their industrial presence with applications that span materials processing; high - precision and high - throughput manufacturing; semiconductors, and defense. Along with high average power CO2 lasers operating at wavelengths of ~ 10 microns, solid state lasers and fiber lasers operating at ~ 1 micron wavelength are now increasingly being used, both in the high average power and high energy pulse regimes. In recent years, polycrystalline diamond has become the material of choice when it comes to making optical components for multi-kilowatt CO2 lasers at 10 micron, outperforming ZnSe due to its superior thermo-mechanical characteristics. For 1 micron laser systems, fused silica has to date been the most popular optical material owing to its outstanding optical properties. This paper characterizes high - power / high - energy performance of anti-reflection coated optical windows made of different grades of diamond (single crystal, polycrystalline) and of fused silica. Thermo-optical modeling results are also presented for water cooled mounted optical windows. Laser - induced damage threshold tests are performed and analyzed. It is concluded that diamond is a superior optical material for working with extremely high-power and high-energy laser beams at 1 micron wavelength.

  3. Fibre ring cavity semiconductor laser

    SciTech Connect

    Duraev, V P; Medvedev, S V

    2013-10-31

    This paper presents a study of semiconductor lasers having a polarisation maintaining fibre ring cavity. We examine the operating principle and report main characteristics of a semiconductor ring laser, in particular in single- and multiple-frequency regimes, and discuss its application areas. (lasers)

  4. High-power disk lasers: advances and applications

    NASA Astrophysics Data System (ADS)

    Havrilla, David; Ryba, Tracey; Holzer, Marco

    2012-03-01

    Though the genesis of the disk laser concept dates to the early 90's, the disk laser continues to demonstrate the flexibility and the certain future of a breakthrough technology. On-going increases in power per disk, and improvements in beam quality and efficiency continue to validate the genius of the disk laser concept. As of today, the disk principle has not reached any fundamental limits regarding output power per disk or beam quality, and offers numerous advantages over other high power resonator concepts, especially over monolithic architectures. With about 2,000 high power disk lasers installations, and a demand upwards of 1,000 lasers per year, the disk laser has proven to be a robust and reliable industrial tool. With advancements in running cost, investment cost and footprint, manufacturers continue to implement disk laser technology with more vigor than ever. This paper will explain recent advances in disk laser technology and process relevant features of the laser, like pump diode arrangement, resonator design and integrated beam guidance. In addition, advances in applications in the thick sheet area and very cost efficient high productivity applications like remote welding, remote cutting and cutting of thin sheets will be discussed.

  5. Long distance high power optical laser fiber break detection and continuity monitoring systems and methods

    DOEpatents

    Rinzler, Charles C.; Gray, William C.; Faircloth, Brian O.; Zediker, Mark S.

    2016-02-23

    A monitoring and detection system for use on high power laser systems, long distance high power laser systems and tools for performing high power laser operations. In particular, the monitoring and detection systems provide break detection and continuity protection for performing high power laser operations on, and in, remote and difficult to access locations.

  6. High power continuous-wave Alexandrite laser with green pump

    NASA Astrophysics Data System (ADS)

    Ghanbari, Shirin; Major, Arkady

    2016-07-01

    We report on a continuous-wave (CW) Alexandrite (Cr:BeAl2O4) laser, pumped by a high power green source at 532 nm with a diffraction limited beam. An output power of 2.6 W at 755 nm, a slope efficiency of 26%, and wavelength tunability of 85 nm have been achieved using 11 W of green pump. To the best of our knowledge, this is the highest CW output power of a high brightness laser pumped Alexandrite laser reported to date. The results obtained in this experiment can lead to the development of a high power tunable CW and ultrafast sources of the near-infrared or ultraviolet radiation through frequency conversion.

  7. High power laser having a trivalent liquid host

    SciTech Connect

    Ault, Earl R.

    2005-08-16

    A laser having a lasing chamber and a semiconductor pumping device with trivalent titanium ions dissolved in a liquid host within the lasing chamber. Since the host is a liquid, it can be removed from the optical cavity when it becomes heated avoiding the inevitable optical distortion and birefringence common to glass and crystal hosts.

  8. Time-resolved far-field analysis of a high power single emitter laser diode

    NASA Technical Reports Server (NTRS)

    Cornwell, Donald M., Jr.; Unge, Glenn L.

    1992-01-01

    A system was developed which is capable of measuring the time-resolved far-field radiation patterns from a high-power semiconductor laser under intensity modulated conditions. Angular steering of the fundamental spatial mode was observed, with pointing variations as large as 0.5 deg, or 7.5 percent of the beamwidth, during the time of the optical pulse. The variations in pointing angle were directly related to gradients in the transverse index profile of the laser, which may oscillate based on lateral spatial hole burning of the gain and carrier density.

  9. High-power YAG laser and its applications

    NASA Astrophysics Data System (ADS)

    Sato, S.; Tsuchiya, Kazuyuki; Owaki, Katsura; Morita, Ichiro

    2000-02-01

    Laser beams have been noticed as new heat resources with high energy concentration, which are different from plasma and arc. Conventionally, the only kW class industrial laser has been a carbon dioxide (CO2) laser. However, recently, several new high power lasers other than CO2 laser have been developed so that new methods of laser material processing have come out. As for YAG lasers, formerly, cw or pulse YAG lasers of several hundreds W class were used for welding or cutting of electrical appliants or cutting of thin metal plates. Now, the power has been raised to 5 - 6 kW, which enables YAG lasers to apply wider applications of material processing in many industrial fields, such as automobile industries, heavy industries and so on. It is a flexible fiber delivery that is the most remarkable advantage of YAG laser, which can be applied to ordinary machinery tools and robotic systems and makes it possible to deliver laser power to remote locations. Moreover, a shorter wavelength (1.06 micrometer) of YAG lasers than that of CO2 lasers is appropriate to metal processing. Figure 1 shows an example of YAG laser processing system utilizing those advantages. Also in IHI, the processing with YAG lasers has been studied for their practical application which has already succeeded in some sections such as cladding, repair welding and subdividing of nuclear power plants making use of YAG lasers' properties of fiber delivery of beam. Moreover, underwater processing technique is studied for practical use. In this paper, the examples of YAG laser application technology were described.

  10. Welding of aluminum alloy with high power direct diode laser

    NASA Astrophysics Data System (ADS)

    Abe, Nobuyuki; Morikawa, Atsuhito; Tsukamoto, Masahiro; Maeda, Koichi; Namba, Keizo

    2003-06-01

    Characterized by high conversion efficiency, small size, light weight and a long lifetime, high power diode lasers are currently being developed for application to various types of metal fabrication, such as welding. In this report, a 4kW high power direct diode laser was used to weld aluminum alloys, which are the focus of increasing attention from the automobile industry because of their light weight, high formability and easy recyclability. The applicability of a direct diode laser to aluminum alloy bead-on plate, butt and lap-fillet welding was studied under various welding conditions. A sound bead without cracks was successfully obtained when 1 mm thick aluminum alloy was welded by bead-on welding at a speed of 12m/min. Moreover, the bead cross section was heat conduction welding type rather than the keyhole welding type of conventional laser welding. Investigation of the welding phenomena with a high-speed video camera showed no spattering or laser plasma, so there was no problem with laser plasma damaging the focusing lens despite the diode laser's short focusing distance.

  11. Heat transfer and thermal lensing in large-mode high-power laser diodes

    NASA Astrophysics Data System (ADS)

    Chan, Paddy K. L.; Pipe, Kevin P.; Plant, Jason J.; Swint, Reuel B.; Juodawlkis, Paul W.

    2007-02-01

    In semiconductor lasers, key parameters such as threshold current, efficiency, wavelength, and lifetime are closely related to temperature. These dependencies are especially important for high-power lasers, in which device heating is the main cause of decreased performance and failure. Heat sources such as non-radiative recombination in the active region typically cause the temperature to be highly peaked within the device, potentially leading to large refractive index variation with bias. Here we apply high-resolution charge-coupled device (CCD) thermoreflectance to generate two dimensional (2D) maps of the facet temperatures of a high power laser with 500 nm spatial resolution. The device under test is a slab-coupled optical waveguide laser (SCOWL) which has a large single mode and high power output. These characteristics favor direct butt-coupling the light generated from the laser diode into a single mode optical fiber. From the high spatial resolution temperature map, we can calculate the non-radiative recombination power and the optical mode size by thermal circuit and finite-element model (FEM) respectively. Due to the thermal lensing effect at high bias, the size of the optical mode will decrease and hence the coupling efficiency between the laser diode and the single mode fiber increases. At I=10I th, we found that the optical mode size has 20% decrease and the coupling efficiency has 10% increase when comparing to I=2I th. This suggests SCOWL is very suitable fr optical communication system.

  12. High-power thulium lasers on a silicon photonics platform.

    PubMed

    Li, Nanxi; Purnawirman, P; Su, Zhan; Salih Magden, E; Callahan, Patrick T; Shtyrkova, Katia; Xin, Ming; Ruocco, Alfonso; Baiocco, Christopher; Ippen, Erich P; Kärtner, Franz X; Bradley, Jonathan D B; Vermeulen, Diedrik; Watts, Michael R

    2017-03-15

    Mid-infrared laser sources are of great interest for various applications, including light detection and ranging, spectroscopy, communication, trace-gas detection, and medical sensing. Silicon photonics is a promising platform that enables these applications to be integrated on a single chip with low cost and compact size. Silicon-based high-power lasers have been demonstrated at 1.55 μm wavelength, while in the 2 μm region, to the best of our knowledge, high-power, high-efficiency, and monolithic light sources have been minimally investigated. In this Letter, we report on high-power CMOS-compatible thulium-doped distributed feedback and distributed Bragg reflector lasers with single-mode output powers up to 267 and 387 mW, and slope efficiencies of 14% and 23%, respectively. More than 70 dB side-mode suppression ratio is achieved for both lasers. This work extends the applicability of silicon photonic microsystems in the 2 μm region.

  13. High Energy Density Sciences with High Power Lasers at SACLA

    NASA Astrophysics Data System (ADS)

    Kodama, Ryosuke

    2013-10-01

    One of the interesting topics on high energy density sciences with high power lasers is creation of extremely high pressures in material. The pressures of more than 0.1 TPa are the energy density corresponding to the chemical bonding energy, resulting in expectation of dramatic changes in the chemical reactions. At pressures of more than TPa, most of material would be melted on the shock Hugoniot curve. However, if the temperature is less than 1eV or lower than a melting point at pressures of more than TPa, novel solid states of matter must be created through a pressured phase transition. One of the interesting materials must be carbon. At pressures of more than TPa, the diamond structure changes to BC and cubic at more than 3TPa. To create such novel states of matter, several kinds of isentropic-like compression techniques are being developed with high power lasers. To explore the ``Tera-Pascal Science,'' now we have a new tool which is an x-ray free electron laser as well as high power lasers. The XFEL will clear the details of the HED states and also efficiently create hot dense matter. We have started a new project on high energy density sciences using an XFEL (SACLA) in Japan, which is a HERMES (High Energy density Revolution of Matter in Extreme States) project.

  14. Cascaded combiners for a high power CW fiber laser

    NASA Astrophysics Data System (ADS)

    Tan, Qirui; Ge, Tingwu; Zhang, Xuexia; Wang, Zhiyong

    2016-02-01

    We report cascaded combiners for a high power continuous wave (CW) fiber laser in this paper. The cascaded combiners are fabricated with an improved lateral splicing process. During the fusing process, there is no stress or tension between the pump fiber and the double-cladding fiber. Thus, the parameters of the combiner are better than those that have been reported. The coupling efficiency is 98.5%, and the signal insertion loss is 1%. The coupling efficiency of the cascaded combiners is 97.5%. The pump lights are individually coupled into the double-cladding fiber via five combiners. The thermal effects cannot cause damage to the combiners and the cascaded combiners can operate stably in high power CW fiber lasers. We also develop a high power CW fiber laser that generates a maximum 780 W of CW signal power at 1080 nm with 71% optical-to-optical conversion efficiency. The fiber laser is pumped via five intra-cavity cascaded combiners and five extra-cavity cascaded combiners with a maximum pump power of 1096 W and a pump wavelength of 975 nm.

  15. Automatic alignment technology in high power laser system

    NASA Astrophysics Data System (ADS)

    Zhang, Xin; Dai, Wan-jun; Wang, Yuan-cheng; Lian, Bo; Yang, Ying; Yuan, Qiang; Deng, Xue-wei; Zhao, Jun-pu; Zhou, Wei

    2015-02-01

    The high power solid laser system is becoming larger and higher energy that requires the beam automatic alignment faster and higher precision to ensure safety running of laser system and increase the shooting success rate. This paper take SGIII laser facility for instance, introduce the basic principle of automatic alignment of large laser system. The automatic alignment based on digital image processing technology which use the imaging of seven-classes spatial filter pinholes for feedback to working. Practical application indicates that automatic alignment system of cavity mirror in SGIII facility can finish the work in 210 seconds of four bundles and will not exceed 270 seconds of all six bundles. The alignment precision promoted to 2.5% aperture from 8% aperture. The automatic alignment makes it possible for fast and safety running of lager laser system.

  16. High power and single mode quantum cascade lasers.

    PubMed

    Bismuto, Alfredo; Bidaux, Yves; Blaser, Stéphane; Terazzi, Romain; Gresch, Tobias; Rochat, Michel; Muller, Antoine; Bonzon, Christopher; Faist, Jerome

    2016-05-16

    We present a single mode quantum cascade laser with nearly 1 W optical power. A buried distributed feedback reflector is used on the back section for wavelength selection. The laser is 6 mm long, 3.5 μm wide, mounted episide-up and the laser facets are left uncoated. Laser emission is centered at 4.68 μm. Single-mode operation with a side mode suppression ratio of more than 30 dB is obtained in whole range of operation. Farfield measurements prove a symmetric, single transverse-mode emission in TM00-mode with typical divergences of 41° and 33° in the vertical and horizontal direction respectively. This work shows the potential for simple fabrication of high power lasers compatible with standard DFB processing.

  17. Modeling compact high power fiber lasers and vecsels

    NASA Astrophysics Data System (ADS)

    Li, Hongbo

    Compact high power fiber lasers and the vertical-external-cavity surface-emitting lasers (VECSELs) are promising candidates for high power laser sources with diffraction-limited beam quality and are currently the subject of intensive research and development. Here three large mode area fiber lasers, namely, the photonic crystal fiber (PCF) laser, the multicore fiber (MCF) laser, and the multimode interference (MMI) fiber laser, as well as the VECSEL are modeled and designed. For the PCF laser, the effective refractive index and the effective core radius of the PCF are investigated using vectorial approaches and reformulated. Then, the classical step-index fiber theory is extended to PCFs, resulting in a highly efficient vectorial effective-index method for the design and analysis of PCFs. The new approach is employed to analyze the modal properties of the PCF lasers with depressed-index cores and to effectively estimate the number of guided modes for PCFs. The MCF laser, consisting of an active MCF and a passive coreless fiber, is modeled using the vectorial mode expansion method developed in this work. The results illustrate that the mode selection in the MCF laser by the coreless fiber section is determined by the MMI effect, not the Talbot effect. Based on the MMI and self-imaging in multimode fibers, the vectorial mode expansion approach is employed to design the first MMI fiber laser demonstrated experimentally. For the design and modeling of VECSELs, the optical, thermal, and structural properties of common material systems are investigated and the most reliable material models are summarized. The nanoscale heat transport theory is applied for the first time, to the best of my knowledge, to design and model VECSELs. In addition, the most accurate strain compensation approach is selected for VECSELs incorporating strained quantum wells to maintain structural stability. The design principles for the VECSEL subcavity are elaborated and applied to design a 1040nm

  18. A 3000W 808nm QCW G-stack semiconductor laser array

    NASA Astrophysics Data System (ADS)

    Zhang, Pu; Wang, Jingwei; Hou, Dong; Wang, Zhenfu; Xiong, Lingling; Liu, Hui; Nie, Zhiqiang; Liu, Xingsheng

    2015-02-01

    With the improvement of output power, efficiency and reliability, high power semiconductor lasers have been applied in more and more fields. In this paper, a conduction-cooled, high peak output power semiconductor laser array was studied and developed. The structure and operation parameters of G-Stack semiconductor laser array were designed and optimized using finite element method (FEM). A Quasi-continuous-wave (QCW) conduction-cooled G-Stack semiconductor laser array with a narrow spectrum width was fabricated successfully.

  19. Reliability of high power laser diodes with external optical feedback

    NASA Astrophysics Data System (ADS)

    Bonsendorf, Dennis; Schneider, Stephan; Meinschien, Jens; Tomm, Jens W.

    2016-03-01

    Direct diode laser systems gain importance in the fields of material processing and solid-state laser pumping. With increased output power, also the influence of strong optical feedback has to be considered. Uncontrolled optical feedback is known for its spectral and power fluctuation effects, as well as potential emitter damage. We found that even intended feedback by use of volume Bragg gratings (VBG) for spectral stabilization may result in emitter lifetime reduction. To provide stable and reliable laser systems design, guidelines and maximum feedback ratings have to be found. We present a model to estimate the optical feedback power coupled back into the laser diode waveguide. It includes several origins of optical feedback and wide range of optical elements. The failure thresholds of InGaAs and AlGaAs bars have been determined not only at standard operation mode but at various working points. The influence of several feedback levels to laser diode lifetime is investigated up to 4000h. The analysis of the semiconductor itself leads to a better understanding of the degradation process by defect spread. Facet microscopy, LBIC- and electroluminescence measurements deliver detailed information about semiconductor defects before and after aging tests. Laser diode protection systems can monitor optical feedback. With this improved understanding, the emergency shutdown threshold can be set low enough to ensure laser diode reliability but also high enough to provide better machine usability avoiding false alarms.

  20. Transmission grating stretcher for contrast enhancement of high power lasers.

    PubMed

    Tang, Yunxin; Hooker, Chris; Chekhlov, Oleg; Hawkes, Steve; Collier, John; Rajeev, P P

    2014-12-01

    We propose, for the first time, a transmission grating stretcher for high power lasers and demonstrate its superiority over conventional, reflective gold grating stretchers in terms of pulse temporal quality. We show that, compared to a conventional stretcher with the same stretching factor, the transmission-grating based stretcher yields more than an order of magnitude improvement in the contrast pedestal. We have also quantitatively characterized the roughness of the grating surfaces and estimated its impact on the contrast pedestal.

  1. Active cooling solutions for high power laser diodes stacks

    NASA Astrophysics Data System (ADS)

    Karni, Yoram; Klumel, Genady; Levy, Moshe; Berk, Yuri; Openhaim, Yaki; Gridish, Yaakov; Elgali, Asher; Avisar, Meir; Blonder, Moshe; Sagy, Hila; Gertsenshtein, Alex

    2008-02-01

    High power water cooled diode lasers find increasing demand in biomedical, cosmetic and industrial applications, where very high brightness and power are required. The high brightness is achieved either by increasing the power of each bar or by reducing the emitting area of the stacks. Two new products will be presented: Horizontal CW stacks with output power as high as 1kW using 80 W bars with emitting area width as low as 50 μm Vertical QCW stacks with output power as high as 1.2kW using 120 W bars. Heat removal from high power laser stacks often requires microchannel coolers operated with finely filtered deionized (DI) water. However, for certain industrial applications the reliability of this cooling method is widely considered insufficient due to leakage failures caused the highly corrosive DI water. Two solutions to the above problem will be discussed. A microchannel cooler-based package, which vastly reduces the corrosion problem, and a novel high-power laser diode stack that completely eliminates it. The latter solution is especially effective for pulsed applications in high duty cycle range.

  2. Further development of high-power pump laser diodes

    NASA Astrophysics Data System (ADS)

    Schmidt, Berthold; Lichtenstein, Norbert; Sverdlov, Boris; Matuschek, Nicolai; Mohrdiek, Stefan; Pliska, Tomas; Mueller, Juergen; Pawlik, Susanne; Arlt, Sebastian; Pfeiffer, Hans-Ulrich; Fily, Arnaud; Harder, Christoph

    2003-12-01

    AlGaAs/InGaAs based high power pump laser diodes with wavelength of around 980 nm are key products within erbium doped fiber amplifiers (EDFA) for today's long haul and metro-communication networks, whereas InGaAsP/InP based laser diodes with 14xx nm emission wavelength are relevant for advanced, but not yet widely-used Raman amplifiers. Due to the changing industrial environment cost reduction becomes a crucial factor in the development of new, pump modules. Therefore, pump laser chips were aggressively optimized in terms of power conversion and thermal stability, which allows operation without active cooling at temperatures exceeding 70°C. In addition our submarine-reliable single mode technology was extended to high power multi-mode laser diodes. These light sources can be used in the field of optical amplifiers as well as for medical, printing and industrial applications. Improvements of pump laser diodes in terms of power conversion efficiency, fiber Bragg grating (FBG) locking performance of single mode devices, noise reduction and reliability will be presented.

  3. High-Power Lasers for Science and Society

    SciTech Connect

    Siders, C. W.; Haefner, C.

    2016-10-05

    Since the first demonstration of the laser in 1960 by Theodore Maiman at Hughes Research Laboratories, the principal defining characteristic of lasers has been their ability to focus unprecedented powers of light in space, time, and frequency. High-power lasers have, over the ensuing five and a half decades, illuminated entirely new fields of scientific endeavor as well as made a profound impact on society. While the United States pioneered lasers and their early applications, we have been eclipsed in the past decade by highly effective national and international networks in both Europe and Asia, which have effectively focused their energies, efforts, and resources to achieve greater scientific and societal impact. This white paper calls for strategic investment which, by striking an appropriate balance between distributing our precious national funds and establishing centers of excellence, will ensure a broad pipeline of people and transformative ideas connecting our world-leading universities, defining flagship facilities stewarded by our national laboratories, and driving innovation across industry, to fully exploit the potential of high-power lasers.

  4. High power diode pumped solid state laser development at Lawrence Livermore National Laboratory

    SciTech Connect

    Solarz, R.; Albrecht, G.; Hackel, L.

    1994-03-01

    The authors recent developments in high powered diode pumped solid state lasers at Lawrence Livermore National Laboratory. Over the past year the authors have made continued improvements to semiconductor pump array technology which includes the development of higher average power and lower cost pump modules. They report the performance of high power AlGaAs, InGaAs, and AlGaInP arrays. They also report on improvement to the integrated micro-optics designs in conjunction with lensing duct technology which gives rise to very high performance end pumping designs for solid state lasers which have major advantages which they detail. Substantial progress on beam quality improvements to near the diffraction limit at very high power have also been made and will be reported. They also will discuss recent experiments on high power non-linear materials for q-switches, harmonic converters, and parametric oscillators. Advances in diode pumped devices at LLNL which include tunable Cr:LiSrAlF{sub 6}, mid-IR Er:YAG, holmium based lasers and other developments will also be outlined. Concepts for delivering up to 30 kilowatts of average power from a DPSSL oscillator will be described.

  5. Innovative high-power CW Yb:YAG cryogenic laser

    NASA Astrophysics Data System (ADS)

    Brown, D. C.; Singley, J. M.; Yager, E.; Kuper, J. W.; Lotito, B. J.; Bennett, L. L.

    2007-04-01

    In this paper we discuss a CW Yb:YAG cryogenic laser program that has resulted in the design and demonstration of a novel high power laser. Cryogenically-cooled crystalline solid-state lasers, and Yb:YAG lasers in particular, are attractive sources of scalable CW output power with very high wallplug efficiency and excellent beam-quality that is independent of the output power. This laser consists of a distributed array of seven highly-doped thin Yb:YAG-sapphire disks in a folded multiple-Z resonator. Individual disks are pumped from opposite sides using fiber-coupled ~ 30W 940nm pump diodes. The laser system we have constructed produces a near-diffraction-limited TEM 00 output beam with the aid of an active conduction-cooling design. In addition, the device can be scaled to very high average power in a MOPA configuration, by increasing the number and diameter of the thin disks, and by increasing the power of the pump diodes with only minor modifications to the current design. The thermal and optical benefits of cryogenically-cooled solid-state lasers will be reviewed, scalability of our Yb:YAG cryogenic laser design will be discussed, and we will present experimental results including output power, slope and optical-optical efficiencies, and beam-quality.

  6. Innovative high-power CW Yb:YAG cryogenic laser

    NASA Astrophysics Data System (ADS)

    Brown, D. C.; Singley, J. M.; Yager, E.; Kuper, J. W.; Lotito, B. J.; Bennett, L. L.

    2007-02-01

    In this paper we discuss a CW Yb:YAG cryogenic laser program that has resulted in the design and demonstration of a novel high power laser. Cryogenically-cooled crystalline solid-state lasers, and Yb:YAG lasers in particular, are attractive sources of scalable CW output power with very high wallplug efficiency and excellent beam-quality that is independent of the output power. This laser consists of a distributed array of seven highly-doped thin Yb:YAG-sapphire disks in a folded multiple-Z resonator. Individual disks are pumped from opposite sides using fiber-coupled ~ 30W 940nm pump diodes. The laser system we have constructed produces a near-diffraction-limited TEM 00 output beam with the aid of an active conduction-cooling design. In addition, the device can be scaled to very high average power in a MOPA configuration, by increasing the number and diameter of the thin disks, and by increasing the power of the pump diodes with only minor modifications to the current design. The thermal and optical benefits of cryogenically-cooled solid-state lasers will be reviewed, scalability of our Yb:YAG cryogenic laser design will be discussed, and we will present experimental results including output power, slope and optical-optical efficiencies, and beam-quality.

  7. High-power diode lasers for optical communications applications

    NASA Technical Reports Server (NTRS)

    Carlin, D. B.; Goldstein, B.; Channin, D. J.

    1985-01-01

    High-power, single-mode, double-heterojunction AlGaAs diode lasers are being developed to meet source requirements for both fiber optic local area network and free space communications systems. An individual device, based on the channeled-substrate-planar (CSP) structure, has yielded single spatial and longitudinal mode outputs of up to 90 mW CW, and has maintained a single spatial mode to 150 mW CW. Phase-locked arrays of closely spaced index-guided lasers have been designed and fabricated with the aim of multiplying the outputs of the individual devices to even higher power levels in a stable, single-lobe, anastigmatic beam. The optical modes of the lasers in such arrays can couple together in such a way that they appear to be emanating from a single source, and can therefore be efficiently coupled into optical communications systems. This paper will review the state of high-power laser technology and discuss the communication system implications of these devices.

  8. Safety approaches for high power modular laser operation

    NASA Astrophysics Data System (ADS)

    Handren, R. T.

    1993-03-01

    Approximately 20 years ago, a program was initiated at the Lawrence Livermore National Laboratory (LLNL) to study the feasibility of using lasers to separate isotopes of uranium and other materials. Of particular interest was the development of a uranium enrichment method for the production of commercial nuclear power reactor fuel to replace current more expensive methods. The Uranium Atomic Vapor Laser Isotope Separation (U-AVLIS) Program progressed to the point where a plant-scale facility to demonstrate commercial feasibility was built and is being tested. The U-AVLIS Program uses copper vapor lasers which pump frequency selective dye lasers to photoionize uranium vapor produced by an electron beam. The selectively ionized isotopes are electrostatically collected. The copper lasers are arranged in oscillator/amplifier chains. The current configuration consists of 12 chains, each with a nominal output of 800 W for a system output in excess of 9 kW. The system requirements are for continuous operation (24 h a day, 7 days a week) and high availability. To meet these requirements, the lasers are designed in a modular form allowing for rapid change-out of the lasers requiring maintenance. Since beginning operation in early 1985, the copper lasers have accumulated over 2 million unit hours at a greater than 90% availability. The dye laser system provides approximately 2.5 kW average power in the visible wavelength range. This large-scale laser system has many safety considerations, including high-power laser beams, high voltage, and large quantities (approximately 3000 gal) of ethanol dye solutions. The Laboratory's safety policy requires that safety controls be designed into any process, equipment, or apparatus in the form of engineering controls. Administrative controls further reduce the risk to an acceptable level. Selected examples of engineering and administrative controls currently being used in the U-AVLIS Program are described.

  9. High power free-electron laser concepts and problems

    SciTech Connect

    Goldstein, J.C.

    1995-03-01

    Free-electron lasers (FELs) have long been thought to offer the potential of high average power operation. That potential exists because of several unique properties of FELs, such as the removal of ``waste heat`` at the velocity of light, the ``laser medium`` (the electron beam) is impervious to damage by very high optical intensitites, and the technology of generating very high average power relativistic electron beams. In particular, if one can build a laser with a power extraction efficiency 11 which is driven by an electron beam of average Power P{sub EB}, one expects a laser output power of P{sub L} = {eta} P{sub EB}. One approach to FEL devices with large values of {eta} (in excess of 10 %) is to use a ``tapered`` (or nonuniform) wiggler. This approach was followed at several laboratories during the FEL development Program for the Strategic Defense Initiative (SDI) project. In this paper, we review some concepts and technical requirements for high-power tapered-wiggler FELs driven by radio-frequency linear accelerators (rf-linacs) which were developed during the SDI project. Contributions from three quite different technologies - rf-accelerators, optics, and magnets - are needed to construct and operate an FEL oscillator. The particular requirements on these technologies for a high-power FEL were far beyond the state of the art in those areas when the SDI project started, so significant advances had to be made before a working device could be constructed. Many of those requirements were not clearly understood when the project started, but were developed during the course of the experimental and theoretical research for the project. This information can be useful in planning future high-power FEL projects.

  10. High-power diode lasers and their direct industrial applications

    NASA Astrophysics Data System (ADS)

    Loosen, Peter; Treusch, Hans-Georg; Haas, C. R.; Gardenier, U.; Weck, Manfred; Sinnhoff, V.; Kasperowski, S.; vor dem Esche, R.

    1995-04-01

    The paper summarizes activities of the two Fraunhofer-Institutes ILT and IPT concerning the development of high-power laser-diode stacks and their direct industrial applications. With microchannel coolers in copper technology and ultra-precision machined micro-optics a stack of 330 - 400 W total power with a maximum intensity of the focused beam of 2 104 W/cm2 has been built and tested in first applications. By further improvements of the lens-fabrication and -alignment technology as well as increase of the number of stacked diodes an output power in the kW-range and intensities up to about 105 W/cm2 shall be achieved in the near future. Applications of such laser sources in surface technology, in the processing of plastics, in laser-assisted machining and in brazing are discussed.

  11. Annular resonators for high-power chemical lasers

    NASA Astrophysics Data System (ADS)

    Wade, Richard C.

    1993-08-01

    Resonators capable of extracting highly coherent energy from DF and HF chemical laser annular gain media have been under investigation for weapon application since 1974. This survey article traces the background of interest in these devices, describes the various concepts that have been experimentally and analytically investigated, and discusses the issues associated with their operation. From the discussion of issues, preferred concepts are selected. Applicability of these concepts to high-power operation is addressed through discussions of past and ongoing high-power demonstration programs and the issues facing their application to weapon sized devices capable of strategic and tactical missions such as ballistic missile defense (BMD), theater missile defense (TMD), and anti satellite (ASAT).

  12. High-Power Fiber Lasers Using Photonic Band Gap Materials

    NASA Technical Reports Server (NTRS)

    DiDomenico, Leo; Dowling, Jonathan

    2005-01-01

    High-power fiber lasers (HPFLs) would be made from photonic band gap (PBG) materials, according to the proposal. Such lasers would be scalable in the sense that a large number of fiber lasers could be arranged in an array or bundle and then operated in phase-locked condition to generate a superposition and highly directed high-power laser beam. It has been estimated that an average power level as high as 1,000 W per fiber could be achieved in such an array. Examples of potential applications for the proposed single-fiber lasers include welding and laser surgery. Additionally, the bundled fibers have applications in beaming power through free space for autonomous vehicles, laser weapons, free-space communications, and inducing photochemical reactions in large-scale industrial processes. The proposal has been inspired in part by recent improvements in the capabilities of single-mode fiber amplifiers and lasers to produce continuous high-power radiation. In particular, it has been found that the average output power of a single strand of a fiber laser can be increased by suitably changing the doping profile of active ions in its gain medium to optimize the spatial overlap of the electromagnetic field with the distribution of active ions. Such optimization minimizes pump power losses and increases the gain in the fiber laser system. The proposal would expand the basic concept of this type of optimization to incorporate exploitation of the properties (including, in some cases, nonlinearities) of PBG materials to obtain power levels and efficiencies higher than are now possible. Another element of the proposal is to enable pumping by concentrated sunlight. Somewhat more specifically, the proposal calls for exploitation of the properties of PBG materials to overcome a number of stubborn adverse phenomena that have impeded prior efforts to perfect HPFLs. The most relevant of those phenomena is amplified spontaneous emission (ASE), which causes saturation of gain and power

  13. Progress in efficiency-optimized high-power diode lasers

    NASA Astrophysics Data System (ADS)

    Pietrzak, A.; Hülsewede, R.; Zorn, M.; Hirsekorn, O.; Sebastian, J.; Meusel, J.; Hennig, P.; Crump, P.; Wenzel, H.; Knigge, S.; Maaßdorf, A.; Bugge, F.; Erbert, G.

    2013-10-01

    High-power diode lasers are highly efficient sources of optical energy for industrial and defense applications, either directly or as pump sources for solid state or fiber lasers. We review here how advances in diode laser design and device technology have enabled the performance to be continuously improved. An overview is presented of recent progress at JENOPTIK in the development of commercial diode lasers optimized for peak performance, robust high-yield manufacture and long lifetimes. These diode lasers are tailored to simultaneously operate with reduced vertical carrier leakage, low thermal and electrical resistance and low optical losses. In this way, the highest electro-optical efficiencies are sustained to high currents. For example, 940-nm bars with high fill factor are shown to deliver continuous wave (CW) output powers of 280 W with conversion efficiency of < 60%. These bars have a vertical far field angle with 95% power content of just 40°. In addition, 955-nm single emitters with 90μm stripe width deliver 12 W CW output with power conversion efficiency at the operating point of 69%. In parallel, the Ferdinand-Braun-Institut (FBH) is working to enable the next generation of high power diode lasers, by determining the key limitations to performance and by pioneering new technologies to address these limits. An overview of recent studies at the FBH will therefore also be presented. Examples will include structures with further reduced far field angles, higher lateral beam quality and increased peak power and efficiency. Prospects for further performance improvement will be discussed.

  14. Improving Reliability of High Power Quasi-CW Laser Diode Arrays for Pumping Solid State Lasers

    NASA Technical Reports Server (NTRS)

    Amzajerdian, Farzin; Meadows, Byron L.; Baker, Nathaniel R.; Barnes, Bruce W.; Baggott, Renee S.; Lockard, George E.; Singh, Upendra N.; Kavaya, Michael J.

    2005-01-01

    Most Lidar applications rely on moderate to high power solid state lasers to generate the required transmitted pulses. However, the reliability of solid state lasers, which can operate autonomously over long periods, is constrained by their laser diode pump arrays. Thermal cycling of the active regions is considered the primary reason for rapid degradation of the quasi-CW high power laser diode arrays, and the excessive temperature rise is the leading suspect in premature failure. The thermal issues of laser diode arrays are even more drastic for 2-micron solid state lasers which require considerably longer pump pulses compared to the more commonly used pump arrays for 1-micron lasers. This paper describes several advanced packaging techniques being employed for more efficient heat removal from the active regions of the laser diode bars. Experimental results for several high power laser diode array devices will be reported and their performance when operated at long pulsewidths of about 1msec will be described.

  15. Design and comparison of laser windows for high-power lasers

    NASA Astrophysics Data System (ADS)

    Niu, Yanxiong; Liu, Wenwen; Liu, Haixia; Wang, Caili; Niu, Haisha; Man, Da

    2014-11-01

    High-power laser systems are getting more and more widely used in industry and military affairs. It is necessary to develop a high-power laser system which can operate over long periods of time without appreciable degradation in performance. When a high-energy laser beam transmits through a laser window, it is possible that the permanent damage is caused to the window because of the energy absorption by window materials. So, when we design a high-power laser system, a suitable laser window material must be selected and the laser damage threshold of the window must be known. In this paper, a thermal analysis model of high-power laser window is established, and the relationship between the laser intensity and the thermal-stress field distribution is studied by deducing the formulas through utilizing the integral-transform method. The influence of window radius, thickness and laser intensity on the temperature and stress field distributions is analyzed. Then, the performance of K9 glass and the fused silica glass is compared, and the laser-induced damage mechanism is analyzed. Finally, the damage thresholds of laser windows are calculated. The results show that compared with K9 glass, the fused silica glass has a higher damage threshold due to its good thermodynamic properties. The presented theoretical analysis and simulation results are helpful for the design and selection of high-power laser windows.

  16. Highly efficient and high-power diode-pumped femtosecond Yb:LYSO laser

    NASA Astrophysics Data System (ADS)

    Tian, Wenlong; Wang, Zhaohua; Zhu, Jiangfeng; Zheng, Lihe; Xu, Jun; Wei, Zhiyi

    2017-04-01

    A diode-pumped high-power femtosecond Yb:LYSO laser with high efficiency is demonstrated. With a semiconductor saturable absorber mirror for passive mode-locking and a Gires–Tournois interferometer mirror for intracavity dispersion compensation, stable mode-locking pulses of 297 fs duration at 1042 nm were obtained. The maximum average power of 3.07 W was realized under 5.17 W absorbed pump power, corresponding to as high as 59.4% opt–opt efficiency. The single pulse energy and peak power are about 35.5 nJ and 119.5 kW, respectively.

  17. Optical monitoring of high power direct diode laser cladding

    NASA Astrophysics Data System (ADS)

    Liu, Shuang; Farahmand, Parisa; Kovacevic, Radovan

    2014-12-01

    Laser cladding is one of the most advanced surface modification techniques which can be used to build and repair high-value components. High power direct diode laser (HPDDL) offers unique quality and cost advantages over other lasers (CO2, Nd:YAG). Especially its rectangular laser beam with top-hat intensity distribution makes HPDDL an ideal tool for large area cladding. In order to utilize this technique successfully, the development of on-line monitoring and process control is necessary. In this study, an optical monitoring system consisting of a high-speed CCD camera, a pyrometer, and an infrared camera was used to analyze the mass- and heat-transfer in the cladding process. The particle transport in flight was viewed by a high-speed CCD camera; the interaction between powder flow and laser beam was observed by an infrared camera; and the thermal behavior of the molten pool was recorded by the pyrometer and the infrared camera. The effects of the processing parameters on the laser attenuation, particle heating and clad properties were investigated based on the obtained signals. The optical monitoring method improved the understanding about mutual interrelated phenomena in the cladding process.

  18. VACUUM WINDOW DESIGN FOR HIGH-POWER LASERS.

    SciTech Connect

    SHAFTAN, T.

    2005-04-21

    One of the problems in the high-power lasers design is in outcoupling of a powerful laser beam out of a vacuum volume into atmosphere. Usually the laser device is located inside a vacuum tank. The laser radiation is transported to the outside world through the transparent vacuum window. While considered transparent, some of the light passing through the glass is absorbed and converted to heat. For most applications, these properties are academic curiosities; however, in multi-kilowatt lasers, the heat becomes significant and can lead to a failure. The absorbed power can result in thermal stress, reduction of light transmission and, consequently, window damage. Modern optical technology has developed different types of glass (Silica, BK7, diamond, etc.) that have high thermal conductivity and damage threshold. However, for kilo- and megawatt lasers the issue still remains open. In this paper we present a solution that may relieve the heat load on the output window. We discuss advantages and issues of this particular window design.

  19. Dichroic mirror for high power Nd:YAG laser

    SciTech Connect

    Dinca, A.; Lupei, V.; Miclea, P.T.; Dinca, M.P.

    1996-12-31

    The paper presents the design of a dichroic mirror used in a Nd:YAG high power laser to reflect the 1.44 {micro}m radiation and to transmit the 1.064 {micro}m one. In order to obtain a wide transmission band, all the solutions for matching basic stack with the substrate, consisting in a number of periods less or equal than three, were investigated and the best was selected. The solutions were obtained by analytical inversion of the equations for the three layer equivalent system.

  20. High-Power LOC Lasers: Synthesis and Mode Control

    DTIC Science & Technology

    1975-03-01

    Wright-Patterson AFB, OH 45433. AFAL ltr 4 Sep 1975 ^F—^»IPl««—-B-^——— ■ - m wmrnmmmmmm i i ^1 AFAL-TR-75-13 OS HIGH-POWER LOC LASERS...AIR FORCE AVIONICS LABORATORY AIR FORCE SYSTEMS COMMAND WRIGHT-PATTERSON AIR FORCE BASE, OHIO 46433 ^^^^^^^^^^^A«^ - — HIWSWWW""^- tmm**~* m ...8217 — ’ - UMUtattiHta 5 y^p^pil m *mMi\\r~r’ FOREWORD This Final Report was prepared by RCA Laboratories, Princeton, New

  1. Control system for high power laser drilling workover and completion unit

    DOEpatents

    Zediker, Mark S; Makki, Siamak; Faircloth, Brian O; DeWitt, Ronald A; Allen, Erik C; Underwood, Lance D

    2015-05-12

    A control and monitoring system controls and monitors a high power laser system for performing high power laser operations. The control and monitoring system is configured to perform high power laser operation on, and in, remote and difficult to access locations.

  2. High-power solid-state cw dye laser.

    PubMed

    Bornemann, R; Thiel, E; Bolívar, P Haring

    2011-12-19

    In the present paper we describe a high-power tunable solid-state dye laser setup that offers peak output power up to 800 mW around 575 nm with excellent long-time power stability and low noise level. The spectral width of the laser emission is less than 3 GHz and can be tuned over more than 30 nm. A nearly circular mode profile is achieved with an M(2) better than 1.4. The device can be integrated in a compact housing (dimensions are 60 × 40 × 20 cm(3)). The limitation of long-time power stability is mainly given by photo decomposition of organic dye molecules. These processes are analyzed in detail via spatially resolved micro-imaging and spectroscopic studies.

  3. Cladded single crystal fibers for high power fiber lasers

    NASA Astrophysics Data System (ADS)

    Kim, W.; Shaw, B.; Bayya, S.; Askins, C.; Peele, J.; Rhonehouse, D.; Meyers, J.; Thapa, R.; Gibson, D.; Sanghera, J.

    2016-09-01

    We report on the recent progress in the development of cladded single crystal fibers for high power single frequency lasers. Various rare earth doped single crystal YAG fibers with diameters down to 17 μm with length > 1 m have been successfully drawn using a state-of-the-art Laser Heated Pedestal Growth system. Single and double cladding on rare earth doped YAG fibers have been developed using glasses where optical and physical properties were precisely matched to doped YAG core single crystal fiber. The double clad Yb:YAG fiber structures have dimensions analogous to large mode area (LMA) silica fiber. We also report successful fabrications of all crystalline core/clad fibers where thermal and optical properties are superior over glass cladded YAG fibers. Various fabrication methods, optical characterization and gain measurements on these cladded YAG fibers are reported.

  4. Extremely high-power CO2 laser beam correction.

    PubMed

    Kudryashov, Alexis; Alexandrov, Alexander; Rukosuev, Alexey; Samarkin, Vadim; Galarneau, Pierre; Turbide, Simon; Châteauneuf, François

    2015-05-10

    This paper presents the results of high-power CO2 laser-aberration correction and jitter stabilization. A bimorph deformable mirror and two tip-tilt piezo correctors were used as executive elements. Two types of wavefront sensors, one Hartmann to measure higher-order aberrations (defocus, astigmatism etc.) based on an uncooled microbolometer long-wave infrared camera and the other a tip-tilt one based on the technology of obliquely sputtered, thin chromium films on Si substrates, were applied to measure wavefront aberrations. We discuss both positive and negative attributes of suggested wavefront sensors. The adaptive system is allowed to reduce aberrations of incoming laser radiation by seven times peak-to-valley and to stabilize the jitter of incoming beams up to 25 μrad at a speed of 100 Hz. The adaptive system frequency range for high-order aberration correction was 50 Hz.

  5. 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.

  6. Latest development of high-power fiber lasers in SPI

    NASA Astrophysics Data System (ADS)

    Norman, Stephen; Zervas, Mikhail N.; Appleyard, Andrew; Durkin, Michael K.; Horley, Ray; Varnham, Malcolm P.; Nilsson, Johan; Jeong, Yoonchan

    2004-06-01

    High Power Fiber Lasers (HPFLs) and High Power Fiber Amplifiers (HPFAs) promise a number of benefits in terms of their high optical efficiency, degree of integration, beam quality, reliability, spatial compactness and thermal management. These benefits are driving the rapid adoption of HPFLs in an increasingly wide range of applications and power levels ranging from a few Watts, in for example analytical applications, to high-power >1kW materials processing (machining and welding) applications. This paper describes SPI"s innovative technologies, HPFL products and their performance capabilities. The paper highlights key aspects of the design basis and provides an overview of the applications space in both the industrial and aerospace domains. Single-fiber CW lasers delivering 1kW output power at 1080nm have been demonstrated and are being commercialized for aerospace and industrial applications with wall-plug efficiencies in the range 20 to 25%, and with beam parameter products in the range 0.5 to 100 mm.mrad (corresponding to M2 = 1.5 to 300) tailored to application requirements. At power levels in the 1 - 200 W range, SPI"s proprietary cladding-pumping technology, GTWaveTM, has been employed to produce completely fiber-integrated systems using single-emitter broad-stripe multimode pump diodes. This modular construction enables an agile and flexible approach to the configuration of a range of fiber laser / amplifier systems for operation in the 1080nm and 1550nm wavelength ranges. Reliability modeling is applied to determine Systems martins such that performance specifications are robustly met throughout the designed product lifetime. An extensive Qualification and Reliability-proving programme is underway to qualify the technology building blocks that are utilized for the fiber laser cavity, pump modules, pump-driver systems and thermo-mechanical management. In addition to the CW products, pulsed fiber lasers with pulse energies exceeding 1mJ with peak pulse

  7. High Power Diode Pumped 1.06 Micron Solid State Laser

    NASA Astrophysics Data System (ADS)

    Arvind, Mukundarajan A.; Martin, Dan W.; Osterhage, R. J.

    1989-07-01

    Diode pumped solid state lasers have been attracting significant interest in recent years due to advances in high power semiconductor diode lasers. They offer considerable advantages over flashlamp pumped lasers such as compact size, high efficiency, lower heat dissipation and solid-state reliability. In this paper, we report on the results of a Nd:YAG laser, transverse pumped by diode laser arrays. We have measured an output power of 1.14 Watts at 1.06 microns with a laser diode power consumption of 40 Watts. This represents the highest reported electrical efficiency (2.85%) for a transverse pumped, CW, TEM00 laser. The diode arrays were selected and tuned to emit at wavelengths close to the peak neodymium absorption line at 0.808 microns with Peltier coolers. Two diode laser bars side pumped a 20 mm long, 1.5 mm diameter Nd:YAG laser rod. The optical cavity is 13.8 cm long consisting of a high reflectivity mirror and a 95% reflectivity output mirror. The output beam divergence was measured to be near diffraction limited at 1.4 milliradians, and the beam diameter was 1 mm.

  8. High power metallic halide laser. [amplifying a copper chloride laser

    NASA Technical Reports Server (NTRS)

    Pivirotto, T. J. (Inventor)

    1982-01-01

    A laser amplification system is disclosed whereby a metallic halide vapor such as copper chloride is caused to flow through a laser amplifier and a heat exchanger in a closed loop system so that the flow rate is altered to control the temperature rise across the length of the laser amplifier. The copper atoms within the laser amplifier should not exceed a temperature of 3000 K, so that the number of copper atoms in the metastable state will not be high enough to prevent amplification in the amplifier. A molecular dissociation apparatus is provided at the input to the laser amplifier for dissociating the copper chloride into copper atoms and ions and chlorine atoms and ions. The dissociation apparatus includes a hollow cathode tube and an annular ring spaced apart from the tube end. A voltage differential is applied between the annular ring and the hollow cathode tube so that as the copper chloride flows through, it is dissociated into copper and chlorine ions and atoms.

  9. Development of High Power Lasers for Materials Interactions

    SciTech Connect

    Hackel, L A

    2003-04-11

    The Lawrence Livermore National Laboratory (LLNL) has a long history of developing high power lasers for use in basic science and applications. The Laser Science and Technology Program (LS&T) at LLNL supports advanced lasers and optics development both for the National Ignition Facility (NIF) as well as for high power lasers and optics technology for a broader range of government, military and industrial applications. The NIF laser is currently under construction with the first of the 192 beamlines being activated. When finished NIF will have an output energy of 2 MJ at 351 nm. This system will be used for studies of high energy density physics, equation of state and inertial confinement fusion. It is now generally acknowledged that the future of laser missile defense lies with solid state lasers. The leading laser technology for theater missile defense is under development within the LS&T and funded by the US Army SMDC. This high average power technology is based on a solid state laser operated in a heat capacity mode. In the concept the heat producing lasing cycle is separated in time from the cooling cycle thus reducing thermal gradients and allowing significantly greater average output power. Under the current program, an LLNL developed laser has achieved a record setting 13 kW of average power in 20 second duration bursts. We have also performed target lethality experiments showing a previously unrecognized advantage of a pulsed laser format. The LLNL work is now focused on achieving improved output beam quality and in developing a 100 kW output with diode pumping of a large aperture crystal gain medium on a compact mobile platform. The Short Pulse Laser Group of LS&T has been developing high power short pulse laser systems for a number of applications. Of great importance is petawatt (10{sup 12} Watt) and greater power output to support experiments on the NIF. We are developing a system of 5 M class output and 5 to 10 ps pulse duration for generating intense

  10. High-power laser diodes based on InGaAsP alloys

    NASA Astrophysics Data System (ADS)

    Razeghi, Manijeh

    1994-06-01

    HIGH-POWER, high-coherence solid-state lasers, based on dielectric materials such as ruby or Nd:YAG (yttrium aluminium garnet), have many civilian and military applications. The active media in these lasers are insulating, and must therefore be excited (or `pumped') by optical, rather than electrical, means. Conventional gas-discharge lamps can be used as the pumping source, but semiconductor diode lasers are more efficient, as their wavelength can be tailored to match the absorption properties of the lasing material. Semiconducting AlGaAs alloys are widely used for this purpose1, 2, but oxidation of the aluminium and the spreading of defects during device operation limit the lifetime of the diodes3, and hence the reliability of the system as a whole. Aluminium-free InGaAsP compounds, on the other hand, do not have these lifetime-limiting properties4-8. We report here the fabrication of high-power lasers based on InGaAsP (lattice-matched to GaAs substrates), which operate over the same wavelength range as conventional AlGaAs laser diodes and show significantly improved reliability. The other optical and electrical properties of these diodes are either comparable or superior to those of the AlGaAs system.

  11. Robust focusing optics for high-power laser welding

    NASA Astrophysics Data System (ADS)

    McAllister, Blake

    2014-02-01

    As available power levels from both fiber and disc lasers rapidly increase, so does the need for more robust beam delivery solutions. Traditional transmissive optics for 1 micron lasers have proven to be problematic in the presence of higher power densities and are more susceptible to focal shift. A new, fully-reflective, optical solution has been developed using mirrors rather than lenses and windows to achieve the required stable focal spot, while still protecting the delicate fiber end. This patent-approved beam focusing solution, referred to as high power reflective focusing optic (HPRFO), involves specialty mirrors and a flowing gas orifice that prevents ingress of contaminants into the optically sensitive region of the assembly. These mirrors also provide a unique solution for increasing the distance between the sensitive optics and the contamination-filled region at the work, without sacrificing spot size. Longer focal lengths and lower power densities on large mass, water-cooled, copper mirrors deliver the robustness needed at increasingly high power levels. The HPRFO exhibits excellent beam quality and minimal focal shift at a fraction of commercially available optics, and has demonstrated consistent reliability on applications requiring 15 kW with prolonged beam-on times.

  12. High power tandem-pumped thulium-doped fiber laser.

    PubMed

    Wang, Yao; Yang, Jianlong; Huang, Chongyuan; Luo, Yongfeng; Wang, Shiwei; Tang, Yulong; Xu, Jianqiu

    2015-02-09

    We propose a cascaded tandem pumping technique and show its high power and high efficient operation in the 2-μm wavelength region, opening up a new way to scale the output power of the 2-μm fiber laser to new levels (e.g. 10 kW). Using a 1942 nm Tm(3+) fiber laser as the pump source with the co- (counter-) propagating configuration, the 2020 nm Tm(3+) fiber laser generates 34.68 W (35.15W) of output power with 84.4% (86.3%) optical-to-optical efficiency and 91.7% (92.4%) slope efficiency, with respect to launched pump power. It provides the highest slope efficiency reported for 2-μm Tm(3+)-doped fiber lasers, and the highest output power for all-fiber tandem-pumped 2-μm fiber oscillators. This system fulfills the complete structure of the proposed cascaded tandem pumping technique in the 2-μm wavelength region (~1900 nm → ~1940 nm → ~2020 nm). Numerical analysis is also carried out to show the power scaling capability and efficiency of the cascaded tandem pumping technique.

  13. High-power lasers for directed-energy applications: comment.

    PubMed

    Vorontsov, Mikhail A; Weyrauch, Thomas

    2016-12-10

    Sprangle et al. [Appl. Opt.54, F201 (2015)APOPAI0003-693510.1364/AO.54.00F201] recently concluded that our experiments on coherent combining of laser beams over an atmospheric path [Opt. Lett.36, 4455 (2011)OPLEDP0146-959210.1364/OL.36.004455] were "effective only because at these low-power levels the linewidth of the lasers was very narrow… and the level of atmospheric turbulence was low…." These conclusions are inaccurate, not relevant to practical high-power coherently combined laser systems, and contradict our most recent experiments with coherent combining of 21 laser beams with a linewidth of about 1 GHz over 7 km distance. In this comment we also challenge the major conclusion of Sprangle et al. [Appl. Opt.54, F201 (2015)APOPAI0003-693510.1364/AO.54.00F201] and the more recently published paper by Nelson et al. [Appl. Opt.55, 1757 (2016)APOPAI0003-693510.1364/AO.55.001757] regarding inefficiency of coherent beam combining under typical atmospheric conditions.

  14. High power continuous-wave titanium:sapphire laser

    DOEpatents

    Erbert, G.V.; Bass, I.L.; Hackel, R.P.; Jenkins, S.L.; Kanz, V.K.; Paisner, J.A.

    1993-09-21

    A high-power continuous-wave laser resonator is provided, wherein first, second, third, fourth, fifth and sixth mirrors form a double-Z optical cavity. A first Ti:sapphire rod is disposed between the second and third mirrors and at the mid-point of the length of the optical cavity, and a second Ti:sapphire rod is disposed between the fourth and fifth mirrors at a quarter-length point in the optical cavity. Each Ti:sapphire rod is pumped by two counter-propagating pump beams from a pair of argon-ion lasers. For narrow band operation, a 3-plate birefringent filter and an etalon are disposed in the optical cavity so that the spectral output of the laser consists of 5 adjacent cavity modes. For increased power, seventy and eighth mirrors are disposed between the first and second mirrors to form a triple-Z optical cavity. A third Ti:sapphire rod is disposed between the seventh and eighth mirrors at the other quarter-length point in the optical cavity, and is pumped by two counter-propagating pump beams from a third pair of argon-ion lasers. 5 figures.

  15. High power continuous-wave titanium:sapphire laser

    DOEpatents

    Erbert, Gaylen V.; Bass, Isaac L.; Hackel, Richard P.; Jenkins, Sherman L.; Kanz, Vernon K.; Paisner, Jeffrey A.

    1993-01-01

    A high-power continuous-wave laser resonator (10) is provided, wherein first, second, third, fourth, fifth and sixth mirrors (11-16) form a double-Z optical cavity. A first Ti:Sapphire rod (17) is disposed between the second and third mirrors (12,13) and at the mid-point of the length of the optical cavity, and a second Ti:Sapphire rod (18) is disposed between the fourth and fifth mirrors (14,15) at a quarter-length point in the optical cavity. Each Ti:Sapphire rod (17,18) is pumped by two counter-propagating pump beams from a pair of argon-ion lasers (21-22, 23-24). For narrow band operation, a 3-plate birefringent filter (36) and an etalon (37) are disposed in the optical cavity so that the spectral output of the laser consists of 5 adjacent cavity modes. For increased power, seventy and eighth mirrors (101, 192) are disposed between the first and second mirrors (11, 12) to form a triple-Z optical cavity. A third Ti:Sapphire rod (103) is disposed between the seventh and eighth mirrors (101, 102) at the other quarter-length point in the optical cavity, and is pumped by two counter-propagating pump beams from a third pair of argon-ion lasers (104, 105).

  16. High-power laser arrays for optical computing

    NASA Astrophysics Data System (ADS)

    Zucker, Erik P.; Craig, Richard R.; Mehuys, David G.; Nam, Derek W.; Welch, David F.; Scifres, Donald R.

    1991-12-01

    We demonstrate both common electrode and addressable arrays of single mode semiconductor lasers suitable for optical computing and optical data storage. In the common electrode geometry, eight lasers have been fabricated on a single chip which show excellent spectral and power uniformity. Total optical power obtained from this array has been in excess of 1.2 Watts CW. We have also fabricated two and nine element monolithic, individually addressable arrays with emitter spacings between 10 jim and 150 p m. Separately addressed, each element emits in a single spatial mode to greater than 0.1 Watts. For the nine element array, uniformity of better than 1.0 nanometer in wavelength and 1 milliamp in operating current across the array has been obtained. Results on crosstalk and reliability of the arrays are presented.

  17. The NASA high power carbon dioxide laser: A versatile tool for laser applications

    NASA Technical Reports Server (NTRS)

    Lancashire, R. B.; Alger, D. L.; Manista, E. J.; Slaby, J. G.; Dunning, J. W.; Stubbs, R. M.

    1976-01-01

    A closed-cycle, continuous wave, carbon dioxide high power laser has been designed and fabricated to support research for the identification and evaluation of possible high power laser applications. The device is designed to generate up to 70 kW of laser power in annular shape beams from 1 to 9 cm in diameter. Electric discharge, either self sustained or electron beam sustained, is used for excitation. This laser facility provides a versatile tool on which research can be performed to advance the state-of-the-art technology of high power CO2 lasers in such areas as electric excitation, laser chemistry, and quality of output beams. The facility provides a well defined, continuous wave beam for various application experiments, such as propulsion, power conversion, and materials processing.

  18. Direct spectroscopic measurement of packaging-induced strains in high-power laser diode arrays

    NASA Astrophysics Data System (ADS)

    Tomm, Jens W.; Mueller, Ralf; Baerwolff, A.; Neuner, M.; Elsaesser, Thomas; Lorenzen, Dirk; Daiminger, Franz X.; Gerhardt, A.; Donecker, J.

    1999-04-01

    High-power diode lasers such as `cm-bar arrays' are important for many applications. The `p-side down packaging', i.e. the direct mounting of the epitaxial layer sequence on a heat spreader ensures sufficient thermal properties, however, in such a geometry, additional mechanical strain of the active region represents a central issue, affecting both the laser parameter as well as lifetime and reliability of the device. Thermally induced strain caused by device packaging is studied in high-power semiconductor laser arrays by a novel non-invasive technique. Photocurrent measurements with intentionally strained laser array devices for 808 nm emission reveal spectral shifts of all allowed optical transitions in the active region. These shifts serve as a measure for strain and are compared with model calculations. Depending on the specific heat spreader materials we find compressive or tensile mounting induced strain contributions. For a given packaging architecture, about one quarter of the mounting induced strain is transferred to the quantum well region of the device. Spatially resolved measurements allow to measure lateral strain gradients in the devices. Using this data for calibration we show that polarization resolved electroluminescence scans can be used as convenient measure for strain homogeneity test also in quantum-well devices.

  19. High power laser welding in hyperbaric gas and water environments

    SciTech Connect

    Shannon, G.J.; McNaught, W.; Deans, W.F.; Watson, J.

    1997-06-01

    As the exploitation of oil and gas reserves moves into deeper water (>500 m), advanced welding techniques will have to be developed for installation and repair as current commercially available arc welding processes can no longer be utilized at depths greater than 300 m due to the detrimental effect of pressure on arc stability. In addition, systems relying on diver intervention are unlikely to be viable due to health and safety considerations. Here, a hyperbaric laser welding facility has been constructed and the feasibility of high power CO{sub 2} and Nd:YAG laser welding in both high pressure gas and water environments, to simulated water depths of 500 m, has been established. From initial trials on welding through water at atmospheric pressure, it was found that the different absorption characteristics of water to 10.6 {micro}m (CO{sub 2} laser) and 1.06 {micro}m (Nd:YAG laser) radiation proved crucial. The Nd:YAG laser was totally unsuitable as the beam was largely diffused in the water, whereas the CO{sub 2} beam was readily absorbed and, using high speed video equipment, was found to form a high irradiance channel and a dry region around the weld area. Welding under a high pressure gas environment produced a highly energized plume which prevented keyhole welding at pressures over 1 {times} 10{sup 6} Pa. An investigation carried out into the efficacy of a gas jet delivery system to alleviate the extent of the plume showed that argon blown horizontally across the weld was the optimum configuration, extending the welding range up to 5 {times} 10{sup 6} Pa. A limited investigation into high pressure underwater welding showed porosity to be a problem although sound welds were produced at pressures up to 2 {times} 10{sup 6} Pa.

  20. High-power fiber laser/amplifier: present and future

    NASA Astrophysics Data System (ADS)

    Manzur, Tariq; Bastien, Steven P.

    2000-03-01

    As a result of the overwhelming demand for bandwidth, the number of channels offered in commercially available DWDM systems has climbed from 8 to 160 in just a few short years. With the growth in channel counts comes increasing demands placed upon optical amplifiers for the long haul market. High powers, flatter gain profiles, extended bandwidths (both C- and L-band), dispersion compensation, longer distances and greater control at the optical level are all capabilities that future networks will require. Today's optical amplifiers must be capable of supporting these services in advance of their installation to prepare networks for these foreseeable demands. Optigain's expertise and focus on optical amplifiers for the telecommunications industry has enabled it to achieve a technology leadership position in the field of optical amplification. Optigain's leadership position in the development of high power amplifiers based upon fiber laser technology will permit the Company to obtain favorable pricing and to gain significant market share in high growth markets. Figures 1 and 2 show the EDFA future global market shares.

  1. Liquid metal heat sink for high-power laser diodes

    NASA Astrophysics Data System (ADS)

    Vetrovec, John; Litt, Amardeep S.; Copeland, Drew A.; Junghans, Jeremy; Durkee, Roger

    2013-02-01

    We report on the development of a novel, ultra-low thermal resistance active heat sink (AHS) for thermal management of high-power laser diodes (HPLD) and other electronic and photonic components. AHS uses a liquid metal coolant flowing at high speed in a miniature closed and sealed loop. The liquid metal coolant receives waste heat from an HPLD at high flux and transfers it at much reduced flux to environment, primary coolant fluid, heat pipe, or structure. Liquid metal flow is maintained electromagnetically without any moving parts. Velocity of liquid metal flow can be controlled electronically, thus allowing for temperature control of HPLD wavelength. This feature also enables operation at a stable wavelength over a broad range of ambient conditions. Results from testing an HPLD cooled by AHS are presented.

  2. Diffuse reflectivity of gold plating with high power laser irradiation

    NASA Astrophysics Data System (ADS)

    Wu, Yong; Zhang, Lei; Yang, Pengling; Wang, Zhenbao; Tao, Mengmeng; Liu, Fuhua; Feng, Guobin

    2015-05-01

    The discoloration and optical characteristics of the gold plating film under long-time high power laser irradiation are investigated. The fabrication process of gold plating on nickel underplate on rough surface of copper and aluminum alloy substrates is introduced. The measurement results of the diffuse reflectivity for the samples with different surface roughness indicate that roughness of the gold layer surface should be 4μm to obtain the maximum value of diffuse reflectivity. The discoloration and variation of diffuse reflectivity are experimentally studied under 2000W irradiation. The research results show that the discoloration and degrading of reflectivity are caused by the diffusion of Ni to the gold plating surface and forming NiO thin film due to the porosity of the gold film and high temperature treatment. A change of diffuse reflectivity related mechanism is described. Several plating solution recipes are used to eliminate the discoloration and mitigate the degrading of the reflectivity on gold surface.

  3. New Yb-doped crystals for high-power and ultrashort lasers

    NASA Astrophysics Data System (ADS)

    Druon, F.; Boudeile, J.; Zaouter, Y.; Hanna, M.; Balembois, F.; Georges, P.; Petit, J.; Goldner, P.; Viana, B.

    2006-09-01

    Since the beginning of the 90's, Titanium Sapphire has become the crystal of choice for the development of ultrashort laser system producing very short and powerful pulses using the Chirped Pulse Amplification technique. In parallel to these developments leading to commercial products, new laser crystals have been studied in order to reach directly other wavelength range and to overcome the need to develop cw or pulsed green laser to pump the Titanium Sapphire crystal. In order to be able to directly pump the crystals with very efficient and high power semiconductor laser, new crystals doped with ytterbium ions have been developed. Actually, in the field of femtosecond lasers, an intense interest has been shown for ytterbium-doped laser-crystals. These crystals are now well-known to be particularly suitable for very efficient, directly-diode-pumped, solid state femtosecond oscillators. However, it has been shown that the spectral properties of the Yb 3+ dopant strongly depend on the matrix host and a lot of works have been done to find the "ideal" matrix allowing both ultrashort-pulsed and high-power lasers. Firstly, in order to take advantage of the very high-power laser diodes available to pump Yb-doped materials, ideal crystals need to be able to hold high power pumping; so high thermal conductivity is required (>5W/m/K, typically). Secondly, to generate very short pulses (<100 fs) ideal crystals have to demonstrate very broad and smooth spectra. Among the numerous Yb-doped crystals already studied, many failed with one of these two contradictory criteria (contradictory because broad spectra are often synonymous of high disorder in the host lattice and the good thermal conductivity requires an ordered matrix to allow good propagation of phonons). In this paper, we are relating the performance of a new Yb-doped crystal: Yb:CaGdAlO4 (Yb:CALGO) and how it takes place in this quest of "ideal" crystal. Actually, this very new crystal allowed, to our best knowledge

  4. High-power quantum-dot tapered tunable external-cavity lasers based on chirped and unchirped structures.

    PubMed

    Haggett, Stephanie; Krakowski, Michel; Montrosset, Ivo; Cataluna, Maria Ana

    2014-09-22

    A high-power tunable external cavity laser configuration with a tapered quantum-dot semiconductor optical amplifier at its core is presented, enabling a record output power for a broadly tunable semiconductor laser source in the 1.2 - 1.3 µm spectral region. Two distinct optical amplifiers are investigated, using either chirped or unchirped quantum-dot structures, and their merits are compared, considering the combination of tunability and high output power generation. At 1230 nm, the chirped quantum-dot laser achieved a maximum power of 0.62 W and demonstrated nearly 100-nm tunability. The unchirped laser enabled a tunability range of 32 nm and at 1254 nm generated a maximum power of 0.97 W, representing a 22-fold increase in output power compared with similar narrow-ridge external-cavity lasers at the same current density.

  5. Next Generation Large Mode Area Fiber Technologies for High Power Fiber Laser Arrays

    DTIC Science & Technology

    2012-06-08

    REPORT Next Generation Large Mode Area Fiber Technologies for High Power Fiber Laser Arrays 14. ABSTRACT 16. SECURITY CLASSIFICATION OF: This program...monolithically-integrated building blocks (individual laser channels) of high power beam-combined fiber laser arrays. Robust single-mode performance...of CCC fibers with core sizes of up to ~60?m has been rigorously demonstrated. Various CCC fiber based high power lasers have been also

  6. Power spectral density specifications for high-power laser systems

    SciTech Connect

    Lawson, J.K.; Aikens, D.A.; English, R.E. Jr.; Wolfe, C.R.

    1996-04-22

    This paper describes the use of Fourier techniques to characterize the transmitted and reflected wavefront of optical components. Specifically, a power spectral density, (PSD), approach is used. High power solid-state lasers exhibit non-linear amplification of specific spatial frequencies. Thus, specifications that limit the amplitude of these spatial frequencies are necessary in the design of these systems. Further, NIF optical components have square, rectangular or irregularly shaped apertures with major dimensions up-to 800 mm. Components with non-circular apertures can not be analyzed correctly with Zernicke polynomials since these functions are an orthogonal set for circular apertures only. A more complete and powerful representation of the optical wavefront can be obtained by Fourier analysis in 1 or 2 dimensions. The PSD is obtained from the amplitude of frequency components present in the Fourier spectrum. The shape of a resultant wavefront or the focal spot of a complex multicomponent laser system can be calculated and optimized using PSDs of the individual optical components which comprise the system. Surface roughness can be calculated over a range of spatial scale-lengths by integrating the PSD. Finally, since the optical transfer function (OTF) of the instruments used to measure the wavefront degrades at high spatial frequencies, the PSD of an optical component is underestimated. We can correct for this error by modifying the PSD function to restore high spatial frequency information. The strengths of PSD analysis are leading us to develop optical specifications incorporating this function for the planned National Ignition Facility (NIF).

  7. New material options for high-power diode laser packaging

    NASA Astrophysics Data System (ADS)

    Zweben, Carl H.

    2004-06-01

    Traditional materials have serious deficiencies in meeting requirements for thermal management and minimization of thermal stresses in high-power laser diode packaging. Copper, the standard material for applications requiring high thermal conductivity, has a coefficient of thermal expansion (CTE) that is much larger than those of ceramics and laser diodes, giving rise to thermal stresses when packages are subjected to thermal excursions. Traditional materials with low CTEs have thermal conductivities that are little or no better than that of aluminum. There are an increasing number of new packaging materials with low, tailorable CTEs and thermal conductivities up to four times those of copper that overcome these limitations. The ability to tailor material CTE has been used to solve critical warping problems in manufacturing, increasing yield from 5% to over 99%. Advanced materials fall into six categories: monolithic carbonaceous materials, metal matrix composites, carbon/carbon composites, ceramic matrix composites, polymer matrix composites, and advanced metallic alloys. This paper provides an overview of the state of the art of advanced packaging materials, including their key properties, state of maturity, using composites to fix manufacturing problems, cost and applications.

  8. Large-area high-power VCSEL pump arrays optimized for high-energy lasers

    NASA Astrophysics Data System (ADS)

    Wang, Chad; Geske, Jonathan; Garrett, Henry; Cardellino, Terri; Talantov, Fedor; Berdin, Glen; Millenheft, David; Renner, Daniel; Klemer, Daniel

    2012-06-01

    Practical, large-area, high-power diode pumps for one micron (Nd, Yb) as well as eye-safer wavelengths (Er, Tm, Ho) are critical to the success of any high energy diode pumped solid state laser. Diode efficiency, brightness, availability and cost will determine how realizable a fielded high energy diode pumped solid state laser will be. 2-D Vertical-Cavity Surface-Emitting Laser (VCSEL) arrays are uniquely positioned to meet these requirements because of their unique properties, such as low divergence circular output beams, reduced wavelength drift with temperature, scalability to large 2-D arrays through low-cost and high-volume semiconductor photolithographic processes, high reliability, no catastrophic optical damage failure, and radiation and vacuum operation tolerance. Data will be presented on the status of FLIR-EOC's VCSEL pump arrays. Analysis of the key aspects of electrical, thermal and mechanical design that are critical to the design of a VCSEL pump array to achieve high power efficient array performance will be presented.

  9. Injection locking of a high power ultraviolet laser diode for laser cooling of ytterbium atoms

    SciTech Connect

    Hosoya, Toshiyuki; Miranda, Martin; Inoue, Ryotaro; Kozuma, Mikio

    2015-07-15

    We developed a high-power laser system at a wavelength of 399 nm for laser cooling of ytterbium atoms with ultraviolet laser diodes. The system is composed of an external cavity laser diode providing frequency stabilized output at a power of 40 mW and another laser diode for amplifying the laser power up to 220 mW by injection locking. The systematic method for optimization of our injection locking can also be applied to high power light sources at any other wavelengths. Our system does not depend on complex nonlinear frequency-doubling and can be made compact, which will be useful for providing light sources for laser cooling experiments including transportable optical lattice clocks.

  10. Advancement of High Power Quasi-CW Laser Diode Arrays For Space-based Laser Instruments

    NASA Technical Reports Server (NTRS)

    Amzajerdian, Farzin; Meadows, Byron L.; Baker, nathaniel R.; Baggott, Renee S.; Singh, Upendra N.; Kavaya, Michael J.

    2004-01-01

    Space-based laser and lidar instruments play an important role in NASA s plans for meeting its objectives in both Earth Science and Space Exploration areas. Almost all the lidar instrument concepts being considered by NASA scientist utilize moderate to high power diode-pumped solid state lasers as their transmitter source. Perhaps the most critical component of any solid state laser system is its pump laser diode array which essentially dictates instrument efficiency, reliability and lifetime. For this reason, premature failures and rapid degradation of high power laser diode arrays that have been experienced by laser system designers are of major concern to NASA. This work addresses these reliability and lifetime issues by attempting to eliminate the causes of failures and developing methods for screening laser diode arrays and qualifying them for operation in space.

  11. Application and the key technology on high power fiber-optic laser in laser weapon

    NASA Astrophysics Data System (ADS)

    Qu, Zhou; Li, Qiushi; Meng, Haihong; Sui, Xin; Zhang, Hongtao; Zhai, Xuhua

    2014-12-01

    The soft-killing laser weapon plays an important role in photoelectric defense technology. It can be used for photoelectric detection, search, blinding of photoelectric sensor and other devices on fire control and guidance devices, therefore it draws more and more attentions by many scholars. High power fiber-optic laser has many virtues such as small volume, simple structure, nimble handling, high efficiency, qualified light beam, easy thermal management, leading to blinding. Consequently, it may be used as the key device of soft-killing laser weapon. The present study introduced the development of high power fiber-optic laser and its main features. Meanwhile the key technology of large mode area (LMA) optical fiber design, the beam combination technology, double-clad fiber technology and pumping optical coupling technology was stated. The present study is aimed to design high doping LMA fiber, ensure single mode output by increasing core diameter and decrease NA. By means of reducing the spontaneous emission particle absorbed by fiber core and Increasing the power density in the optical fiber, the threshold power of nonlinear effect can increase, and the power of single fiber will be improved. Meantime, high power will be obtained by the beam combination technology. Application prospect of high power fiber laser in photoelectric defense technology was also set forth. Lastly, the present study explored the advantages of high power fiber laser in photoelectric defense technology.

  12. High power diode laser Master Oscillator-Power Amplifier (MOPA)

    NASA Technical Reports Server (NTRS)

    Andrews, John R.; Mouroulis, P.; Wicks, G.

    1994-01-01

    High power multiple quantum well AlGaAs diode laser master oscillator - power amplifier (MOPA) systems were examined both experimentally and theoretically. For two pass operation, it was found that powers in excess of 0.3 W per 100 micrometers of facet length were achievable while maintaining diffraction-limited beam quality. Internal electrical-to-optical conversion efficiencies as high as 25 percent were observed at an internal amplifier gain of 9 dB. Theoretical modeling of multiple quantum well amplifiers was done using appropriate rate equations and a heuristic model of the carrier density dependent gain. The model gave a qualitative agreement with the experimental results. In addition, the model allowed exploration of a wider design space for the amplifiers. The model predicted that internal electrical-to-optical conversion efficiencies in excess of 50 percent should be achievable with careful system design. The model predicted that no global optimum design exists, but gain, efficiency, and optical confinement (coupling efficiency) can be mutually adjusted to meet a specific system requirement. A three quantum well, low optical confinement amplifier was fabricated using molecular beam epitaxial growth. Coherent beam combining of two high power amplifiers injected from a common master oscillator was also examined. Coherent beam combining with an efficiency of 93 percent resulted in a single beam having diffraction-limited characteristics. This beam combining efficiency is a world record result for such a system. Interferometric observations of the output of the amplifier indicated that spatial mode matching was a significant factor in the less than perfect beam combining. Finally, the system issues of arrays of amplifiers in a coherent beam combining system were investigated. Based upon experimentally observed parameters coherent beam combining could result in a megawatt-scale coherent beam with a 10 percent electrical-to-optical conversion efficiency.

  13. Tapered fiber bundles for combining high-power diode lasers.

    PubMed

    Kosterin, Andrey; Temyanko, Valery; Fallahi, Mahmoud; Mansuripur, Masud

    2004-07-01

    Tapered fiber bundles are often used to combine the output power of several semiconductor lasers into a multimode optical fiber for the purpose of pumping fiber lasers and amplifiers. It is generally recognized that the brightness of such combiners does not exceed the brightness of the individual input fibers. We report that the brightness of the tapered fibers (and fiber bundles) depends on both the taper ratio and the mode-filling properties of the beams launched into the individual fibers. Brightness, therefore, can be increased by selection of sources that fill a small fraction of the input fiber's modal capacity. As proof of concept, we present the results of measurements on tapered fiber-bundle combiners having a low-output étendue. Under low mode-filling conditions per input multimode fiber (i.e., fraction of filled modes < or =0.29), we report brightness enhancements of 8.0 dB for 19 x 1 bundles, 6.7 dB for 7 x 1 bundles, and 4.0 dB for 3 x 1 combiners. Our measured coupling efficiency variations of approximately 1%-2% among the various fibers in a given bundle confirm the uniformity and quality of the fabricated devices.

  14. Semiconductor processing with excimer lasers

    SciTech Connect

    Young, R.T.; Narayan, J.; Christie, W.H.; van der Leeden, G.A.; Rothe, D.E.; Cheng, L.J.

    1983-01-01

    The advantages of pulsed excimer lasers for semiconductor processing are reviewed. Extensive comparisons of the quality of annealing of ion-implanted Si obtained with XeCl and ruby lasers have been made. The results indicate that irrespective of the large differences in the optical properties of Si at uv and visible wavelengths, the efficiency of usage of the incident energy for annealing is comparable for the two lasers. However, because of the excellent optical beam quality, the XeCl laser can provide superior control of the surface melting and the resulting junction depth. Furthermore, the concentrations of electrically active point defects in the XeCl laser annealed region are 2 to 3 orders of magnitude lower than that obtained from ruby or Nd:YAG lasers. All these results seem to suggest that XeCl lasers should be suitable for fabricating not only solar cells but also the more advanced device structures required for VLSI or VHSIC applications.

  15. EDITORIAL: Semiconductor lasers: the first fifty years Semiconductor lasers: the first fifty years

    NASA Astrophysics Data System (ADS)

    Calvez, S.; Adams, M. J.

    2012-09-01

    achievements in the June 1987 Special Issue of IEEE Journal of Quantum Electronics. The Millennium Issue of IEEE Journal of Selected Topics in Quantum Electronics presented a further set of articles on historical aspects of the subject as well as a 'snapshot' of current research in June 2000. It is not the intention here to duplicate any of this historical material that is already available, but rather to complement it with personal recollections from researchers who were involved in laser development in the USA, France, Russia and the UK. Hence, in addition to fascinating accounts of the discovery of the theoretical condition for stimulated emission from semiconductors and of the pioneering work at IBM, there are two complementary views of the laser research at the Lebedev Institute, and personal insights into the developments at STL and at Bell Laboratories. These are followed by an account of the scientific and technological connections between the early pioneering breakthroughs and the commercialisation of semiconductor laser products. Turning to the papers from today's researchers, there is coverage of many of the current 'hot' topics including quantum cascade lasers, mid-infrared lasers, high-power lasers, the exciting developments in understanding and exploiting the nonlinear dynamics of lasers, and photonic integrated circuits with extremely high communication data capacity, as well as reports of recent progress on laser materials such as dilute nitrides and bismides, photonic crystals, quantum dots and organic semiconductors. Thanks are due to Jarlath McKenna for sterling support from IOP Publishing and to Peter Blood for instigating this Special Issue and inviting us to serve as Guest Editors.

  16. Systems and assemblies for transferring high power laser energy through a rotating junction

    DOEpatents

    Norton, Ryan J.; McKay, Ryan P.; Fraze, Jason D.; Rinzler, Charles C.; Grubb, Daryl L.; Faircloth, Brian O.; Zediker, Mark S.

    2016-01-26

    There are provided high power laser devices and systems for transmitting a high power laser beam across a rotating assembly, including optical slip rings and optical rotational coupling assemblies. These devices can transmit the laser beam through the rotation zone in free space or within a fiber.

  17. Method and apparatus for delivering high power laser energy over long distances

    DOEpatents

    Zediker, Mark S; Rinzler, Charles C; Faircloth, Brian O; Koblick, Yeshaya; Moxley, Joel F

    2015-04-07

    Systems, devices and methods for the transmission and delivery of high power laser energy deep into the earth and for the suppression of associated nonlinear phenomena. Systems, devices and methods for the laser drilling of a borehole in the earth. These systems can deliver high power laser energy down a deep borehole, while maintaining the high power to advance such boreholes deep into the earth and at highly efficient advancement rates.

  18. High power lasers and their industrial applications; Proceedings of the Meeting, Innsbruck, Austria, Apr. 15-18, 1986

    NASA Astrophysics Data System (ADS)

    Schuoecker, Dieter

    1986-01-01

    Papers are presented on the discharge behavior of an RF excited high power CO2 laser at different excitation frequencies; high power CO2 lasers for materials processing; a semiconductive preionization technique; high power Nd lasers for industrial applications; high power light transmission in optical waveguides; beam delivery systems for high power lasers; and quality control for high power CO2 laser optics. Topics discussed include the monitoring of laser material processes; measuring the quality of high power laser beams; the physics of laser material processing; metal precision drilling with lasers; and the evolution of microstructure for laser clad Fe-Cr-Mn-C alloys. Consideration is given to robotic manipulation for laser processing; laser cutting; the use of the laser versus the electron beam in welding the surface treatments; high power laser safety; and laser protective filters for the visible and near-IR spectrum.

  19. Tunable Infrared Semiconductor Lasers

    DTIC Science & Technology

    2013-12-20

    is a thulium fiber laser that has output of 20Watts at 1.908 µm with a collimated output beam diameter of about 5 mm. With a cylindrical lens, a...the device onto a copper heat sink and then to the cold finger of liquid nitrogen Dewar. In characterization, a thulium fiber laser at 1.908 nm

  20. Advanced specialty fiber designs for high power fiber lasers

    NASA Astrophysics Data System (ADS)

    Gu, Guancheng

    The output power of fiber lasers has increased rapidly over the last decade. There are two major limiting factors, namely nonlinear effects and transverse mode instability, prohibiting the power scaling capability of fiber lasers. The nonlinear effects, originating from high optical intensity, primarily limit the peak power scaling. The mode instability, on the other hand, arises from quantum-defect driven heating, causing undesired mode coupling once the power exceeds the threshold and degradation of beam quality. The mode instability has now become the bottleneck for average output power scaling of fiber lasers. Mode area scaling is the most effective way to mitigate nonlinear effects. However, the use of large mode area may increase the tendency to support multiple modes in the core, resulting in lower mode instability threshold. Therefore, it is critical to maintain single mode operation in a large mode area fiber. Sufficient higher order mode suppression can lead to effective single-transverse-mode propagation. In this dissertation, we explore the feasibility of using specialty fiber to construct high power fiber lasers with robust single-mode output. The first type of fiber discussed is the resonantly-enhanced leakage channel fiber. Coherent reflection at the fiber outer boundary can lead to additional confinement especially for highly leaky HOM, leading to lower HOM losses than what are predicted by conventional finite element mothod mode solver considering infinite cladding. In this work, we conducted careful measurements of HOM losses in two leakage channel fibers (LCF) with circular and rounded hexagonal boundary shapes respectively. Impact on HOM losses from coiling, fiber boundary shapes and coating indexes were studied in comparison to simulations. This work demonstrates the limit of the simulation method commonly used in the large-mode-area fiber designs and the need for an improved approach. More importantly, this work also demonstrates that a

  1. High-Power Solid-State Lasers from a Laser Glass Perspective

    SciTech Connect

    Campbell, J H; Hayden, J S; Marker, A J

    2010-12-17

    Advances in laser glass compositions and manufacturing have enabled a new class of high-energy/high-power (HEHP), petawatt (PW) and high-average-power (HAP) laser systems that are being used for fusion energy ignition demonstration, fundamental physics research and materials processing, respectively. The requirements for these three laser systems are different necessitating different glasses or groups of glasses. The manufacturing technology is now mature for melting, annealing, fabricating and finishing of laser glasses for all three applications. The laser glass properties of major importance for HEHP, PW and HAP applications are briefly reviewed and the compositions and properties of the most widely used commercial laser glasses summarized. Proposed advances in these three laser systems will require new glasses and new melting methods which are briefly discussed. The challenges presented by these laser systems will likely dominate the field of laser glass development over the next several decades.

  2. Thermal runaway in semiconductor laser windows.

    PubMed

    Johnson, R L; O'Keefe, J D

    1972-12-01

    A small perturbation model is used to obtain analytical expressions for the critical or runaway power density for laser windows constructed of semiconductor materials. These equations are used to compute the critical power density for several realistic window installations taking account of the finite value of realizable convection cooling coefficients. Computations were prepared for silicon transmitting 4 .0-micro. radiation and for germanium at 10.6 micro. In this way it is shown that power densities are principally limited by the effectiveness of cooling from the face of the window, that is, the surface perpendicular to the laser beam. Since convection cooling coefficients are small the transmission of high power densities through semiconductor windows is therefore contingent upon finding more effective means to cool the window from the face. Finally, a simplified calculation was made in an attempt to account for nonuniformity of the incident laser beam. a given window, but not severely. The results show the onuniformity reduces the runaway power for a given window, but not severely.

  3. Electron beam pumped semiconductor laser

    NASA Technical Reports Server (NTRS)

    Hug, William F. (Inventor); Reid, Ray D. (Inventor)

    2009-01-01

    Electron-beam-pumped semiconductor ultra-violet optical sources (ESUVOSs) are disclosed that use ballistic electron pumped wide bandgap semiconductor materials. The sources may produce incoherent radiation and take the form of electron-beam-pumped light emitting triodes (ELETs). The sources may produce coherent radiation and take the form of electron-beam-pumped laser triodes (ELTs). The ELTs may take the form of electron-beam-pumped vertical cavity surface emitting lasers (EVCSEL) or edge emitting electron-beam-pumped lasers (EEELs). The semiconductor medium may take the form of an aluminum gallium nitride alloy that has a mole fraction of aluminum selected to give a desired emission wavelength, diamond, or diamond-like carbon (DLC). The sources may be produced from discrete components that are assembled after their individual formation or they may be produced using batch MEMS-type or semiconductor-type processing techniques to build them up in a whole or partial monolithic manner, or combination thereof.

  4. High power, short pulses ultraviolet laser for the development of a new x-ray laser

    SciTech Connect

    Meixler, L.; Nam, C.H.; Robinson, J.; Tighe, W.; Krushelnick, K.; Suckewer, S.; Goldhar, J.; Seely, J.; Feldman, U.

    1989-04-01

    A high power, short pulse ultraviolet laser system (Powerful Picosecond-Laser) has been developed at the Princeton Plasma Physics Laboratory (PPPL) as part of experiments designed to generate shorter wavelength x-ray lasers. With the addition of pulse compression and a final KrF amplifier the laser output is expected to have reached 1/3-1/2 TW (10/sup 12/ watts) levels. The laser system, particularly the final amplifier, is described along with some initial soft x-ray spectra from laser-target experiments. The front end of the PP-Laser provides an output of 20--30 GW (10/sup 9/ watts) and can be focussed to intensities of /approximately/10/sup 16/ W/cm/sup 2/. Experiments using this output to examine the effects of a prepulse on laser-target interaction are described. 19 refs., 14 figs.

  5. A NASA high-power space-based laser research and applications program

    NASA Technical Reports Server (NTRS)

    Deyoung, R. J.; Walberg, G. D.; Conway, E. J.; Jones, L. W.

    1983-01-01

    Applications of high power lasers are discussed which might fulfill the needs of NASA missions, and the technology characteristics of laser research programs are outlined. The status of the NASA programs or lasers, laser receivers, and laser propulsion is discussed, and recommendations are presented for a proposed expanded NASA program in these areas. Program elements that are critical are discussed in detail.

  6. Power semiconductor laser diode arrays characterization

    NASA Astrophysics Data System (ADS)

    Zeni, Luigi; Campopiano, Stefania; Cutolo, Antonello; D'Angelo, Giuseppe

    2003-09-01

    Nowadays, power semiconductor laser diode arrays are becoming a widespread source for a large variety of industrial applications. In particular, the availability of low-cost high-power laser diode arrays makes their use possible in the industrial context for material cutting, welding, diagnostics and processing. In the above applications, the exact control of the beam quality plays a very important role because it directly affects the reliability of the final result. In this paper, we present two different approaches useful for the characterization of the beam quality in laser diode arrays. The first one, starting from total intensity measurements on planes orthogonal to the beam propagation path, is able to deduce the working conditions of each laser setting up the array. The second one is aimed at the measurement of a global quality factor of the array itself; to this end, the empirical extension of the M2 concept to composite beams is presented along with some experimental results. As the first technique is especially intended for the non-destructive detection of design problems in the array itself and in the bias circuitry, the second one represents a powerful tool for the rapid on-line diagnostics of the laser beam during its use.

  7. GaAs Substrates for High-Power Diode Lasers

    NASA Astrophysics Data System (ADS)

    Mueller, Georg; Berwian, Patrick; Buhrig, Eberhard; Weinert, Berndt

    GaAs substrate crystals with low dislocation density (Etch-Pit Density (EPD) < 500,^-2) and Si-doping ( ~10^18,^-3) are required for the epitaxial production of high-power diode-lasers. Large-size wafers (= 3 mathrm{in} -> >=3,) are needed for reducing the manufacturing costs. These requirements can be fulfilled by the Vertical Bridgman (VB) and Vertical Gradient Freeze (VGF) techniques. For that purpose we have developed proper VB/VGF furnaces and optimized the thermal as well as the physico-chemical process conditions. This was strongly supported by extensive numerical process simulation. The modeling of the VGF furnaces and processes was made by using a new computer code called CrysVUN++, which was recently developed in the Crystal Growth Laboratory in Erlangen.GaAs crystals with diameters of 2 and 3in were grown in pyrolytic Boron Nitride (pBN) crucibles having a small-diameter seed section and a conical part. Boric oxide was used to fully encapsulate the crystal and the melt. An initial silicon content in the GaAs melt of c (melt) = 3 x10^19,^-3 has to be used in order to achieve a carrier concentration of n = (0.8- 2) x10^18,^-3, which is the substrate specification of the device manufacturer of the diode-laser. The EPD could be reduced to values between 500,^-2 and 50,^-2 with a Si-doping level of 8 x10^17 to 1 x10^18,^-3. Even the 3in wafers have rather large dislocation-free areas. The lowest EPDs ( <100,^-2) are achieved for long seed wells of the crucible.

  8. The NASA high-power carbon dioxide laser - A versatile tool for laser applications

    NASA Technical Reports Server (NTRS)

    Lancashire, R. B.; Alger, D. L.; Manista, E. J.; Slaby, J. G.; Dunning, J. W.; Stubbs, R. M.

    1977-01-01

    The NASA Lewis Research Center has designed and fabricated a closed-cycle, continuous wave (CW), carbon dioxide (CO2) high-power laser to support research for the identification and evaluation of possible high-power laser applications. The device is designed to generate up to 70 kW of laser power in annular-shape beams from 1 to 9 cm in diameter. Electric discharge, either self-sustained or electron-beam-sustained, is used for excitation. This laser facility can be used in two ways. First, it provides a versatile tool on which research can be performed to advance the state-of-the-art technology of high-power CO2 lasers in such areas as electric excitation, laser chemistry, and quality of output beams, all of which are important whether the laser application is government or industry oriented. Second, the facility provides a well-defined, continuous wave beam for various application experiments, such as propulsion, power conversion, and materials processing.

  9. Random fiber laser directly pumped by a high-power laser diode.

    PubMed

    Babin, S A; Dontsova, E I; Kablukov, S I

    2013-09-01

    A random lasing based on Rayleigh scattering (RS) in a passive fiber directly pumped by a high-power laser diode (LD) has been demonstrated. Owing to the RS-based random distributed feedback (RDFB) the low-quality LD beam (938 nm) is converted into the high-quality laser output (980 nm). Because of the relatively low excess above the threshold with the available LD, the RDFB laser output is not stationary and limited in power at the 0.5 W level. In the used gradient-index fiber, the output beam has 4.5 lower divergence as compared with the pump beam thus demonstrating a new way for development of high-power fiber lasers with high-quality output.

  10. Advanced Splicing and High-Resolution Imaging Facility for High Power PCF Laser Fabrication

    DTIC Science & Technology

    2014-10-31

    process, and integrate PCF’s into all-fiber high power laser systems. Specifically, a tabletop scanning electron microscope (SEM) and a CO2 laser ...PERCENT_SUPPORTEDNAME FTE Equivalent: Total Number: ...... ...... Technology Transfer No technology transfers are reported during this project Final Report CO2 Laser ...characterize, process, and integrate PCF’s into all-fiber high power laser systems. Specifically, a tabletop scanning electron microscope (SEM) and a CO2

  11. Many-sided electron beam pumping of high-power lasers

    NASA Astrophysics Data System (ADS)

    Ryzhov, V. V.; Turchanovskii, I. Y.

    1997-04-01

    To study the performance of high power lasers with a many- sided electron beam injection, MUFLON-code has been developed. This code was used to choose and design optimum injection schemes for the excitation of the high-power gas lasers developed at the High Current Electronics Institute.

  12. Trend of High-Power Laser Diodes for Recordable Optical Disc Drive

    NASA Astrophysics Data System (ADS)

    Yagi, Tetsuya

    Historical development trend of high-power laser diodes for recordable optical disc as CD-R and DVD-R is explained in a view point of not only how to realize highly reliable high-power operation but also how to adopt laser diodes into optical disc drives.

  13. High-Power X-Band Semiconductor RF Switch for Pulse Compression Systems of Future Colliders

    NASA Astrophysics Data System (ADS)

    Tantawi, Sami G.; Tamura, Fumihiko

    2000-04-01

    We describe the potential of semiconductor X-band RF switch arrays as a means of developing high power RF pulse compression systems for future linear colliders. The switch systems described here have two designs. Both designs consist of two 3dB hybrids and active modules. In the first design the module is composed of a cascaded active phase shifter. In the second design the module uses arrays of SPST (Single Pole Single Throw) switches. Each cascaded element of the phase shifter and the SPST switch has similar design. The active element consists of symmetrical three-port tee-junctions and an active waveguide window in the symmetrical arm of the tee-junction. The design methodology of the elements and the architecture of the whole switch system are presented. We describe the scaling law that governs the relation between power handling capability and number of elements. The design of the active waveguide window is presented. The waveguide window is a silicon wafer with an array of four hundred PIN/NIP diodes covering the surface of the window. This waveguide window is located in an over-moded TE01 circular waveguide. The results of high power RF measurements of the active waveguide window are presented. The experiment is performed at power levels of tens of megawatts at X-band.

  14. Slow Light Semiconductor Laser

    DTIC Science & Technology

    2015-02-02

    Painter, “Nonlinear response of silicon photonic crystal microresonators excited via an integrated waveguide and fiber taper,” Opt. Express, vol. 13, pp...exceeding 106 (figure 2g), which represent record high Q for 1D photonic crystal waveguide resonators on Si-on-insulator (SOI). In the hybrid lasers, the...1 million) of photonic crystal nanocavities. Optics Express 14:1996–2002. [14] Akahane Y, Asano T, Song BS, Noda S (2003) High-Q photonic nanocavity

  15. 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.

  16. Effect of interface layer on the performance of high power diode laser arrays

    NASA Astrophysics Data System (ADS)

    Zhang, Pu; Wang, Jingwei; Xiong, Lingling; Li, Xiaoning; Hou, Dong; Liu, Xingsheng

    2015-02-01

    Packaging is an important part of high power diode laser (HPLD) development and has become one of the key factors affecting the performance of high power diode lasers. In the package structure of HPLD, the interface layer of die bonding has significant effects on the thermal behavior of high power diode laser packages and most degradations and failures in high power diode laser packages are directly related to the interface layer. In this work, the effects of interface layer on the performance of high power diode laser array were studied numerically by modeling and experimentally. Firstly, numerical simulations using finite element method (FEM) were conducted to analyze the effects of voids in the interface layer on the temperature rise in active region of diode laser array. The correlation between junction temperature rise and voids was analyzed. According to the numerical simulation results, it was found that the local temperature rise of active region originated from the voids in the solder layer will lead to wavelength shift of some emitters. Secondly, the effects of solder interface layer on the spectrum properties of high power diode laser array were studied. It showed that the spectrum shape of diode laser array appeared "right shoulder" or "multi-peaks", which were related to the voids in the solder interface layer. Finally, "void-free" techniques were developed to minimize the voids in the solder interface layer and achieve high power diode lasers with better optical-electrical performances.

  17. Widely tunable lasers based on mode-hop-free semiconductor laser array

    NASA Astrophysics Data System (ADS)

    Kurobe, T.; Kimoto, T.; Muranushi, K.; Mukaihara, T.; Ariga, M.; Kagimoto, T.; Kagi, N.; Matsuo, N.; Kasukawa, A.

    2007-11-01

    Integration of mode-hop-free tunable laser array and a semiconductor optical amplifier is most reliable approach to realize widely tunable lasers. We have developed two types of tunable lasers, one is a thermally tunable DFB laser array for DWDM tunable transponders, which has shown high power and wide tunability covering Cband or L-band, housing in compact butterfly packages with robust wavelength locker. Another is a short-cavity DBR laser array for optical burst switching, whose lasing frequency can be monotonously tuned and locked on the ITU grid within 5 microseconds. Both lasers have demonstrated superior performances in system experiments.

  18. [Development of a High Power Green Laser Therapeutic Equipment for Hyperplasia of Prostate].

    PubMed

    Liang, Jie; Kang, Hongxiang; Shen, Benjian; Zhao, Lusheng; Wu, Xinshe; Chen, Peng; Chang, Aihong; Guo Hua; Guo, Jiayu

    2015-09-01

    The basic theory of high power green laser equipment for prostate hyperplasia therapy and the components of the system developed are introduced. Considering the requirements of the clinical therapy, the working process of the high power green laser apparatus are designed and the laser with stable output at 120 W is achieved. The controlling hardware and application software are developed, and the safety step is designed. The high power green laser apparatus manufactured with characteristics of stable output, multifunctional and friendly interface provides a choices of prostate hyperplasia therapy for using nationalization instrument.

  19. On-shot laser beam diagnostics for high-power laser facility with phase modulation imaging

    NASA Astrophysics Data System (ADS)

    Pan, X.; Veetil, S. P.; Liu, C.; Tao, H.; Jiang, Y.; Lin, Q.; Li, X.; Zhu, J.

    2016-05-01

    A coherent-modulation-imaging-based (CMI) algorithm has been employed for on-shot laser beam diagnostics in high-power laser facilities, where high-intensity short-pulsed lasers from terawatt to petawatt are designed to realize inertial confinement fusion (ICF). A single-shot intensity measurement is sufficient for wave-front reconstruction, both for the near-field and far-field at the same time. The iterative reconstruction process is computationally very efficient and was completed in dozens of seconds by the additional use of a GPU device to speed it up. The compact measurement unit—including a CCD and a piece of pre-characterized phase plate—makes it convenient for focal-spot intensity prediction in the target chamber. It can be placed almost anywhere in high-power laser facilities to achieve near-field wave-front diagnostics. The feasibility of the method has been demonstrated by conducting a series of experiments with diagnostic beams and seed pulses with deactivated amplifiers in our high-power laser system.

  20. Performance of high-power laser diode arrays for spaceborne lasers.

    PubMed

    Durand, Yannig; Culoma, Alain; Meynart, Roland; Pinsard, Jean-Luc; Volluet, Gerard

    2006-08-01

    The adequacy of commercial quasi-continuous high-power laser diode arrays (HPLDAs) as pump sources for spaceborne lasers has been assessed by endurance tests up to 3 x 10(9) shots under various stress conditions, vacuum operation up to 0.36 x 10(9) shots, and proton radiation tests. Observations of the evolution of the electro-optic parameters and of the near-field patterns of the HPLDAs during endurance tests have revealed that some diode bars could reach the required lifetime of a multibillion shots, suggesting how to build long lifetime HPLDAs by proper selection of the diode bars. The robustness of the HPLDAs against the proton environment experienced in a typical low Earth orbit has been checked. Finally, high-power laser diode arrays have been operated under vacuum, showing a behavior similar to that of HPLDAs operating in atmospheric conditions.

  1. Use of high-power lasers in oral surgery

    NASA Astrophysics Data System (ADS)

    Gaspar, Lajos

    1993-12-01

    The treatment of 2989 patients with different type of lasers was described. The argon laser beam was used in 57 cases (portwine stains, telangiectasias, angiofibromas and other vascular lesions) and 84 operations were performed by Nd:YAG laser (leukoplakia, hemangioma etc.) furthermore 53 operations by combined laser beam. 2795 operations by carbon dioxide laser were performed in precancerous states and other white lesions, benign tumors and tumor-like states, malignant tumors and other lesions.

  2. High power laser-mechanical drilling bit and methods of use

    DOEpatents

    Grubb, Daryl L.; Kolachalam, Sharath K.; Faircloth, Brian O.; Rinzler, Charles C.; Allen, Erik C.; Underwood, Lance D.; Zediker, Mark S.

    2017-02-07

    An apparatus with a high power laser-mechanical bit for use with a laser drilling system and a method for advancing a borehole. The laser-mechanical bit has a beam path and mechanical removal devices that provide for the removal of laser-affected rock to advance a borehole.

  3. Target isolation system, high power laser and laser peening method and system using same

    DOEpatents

    Dane, C. Brent; Hackel, Lloyd A.; Harris, Fritz

    2007-11-06

    A system for applying a laser beam to work pieces, includes a laser system producing a high power output beam. Target delivery optics are arranged to deliver the output beam to a target work piece. A relay telescope having a telescope focal point is placed in the beam path between the laser system and the target delivery optics. The relay telescope relays an image between an image location near the output of the laser system and an image location near the target delivery optics. A baffle is placed at the telescope focal point between the target delivery optics and the laser system to block reflections from the target in the target delivery optics from returning to the laser system and causing damage.

  4. Semiconductor laser device

    SciTech Connect

    Namizaki, H.; Susaki, W.; Takamiya, S.; Tanaka, T.

    1981-07-07

    A first N-AlGaAs and a second N-GaAs layer are successively grown on an I-GaAs substrate. A third N-AlGaAs, a fourth P-AlGaAs and a fifth N-GaAs layer superpose one another on the second layer except for one lateral portion. Those portions of the five layers remote from the exposed second layer portion are changed into a P+ type and surrounded by a P zone. A positive and a negative electrode are located on the fifth layer and the exposed second layer portion, respectively. The negative electrode is nearest to a laser region located in the second layer and can be secured to a heat sink.

  5. Methods for enhancing the efficiency of creating a borehole using high power laser systems

    SciTech Connect

    Zediker, Mark S.; Rinzler, Charles C.; Faircloth, Brian O.; Koblick, Yeshaya; Moxley, Joel F.

    2014-06-24

    Methods for utilizing 10 kW or more laser energy transmitted deep into the earth with the suppression of associated nonlinear phenomena to enhance the formation of Boreholes. Methods for the laser operations to reduce the critical path for forming a borehole in the earth. These methods can deliver high power laser energy down a deep borehole, while maintaining the high power to perform operations in such boreholes deep within the earth.

  6. Method and apparatus for delivering high power laser energy over long distances

    DOEpatents

    Zediker, Mark S; Rinzler, Charles C; Faircloth, Brian O; Koblick, Yeshaya; Moxley, Joel F

    2013-08-20

    Systems, devices and methods for the transmission of 1 kW or more of laser energy deep into the earth and for the suppression of associated nonlinear phenomena. Systems, devices and methods for the laser drilling of a borehole in the earth. These systems can deliver high power laser energy down a deep borehole, while maintaining the high power to advance such boreholes deep into the earth and at highly efficient advancement rates.

  7. Method and system for advancement of a borehole using a high power laser

    DOEpatents

    Moxley, Joel F.; Land, Mark S.; Rinzler, Charles C.; Faircloth, Brian O.; Zediker, Mark S.

    2014-09-09

    There is provided a system, apparatus and methods for the laser drilling of a borehole in the earth. There is further provided with in the systems a means for delivering high power laser energy down a deep borehole, while maintaining the high power to advance such boreholes deep into the earth and at highly efficient advancement rates, a laser bottom hole assembly, and fluid directing techniques and assemblies for removing the displaced material from the borehole.

  8. Development of high-power CO2 lasers and laser material processing

    NASA Astrophysics Data System (ADS)

    Nath, Ashish K.; Choudhary, Praveen; Kumar, Manoj; Kaul, R.

    2000-02-01

    Scaling laws to determine the physical dimensions of the active medium and optical resonator parameters for designing convective cooled CO2 lasers have been established. High power CW CO2 lasers upto 5 kW output power and a high repetition rate TEA CO2 laser of 500 Hz and 500 W average power incorporated with a novel scheme for uniform UV pre- ionization have been developed for material processing applications. Technical viability of laser processing of several engineering components, for example laser surface hardening of fine teeth of files, laser welding of martensitic steel shroud and titanium alloy under-strap of turbine, laser cladding of Ni super-alloy with stellite for refurbishing turbine blades were established using these lasers. Laser alloying of pre-placed SiC coating on different types of aluminum alloy, commercially pure titanium and Ti-6Al-4V alloy, and laser curing of thermosetting powder coating have been also studied. Development of these lasers and results of some of the processing studies are briefly presented here.

  9. Effects of High Power Lasers, No. 6 March - October 1975

    DTIC Science & Technology

    1975-11-12

    breakdown in air are described by Dabu; other reports include one by Min’ko on laser plasma generators, and an analysis of trace elements in a...laser plasma. Finally, Berezhnaya describes a polarimetry technique for laser plasma analysis , using a submillimeter laser. ; m Mk...ether and glycerin, buth the analysis is limited to the distilled water case. Results show a general similarity in the character of crater

  10. Application of high power lasers to space power and propulsion

    NASA Technical Reports Server (NTRS)

    Nored, D. L.

    1976-01-01

    The transmission of laser power over long distances for applications such as direct conversion to propulsive thrust or electrical power is considered. Factors discussed include: problems inherent in transmitting, propagating, and receiving the laser beam over long ranges; high efficiency, closed-cycle, continuous wave operation; advancement of CO2 laser technology; and compatibility with photovoltaic power conversion devices.

  11. Radial current high power dummy load for characterizing the high power laser triggered transformer-type accelerator

    NASA Astrophysics Data System (ADS)

    Yin, Yi; Zhong, Hui-Huang; Liu, Jin-Liang; Ren, He-Ming; Yang, Jian-Hua; Zhang, Xiao-Ping; Hong, Zhi-qiang

    2010-09-01

    A radial-current aqueous resistive solution load was applied to characterize a laser triggered transformer-type accelerator. The current direction in the dummy load is radial and is different from the traditional load in the axial. Therefore, this type of dummy load has smaller inductance and fast response characteristic. The load was designed to accommodate both the resistance requirement of accelerator and to allow optical access for the laser. Theoretical and numerical calculations of the load's inductance and capacitance are given. The equivalent circuit of the dummy load is calculated in theory and analyzed with a PSPICE code. The simulation results agree well with the theoretical analysis. At last, experiments of the dummy load applied to the high power spiral pulse forming line were performed; a quasisquare pulse voltage is obtained at the dummy load.

  12. Radial current high power dummy load for characterizing the high power laser triggered transformer-type accelerator.

    PubMed

    Yin, Yi; Zhong, Hui-Huang; Liu, Jin-Liang; Ren, He-Ming; Yang, Jian-Hua; Zhang, Xiao-Ping; Hong, Zhi-qiang

    2010-09-01

    A radial-current aqueous resistive solution load was applied to characterize a laser triggered transformer-type accelerator. The current direction in the dummy load is radial and is different from the traditional load in the axial. Therefore, this type of dummy load has smaller inductance and fast response characteristic. The load was designed to accommodate both the resistance requirement of accelerator and to allow optical access for the laser. Theoretical and numerical calculations of the load's inductance and capacitance are given. The equivalent circuit of the dummy load is calculated in theory and analyzed with a PSPICE code. The simulation results agree well with the theoretical analysis. At last, experiments of the dummy load applied to the high power spiral pulse forming line were performed; a quasisquare pulse voltage is obtained at the dummy load.

  13. Laser remelting of Ti6AL4V using high power diode laser

    NASA Astrophysics Data System (ADS)

    Amaya-Vázquez, M. R.; Sánchez-Amaya, J. M.; Boukha, Z.; El Amrani, K.; Botana, F. J.

    2012-04-01

    Titanium alloys present excellent mechanical and corrosion properties, being widely employed in different industries such as medical, aerospace, automotive, petrochemical, nuclear and power generation, etc. Ti6Al4V is the α-β alloy most employed in industry. The modification of its properties can be achieved with convectional heat treatments and/or with laser processing. Laser remelting (LR) is a technology applied to Ti6Al4V by other authors with excimer and Nd-Yag laser with pure argon shielding gas to prevent risk of oxidation. In the present contribution, laser remelting has been applied for the first time to Ti6Al4V with a high power diode laser (with pure argon as shielding gas). Results showed that remelted samples (with medium energy densities) have higher microhardness and better corrosion resistance than Ti6Al4V base metal.

  14. High power tube solid-state laser with zigzag propagation of pump and laser beam

    NASA Astrophysics Data System (ADS)

    Savich, Michael

    2015-02-01

    A novel resonator and pumping design with zigzag propagation of pumping and laser beams permits to design an improved tube Solid State Laser (SSL), solving the problem of short absorption path to produce a high power laser beam (100 - 1000kW). The novel design provides an amplifier module and laser oscillator. The tube-shaped SSL includes a gain element fiber-optically coupled to a pumping source. The fiber optic coupling facilitates light entry at compound Brewster's angle of incidence into the laser gain element and uses internal reflection to follow a "zigzag" path in a generally spiral direction along the length of the tube. Optics are arranged for zigzag propagation of the laser beam, while the cryogenic cooling system is traditional. The novel method of lasing uses advantages of cylindrical geometry to reach the high volume of gain medium with compactness and structural rigidity, attain high pump density and uniformity, and reach a low threshold without excessive increase of the temperature of the crystal. The design minimizes thermal lensing and stress effects, and provides high gain amplification, high power extraction from lasing medium, high pumping and lasing efficiency and a high beam quality.

  15. Ultrahigh-power semiconductor lasers and their applications

    NASA Astrophysics Data System (ADS)

    He, Xiaoguang; Srinivasan, Swaminathan T.; Gupta, Shantanu; Patel, Rushikesh M.

    1998-08-01

    High power semiconductor laser diodes have found their place in a wide variety of markets such as printing, pumping of solid state lasers, illumination, medical diagnosis, surgery, spectroscopy and material processing. In the past two years, the performance of the commercial available multi-mode semiconductor laser diodes has been elevated to a ultra high power level (continuous wave (CW) power density higher than 15 mW/micrometers -aperture for single emitter devices and 10 mW/micrometers -aperture per cm wide bar for monolithic arrays) as the result of breakthrough in device design, processing and packaging. We present in this paper record setting performance of these ultra high power devices in terms of CW power (> 10.6 W from 100 micrometers aperture, > 180 W from 1 cm wide array) and efficiency (wall plug-in efficiency 59%, differential quantum efficiency 87%). Reliability tests of these ultra high power devices indicates that these devices have equivalent to or better reliability than conventional lower power commercial devices. We will discuss the significance of these devices in enabling new applications and empowering current applications.

  16. Transmission line pulse system for avalanche characterization of high power semiconductor devices

    NASA Astrophysics Data System (ADS)

    Riccio, Michele; Ascione, Giovanni; De Falco, Giuseppe; Maresca, Luca; De Laurentis, Martina; Irace, Andrea; Breglio, Giovanni

    2013-05-01

    Because of the increasing in power density of electronic devices for medium and high power application, reliabilty of these devices is of great interest. Understanding the avalanche behaviour of a power device has become very important in these last years because it gives an indication of the maximum energy ratings which can be seen as an index of the device ruggedness. A good description of this behaviour is given by the static IV blocking characteristc. In order to avoid self heating, very relevant in high power devices, very short pulses of current have to be used, whose value can change from few milliamps up to tens of amps. The most used method to generate short pulses is the TLP (Transmission Line Pulse) test, which is based on charging the equivalent capacitance of a transmission line to high value of voltage and subsequently discharging it onto a load. This circuit let to obtain very short square pulses but it is mostly used for evaluate the ESD capability of semiconductor and, in this environment, it generates pulses of low amplitude which are not high enough to characterize the avalanche behaviour of high power devices . Advanced TLP circuit able to generate high current are usually very expensive and often suffer of distorption of the output pulse. In this article is proposed a simple, low cost circuit, based on a boosted-TLP configuration, which is capable to produce very square pulses of about one hundreds of nanosecond with amplitude up to some tens of amps. A prototype is implemented which can produce pulses up to 20A of amplitude with 200 ns of duration which can characterize power devices up to 1600V of breakdown voltage. Usage of microcontroller based logic make the circuit very flexible. Results of SPICE simulation are provided, together with experimental results. To prove the effectiveness of the circuit, the I-V blocking characteristics of two commercial devices, namely a 600V PowerMOS and a 1200V Trench-IGBT, are measured at different

  17. Applications of high power lasers in the battlefield

    NASA Astrophysics Data System (ADS)

    Kalisky, Yehoshua

    2009-09-01

    Laser weapon is currently considered as tactical as well as strategic beam weapons, and is considered as a part of a general layered defense system against ballistic missiles and short-range rockets. This kind of weapon can disable or destroy military targets or incoming objects used by small groups of terrorists or countries, at the speed of light. Laser weapon is effective at long or short distances, owing to beam's unique characteristics such as narrow bandwidth, high brightness, coherent both in time and space, and it travels at the speed of light. Unlike kinetic weapon, laser weapon converts the energy stored in an electromagnetic laser beam into a large amount of heat aimed on a small area spot at the skin of the missile, usually close to the liquid fuel storage tank, warhead case or engine area, following by a temperature increase and finally-catastrophic failure by material ablation or melt. The usefulness of laser light as a weapon has been studied for decades but only in recent years became feasible. There are two types of lasers being used: gas lasers and solid state lasers, including fiber lasers. All these types of lasers will be discussed below.

  18. High-power free-electron lasers-technology and future applications

    NASA Astrophysics Data System (ADS)

    Socol, Yehoshua

    2013-03-01

    Free-electron laser (FEL) is an all-electric, high-power, high beam-quality source of coherent radiation, tunable - unlike other laser sources - at any wavelength within wide spectral region from hard X-rays to far-IR and beyond. After the initial push in the framework of the “Star Wars” program, the FEL technology benefited from decades of R&D and scientific applications. Currently, there are clear signs that the FEL technology reached maturity, enabling real-world applications. E.g., successful and unexpectedly smooth commissioning of the world-first X-ray FEL in 2010 increased in one blow by more than an order of magnitude (40×) wavelength region available by FEL technology and thus demonstrated that the theoretical predictions just keep true in real machines. Experience of ordering turn-key electron beamlines from commercial companies is a further demonstration of the FEL technology maturity. Moreover, successful commissioning of the world-first multi-turn energy-recovery linac demonstrated feasibility of reducing FEL size, cost and power consumption by probably an order of magnitude in respect to previous configurations, opening way to applications, previously considered as non-feasible. This review takes engineer-oriented approach to discuss the FEL technology issues, keeping in mind applications in the fields of military and aerospace, next generation semiconductor lithography, photo-chemistry and isotope separation.

  19. Measurement of mounting-induced strain in high-power laser diode arrays

    NASA Astrophysics Data System (ADS)

    Tomm, Jens W.; Mueller, Ralf; Baerwolff, A.; Lorenzen, Dirk

    1999-11-01

    Thermally induced strain caused by device packaging is studied in high-power semiconductor laser arrays by a novel non-invasive technique. Measurements with intentionally strained laser array devices for 808 nm emission reveal spectral shifts of quantum-confined optical transitions in the optical active region. These shifts by up to 10 meV serve as a measure for strain and are compared with model calculations. We demonstrate that different packaging techniques cause different packaging-induced strains. We also show that the packaging-induced strain portion, which gets transmitted through the solder material, differs for different packaging technologies. An intentionally strain- reduced packaging technique is shown to transmit about one quarter of the potential packaging-induced strain towards the optical active layer, whereas another packaging technique, which provides highly reliable 'single-chip' devices is found to transmit about half of the potential amount. Spatially resolved measurements demonstrate strain gradients within the devices. Also temporal strain evolution is monitored. We show that 'the burn-in' is accompanied by strain accumulation whereas for long-term operation strain relaxation occurs.

  20. Beam breakup integral measurement on high-power laser chains.

    PubMed

    Villate, Denis; Blanchot, Nathalie; Rouyer, Claude

    2007-03-01

    We experimentally demonstrate the efficiency of a single-shot method to measure the beam breakup integral (B) accumulated across a high power chain. The technique uses spectrally shaped strongly chirped femtosecond pulses and takes advantage of time-to-spectral coupling generated by nonlinear effects. We performed B measurements on regenerative amplifiers (Ti:sapphire) and on the ALISE 200 J facility currently installed at CEA-CESTA (France).

  1. A stable, high power optically pumped far infrared laser system

    NASA Technical Reports Server (NTRS)

    Farhoomand, Jam; Pickett, Herbert M.

    1988-01-01

    The generation of 1.25 watts of CW laser power at the 119-micron (2522.8 GHz) methanol line is reported. The maximum frequency fluctuation of the free running laser is less than + or - 100 kHz per hour. This laser has also been tested on numerous other lines ranging from 403.7 GHz (HCOOH) to 5260 GHz (CH3OD) with improved power and stability.

  2. High power CW iodine laser pumped by solar simulator

    NASA Technical Reports Server (NTRS)

    Lee, Ja H.; Lee, Min H.; Weaver, Willard R.

    1987-01-01

    An iodine photodissociation laser was pumped by a long Ar arc as the solar simulator to produce a 10-W CW output. Continuous lasing for 1 h was achieved with a flow of the laser material n-C3F7I. The 10-W CW output is the highest produced to date and establishes the feasibility of developing a solar-pumped laser for space power transmission.

  3. Statistical optics applied to high-power glass lasers

    SciTech Connect

    Manes, K.R.; Simmons, W.W.

    1985-04-01

    Multiterawatt laser systems, particularly the Novette system at the Lawrence Livermore National Laboratory, are simulated using statistical-optics techniques. The results are compared with experimental observations.

  4. High power visible diode laser for the treatment of eye diseases by laser coagulation

    NASA Astrophysics Data System (ADS)

    Heinrich, Arne; Hagen, Clemens; Harlander, Maximilian; Nussbaumer, Bernhard

    2015-03-01

    We present a high power visible diode laser enabling a low-cost treatment of eye diseases by laser coagulation, including the two leading causes of blindness worldwide (diabetic retinopathy, age-related macular degeneration) as well as retinopathy of prematurely born children, intraocular tumors and retinal detachment. Laser coagulation requires the exposure of the eye to visible laser light and relies on the high absorption of the retina. The need for treatment is constantly increasing, due to the demographic trend, the increasing average life expectancy and medical care demand in developing countries. The World Health Organization reacts to this demand with global programs like the VISION 2020 "The right to sight" and the following Universal Eye Health within their Global Action Plan (2014-2019). One major point is to motivate companies and research institutes to make eye treatment cheaper and easily accessible. Therefore it becomes capital providing the ophthalmology market with cost competitive, simple and reliable technologies. Our laser is based on the direct second harmonic generation of the light emitted from a tapered laser diode and has already shown reliable optical performance. All components are produced in wafer scale processes and the resulting strong economy of scale results in a price competitive laser. In a broader perspective the technology behind our laser has a huge potential in non-medical applications like welding, cutting, marking and finally laser-illuminated projection.

  5. Faraday isolator based on TSAG crystal for high power lasers.

    PubMed

    Mironov, E A; Palashov, O V

    2014-09-22

    A Faraday isolator based on a new magneto-optical medium, TSAG (terbium scandium aluminum garnet) crystal, has been constructed and investigated experimentally. The device provides an isolation ratio of more than 30 dB at 500 W laser power. It is shown that this medium can be used in Faraday isolators for kilowatt-level laser powers.

  6. Industrial applications of high-power copper vapor lasers

    SciTech Connect

    Warner, B.E.; Boley, C.D.; Chang, J.J.; Dragon, E.P.; Havstad, M.A.; Martinez, M.; McLean, W. II

    1995-08-01

    A growing appreciation has developed in the last several years for the copper vapor laser because of its utility in ablating difficult materials at high rates. Laser ablation at high rates shows promise for numerous industrial applications such as thin film deposition, precision hole drilling, and machining of ceramics and other refractories.

  7. Characterization of High-power Quasi-cw Laser Diode Arrays

    NASA Technical Reports Server (NTRS)

    Stephen, Mark A.; Vasilyev, Aleksey; Troupaki, Elisavet; Allan, Graham R.; Kashem, Nasir B.

    2005-01-01

    NASA s requirements for high reliability, high performance satellite laser instruments have driven the investigation of many critical components; specifically, 808 nm laser diode array (LDA) pump devices. Performance and comprehensive characterization data of Quasi-CW, High-power, laser diode arrays is presented.

  8. Integrated injection-locked semiconductor diode laser

    DOEpatents

    Hadley, G. Ronald; Hohimer, John P.; Owyoung, Adelbert

    1991-01-01

    A continuous wave integrated injection-locked high-power diode laser array is provided with an on-chip independently-controlled master laser. The integrated injection locked high-power diode laser array is capable of continuous wave lasing in a single near-diffraction limited output beam at single-facet power levels up to 125 mW (250 mW total). Electronic steering of the array emission over an angle of 0.5 degrees is obtained by varying current to the master laser. The master laser injects a laser beam into the slave array by reflection of a rear facet.

  9. Integrated injection-locked semiconductor diode laser

    DOEpatents

    Hadley, G.R.; Hohimer, J.P.; Owyoung, A.

    1991-02-19

    A continuous wave integrated injection-locked high-power diode laser array is provided with an on-chip independently-controlled master laser. The integrated injection locked high-power diode laser array is capable of continuous wave lasing in a single near-diffraction limited output beam at single-facet power levels up to 125 mW (250 mW total). Electronic steering of the array emission over an angle of 0.5 degrees is obtained by varying current to the master laser. The master laser injects a laser beam into the slave array by reflection of a rear facet. 18 figures.

  10. Optical isolator for semiconductor lasers.

    PubMed

    Kuwahara, H

    1980-01-15

    An optical isolator for semiconductor lasers, consisting of a polarizer and a quarterwave plate, was investigated experimentally. It was assembled in a compact laser-to-fiber coupling module. Experiment showed forward loss of 1.15 dB, backward loss of 24.8 dB, and rotative tolerance of 2.4 deg for 1 dB down. The length of the module is 43.2 mm. The coupling efficiency to a graded-index multimode fiber is 37.5%. The extinction ratio is improved by 6.75 dB. The suppression effect on the influence of reflected light was investigated, using the assembled module.

  11. All solid-state high power visible laser

    NASA Technical Reports Server (NTRS)

    Grossman, William M.

    1993-01-01

    The overall objective of this Phase 2 effort was to develop and deliver to NASA a high repetition rate laser-diode-pumped solid-state pulsed laser system with output in the green portion of the spectrum. The laser is for use in data communications, and high efficiency, short pulses, and low timing jitter are important features. A short-pulse 1 micron laser oscillator, a new multi-pass amplifier to boost the infrared power, and a frequency doubler to take the amplified infrared pulsed laser light into the green. This produced 1.5 W of light in the visible at a pulse repetition rate of 20 kHz in the laboratory. The pulses have a full-width at half maximum of near 1 ns. The results of this program are being commercialized.

  12. 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.

  13. Solar Pumped High Power Solid State Laser for Space Applications

    NASA Technical Reports Server (NTRS)

    Fork, Richard L.; Laycock, Rustin L.; Green, Jason J. A.; Walker, Wesley W.; Cole, Spencer T.; Frederick, Kevin B.; Phillips, Dane J.

    2004-01-01

    Highly coherent laser light provides a nearly optimal means of transmitting power in space. The simplest most direct means of converting sunlight to coherent laser light is a solar pumped laser oscillator. A key need for broadly useful space solar power is a robust solid state laser oscillator capable of operating efficiently in near Earth space at output powers in the multi hundred kilowatt range. The principal challenges in realizing such solar pumped laser oscillators are: (1) the need to remove heat from the solid state laser material without introducing unacceptable thermal shock, thermal lensing, or thermal stress induced birefringence to a degree that improves on current removal rates by several orders of magnitude and (2) to introduce sunlight at an effective concentration (kW/sq cm of laser cross sectional area) that is several orders of magnitude higher than currently available while tolerating a pointing error of the spacecraft of several degrees. We discuss strategies for addressing these challenges. The need to remove the high densities of heat, e.g., 30 kW/cu cm, while keeping the thermal shock, thermal lensing and thermal stress induced birefringence loss sufficiently low is addressed in terms of a novel use of diamond integrated with the laser material, such as Ti:sapphire in a manner such that the waste heat is removed from the laser medium in an axial direction and in the diamond in a radial direction. We discuss means for concentrating sunlight to an effective areal density of the order of 30 kW/sq cm. The method integrates conventional imaging optics, non-imaging optics and nonlinear optics. In effect we use a method that combines some of the methods of optical pumping solid state materials and optical fiber, but also address laser media having areas sufficiently large, e.g., 1 cm diameter to handle the multi-hundred kilowatt level powers needed for space solar power.

  14. High power laser for peening of metals enabling production technology

    SciTech Connect

    Daly, J; Dane, C B; Hackel, L A; Harrison, J

    1998-06-11

    Laser shot peening, a surface treatment for metals, is known to induce compressive residual stresses of over 0.040 inch depth providing improved component resistance to various forms of failure. Additionally recent information suggests that thermal relaxation of the laser induced stress is significantly less than that experienced by other forms of surface stressing that involve significantly higher levels of cold work. We have developed a unique solid state laser technology employing Nd:glass slabs and phase conjugation that enables this process to move into high throughput production processing.

  15. High-power 0.87-micron channel substrate planar lasers for spaceborne communications

    NASA Technical Reports Server (NTRS)

    Connolly, J. C.; Stewart, T. R.; Gilbert, D. B.; Slavin, S. E.; Carlin, D. B.

    1988-01-01

    High-power single-mode channeled-substrate planar AlGaAs diode lasers are being developed for reliable high-power operation for use as sources in spaceborne optical communication systems. The CSP laser structure has been optimized for operation at an emission wavelength of 870 nm. Such devices have exhibited output powers in excess of 80 mW CW at an operating temperature of 80 C.

  16. Progress on the optical materials and components for the high power laser system in China

    NASA Astrophysics Data System (ADS)

    Shao, Jian-Da; Dai, Ya-Ping; Xu, Qiao

    2011-11-01

    The paper summarizes the recent progress on the optical materials and components for the high power laser system in China. The amplifier material, Nd glass, has been developed with continuous melt. Non-linear crystals, KDP/DKDP, have been grown with rapid and traditional growth method. Fused silica and K9 glass has been achieved high quality. Some potential materials for next generation high power laser system are also evinced in this summary.

  17. Progress on the optical materials and components for the high power laser system in China

    NASA Astrophysics Data System (ADS)

    Shao, Jian-da; Dai, Ya-ping; Xu, Qiao

    2012-01-01

    The paper summarizes the recent progress on the optical materials and components for the high power laser system in China. The amplifier material, Nd glass, has been developed with continuous melt. Non-linear crystals, KDP/DKDP, have been grown with rapid and traditional growth method. Fused silica and K9 glass has been achieved high quality. Some potential materials for next generation high power laser system are also evinced in this summary.

  18. High-power CW laser using hydrogen-fluorine reaction

    NASA Technical Reports Server (NTRS)

    Moynihan, P. I.

    1975-01-01

    Continuous-wave laser has been proposed based on reaction of hydrogen and fluorine. Hydrogen is produced by dissociation of hydrazine, which can be stored as liquid in light containers at room temperature.

  19. Near fundamental mode high-power thin-disk laser

    NASA Astrophysics Data System (ADS)

    Schad, Sven-Silvius; Kuhn, Vincent; Gottwald, Tina; Negoita, Viorel; Killi, Alexander; Wallmeroth, Klaus

    2014-02-01

    We report on our latest results of near fundamental mode operation of Yb-doped thin-disk lasers. 4 kW of continuous wave output power at M²<1.4 has been achieved by using one disk only. To the best of our knowledge this is the highest cw output power ever extracted from a single disk resonator design aiming for fundamental mode beam quality. Furthermore, a promising optical-to-optical efficiency of up to 56% at peak power has been achieved by pumping at 969 nm. Besides zero phonon line pumping, standard resonator components of our TruDisk thin-disk laser product series have been used such as the laser disk, and the pump optics which allows for 44 passes of the pump light through the laser crystal. It should be noticed that neither aberration correction methods nor a vacuum resonator design have been necessary to achieve this result.

  20. Laser surface texturization for high power cladding light stripper

    NASA Astrophysics Data System (ADS)

    Berisset, Michael; Lebrun, Léo.; Faucon, Marc; Kling, Rainer; Boullet, Johan; Aguergaray, Claude

    2016-03-01

    We demonstrated herein a new type of cladding light strippers suitable for high power systems. By precisely micro-machining the surface of the fiber we create CLS with efficiencies as high as 97 % for large NA, multi-mode, cladding light (NA = 0.3), and 70 % for single-mode, low NA, light. The NA of the cladding light is reduced from 0.3 down to 0.08. The CLS exhibit a 1°C/stripped-Watt temperature elevation making them very suitable for high power applications. This fabrication method is simple and reliable. We have tested different texturization geometries on several different fibers: 20/400 from Nufern, KAGOME, and LMA 10 and LMA 15 fibers (results not shown herein) and we observed good efficiencies and temperature elevation behavior for all of them. Finally, large scale production of CLS with this method is possible since the time necessary to prepare on CLS is very small, in the order of few seconds.

  1. Limitations on the Attainable Intensity of High Power Lasers

    SciTech Connect

    Fedotov, A. M.; Narozhny, N. B.; Mourou, G.; Korn, G.

    2010-08-20

    It is shown that even a single e{sup -}e{sup +} pair created by a superstrong laser field in vacuum would cause development of an avalanchelike QED cascade which rapidly depletes the incoming laser pulse. This confirms Bohr's old conjecture that the electric field of the critical QED strength E{sub S}=m{sup 2}c{sup 3}/e({h_bar}/2{pi}) could never be created.

  2. Research with high-power short-wavelength lasers

    SciTech Connect

    Holzrichter, J.F.; Campbell, E.M.; Lindl, J.D.; Storm, E.

    1985-03-05

    Three important high-temperature, high-density experiments were conducted recently using the 10-TW, short-wavelength Novette laser system at the Lawrence Livermore National Laboratory. These experiments demonstrated successful solutions to problems that arose during previous experiments with long wavelength lasers (lambda greater than or equal to 1..mu..m) in which inertial confinement fusion (ICF), x-ray laser, and other high-temperature physics concepts were being tested. The demonstrations were: (1) large-scale plasmas (typical dimensions of up to 1000 laser wavelengths) were produced in which potentially deleterious laser-plasma instabilities were collisionally damped. (2) Deuterium-tritium fuel was imploded to a density of 20 g/cm/sup 3/ and a pressure of 10/sup 10/ atm. (3) A 700-fold amplification of soft x rays by stimulated emission at 206 and 209 A (62 eV) from Se/sup +24/ ions was observed in a laser-generated plasma. Isoelectronic scaling to 155 A (87 eV) in Y/sup +29/ was also demonstrated.

  3. Laser assisted die bending: a new application of high power diode lasers

    NASA Astrophysics Data System (ADS)

    Schuöcker, D.; Schumi, T.; Spitzer, O.; Bammer, F.; Schuöcker, G.; Sperrer, G.

    2015-02-01

    Nowadays high power lasers are mainly used for cutting of sheet metals, for welding, hardening and rapid prototyping. In the forming of sheet metals as bending or deep drawing lasers are not used. Nevertheless a few years ago a new application of high power lasers has been invented, where bending of materials that break at room temperature becomes possible by heating them along the bending edge with high power lasers thus allowing their treatment without cracks and rupture. For this purpose a large number of diode lasers are arranged in the bottom tool of a bending machine (a V-shaped die) which heat up the initially flat sheet metal during the bending process what is performed by pressing it into the die with a knife shaped upper tool where due to the laser heating the material is softened and thus cracks are avoided. For the technical realization of the new process of laser assisted die bending, modules equipped with numerous laser diodes and a total beam power of 2,5 kW are used. The light emitted by these modules enters a tool with a length of 15cm and is deflected towards the workpiece. By using ten of these modules with adjacent dies and by integrating those in a bending press a bending edge of sheet metals with a length of 1500mm can be realized. Such a bending press with laser assistance also needs energization with a power of practically 50kW, a respective water flow, a heat exchanger system and also a control for all functions of this system. Special measures have also been developed to avoid radiating of those tools that are not covered by a workpiece in the case of bending edges shorter than the full length of the bending tools whereas individual short circuiting of diode modules can be performed. Specific measures to ensure a safe operation without any harm to the operational person have been realized. Exploitation of the bending process has been carried out for titanium, where material thicknesses up to 3mm have been bent successfully.

  4. High power ytterbium-doped fiber lasers — fundamentals and applications

    NASA Astrophysics Data System (ADS)

    Zervas, Michalis N.

    2014-03-01

    In this paper, we summarize the fundamental properties and review the latest developments in high power ytterbium-doped fiber (YDF) lasers. The review is focused primarily on the main fiber laser configurations and the related cladding pumping issues. Special attention is placed on pump combination techniques and the parameters that affect the brightness enhancements observed in high power fiber lasers. The review also includes the major limitations imposed by fiber nonlinearities and other parasitic effects, such as optical damage, modal instabilities and photodarkening. The paper summarizes the power evolution in continuous-wave (CW) and pulsed YDF lasers and their impact on material processing and other industrial applications.

  5. Semiconductor disk laser-pumped subpicosecond holmium fibre laser

    SciTech Connect

    Chamorovskiy, A Yu; Marakulin, A V; Leinonen, T; Kurkov, Andrei S; Okhotnikov, Oleg G

    2012-01-31

    The first passively mode-locked holmium fibre laser has been demonstrated, with a semiconductor saturable absorber mirror (SESAM) as a mode locker. Semiconductor disk lasers have been used for the first time to pump holmium fibre lasers. We obtained 830-fs pulses at a repetition rate of 34 MHz with an average output power of 6.6 mW.

  6. Vectorial analytical description of the polarized light of a high-power laser diode.

    PubMed

    Xu, Qiang; Wang, Jiajie; Han, Yiping; Wu, Zhensen

    2013-03-10

    A mathematical model to describe the far-field of a high-power laser diode (LD) beam is presented. The laser beam propagation is studied by the vector Rayleigh-Sommerfeld far-field diffraction integral formula The far-field distribution of the LD beam is studied in detail; the light polarized parallel and perpendicular to the junction plane are all considered. This model is employed to predict the light intensity of high-power LDs. The computed intensity distributions are in a good agreement with the corresponding measurements. This model can be easily used to analyze the propagation properties of the high-power LD beam.

  7. High-power pulsed 976-nm DFB laser diodes

    NASA Astrophysics Data System (ADS)

    Zeller, Wolfgang; Kamp, Martin; Koeth, Johannes; Worschech, Lukas

    2010-04-01

    Distributed feedback (DFB) laser diodes nowadays provide stable single mode emission for many different applications covering a wide wavelength range. The available output power is usually limited because of catastrophical optical mirror damage (COD) caused by the small facet area. For some applications such as trace gas detection output powers of several ten milliwatts are sufficiently high, other applications like distance measurement or sensing in harsh environments however require much higher output power levels. We present a process combining optimizations of the layer structure with a new lateral design of the ridge waveguide which is fully compatible with standard coating and passivation processes. By implementing a large optical cavity with the active layer positioned not in the middle of the waveguide layers but very close to the upper edge, the lasers' farfield angles can be drastically reduced. Furthermore, the travelling light mode can be pushed down into the large optical cavity by continuously decreasing the ridge waveguide width towards both laser facets. The light mode then spreads over a much larger area, thus reducing the surface power density which leads to significantly higher COD thresholds. Laterally coupled DFB lasers based on this concept emitting at wavelengths around 976 nm yield hitherto unachievable COD thresholds of 1.6 W under pulsed operation. The high mode stability during the 50 ns pulses means such lasers are ideally suited for high precision distance measurement or similar tasks.

  8. Adaptive resonator control techniques for high-power lasers

    SciTech Connect

    Freeman, R.H.; Spinhirne, J.M.; Anafi, D.

    1981-01-01

    Experimental results and interpretations for correcting tilt and astigmatism aberrations using intracavity adaptive optics versus extracavity adaptive optics are presented, along with control algorithm and resonator design considerations when utilizing a multidither COAT control system for astigmatism and tilt correction. It is shown that in a high-power device, PIB (Power-in-the-Bucket) optimization, with the possible added requirement of extracavity beam clean-up to achieve good beam quality, would be a more desirable control algorithm than BQ (beam quality) optimization. Zonal multidither hill-climbing servo COAT techniques applied to tilt correction fail to achieve good correction for large tilt amplitudes when the control loop is closed after tilt is introduced. Therefore, it is suggested that a separate tilt sensor be used to provide error signal for correction of tilt and let the multidither system COAT correct for higher order aberrations

  9. Research and development of neodymium phosphate laser glass for high power laser application

    NASA Astrophysics Data System (ADS)

    Hu, Lili; He, Dongbing; Chen, Huiyu; Wang, Xin; Meng, Tao; Wen, Lei; Hu, Junjiang; Xu, Yongchun; Li, Shunguang; Chen, Youkuo; Chen, Wei; Chen, Shubin; Tang, Jingping; Wang, Biao

    2016-12-01

    Neodymium phosphate laser glass is a key optical element for high-power laser facility. In this work, the latest research and development of neodymium phosphate laser glass at the Shanghai Institute of Optics and Fine Mechanics (SIOM), China, is addressed. Neodymium phosphate laser glasses, N31, N41, NAP2, and NAP4, for high peak power and high average power applications have been developed. The properties of these glasses are presented and compared to those of other commercial neodymium phosphate laser glass from the Schott and Hoya companies and the Vavilov State Optical Institute (GOI), Russia. Continuous melting and edge cladding are the two key fabrication techniques that are used for the mass production of neodymium phosphate laser glass slabs. These techniques for the fabrication of large-aperture N31 neodymium phosphate laser glass slabs with low stress birefringence and residual reflectivity have been developed by us The effect of acid etching on the microstructure, optical transmission, and mechanical properties of NAP2 glass is also discussed.

  10. Research and development of neodymium phosphate laser glass for high power laser application

    NASA Astrophysics Data System (ADS)

    Hu, Lili; He, Dongbing; Chen, Huiyu; Wang, Xin; Meng, Tao; Wen, Lei; Hu, Junjiang; Xu, Yongchun; Li, Shunguang; Chen, Youkuo; Chen, Wei; Chen, Shubin; Tang, Jingping; Wang, Biao

    2017-01-01

    Neodymium phosphate laser glass is a key optical element for high-power laser facility. In this work, the latest research and development of neodymium phosphate laser glass at the Shanghai Institute of Optics and Fine Mechanics (SIOM), China, is addressed. Neodymium phosphate laser glasses, N31, N41, NAP2, and NAP4, for high peak power and high average power applications have been developed. The properties of these glasses are presented and compared to those of other commercial neodymium phosphate laser glass from the Schott and Hoya companies and the Vavilov State Optical Institute (GOI), Russia. Continuous melting and edge cladding are the two key fabrication techniques that are used for the mass production of neodymium phosphate laser glass slabs. These techniques for the fabrication of large-aperture N31 neodymium phosphate laser glass slabs with low stress birefringence and residual reflectivity have been developed by us The effect of acid etching on the microstructure, optical transmission, and mechanical properties of NAP2 glass is also discussed.

  11. High density semiconductor nanodots by direct laser fabrication

    NASA Astrophysics Data System (ADS)

    Haghizadeh, Anahita; Yang, Haeyeon

    2016-03-01

    We report a direct method of fabricating high density nanodots on the GaAs(001) surfaces using laser irradiations on the surface. Surface images indicate that the large clumps are not accompanied with the formation of nanodots even though its density is higher than the critical density above which detrimental large clumps begin to show up in the conventional Stranski-Krastanov growth technique. Atomic force microscopy is used to image the GaAs(001) surfaces that are irradiated by high power laser pulses interferentially. The analysis suggests that high density quantum dots be fabricated directly on semiconductor surfaces.

  12. Relay telescope for high power laser alignment system

    DOEpatents

    Dane, C. Brent; Hackel, Lloyd; Harris, Fritz B.

    2006-09-19

    A laser system includes an optical path having an intracavity relay telescope with a telescope focal point for imaging an output of the gain medium between an image location at or near the gain medium and an image location at or near an output coupler for the laser system. A kinematic mount is provided within a vacuum chamber, and adapted to secure beam baffles near the telescope focal point. An access port on the vacuum chamber is adapted for allowing insertion and removal of the beam baffles. A first baffle formed using an alignment pinhole aperture is used during alignment of the laser system. A second tapered baffle replaces the alignment aperture during operation and acts as a far-field baffle in which off angle beams strike the baffle a grazing angle of incidence, reducing fluence levels at the impact areas.

  13. Photonic crystal fiber amplifiers for high power ultrafast fiber lasers

    NASA Astrophysics Data System (ADS)

    Alkeskjold, Thomas T.; Laurila, Marko; Weirich, Johannes; Johansen, Mette M.; Olausson, Christina B.; Lumholt, Ole; Noordegraaf, Danny; Maack, Martin D.; Jakobsen, Christian

    2013-12-01

    In recent years, ultrafast laser systems using large-mode-area fiber amplifiers delivering several hundreds of watts of average power has attracted significant academic and industrial interest. These amplifiers can generate hundreds of kilowatts to megawatts of peak power using direct amplification and multi-gigawatts of peak power using pulse stretching techniques. These amplifiers are enabled by advancements in Photonic Crystal Fiber (PCF) design and manufacturing technology. In this paper, we will give a short overview of state-of-the-art PCF amplifiers and describe the performance in ultrafast ps laser systems.

  14. Improvements in a calorimeter for high-power CW lasers

    NASA Technical Reports Server (NTRS)

    Chamberlain, G. E.; Simpson, P. A.; Smith, R. L.

    1978-01-01

    A technique for improving the measurement certainty with the BB series (Smith et al., 1972) of electrically calibrated calorimeters used in high-energy lasers is described. The technique is based on monitoring the energy which is backscattered from the meter and monitoring the overspill radiation impinging on the calorimeter at the entrance aperture. The design and performance of a second generation BB meter is discussed and compared to that of the original device in terms of number of electrical calibrations, the residual standard deviation of electrical calibration, the calibration constant for laser energy, the correcting factor for systematics, inaccuracy, imprecision, and uncertainty.

  15. Experimental study on artificially triggered lightning using high power lasers

    SciTech Connect

    Uchida, S.; Shimada, Y.; Yasuda, H.; Yamanaka, C.; Fujita, H.; Izawa, Y.; Yamanaka, T.; Wang, D.; Kawasaki, Z.; Matsu-ura, K.; Ishikubo, Y.; Adachi, M.

    1996-05-01

    A series of laboratory experiments has been conducted to investigate the initiating effects of laser plasma channel on electrical discharge. It was confirmed that the plasma channels reduce the required electrical field strength for electrical discharges to occur by a factor of 6. A field experimental site targeting natural lightning is being prepared. The thunderstorm monitoring system and the laser and optical systems have been developed and tested against various weather conditions. The results from the laboratory experiments and field experiments will be discussed. {copyright} {ital 1996 American Institute of Physics.}

  16. High power 938 nanometer fiber laser and amplifier

    DOEpatents

    Dawson, Jay W.; Liao, Zhi Ming; Beach, Raymond J.; Drobshoff, Alexander D.; Payne, Stephen A.; Pennington, Deanna M.; Hackenberg, Wolfgang; Calia, Domenico Bonaccini; Taylor, Luke

    2006-05-02

    An optical fiber amplifier includes a length of silica optical fiber having a core doped with neodymium, a first cladding and a second cladding each with succeeding lower refractive indices, where the first cladding diameter is less than 10 times the diameter of the core. The doping concentration of the neodymium is chosen so that the small signal absorption for 816 nm light traveling within the core is less than 15 dB/m above the other fiber losses. The amplifier is optically pumped with one laser into the fiber core and with another laser into the first cladding.

  17. Generation of high-power nanosecond pulses from laser diode-pumped Nd:YAG lasers

    NASA Technical Reports Server (NTRS)

    Chan, Kinpui

    1988-01-01

    Simulation results are used to compare the pulse energy levels and pulse energy widths that can be achieved with LD-pumped Nd:YAG lasers for both the pulse-transmission mode (PTM) and pulse-reflection mode (PRM) Q-switching methods for pulse energy levels up to hundreds of microjoules and pulse widths as short as 1 ns. It is shown that high-power pulses with pulse widths as short as 1 ns can be generated with PTM Q-switched in LD-pumped Nd:YAG lasers. With the PRM Q-switching method, pulse widths as short as 2 ns and pulse energy at the level of a few hundred microjoules can also be achieved but require pumping with 8-10-mJ AlGaAs laser diode arrays.

  18. Advances in CO2 laser fabrication for high power fibre laser devices

    NASA Astrophysics Data System (ADS)

    Boyd, Keiron; Rees, Simon; Simakov, Nikita; Daniel, Jae M. O.; Swain, Robert; Mies, Eric; Hemming, Alexander; Clarkson, W. A.; Haub, John

    2016-03-01

    CO2 laser processing facilitates contamination free, rapid, precise and reproducible fabrication of devices for high power fibre laser applications. We present recent progress in fibre end-face preparation and cladding surface modification techniques. We demonstrate a fine feature CO2 laser process that yields topography significantly smaller than that achieved with typical mechanical cleaving processes. We also investigate the side processing of optical fibres for the fabrication of all-glass cladding light strippers and demonstrate extremely efficient cladding mode removal. We apply both techniques to fibres with complex designs containing multiple layers of doped and un-doped silica as well as shaped and circularly symmetric structures. Finally, we discuss the challenges and approaches to working with various fibre and glass-types.

  19. Propagation of High-Power, Femtosecond Laser Radiation through the Atmosphere

    DTIC Science & Technology

    2004-10-19

    achieved recently in development of new laser technologies stimulates their active use in optics of natural media. Unique properties of laser radiation...allow new information on the objects under study to be obtained. A prominent example is the application of femtosecond lasers to atmospheric sensing...sensing of ecologically dangerous gaseous and aerosol substances. For efficient application of high-power lasers in the environmental research, it is

  20. High power fiber lasers in geothermal, oil and gas

    NASA Astrophysics Data System (ADS)

    Zediker, Mark S.

    2014-03-01

    The subject of this paper is the requirements, design, fabrication, and testing of a prototype laser rock drilling system capable of penetrating even the hardest rocks found deep in the earth. The Oil and Gas industry still uses many of the technologies that were in use at the turn of the 19th century. The drilling industry started with a great innovation with the introduction of the tri-cone bit by Howard Hughes in 1908. Since then, the industry has modified and optimized drilling systems with incremental advancement in the ability to penetrate hard crystalline rock structures. Most oil producing reservoirs are located in or below relatively soft rock formations, however, with the growing need for energy, oil companies are now attempting to drill through very hard surface rock and deep ocean formations with limited success. This paper will discuss the types of laser suitable for this application, the requirements for putting lasers in the field, the technology needed to support this laser application and the test results of components developed specifically by Foro Energy for the drilling application.

  1. High power laser for peening of metals enabling production technology

    SciTech Connect

    Daly, J.; Dane, C.B.; Hackel, L.A.; Harrison, J.

    1998-06-18

    Cryogenic energy-dispersive x-ray detectors are being developed because of their superior energy resolution ((less than or equal to) 10 eV FWHM for keV x rays) compared to semiconductor EDS systems. So far, their range of application is limited due to their comparably small size and low count rate. We present data on the development of superconducting tunnel junction (STJ) detector arrays to address both of these issues. A single STJ detector has a resolution around 10 eV below 1 keV and can be operated at count rates of order 10,000 counts/s. We show that the simultaneous operation of several STJ detectors does not diminish their energy resolution significantly, while increasing the detector area and the maximum count rate by a factor given by the total number of independent channels.

  2. Microgravity Spray Cooling Research for High Powered Laser Applications

    NASA Technical Reports Server (NTRS)

    Zivich, Chad P.

    2004-01-01

    An extremely powerful laser is being developed at Goddard Space Flight Center for use on a satellite. This laser has several potential applications. One application is to use it for upper atmosphere weather research. In this case, the laser would reflect off aerosols in the upper atmosphere and bounce back to the satellite, where the aerosol velocities could be calculated and thus the upper atmosphere weather patterns could be monitored. A second application would be for the US. Air Force, which wants to use the laser strategically as a weapon for satellite defense. The Air Force fears that in the coming years as more and more nations gain limited space capabilities that American satellites may become targets, and the laser could protect the satellites. Regardless of the ultimate application, however, a critical step along the way to putting the laser in space is finding a way to efficiently cool it. While operating the laser becomes very hot and must be cooled to prevent overheating. On earth, this is accomplished by simply running cool tap water over the laser to keep it cool. But on a satellite, this is too inefficient. This would require too much water mass to be practical. Instead, we are investigating spray cooling as a means to cool the laser in microgravity. Spray cooling requires much less volume of fluid, and thus could be suitable for use on a satellite. We have inherited a 2.2 second Drop Tower rig to conduct our research with. In our experiments, water is pressurized with a compressed air tank and sprayed through a nozzle onto our test plate. We can vary the pressure applied to the water and the temperature of the plate before an experiment trial. The whole process takes place in simulated microgravity in the 2.2 second Drop Tower, and a high speed video camera records the spray as it hits the plate. We have made much progress in the past few weeks on these experiments. The rig originally did not have the capability to heat the test plate, but I did

  3. High-power laser damage in fused silica

    NASA Astrophysics Data System (ADS)

    Salleo, Alberto

    Laser-induced damage (LID) at the surface of transparent materials is widely considered the main obstacle in the development of inertial confinement fusion (ICF) facilities. This dissertation is a study, both theoretical and experimental, of LID initiation and propagation at fused silica surfaces. Numerical simulation of light propagation shows that micro-cracks due to polishing amplify light intensity in their vicinity at the air/glass boundary. The mechanism of light amplification is a combination of partial reflection at air/glass boundaries and constructive interference of the reflected waves. The maximum amplification factor for a single crack is 10.7. Multiple cracks interact cooperatively and generate higher amplification factors. Conical cracks generate amplification factors of 20. The electric field intensity profile at the glass surface due to underlying conical cracks correlates well with observed LID morphology. Light amplification at micro-cracks may also play a role in LID propagation. LID propagation rates under repetitive illumination are measured. Rear-surface LID propagates from pre-existing damage sites at sub-threshold fluence. Rear-surface propagation rates depend linearly on laser fluence and are independent of environment or beam size. Rear-surface LID propagates faster in the UV than in the IR. Front-surface LID propagation is two orders of magnitude slower than rear-surface propagation. Pump and probe experiments of LID confirm that this difference is due to laser-plasma interactions. At the front-surface, up to 60% of the laser energy is dispersed outside the glass. At the rear-surface, 35% of the laser energy is dispersed outside the glass, thus more energy is available for damage propagation. Based on these observations, a model of LID propagation is developed based on the physics of impact cratering. Laser-induced transformations of glass are studied. High pressures associated with LID permanently densify fused silica by as much as 20

  4. Real-time power measurement and control for high power diode laser

    NASA Astrophysics Data System (ADS)

    Qin, Wen-bin; Liu, You-qiang; Cao, Yin-hua; Wang, Zhi-yong

    2011-06-01

    As the continual improvement of technology and beam quality, diode laser, with poor beam quality, no longer just apply to pump solid-state laser. As a kind of implement of laser materials processing, high-power diode laser has been used in manufacture, as a brand new means of laser processing. Due to the influence of inevitable unstable factors, for example, the temperature of water-cooler, the current of power supply, etc, the output power of diode laser will be unstable. And laser output power, as an important parameter, frequently affects the performance of the laser beam and the experimental results of processing, especially in the laser materials processing. Therefore, researching the real-time power measurement and control of high power diode laser has great significance, and for diode laser, it would improve performance of itself. To achieve the purpose of real-time detection, traditional measuring method, placing a power sensor behind the total-reflection mirror of laser resonant cavity, is mainly applied in the system of gas laser and solid-state laser. However, Owing to the high integration level of diode laser, traditional measuring method can't be adopted. A technique for real-time measure output power of high power diode laser is developed to improve quality of the laser in this paper. A lens placed at an angle of 45° in the system was used to sample output light of laser, and a piece of ground glass was used to uniform the beam power density, then the photoelectric detector received an optic signal and converted it into electric signal. This feeble signal was processed by amplification circuit with a filter. Finally, this detected electric signal was applied to accomplish the closed-loop control of power. The performance of power measurement and control system was tested with the 300W diode laser, and the measuring inaccuracy achieved was less than +/-1%.

  5. Numerical investigations on high-power laser cutting of metals

    NASA Astrophysics Data System (ADS)

    Amara, E. H.; Kheloufi, K.; Tamsaout, T.; Fabbro, R.; Hirano, K.

    2015-06-01

    A theoretical approach based on a numerical simulation using experimental data is proposed as a contribution for the study of laser metal cutting under gas assistance. The aim is to simulate the stages of the kerf formation by considering the induced generated melt film dynamics, while it interacts with the laser beam and the assisting gas jet. For normal atmospheric conditions, a 3D model is developed using the finite volume method to solve the governing hydrodynamic equations, supplied with the species conservation equation. The present air, the metallic liquid, and the solid metal are considered as phases, where the interface positions are tracked by implementation of the volume-of-fluid method through Fluent CFD code, whereas an enthalpic method is used to take into account the material melting and resolidification. The results for six operating conditions in relation to the cutting velocity show an interesting agreement with the experimental observations.

  6. High Power Selective Laser Melting (HP SLM) of Aluminum Parts

    NASA Astrophysics Data System (ADS)

    Buchbinder, D.; Schleifenbaum, H.; Heidrich, S.; Meiners, W.; Bültmann, J.

    Selective Laser Melting (SLM) is one of the Additive Manufacturing (AM) technologies that enables the production of light weight structured components with series identical mechanical properties without the need for part specific tooling or downstream sintering processes, etc. Especially aluminum is suited for such eco-designed components due to its low weight and superior mechanical and chemical properties. However, SLM's state-of-the-art process and cost efficiency is not yet suited for series-production. In order to improve this efficiency it is indispensable to increase the build rate significantly. Thus, aluminum is qualified for high build rate applications using a new prototype machine tool including a 1 kW laser and a multi-beam system.

  7. Recent advances in phosphate laser glasses for high power applications

    SciTech Connect

    Campbell, J.H.

    1996-05-14

    Recent advances in Nd-doped phosphate laser glasses for high-peak-power and high-average-power applications are reviewed. Compositional studies have progressed to the point that glasses can be tailored to have specific properties for specific applications. Non-radiative relaxation effects can be accurately modeled and empirical expressions have been developed to evaluate both intrinsic (structural) and extrinsic (contamination induced) relaxation effects. Losses due to surface scattering and bulk glass absorption have been carefully measured and can be accurately predicted. Improvements in processing have lead to high damage threshold (e.g. Pt inclusion free) and high thermal shock resistant glasses with improved edge claddings. High optical quality pieces up to 79 x 45 x 4cm{sup 3} have been made and methods for continuous melting laser glass are under development.

  8. Laminar shocks in high power laser plasma interactions

    SciTech Connect

    Cairns, R. A.; Bingham, R.; Norreys, P.; Trines, R.

    2014-02-15

    We propose a theory to describe laminar ion sound structures in a collisionless plasma. Reflection of a small fraction of the upstream ions converts the well known ion acoustic soliton into a structure with a steep potential gradient upstream and with downstream oscillations. The theory provides a simple interpretation of results dating back more than forty years but, more importantly, is shown to provide an explanation for recent observations on laser produced plasmas relevant to inertial fusion and to ion acceleration.

  9. Department of Defense High Power Laser Program Guidance

    DTIC Science & Technology

    1994-06-06

    Air Force Phillips Laboratory . Through FY94, laboratory operational funding, including civilian... Laboratory Effort and Air Materiel Command Ground-Based Laser (GBL) - Space Control USSPACECOM AF Phillips Laboratory Effort Point Defense Demonstration - Anti...ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING I.GANIZATION Phi 1l i ps Laboratory /LID REPORT numP•R 3550 Aberdeen Avenue, S.E. Kirtland AFB, NM

  10. Shock propagation and attenuation in high-power excimer lasers

    NASA Astrophysics Data System (ADS)

    Holzwarth, Achim; Berger, Peter; Huegel, Helmut

    1993-05-01

    Theoretical and experimental investigations on the propagation, reflection, and attenuation of shock waves as they occur in excimer lasers have been performed. The numerical simulations have been carried out using a two-dimensional, unsteady finite difference scheme. The experimental setup is a piston driven shock tube with a rectangular cross section working in air at atmospheric pressure. The shocks were detected interferometrically as well as by means of pressure transducers. This shock tube allows us to investigate basic phenomena of shock diffraction which can be used to confirm the computational results in the range of weak shock waves. In particular, the influence of the shape of the wall contour on the reflection of shock waves has been investigated theoretically. The decay time of pressure and density perturbations differs for various wall configurations in such a way that short electrodes accelerate the attenuation as well as does a strong area increase in the vicinity of them. After each laser pulse there is a shock travelling into the laser channel. Experiments have been carried out on the reflection of this shock at a specially formed bend that is able to focus the shock into a muffling element.

  11. High power laser heating of low absorption materials

    SciTech Connect

    Olson, K.; Talghader, J.; Ogloza, A.; Thomas, J.

    2014-09-28

    A model is presented and confirmed experimentally that explains the anomalous behavior observed in continuous wave (CW) excitation of thermally isolated optics. Distributed Bragg Reflector (DBR) high reflective optical thin film coatings of HfO₂ and SiO₂were prepared with a very low absorption, about 7 ppm, measured by photothermal common-path interferometry. When illuminated with a 17 kW CW laser for 30 s, the coatings survived peak irradiances of 13 MW/cm², on 500 μm diameter spot cross sections. The temperature profile of the optical surfaces was measured using a calibrated thermal imaging camera for illuminated spot sizes ranging from 500 μm to 5 mm; about the same peak temperatures were recorded regardless of spot size. This phenomenon is explained by solving the heat equation for an optic of finite dimensions and taking into account the non-idealities of the experiment. An analytical result is also derived showing the relationship between millisecond pulse to CW laser operation where (1) the heating is proportional to the laser irradiance (W/m²) for millisecond pulses, (2) the heating is proportional to the beam radius (W/m) for CW, and (3) the heating is proportional to W/m∙ tan⁻¹(√(t)/m) in the transition region between the two.

  12. High power VCSEL array pumped Q-switched Nd:YAG lasers

    NASA Astrophysics Data System (ADS)

    Xiong, Yihan; Van Leeuwen, Robert; Watkins, Laurence S.; Seurin, Jean-Francois; Xu, Guoyang; Miglo, Alexander; Wang, Qing; Ghosh, Chuni

    2012-03-01

    Solid-state lasers pumped by high-power two-dimensional arrays of vertical-cavity surface-emitting lasers (VCSELs) were investigated. Both end-pumping and side-pumping schemes of Nd:YAG lasers with high power kW-class 808 nm VCSEL pump modules were implemented. For one application 10 mJ blue laser pulses were obtained from a frequencydoubled actively Q-switched VCSEL-array dual side-pumped Nd:YAG laser operating at 946 nm. For another application 10 mJ green laser pulses were obtained from a frequency-doubled passively Q-switched VCSEL-array endpumped Nd:YAG laser operating at 1064 nm. Both QCW and CW pumping schemes were investigated to achieve high average Q-switched power.

  13. Water Vapour Propulsion Powered by a High-Power Laser-Diode

    NASA Astrophysics Data System (ADS)

    Minami, Y.; Uchida, S.

    Most of the laser propulsion schemes now being proposed and developed assume neither power supplies nor on-board laser devices and therefore are bound to remote laser stations like a kite via a laser beam “string”. This is a fatal disadvantage for a space vehicle that flies freely though it is often said that no need of installing an energy source is an advantage of a laser propulsion scheme. The possibility of an independent laser propulsion space vehicle that carries a laser source and a power supply on board is discussed. This is mainly due to the latest development of high power laser diode (LD) technology. Both high specific impulse-low thrust mode and high thrust-low specific impulse mode can be selected by controlling the laser output by using vapour or water as a propellant. This mode change can be performed by switching between a high power continuous wave (cw), LD engine for high thrust with a low specific impulse mode and high power LD pumping Q-switched Nd:YAG laser engine for low thrust with the high specific impulse mode. This paper describes an Orbital Transfer Vehicle equipped with the above-mentioned laser engine system and fuel cell that flies to the Moon from a space platform or space hotel in Earth orbit, with cargo shipment from lunar orbit to the surface of the Moon, including the possibility of a sightseeing trip.

  14. High power singlemode GaInAs lasers with distributed Bragg reflectors

    NASA Technical Reports Server (NTRS)

    O'Brien, S.; Parke, R.; Welch, D. F.; Mehuys, D.; Scifres, D.

    1992-01-01

    High power singlemode strained GaInAs lasers have been fabricated which use buried second order gratings as distributed Bragg reflectors. The lasers operate in an edge emitting fashion with CW powers in excess of 110 mW with single longitudinal and transverse mode operation at 971.9 nm up to 42 mW.

  15. Rugged passively cooled high power laser fiber optic connectors and methods of use

    DOEpatents

    Rinzler, Charles C.; Gray, William C.; Fraze, Jason D.; Faircloth, Brian O.; Zediker, Mark S.; McKay, Ryan P.

    2016-06-07

    There are provided high power laser connectors and couplers and methods that are capable of providing high laser power without the need for active cooling to remote, harsh and difficult to access locations and under difficult and harsh conditions and to manage and mitigate the adverse effects of back reflections.

  16. Nd:YAG Ceramic ThinZag (registered trademark) High-Power Laser Development

    DTIC Science & Technology

    2011-01-01

    CHAPTER 9 Nd:YAG Ceramic ThinZag® High-Power Laser Development Daniel E. Klimek Principal Research Scientist, Textron Defense Systems, Wilmington...ThinZag High-Power Laser Development 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER...Power Laser Development N d : Y A G C e r a m i c T h i n Z a g ® H i g h - P o w e r L a s e r D e v e l o p m e n t 209 over the years at

  17. Cladding glass ceramic for use in high powered lasers

    DOEpatents

    Marker, Alexander J.; Campbell, John H.

    1998-01-01

    A Cu-doped/Fe-doped low expansion glass ceramic composition comprising in Wt. %: SiO{sub 2} 50--65; Al{sub 2}O{sub 3} 18--27; P{sub 2}O{sub 5} 0--10; Li{sub 2}O 2--6; Na{sub 2}O 0--2; K{sub 2}O 0--2; B{sub 2}O{sub 3} 0--1; MgO 0--4; ZnO 0--5; CaO 0--4; BaO 0--5; TiO{sub 2} 1--3; ZrO{sub 3} 1--3; As{sub 2}O{sub 3} 0--1.5; Sb{sub 2}O{sub 3} 0--1.5; CuO 0--3; and Fe{sub 2}O{sub 3} 0--1 wherein the total amount of SiO{sub 2}, Al{sub 2}O{sub 3} and P{sub 2}O{sub 5} is 80--89 wt. %, and said glass ceramic contains as a dopant 0.1--3 wt. % CuO, 0.1--1 wt. % Fe{sub 2}O{sub 3} or a combined CuO+Fe{sub 2}O{sub 3} amount of 0.1--4 wt. %. The glass ceramic composition is suitable for use as a cladding material for solid laser energy storage mediums as well as for use in beam attenuators for measuring laser energy level and beam blocks or beam dumps used for absorbing excess or unused laser energy.

  18. Cladding glass ceramic for use in high powered lasers

    DOEpatents

    Marker, A.J.; Campbell, J.H.

    1998-02-17

    A Cu-doped/Fe-doped low expansion glass ceramic composition comprising in Wt. %: SiO{sub 2} 50--65; Al{sub 2}O{sub 3} 18--27; P{sub 2}O{sub 5} 0--10; Li{sub 2}O 2--6; Na{sub 2}O 0--2; K{sub 2}O 0--2; B{sub 2}O{sub 3} 0--1; MgO 0--4; ZnO 0--5; CaO 0--4; BaO 0--5; TiO{sub 2} 1--3; ZrO{sub 3} 1--3; As{sub 2}O{sub 3} 0--1.5; Sb{sub 2}O{sub 3} 0--1.5; CuO 0--3; and Fe{sub 2}O{sub 3} 0--1 wherein the total amount of SiO{sub 2}, Al{sub 2}O{sub 3} and P{sub 2}O{sub 5} is 80--89 wt. %, and said glass ceramic contains as a dopant 0.1--3 wt. % CuO, 0.1--1 wt. % Fe{sub 2}O{sub 3} or a combined CuO+Fe{sub 2}O{sub 3} amount of 0.1--4 wt. %. The glass ceramic composition is suitable for use as a cladding material for solid laser energy storage mediums as well as for use in beam attenuators for measuring laser energy level and beam blocks or beam dumps used for absorbing excess or unused laser energy.

  19. High-Power, High-Intensity Laser Propagation and Interactions

    DTIC Science & Technology

    2014-03-10

    Figure 3. Radiation beam is guided (Δk > 0) by electron beam in an FEL amplifier. wave fronts e - beam 6 b) Efficiency Enhancement...wave Brillouin mixing [89,90]. transmitted beam is phase conjugated target initial wave front nn  1 turbulent air Figure 14. Using phase and...presence of radioactive material ( rad ). The electron density at the end of the ionizing laser pulse approaches the value of 3cm eN

  20. Development of fluorides for high power laser optics

    SciTech Connect

    Ready, J.F.; Vora, H.

    1980-07-01

    The laser-assisted thermonuclear fusion program has significant needs for improved optical materials with high transmission in the ultraviolet, and with low values of nonlinear index of refraction. Lithium fluoride (LiF) possesses a combination of optical properties which are of potential use. Single-crystalline LiF is limited by low mechanical strength. In this program, we investigated the technique of press-forging to increase the mechanical strength. LiF single crystals were press-forged over the temperature range 300 to 600/sup 0/C to produce fine-grained polycrystalline material.

  1. Frequency modulation of semiconductor disk laser pulses

    SciTech Connect

    Zolotovskii, I O; Korobko, D A; Okhotnikov, O G

    2015-07-31

    A numerical model is constructed for a semiconductor disk laser mode-locked by a semiconductor saturable absorber mirror (SESAM), and the effect that the phase modulation caused by gain and absorption saturation in the semiconductor has on pulse generation is examined. The results demonstrate that, in a laser cavity with sufficient second-order dispersion, alternating-sign frequency modulation of pulses can be compensated for. We also examine a model for tuning the dispersion in the cavity of a disk laser using a Gires–Tournois interferometer with limited thirdorder dispersion. (control of radiation parameters)

  2. Long-term research in Japan: amorphous metals, metal oxide varistors, high-power semiconductors and superconducting generators

    SciTech Connect

    Hane, G.J.; Yorozu, M.; Sogabe, T.; Suzuki, S.

    1985-04-01

    The review revealed that significant activity is under way in the research of amorphous metals, but that little fundamental work is being pursued on metal oxide varistors and high-power semiconductors. Also, the investigation of long-term research program plans for superconducting generators reveals that activity is at a low level, pending the recommendations of a study currently being conducted through Japan's Central Electric Power Council.

  3. Semiconductor Lasers and Their Application in Optical Fiber Communication.

    ERIC Educational Resources Information Center

    Agrawal, Govind P.

    1985-01-01

    Working principles and operating characteristics of the extremely compact and highly efficient semiconductor lasers are explained. Topics include: the p-n junction; Fabry-Perot cavity; heterostructure semiconductor lasers; materials; emission characteristics; and single-frequency semiconductor lasers. Applications for semiconductor lasers include…

  4. Ultraprecision grinding of optical materials for high-power lasers

    NASA Astrophysics Data System (ADS)

    Namba, Yoshiharu; Yoshida, Kunio; Yoshida, Hidetsugu; Nakai, Sadao

    1998-04-01

    Grinding is considered to be a rough machining process in the field of optics; a polishing process must follow the grinding process for getting optical-quality surfaces. An ultraprecision surface grinder with hydrostatic oil bearings and a glass-ceramic spindle of extremely low thermal expansion was developed to get smooth optical surfaces without any polishing process. Various optical materials such as NbF1, BK7, LHG08 fused silica, KTP, KDP and CLBO were ground into optical surfaces after empirically determining the conditions required to attain ductile-mode grinding. An extremely smooth surface less than 0.1 nm rms was obtained on BK7 glass by the ultraprecision grinding process. The laser-induced damage threshold was measured on variously finished LHG-8 laser glass at (lambda) equals 1.053 micrometers and 1-ns pulse width. The damage threshold was measured at 22.2 J/cm2 on a ground surface with the polarization parallel to the grinding direction. This number is higher than that obtained by optical polish. The damage threshold of 293 J/cm2 was also obtained on a ground LHG-8 glass surface at (lambda) equals 1.053 micrometers and 30-ns pulse width.

  5. Novel fiber-MOPA-based high power blue laser

    NASA Astrophysics Data System (ADS)

    Engin, Doruk; Fouron, Jean-Luc; Chen, Youming; Huffman, Andromeda; Fitzpatrick, Fran; Burnham, Ralph; Gupta, Shantanu

    2012-06-01

    5W peak power at 911 nm is demonstrated with a pulsed Neodymium (Nd) doped fiber master oscillator power amplifier (MOPA). This result is the first reported high gain (16dB) fiber amplifier operation at 911nm. Pulse repetition frequency (PRF) and duty-cycle dependence of the all fiber system is characterized. Negligible performance degreadation is observed down to 1% duty cycle and 10 kHz PRF, where 2.5μJ of pulse energy is achieved. Continuous wave (CW) MOPA experiments achieved 55mW average power and 9dB gain with 15% optical to optical (o-o) efficiency. Excellent agreement is established between dynammic fiber MOPA simulation tool and experimental results in predicting output amplified spontaneous emission (ase) and signal pulse shapes. Using the simulation tool robust Stimulated Brillion Scattering (SBS) free operation is predicted out of a two stage all fiber system that generates over 10W's of peak power with 500 MHz line-width. An all fiber 911 nm pulsed laser source with >10W of peak power is expected to increase reliability and reduce complexity of high energy 455 nm laser system based on optical parametric amplification for udnerwater applications. The views expressed are thos of the author and do not reflect the official policy or position of the Department of Defense or the U.S. Government.

  6. Recent development on high-power tandem-pumped fiber laser

    NASA Astrophysics Data System (ADS)

    Zhou, Pu; Xiao, Hu; Leng, Jinyong; Zhang, Hanwei; Xu, Jiangmin; Wu, Jian

    2016-11-01

    High power fiber laser is attracting more and more attention due to its advantage in excellent beam quality, high electricto- optical conversion efficiency and compact system configuration. Power scaling of fiber laser is challenged by the brightness of pump source, nonlinear effect, modal instability and so on. Pumping active fiber by using high-brightness fiber laser instead of common laser diode may be the solution for the brightness limitation. In this paper, we will present the recent development of various kinds of high power fiber laser based on tandem pumping scheme. According to the absorption property of Ytterbium-doped fiber, Thulium-doped fiber and Holmium-doped fiber, we have theoretically studied the fiber lasers that operate at 1018 nm, 1178 nm and 1150 nm, respectively in detail. Consequently, according to the numerical results we have optimized the fiber laser system design, and we have achieved (1) 500 watt level 1018nm Ytterbium-doped fiber laser (2) 100 watt level 1150 nm fiber laser and 100 watt level random fiber laser (3) 30 watt 1178 nm Ytterbium-doped fiber laser, 200 watt-level random fiber laser. All of the above-mentioned are the record power for the corresponded type of fiber laser to the best of our knowledge. By using the high-brightness fiber laser operate at 1018 nm, 1178 nm and 1150 nm that we have developed, we have achieved the following high power fiber laser (1) 3.5 kW 1090 nm Ytterbium-doped fiber amplifier (2) 100 watt level Thulium-doped fiber laser and (3) 50 watt level Holmium -doped fiber laser.

  7. Modulation characteristics of a high-power semiconductor Master Oscillator Power Amplifier (MOPA)

    NASA Technical Reports Server (NTRS)

    Cornwell, Donald Mitchell, Jr.

    1992-01-01

    A semiconductor master oscillator-power amplifier was demonstrated using an anti-reflection (AR) coated broad area laser as the amplifier. Under CW operation, diffraction-limited single-longitudinal-mode powers up to 340 mW were demonstrated. The characteristics of the far-field pattern were measured and compared to a two-dimensional reflective Fabry-Perot amplifier model of the device. The MOPA configuration was modulated by the master oscillator. Prior to injection into the amplifier, the amplitude and frequency modulation properties of the master oscillator were characterized. The frequency response of the MOPA configuration was characterized for an AM/FM modulated injection beam, and was found to be a function of the frequency detuning between the master oscillator and the resonant amplifier. A shift in the phase was also observed as a function of frequency detuning; this phase shift is attributed to the optical phase shift imparted to a wave reflected from a Fabry-Perot cavity. Square-wave optical pulses were generated at 10 MHz and 250 MHz with diffraction-limited peak powers of 200 mW and 250 mW. The peak power for a given modulation frequency is found to be limited by the injected power and the FM modulation at that frequency. The modulation results make the MOPA attractive for use as a transmitter source in applications such as free-space communications and ranging/altimetry.

  8. Laboratory Astrophysics on High Power Lasers and Pulsed Power Facilities

    SciTech Connect

    Remington, B A

    2002-02-05

    Over the past decade a new genre of laboratory astrophysics has emerged, made possible by the new high energy density (HED) experimental facilities, such as large lasers, z-pinch generators, and high current particle accelerators. (Remington, 1999; 2000; Drake, 1998; Takabe, 2001) On these facilities, macroscopic collections of matter can be created in astrophysically relevant conditions, and its collective properties measured. Examples of processes and issues that can be experimentally addressed include compressible hydrodynamic mixing, strong shock phenomena, radiative shocks, radiation flow, high Mach-number jets, complex opacities, photoionized plasmas, equations of state of highly compressed matter, and relativistic plasmas. These processes are relevant to a wide range of astrophysical phenomena, such as supernovae and supernova remnants, astrophysical jets, radiatively driven molecular clouds, accreting black holes, planetary interiors, and gamma-ray bursts. These phenomena will be discussed in the context of laboratory astrophysics experiments possible on existing and future HED facilities.

  9. Experimental astrophysics with high power lasers and Z pinches

    SciTech Connect

    Remington, B A; Drake, R P; Ryutov, D D

    2004-12-10

    With the advent of high energy density (HED) experimental facilities, such as high-energy lasers and fast Z-pinch, pulsed-power facilities, mm-scale quantities of matter can be placed in extreme states of density, temperature, and/or velocity. This has enabled the emergence of a new class of experimental science, HED laboratory astrophysics, wherein the properties of matter and the processes that occur under extreme astrophysical conditions can be examined in the laboratory. Areas particularly suitable to this class of experimental astrophysics include the study of opacities relevant to stellar interiors; equations of state relevant to planetary interiors; strong shock driven nonlinear hydrodynamics and radiative dynamics, relevant to supernova explosions and subsequent evolution; protostellar jets and high Mach-number flows; radiatively driven molecular clouds and nonlinear photoevaporation front dynamics; and photoionized plasmas relevant to accretion disks around compact objects, such as black holes and neutron stars.

  10. Semiconductor Laser Low Frequency Noise Characterization

    NASA Technical Reports Server (NTRS)

    Maleki, Lute; Logan, Ronald T.

    1996-01-01

    This work summarizes the efforts in identifying the fundamental noise limit in semiconductor optical sources (lasers) to determine the source of 1/F noise and it's associated behavior. In addition, the study also addresses the effects of this 1/F noise on RF phased arrays. The study showed that the 1/F noise in semiconductor lasers has an ultimate physical limit based upon similar factors to fundamental noise generated in other semiconductor and solid state devices. The study also showed that both additive and multiplicative noise can be a significant detriment to the performance of RF phased arrays especially in regard to very low sidelobe performance and ultimate beam steering accuracy. The final result is that a noise power related term must be included in a complete analysis of the noise spectrum of any semiconductor device including semiconductor lasers.

  11. Transmyocardial laser revascularization with a high-power (800 W) CO2 laser: clinical report with 50 cases

    NASA Astrophysics Data System (ADS)

    Qu, Zheng; Zhang, Zhaoguang; Ye, Jianguang; Yu, Jianbo

    1999-09-01

    This paper reports the clinical experience in transmyocardial laser revascularization (TMLR) with high power CO2 laser and evaluates the preliminary results of TMLR. TMLR may improve angina pectoris and myocardial perfusion significantly. To switch on the laser in proper order may be helpful to shorten duration of surgery. A gentle removal of fat on the apex may increase the successful transmyocardial penetration.

  12. 2.1 μm high-power laser diode beam combining(Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Berrou, Antoine P. C.; Elder, Ian F.; Lamb, Robert A.; Esser, M. J. Daniel

    2016-10-01

    Laser power and brightness scaling, in "eye safe" atmospheric transmission windows, is driving laser system research and development. High power lasers with good beam quality, at wavelength around 2.1 µm, are necessary for optical countermeasure applications. For such applications, focusing on efficiency and compactness of the system is mandatory. In order to cope with these requirements, one must consider the use of laser diodes which emit directly in the desired spectral region. The challenge for these diodes is to maintain a good beam quality factor as the output power increases. 2 µm diodes with excellent beam quality in both axes are available with output powers of 100 mW. Therefore, in order to reach multi-watt of average output power, broad-area single emitters and beam combining becomes relevant. Different solutions have been implemented in the 1.9 to 2 µm wavelength range, one of which is to stack multiple emitter bars reaching more than one hundred watt, while another is a fibre coupled diode module. The beam propagation factor of these systems is too high for long atmospheric propagation applications. Here we describe preliminary results on non-coherent beam combining of 2.1 µm high power Fabry-Perot GaSb laser diodes supplied by Brolis Semiconductors Ltd. First we evaluated single mode diodes (143 mW) with good beam quality (M2 < 1.5 for slow axis and < 1.1 for fast axis). Then we characterized broad-area single emitter diodes (808 mW) with an electrical-to-optical efficiency of 19 %. The emitter width was 90 µm with a cavity length of 1.5 mm. In our experiments we found that the slow axis multimode output beam consisted of two symmetric lobes with a total full width at half maximum (FWHM) divergence angle of 25 degrees, corresponding to a calculated beam quality factor of M2 = 25. The fast axis divergence was specified to be 44 degrees, with an expected beam quality factor close to the diffraction limit, which informed our selection of collimation

  13. Cryogenic, high power, near diffraction limited, Yb:YAG slab laser.

    PubMed

    Ganija, Miftar; Ottaway, David; Veitch, Peter; Munch, Jesper

    2013-03-25

    A cryogenic slab laser that is suitable for scaling to high power, while taking full advantage of the improved thermo-optical and thermo-mechanical properties of Yb:YAG at cryogenic temperatures is described. The laser uses a conduction cooled, end pumped, zigzag slab geometry resulting in a near diffraction limited, robust, power scalable design. The design and the initial characterization of the laser up to 200W are presented.

  14. High-power 83 W holmium-doped silica fiber laser operating with high beam quality.

    PubMed

    Jackson, Stuart D; Sabella, Alex; Hemming, Alex; Bennetts, Shayne; Lancaster, David G

    2007-02-01

    A high-power 83 W cladding-pumped Tm3+-Ho3+-doped silica fiber laser is reported. Using bidirectional 793 nm diode pumping, a maximum slope efficiency of 42% was produced after a threshold launched pump power of 12 W was exceeded. The laser operated at wavelengths near 2105 nm with moderate beam quality, i.e., M2 approximately 1.5. Further power scaling of the fiber laser was limited by thermal failure of the fiber ends.

  15. High-power 83 W holmium-doped silica fiber laser operating with high beam quality

    NASA Astrophysics Data System (ADS)

    Jackson, Stuart D.; Sabella, Alex; Hemming, Alex; Bennetts, Shayne; Lancaster, David G.

    2007-02-01

    A high-power 83W cladding-pumped Tm3+-Ho3+-doped silica fiber laser is reported. Using bidirectional 793nm diode pumping, a maximum slope efficiency of 42% was produced after a threshold launched pump power of 12W was exceeded. The laser operated at wavelengths near 2105nm with moderate beam quality, i.e., M2˜1.5. Further power scaling of the fiber laser was limited by thermal failure of the fiber ends.

  16. Spectrally beam combined fiber lasers for high power, efficiency, and brightness

    NASA Astrophysics Data System (ADS)

    Honea, Eric; Afzal, Robert S.; Savage-Leuchs, Matthias; Gitkind, Neil; Humphreys, Richard; Henrie, Jason; Brar, Khush; Jander, Don

    2013-03-01

    Spectral Beam Combining (SBC) of fiber lasers provides a simple, robust architecture for power scaling lasers to high power. With appropriate designs, power scaling beyond the single fiber limit can be achieved while maintaining near diffraction limited beam quality and high efficiency. We present experimental results where we achieved > 3 kW at an M2 = 1.35 and > 39% E-O efficiency by combining 12 individual fiber lasers into a single high brightness beam.

  17. High-power terahertz optically pumped NH{sub 3} laser for plasma diagnostics

    SciTech Connect

    Mishchenko, V. A.; Petrushevich, Yu. V.; Sobolenko, D. N.; Starostin, A. N.

    2012-06-15

    The parameter of a terahertz (THz) laser intended for plasma diagnostics in electrodynamic accelerators and tokamaks with a strong magnetic field are discussed. Generation of THz radiation in an ammonia laser under the action of high-power pulsed optical pumping by the radiation of a 10P(32) CO{sub 2} laser is simulated numerically. The main characteristics of the output radiation, such as its spectrum, peak intensity, time dependence, and total energy, are calculated.

  18. Blue and UV Semiconductor Lasers

    NASA Astrophysics Data System (ADS)

    Krukowski, S.; Skierbiszewski, C.; Perlin, P.; Leszczynski, M.; Bockowski, M.; Porowski, S.

    2006-04-01

    Despite many technological difficulties the group III nitrides: GaN, AlN and InN and their alloys are primary candidates for electro-optical coherent light sources. In the recent years the research and technology of the nitride based continuous wave (CW) laser diodes (LDs) led to creation of blue-violet coherent light sources of power up to 200 mW. The progress has been attained by using various ways to attack the main obstacles in the technology of these devices such as insufficient size of high quality lattice matched substrates, low p-doping efficiency of Mg acceptor, poor contact to p-type semiconductor and low efficiency of radiative recombination. The two different approaches were used to overcome the substrate problem: hetero-epitaxy and homoepitaxy. Homoepitaxy used high pressure GaN high quality crystals. Heteroepitaxy used sapphire, SiC or GaAs substrates and very sophisticated techniques of reduction of the dislocation density. The low p-doping efficiency by using Mg acceptor is related to creation of Mg--H complexes due to hydrogen presence during the growth of laser diode quantum structures. In addition, Mg acceptor has low efficiency due to its high energy. High Mg concentrations can be obtained by using either MOCVD or ammonia source MBE growth. An alternative route is to use hydrogen-free plasma activated MBE (PA-MBE) method. The recent advances and the prospects of both approaches will be discussed. Solid AlGaInN solution offers a possibility to cover wide spectral range, starting from near UV to blue, green and red. Arsenide based laser diodes (LDs) are efficient coherent red light sources. Therefore, nitride based LDs are considered to be devices of choice for green, blue and UV spectral range. So far only blue and violet laser has been realized. The progress toward green and UV lasers is far less spectacular. The results in all these areas and future prospects will be discussed.

  19. Packaging of complete indium-free high reliable and high power diode laser array

    NASA Astrophysics Data System (ADS)

    Wang, Jingwei; Li, Xiaoning; Feng, Feifei; Liu, Yalong; Hou, Dong; Liu, Xingsheng

    2015-02-01

    High power diode lasers have been widely used in many fields. For many applications, a diode laser needs to be robust under on-off power-cycling as well as environmental thermal cycling conditions. To meet the requirements, the conduction cooled single bar CS-packaged diode laser arrays must have high durability to withstand thermal fatigue and long lifetime. In this paper, a complete indium-free bonding technology is presented for packaging high power diode laser arrays. Numerical simulations on the thermal behavior of CS-packaged diode laser array with different packaging structure were conducted and analyzed. Based on the simulation results, the device structure and packaging process of complete indium-free CS-packaged diode laser array were optimized. A series of high power hard solder CS (HCS) diode laser arrays were fabricated and characterized. Under the harsh working condition of 90s on and 30s off, good lifetime was demonstrated on 825nm 60W single bar CS-packaged diode laser with a lifetime test of more than 6100hours achieved so far with less 5% power degradation and less 1.5nm wavelength shift. Additionally, the measurement results indicated that the lower smile of complete indium-free CS-packaged diode laser arrays were achieved by advanced packaging process.

  20. Fiber laser pumped high power mid-infrared laser with picosecond pulse bunch output.

    PubMed

    Wei, Kaihua; Chen, Tao; Jiang, Peipei; Yang, Dingzhong; Wu, Bo; Shen, Yonghang

    2013-10-21

    We report a novel quasi-synchronously pumped PPMgLN-based high power mid-infrared (MIR) laser with picosecond pulse bunch output. The pump laser is a linearly polarized MOPA structured all fiberized Yb fiber laser with picosecond pulse bunch output. The output from a mode-locked seed fiber laser was directed to pass through a FBG reflector via a circulator to narrow the pulse duration from 800 ps to less than 50 ps and the spectral FWHM from 9 nm to 0.15 nm. The narrowed pulses were further directed to pass through a novel pulse multiplier through which each pulse was made to become a pulse bunch composing of 13 sub-pulses with pulse to pulse time interval of 1.26 ns. The pulses were then amplified via two stage Yb fiber amplifiers to obtain a linearly polarized high average power output up to 85 W, which were then directed to pass through an isolator and to pump a PPMgLN-based optical parametric oscillator via quasi-synchronization pump scheme for ps pulse bunch MIR output. High MIR output with average power up to 4 W was obtained at 3.45 micron showing the feasibility of such pump scheme for ps pulse bunch MIR output.

  1. High-power diode laser versus electrocautery surgery on human papillomavirus lesion treatment.

    PubMed

    Baeder, Fernando Martins; Santos, Maria Teresa Botti R; Pelino, Jose Eduardo Pelizon; Duarte, Danilo Antonio; Genovese, Walter Joao

    2012-05-01

    The use of high-power lasers has facilitated and improved human papillomavirus (HPV) treatment protocols and has also become very popular in recent years. This application has been more frequently used in hospitals, especially in gynecology. The present study aimed to evaluate the effects of high-power diode laser to remove oral lesions caused by HPV and the consequent effects on virus load following the wound tissue healing process compared with one of the most conventional surgical techniques involving electrocautery. Surgeries were performed on 5 patients who had 2 distinct lesions caused by HPV. All patients were submitted to both electrocautery and high-power diode laser. Following a 20-day period, when the area was healed, sample material was collected through curettage for virus load quantitative analysis.Observation verified the presence of virus in all the samples; however, surgeries performed with the laser also revealed a significant reduction in virus load per cell compared with those performed with electrocautery. The ease when handling the diode laser, because of the flexibility of its fibers and precision of its energy delivery system, provides high-accuracy surgery, which facilitates the treatment of large and/or multifocal lesions. The use of high-power diode laser is more effective in treatment protocols of lesions caused by HPV.

  2. Fiber optic cables for transmission of high-power laser pulses

    NASA Astrophysics Data System (ADS)

    Thomes, W. Joe, Jr.; Ott, Melanie N.; Chuska, Richard F.; Switzer, Robert C.; Blair, Diana E.

    2011-09-01

    High power pulsed lasers are commonly deployed in harsh environments, like space flight and military missions, for a variety of systems such as LIDAR, optical communications over long distances, or optical firing of explosives. Fiber coupling of the laser pulse from the laser to where it is needed can often save size, reduce weight, and lead to a more robust and reliable system. Typical fiber optic termination procedures are not sufficient for injection of these high power laser pulses without catastrophic damage to the fiber endface. In the current study, we will review the causes of fiber damage during high power injection and discuss methods used to avoid these issues to permit fiber use with high reliability in these applications. A brief review of the design considerations for high peak power laser pulse injection will be presented to familiarize the audience with all the areas that need to be considered during the design phase. The majority of this paper focuses on the proper fiber polishing methods for high power use with an emphasis on laser polishing of the fibers. Results from recently build fibers will be shown to demonstrate the techniques.

  3. Third order mode optically pumped semiconductor laser

    NASA Astrophysics Data System (ADS)

    De Rossi, A.; Semaltianos, N.; Chirlias, E.; Vinter, B.; Ortiz, V.; Berger, V.

    2002-06-01

    Lasing action on a third order waveguide mode is demonstrated at room temperature under optical pumping, in a specifically designed quantum well laser structure. The AlGaAs heterostructure involves barriers which ensure that the third order waveguide mode has a higher overlap with the single quantum well emitter than the fundamental mode. Third order mode operation of a laser structure opens the way to modal phase matched parametric down conversion inside the semiconductor laser itself. It is a first step towards the realization of semiconductor twin photon laser sources, needed for quantum information experiments.

  4. Coilable single crystal fibers of doped-YAG for high power laser applications

    NASA Astrophysics Data System (ADS)

    Maxwell, Gisele; Soleimani, Nazila; Ponting, Bennett; Gebremichael, Eminet

    2013-05-01

    Single crystal fibers are an intermediate between laser crystals and doped glass fibers. They can combine the advantages of both by guiding laser light and matching the efficiencies found in bulk crystals, making them ideal candidates for high-power laser and fiber laser applications. In particular, a very interesting feature of single crystal fiber is that they can generate high power in the eye-safe range (Er:YAG) with a high efficiency, opening new possibilities for portable directed energy weapons. This work focuses on the growth of a flexible fiber with a core of dopant (Er, Nd, Yb, etc…) that will exhibit good waveguiding properties. Direct growth or a combination of growth and cladding experiments are described. We have, to date, demonstrated the growth of a flexible foot long 45 microns doped YAG fiber. Scattering loss measurements at visible wavelengths along with dopant profile characterization are also presented. Laser characterization for these fibers is in progress.

  5. Reliability of high power/brightness diode lasers emitting from 790 to 980 nm

    NASA Astrophysics Data System (ADS)

    Bao, L.; Bai, J.; Price, K.; Devito, M.; Grimshaw, M.; Dong, W.; Guan, X.; Zhang, S.; Zhou, H.; Bruce, K.; Dawson, D.; Kanskar, M.; Martinsen, R.; Haden, J.

    2013-02-01

    This paper presents recent progress in the development of high power single emitter laser diodes from 790 nm to 980 nm for reliable use in industrial and pumping applications. High performance has been demonstrated on diode lasers from 790 nm to 980 nm, with corresponding peak efficiency ~65%. Reliability has been fully demonstrated on high power diode lasers of 3.8 mm laser cavity at 3 major wavelengths. We report on the correlation between photon-energy (wavelength) and device failure modes (reliability). A newly released laser design demonstrates diode lasers with 5.0 mm laser cavity at 915-980 nm and 790 nm, with efficiency that matches the values achieved with 3.8 mm cavity length. 915-980 nm single emitters with 5.0 mm laser cavity were especially designed for high power and high brightness applications and can be reliably operated at 12 W to 18 W. These pumps have been incorporated into nLIGHT's newly developed fiber coupled pump module, elementTM. Ongoing highly accelerated diode life-tests have accumulated over 200,000 raw device hours, with extremely low failure rate observed to date. High reliability has also been demonstrated from multiple accelerated module-level lifetests.

  6. Beam shaping design for coupling high power diode laser stack to fiber.

    PubMed

    Ghasemi, Seyed Hamed; Hantehzadeh, Mohammad-Reza; Sabbaghzadeh, Jamshid; Dorranian, Davoud; Lafooti, Majid; Vatani, Vahid; Rezaei-Nasirabad, Reza; Hemmati, Atefeh; Amidian, Ali Asghar; Alavian, Seyed Ali

    2011-06-20

    A beam shaping technique that rearranges the beam for improving the beam symmetry and power density of a ten-bar high power diode laser stack is simulated considering a stripe mirror plate and a V-Stack mirror in the beam shaping system. In this technique, the beam of a high power diode laser stack is effectively coupled into a standard 550 μm core diameter and a NA=0.22 fiber. By this technique, compactness, higher efficiency, and lower cost production of the diode are possible.

  7. Case studies of industrial applications of high-power diode laser in Finland

    NASA Astrophysics Data System (ADS)

    Hovikorpi, Jari; Jansson, Anssi; Salminen, Antti

    2003-06-01

    The high power diode laser is a new industrial tool. It has several advantages and disadvantages compared to the conventional industrially used CO2 and Nd:YAG laser. The most promising areas of application of diode laser have been considered to be thin sheet welding and hardening. Quite a few feasibility studies of the use of diode laser have been carried out in Finland. So far there has been some application in which diode laser is the most suitable laser. Typically, the HPDL is integrated to an industrial robot. The welding of stainless steel housing, car door lock and catalytic converters are typical examples of applications in which diode laser has technological as well as economical advantages over the conventional laser and welding techniques. The welding of these products requires good control over the heat input, short through put time and low investment. The weld cross-section of a diode laser weld is, because of conduction limited welding process, more suitable for these applications than the keyhole welding. Hardening of a large gear wheel presents also a good example of an application in which the diode laser makes it possible to economically produce structures that have not earlier been possible. Hardening requires a special form of heat delivery in order to ensure evenly hardened zone and acceptable quality. The application was performed with two high power diode lasers. The case studies of these four applications are presented and discussed in details in this paper.

  8. High-Power Broad-Area Diode Lasers and Laser Bars

    NASA Astrophysics Data System (ADS)

    Erbert, Goetz; Baerwolff, Arthur; Sebastian, Juergen; Tomm, Jens

    This review presents the basic ideas and some examples of the chip technology of high-power diode lasers ( λ= 650,-1060,) in connection with the achievements of mounted single-stripe emitters in recent years.In the first section the optimization of the epitaxial layer structure for a low facet load and high conversion efficiency is discussed. The so-called broadened waveguide Large Optical Cavity (LOC) concept is described and also some advantages and disadvantages of Al-free material. The next section deals with the processing steps of epitaxial wafers to make single emitters and bars. Several possibilities to realize contact windows (implantation, insulators, and wet chemical oxidation) and laser mirrors are presented. The impact of heating in the CW regime and some aspects of reliability are the following topics. The calculation of thermal distributions in diode lasers, which shows the need for sophisticated mounting, will be given. In the last part the current state-of-the-art of single-stripe emitters will be reviewed.

  9. High-power thulium fiber laser ablation of the canine prostate

    NASA Astrophysics Data System (ADS)

    Fried, Nathaniel M.; Murray, Keith E.

    2005-04-01

    The Thulium fiber laser may have several advantages over current urology lasers, including smaller size, more efficient operation, improved spatial beam quality, more precise tissue incision, and operation in pulsed or continuous-wave modes. However, previous laser-tissue interaction studies utilizing the Thulium fiber laser have been limited to laser powers of less than 5 W. This study describes high-power Thulium fiber laser vaporization of the canine prostate, ex vivo. A continuous-wave, 110-watt Thulium fiber laser operating at a wavelength of 1.91 mm, delivered 88.5 +/- 2.3 W of power through a 600-mm-core silica fiber for non-contact vaporization of canine prostates (n=6). The Thulium fiber laser vaporized prostate tissue at a rate of 0.83 +/- 0.11 g/min. The thermal coagulation zone measured 500-2000 mm. The high-power Thulium fiber laser is capable of rapid vaporization and coagulation of the prostate, ex vivo. In vivo animal studies are currently in development for evaluation of the Thulium fiber laser for prostate vaporization and potential treatment of benign prostate hyperplasia.

  10. Generation of doughnut spot for high-power laser technologies using refractive beam shaping

    NASA Astrophysics Data System (ADS)

    Laskin, Alexander; Laskin, Vadim; Ostrun, Aleksei

    2015-03-01

    Doughnut and inverse-Gauss intensity distributions of laser spot are required in laser technologies like welding, cladding where high power fiber coupled diode or solid-state lasers as well as fiber lasers are used. In comparison to Gaussian and flat-top distributions the doughnut and inverse-Gauss profiles provide more uniform temperature distribution on a work piece - this improves the technology, increase stability of processes and efficiency of using the laser energy, reduce the heat affected zone (HAZ). This type of beam shaping has become frequently asked by users of multimode lasers, especially multimode fiber coupled diode lasers. Refractive field mapping beam shapers are applied as one of solutions for the task to manipulate intensity distribution of multimode lasers. The operation principle of these devices presumes almost lossless transformation of laser beam irradiance from Gaussian to flat-top, doughnut or inverse-Gauss through controlled wavefront manipulation inside a beam shaper using lenses with smooth optical surfaces. This paper will describe some design basics of refractive beam shapers of the field mapping type and optical layouts of their applying with high-power multimode lasers. Examples of real implementations and experimental results will be presented as well.

  11. High-power AlGaAs channeled substrate planar diode lasers for spaceborne communications

    NASA Technical Reports Server (NTRS)

    Connolly, J. C.; Goldstein, B.; Pultz, G. N.; Slavin, S. E.; Carlin, D. B.; Ettenberg, M.

    1988-01-01

    A high power channeled substrate planar AlGaAs diode laser with an emission wavelength of 8600 to 8800 A was developed. The optoelectronic behavior (power current, single spatial and spectral behavior, far field characteristics, modulation, and astigmatism properties) and results of computer modeling studies on the performance of the laser are discussed. Lifetest data on these devices at high output power levels is also included. In addition, a new type of channeled substrate planar laser utilizing a Bragg grating to stabilize the longitudinal mode was demonstrated. The fabrication procedures and optoelectronic properties of this new diode laser are described.

  12. Progress in single quantum well structures for high power laser device applications

    NASA Astrophysics Data System (ADS)

    Waters, R. G.; Tihanyi, P. L.; Hill, D. S.; Soltz, B. A.

    1988-01-01

    Recent advances made toward performance optimization of (Al)GaAs quantum well lasers are described. Topics covered include: laser reliability for broad-area devices emitting less than 300 mW and its relation to the epitaxial structure and operating current density; parametric crystal growth studies and the implications for device efficiency; realization of 57 percent cw power conversion efficiency in an oxide-defined device; progress in dry-etching technology including array fabrication and development of device-quality laser facets suitable for integration. Finally, work in the high-power regime is discussed. This includes broad-area, single-emitter lasers emitting 6W cw.

  13. DIAL monitoring of atmospheric climate-determining gases employing high-power pulsed laser diodes

    NASA Astrophysics Data System (ADS)

    Penchev, Stoyan P.; Naboko, Sergei V.; Naboko, Vassily N.; Pencheva, Vasilka H.; Donchev, T.; Pavlov, Lyubomir Y.; Simeonov, P.

    2003-11-01

    High-power pulsed laser diodes are employed for determining atmospheric humidity and methane. The proposed DIAL method optimizes the spectral properties of laser radiation within the molecular absorption bands of 0.86 - 0.9 μm of these major greenhouse gases. The explicit absorption spectrum is explored by computational convolution method based on reference data on spectral linestrengths modulated by the characteristic broad laser line of the selected laser diodes. The lidar scheme is ultimately compact, of low-energy consumption and suggests a large potential for ecological monitoring.

  14. Character and structure of oxide ceramics synthesis using a high-power CO2 laser

    NASA Astrophysics Data System (ADS)

    Zheng, Qiguang; Wang, Tao; Tao, Xingzhi; Gu, Jianhui; Xu, Desheng; Li, Zaiguang; Zheng, Fang; Li, Xingjiao

    1996-09-01

    The oxide ceramic powders have been sintered with a high power CW CO2 laser. The products of Al2(WO3)2 as a new compound which can not be found in 2D equilibrium phase diagrams. The hardness of laser synthesized materials are shown to be higher than that produced with the general sintering method in furnace. The microstructure and character is of oxide ceramics synthesis using CW CO2 laser have investigated. We found that the products of laser sintering Al2O3-50mol percent WO3 have the electrical resistance characters varied linearly of negative temperature coefficient from the room temperature to 220 degrees C.

  15. Two-photon fluorescence bioimaging with an all-semiconductor laser picosecond pulse source.

    PubMed

    Kuramoto, Masaru; Kitajima, Nobuyoshi; Guo, Hengchang; Furushima, Yuji; Ikeda, Masao; Yokoyama, Hiroyuki

    2007-09-15

    We have demonstrated successful two-photon excitation fluorescence bioimaging using a high-power pulsed all-semiconductor laser. Toward this purpose, we developed a pulsed light source consisting of a mode-locked laser diode and a two-stage diode laser amplifier. This pulsed light source provided optical pulses of 5 ps duration and having a maximum peak power of over 100 W at a wavelength of 800 nm and a repetition frequency of 500 MHz.

  16. Thermal tuning of volume Bragg gratings for spectral beam combining of high-power fiber lasers.

    PubMed

    Drachenberg, Derrek R; Andrusyak, Oleksiy; Venus, George; Smirnov, Vadim; Glebov, Leonid B

    2014-02-20

    High-radiance lasers are desired for many applications in defense and manufacturing. Spectral beam combining (SBC) by volume Bragg gratings (VBGs) is a very promising method for high-radiance lasers that need to achieve 100 kW level power. Laser-induced heating of VBGs under high-power radiation presents a challenge for maintaining Bragg resonance at various power levels without mechanical realignment. A novel thermal tuning technique and apparatus is presented that enables maintaining peak efficiency operation of the SBC system at various power levels without any mechanical adjustment. The method is demonstrated by combining two high-power ytterbium fiber lasers with high efficiency from low power to full combined power of 300 W (1.5 kW effective power), while maintaining peak combining efficiency within 0.5%.

  17. High-efficiency high-power cw solid state lasers for material processing

    NASA Astrophysics Data System (ADS)

    Weber, Heinz P.; Graf, Thomas; Weber, Rudolf

    2000-02-01

    The maximum power range over which a laser resonator supports stable oscillation is mainly determined by the material constants of the active medium and by the cooling schemes. The power range for stable fundamental-mode operation can be shifted to higher powers with special cavity design and intra-cavity optics but the width of the stability range will be unaffected and can be enlarged only with adaptive optics. We present investigations on a multi- rod laser cavity and a high-power side-pumped laser system. In order to obtain constant beam parameters with varying power we prose a novel self-adaptive method to compensate for the power-dependent thermal lenses in high-power lasers.

  18. High power 808 nm vertical cavity surface emitting laser with multi-ring-shaped-aperture structure

    NASA Astrophysics Data System (ADS)

    Hao, Y. Q.; Shang, C. Y.; Feng, Y.; Yan, C. L.; Zhao, Y. J.; Wang, Y. X.; Wang, X. H.; Liu, G. J.

    2011-02-01

    The carrier conglomeration effect has been one of the main problems in developing electrically pumped high power vertical cavity surface emitting laser (VCSEL) with large aperture. We demonstrate a high power 808 nm VCSEL with multi-ring-shaped-aperture (MRSA) to weaken the carrier conglomeration effect. Compared with typical VCSEL with single large aperture (SLA), the 300-μm-diameter VCSEL with MRSA has more uniform near field and far field patterns. Moreover, MRSA laser exhibits maximal CW light output power 0.3 W which is about 3 times that of SLA laser. And the maximal wall-plug efficiency of 17.4% is achieved, higher than that of SLA laser by 10%.

  19. Semiconductor laser gyro with optical frequency dithering

    SciTech Connect

    Prokof'eva, L P; Sakharov, V K; Shcherbakov, V V

    2014-04-28

    The semiconductor laser gyro is described, in which the optical frequency dithering implemented by intracavity phase modulation suppresses the frequency lock-in and provides the interference of multimode radiation. The sensitivity of the device amounted to 10–20 deg h{sup -1}. (laser gyroscopes)

  20. Semiconductor laser with multiple lasing wavelengths

    DOEpatents

    Fischer, Arthur J.; Choquette, Kent D.; Chow, Weng W.

    2003-07-29

    A new class of multi-terminal vertical-cavity semiconductor laser components has been developed. These multi-terminal laser components can be switched, either electrically or optically, between distinct lasing wavelengths, or can be made to lase simultaneously at multiple wavelengths.

  1. High-power and highly efficient diode-cladding-pumped Ho3+-doped silica fiber lasers.

    PubMed

    Jackson, Stuart D; Bugge, Frank; Erbert, Götz

    2007-11-15

    We demonstrate high-power operation from a singly Ho3+-doped silica fiber laser that is cladding pumped directly with diode lasers operating at 1150 nm. Internal slope efficiencies approaching the Stokes limit were produced, and the maximum output power was 2.2W. This result was achieved using a low Ho3+-ion concentration and La3+-ion codoping, which together limit the transfer of energy between excited Ho3+ ions.

  2. Coherent addition of high power laser diode array with a V-shape external Talbot cavity.

    PubMed

    Liu, B; Liu, Y; Braiman, Y

    2008-12-08

    We designed a V-shape external Talbot cavity for a broad-area laser diode array and demonstrated coherent laser beam combining at high power with narrow spectral linewidth. The V-shape external Talbot cavity provides good mode-discrimination and does not require a spatial filter. A multi-lobe far-field profile generated by a low filling-factor phase-locked array is confirmed by our numerical simulation.

  3. Study of the high power laser-metal interactions in the gaseous atmospheres

    NASA Astrophysics Data System (ADS)

    Lugomer, Stjepan; Bitelli, G.; Stipancic, M.; Jovic, F.

    1994-08-01

    The tantalum and titanium plates were treated by pulsed, high power CO2 laser in the pressurized atmospheres of N2 and O2. Studies performed by the optical microscopy, microhardness measurements, and the auger electron spectroscopy revealed: (1) topographic modification of the surface caused by the temperature field; (2) metal hardening, caused by the laser shock; and (3) alloying/cladding, caused by the chemical reaction between the metal surface and the gaseous atmosphere.

  4. Collisionless dissociation and isotopic enrichment of SF6 using high-powered CO2 laser radiation

    NASA Technical Reports Server (NTRS)

    Gower, M. C.; Billman, K. W.

    1977-01-01

    Dissociation of S-32F6 and the resultant isotopic enrichment of S-34F6 using high-powered CO2 laser radiation has been studied with higher experimental sensitivity than previously reported. Enrichment factors have been measured as a function of laser pulse number, wavelength, energy and time duration. A geometry independent dissociation cross section is introduced and measured values are presented. Threshold energy densities, below which no dissociation was observed, were also determined.

  5. Studies of basic mechanisms in high pressure gases: Applications to high efficiency high power lasers

    NASA Technical Reports Server (NTRS)

    Verdeyen, J. T.; Cherrington, B. E.; Leslie, S. G.; Millar, W. S.; Edwards, B. E.

    1976-01-01

    A high power pulsed dye laser was used to optically excite high pressure cesium-xenon mixtures and the resulting measurements are presented. A microwave discharge in rubidium at relatively high xenon pressure was achieved. Preliminary studies of cadium-rare gas mixtures are discussed and a detailed description of the entire experimental apparatus is given.

  6. Diffractive optics development for application on high-power solid state lasers

    NASA Astrophysics Data System (ADS)

    Bett, Thomas H.; Stevenson, R. M.; Taghizadeh, Mohammad R.; Miller, J. M.; Lightbody, Malcolm T. M.; Blair, Paul; Layet, Ben; Watson, Norman F.; Barton, Ian M.; Robb, Graeme; McMonagle, J.

    1995-12-01

    This paper reports on the development of several diffractive optical elements (DOE) to fulfill applications on high power Nd glass laser systems. The measured performance for those components realized is discussed. These are focusing beam samplers, beam shapers, and harmonic separation filters (HSF). Designs of more demanding components operating in the resonance domain are also presented. These are linear polarizing elements and beam deflectors.

  7. Status of the high power free electron laser using the race-track microtron-recuperator

    NASA Astrophysics Data System (ADS)

    Vinokurov, N. A.; Gavrilov, N. G.; Gorniker, E. I.; Kulipanov, G. N.; Kuptsov, I. V.; Kurkin, G. Ya.; Erg, G. I.; Levashov, Yu. I.; Oreshkov, A. D.; Petrov, S. P.; Petrov, V. M.; Pinayev, I. V.; Popik, V. M.; Sedlyarov, I. K.; Shaftan, T. V.; Skrinsky, A. N.; Sokolov, A. S.; Veshcherevich, V. G.; Vobly, P. D.

    1996-02-01

    The high power infrared free electron laser is under construction at the Novosibirsk Scientific Centre. The goal of this project is to provide a user facility for Siberian Centre of Photochemical Researches. The features of the installation and its status are described.

  8. Computer simulation of effect of conditions on discharge-excited high power gas flow CO laser

    NASA Astrophysics Data System (ADS)

    Ochiai, Ryo; Iyoda, Mitsuhiro; Taniwaki, Manabu; Sato, Shunichi

    2017-01-01

    The authors have developed the computer simulation codes to analyze the effect of conditions on the performances of discharge excited high power gas flow CO laser. The six be analyzed. The simulation code described and executed by Macintosh computers consists of some modules to calculate the kinetic processes. The detailed conditions, kinetic processes, results and discussions are described in this paper below.

  9. High Power Gas-Discharge and Laser-Plasma Based EUV Sources

    DTIC Science & Technology

    2002-01-24

    of a pulsed high power laser and V. Borisov, A. Ivanov, 0. Khristoforov and A. Vinokhodov from State Research Center of Russian Federation, Troitsk...U. Stamm, D. Basting, 0. Khristoforov , A. Vinokhodov, V. Borisov, ,,Compact ZLpinch EUV source for photolithography", Proc. SPIE 4343, 615 - 620

  10. All-optical Q-switching limiter for high-power gigahertz modelocked diode-pumped solid-state lasers.

    PubMed

    Klenner, Alexander; Keller, Ursula

    2015-04-06

    Passively modelocked diode-pumped solid-state lasers (DPSSLs) with pulse repetition rates in the gigahertz regime suffer from an increased tendency for Q-switching instabilities. Low saturation fluence intracavity saturable absorbers - such as the semiconductor saturable absorber mirrors (SESAMs) - can solve this problem up to a certain average output power limited by the onset of SESAM damage. Here we present a passive stabilization mechanism, an all-optical Q-switching limiter, to reduce the impact of Q-switching instabilities and increase the potential output power of SESAM modelocked lasers in the gigahertz regime. With a proper cavity design a Kerr lens induced negative saturable absorber clamps the maximum fluence on the SESAM and therefore limits the onset of Q-switching instabilities. No critical cavity alignment is required because this Q-switching limiter acts well within the cavity stability regime. Using a proper cavity design, a high-power diode-pumped Yb:CALGO solid-state laser generated sub-100 fs pulses with an average output power of 4.1 W at a pulse repetition rate of 5 GHz. With a pulse duration of 96 fs we can achieve a peak power as high as 7.5 kW directly from the SESAM modelocked laser oscillator without any further external pulse amplification and/or pulse compression. We present a quantitative analysis of this Kerr lens induced Q-switching limiter and its impact on modelocked operation. Our work provides a route to compact high-power multi-gigahertz frequency combs based on SESAM modelocked diode-pumped solid-state lasers without any additional external amplification or pulse compression.

  11. Injection locking of a low cost high power laser diode at 461 nm.

    PubMed

    Pagett, C J H; Moriya, P H; Celistrino Teixeira, R; Shiozaki, R F; Hemmerling, M; Courteille, Ph W

    2016-05-01

    Stable laser sources at 461 nm are important for optical cooling of strontium atoms. In most existing experiments, this wavelength is obtained by frequency doubling infrared lasers, since blue laser diodes either have low power or large emission bandwidths. Here, we show that injecting less than 10 mW of monomode laser radiation into a blue multimode 500 mW high power laser diode is capable of slaving at least 50% of the power to the desired frequency. We verify the emission bandwidth reduction by saturation spectroscopy on a strontium gas cell and by direct beating of the slave with the master laser. We also demonstrate that the laser can efficiently be used within the Zeeman slower for optical cooling of a strontium atomic beam.

  12. Injection locking of a low cost high power laser diode at 461 nm

    NASA Astrophysics Data System (ADS)

    Pagett, C. J. H.; Moriya, P. H.; Celistrino Teixeira, R.; Shiozaki, R. F.; Hemmerling, M.; Courteille, Ph. W.

    2016-05-01

    Stable laser sources at 461 nm are important for optical cooling of strontium atoms. In most existing experiments, this wavelength is obtained by frequency doubling infrared lasers, since blue laser diodes either have low power or large emission bandwidths. Here, we show that injecting less than 10 mW of monomode laser radiation into a blue multimode 500 mW high power laser diode is capable of slaving at least 50% of the power to the desired frequency. We verify the emission bandwidth reduction by saturation spectroscopy on a strontium gas cell and by direct beating of the slave with the master laser. We also demonstrate that the laser can efficiently be used within the Zeeman slower for optical cooling of a strontium atomic beam.

  13. 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.

  14. Reviews of a Diode-Pumped Alkali Laser (DPAL): a potential high powered light source

    NASA Astrophysics Data System (ADS)

    Cai, He; Wang, You; Han, Juhong; An, Guofei; Zhang, Wei; Xue, Liangping; Wang, Hongyuan; Zhou, Jie; Gao, Ming; Jiang, Zhigang

    2015-03-01

    Diode pumped alkali vapor lasers (DPALs) were first developed by in W. F. Krupke at the beginning of the 21th century. In the recent years, DPALs have been rapidly developed because of their high Stokes efficiency, good beam quality, compact size and near-infrared emission wavelengths. The Stokes efficiency of a DPAL can achieve a miraculous level as high as 95.3% for cesium (Cs), 98.1% for rubidium (Rb), and 99.6% for potassium (K), respectively. The thermal effect of a DPAL is theoretically smaller than that of a normal diode-pumped solid-state laser (DPSSL). Additionally, generated heat of a DPAL can be removed by circulating the gases inside a sealed system. Therefore, the thermal management would be relatively simple for realization of a high-powered DPAL. In the meantime, DPALs combine the advantages of both DPSSLs and normal gas lasers but evade the disadvantages of them. Generally, the collisionally broadened cross sections of both the D1 and the D2 lines for a DPAL are much larger than those for the most conventional solid-state, fiber and gas lasers. Thus, DPALs provide an outstanding potentiality for realization of high-powered laser systems. It has been shown that a DPAL is now becoming one of the most promising candidates for simultaneously achieving good beam quality and high output power. With a lot of marvelous merits, a DPAL becomes one of the most hopeful high-powered laser sources of next generation.

  15. Performance and reliability of high power 7xx nm laser diodes

    NASA Astrophysics Data System (ADS)

    Bao, Ling; Wang, Jun; Devito, Mark; Xu, Dapeng; Grimshaw, Mike; Dong, Weimin; Guan, Xingguo; Huang, Hua; Leisher, Paul; Zhang, Shiguo; Wise, Damian; Martinsen, Robert; Haden, Jim

    2011-02-01

    High power diode lasers in 7xx-nm region, have been needed for various applications. Compared to 9xx nm lasers that have been developed extensively in the last 20 years, high power lasers at 7xx-nm region presents much more challenges for operation power, efficiency, temperature performance and reliability. This paper will present recent progresses on 7xx nm laser diodes for the above attributes. Two laser designs will be reviewed and high power diode laser performance and reliability will be presented. Single emitter devices, with 200μm wide emitting width, show up to 10W reliable operation power, with peak efficiency more than 65%. Accelerated life testing at 12A, 50°C heatsink temperature has been running for thousands of hours. High temperature performance and high COMD threshold (> 20W) will also be shown. Life-test failure modes will also be discussed. In summary, with advanced epitaxial structure design and MOCVD process, critical facet passivation and advanced heatsink and bonding technology, 7xx-8xx nm devices have been demonstrated with high performance and reliability similar to those of 9xx nm devices.

  16. Atmospheric propagation of high power laser radiation at different weather conditions

    NASA Astrophysics Data System (ADS)

    Pargmann, Carsten; Hall, Thomas; Duschek, Frank; Handke, Jürgen

    2016-05-01

    Applications based on the propagation of high power laser radiation through the atmosphere are limited in range and effect, due to weather dependent beam wandering, beam deterioration, and scattering processes. Security and defense related application examples are countermeasures against hostile projectiles and the powering of satellites and aircrafts. For an examination of the correlations between weather condition and laser beam characteristics DLR operates at Lampoldshausen a 130 m long free transmission laser test range. Sensors around this test range continuously monitor turbulence strength, visibility, precipitation, temperature, and wind speed. High power laser radiation is obtained by a TruDisk 6001 disk laser (Trumpf company) yielding a maximum output power of 6 kW at a wavelength of 1030 nm. The laser beam is expanded to 180 mm and focused along the beam path. Power and intensity distribution are measured before and after propagation, providing information about the atmospheric transmission and alterations of diameter and position of the laser beam. Backscattered laser light is acquired by a photo receiver. As a result, measurements performed at different weather conditions show a couple of correlations to the characteristics of the laser beam. The experimental results are compared to a numerical analysis. The calculations are based on the Maxwell wave equation in Fresnel approximation. The turbulence is considered by the introduction of phase screens and the "von Karman" spectrum.

  17. Scalable high-power and high-brightness fiber coupled diode laser devices

    NASA Astrophysics Data System (ADS)

    Köhler, Bernd; Ahlert, Sandra; Bayer, Andreas; Kissel, Heiko; Müntz, Holger; Noeske, Axel; Rotter, Karsten; Segref, Armin; Stoiber, Michael; Unger, Andreas; Wolf, Paul; Biesenbach, Jens

    2012-03-01

    The demand for high-power and high-brightness fiber coupled diode laser devices is mainly driven by applications for solid-state laser pumping and materials processing. The ongoing power scaling of fiber lasers requires scalable fibercoupled diode laser devices with increased power and brightness. For applications in materials processing multi-kW output power with beam quality of about 30 mm x mrad is needed. We have developed a modular diode laser concept combining high power, high brightness, wavelength stabilization and optionally low weight, which becomes more and more important for a multitude of applications. In particular the defense technology requires robust but lightweight high-power diode laser sources in combination with high brightness. Heart of the concept is a specially tailored diode laser bar, whose epitaxial and lateral structure is designed such that only standard fast- and slow-axis collimator lenses in combination with appropriate focusing optics are required to couple the beam into a fiber with a core diameter of 200 μm and a numerical aperture (NA) of 0.22. The spectral quality, which is an important issue especially for fiber laser pump sources, is ensured by means of Volume Holographic Gratings (VHG) for wavelength stabilization. In this paper we present a detailed characterization of different diode laser sources based on the scalable modular concept. The optical output power is scaled from 180 W coupled into a 100 μm NA 0.22 fiber up to 1.7 kW coupled into a 400 μm NA 0.22 fiber. In addition we present a lightweight laser unit with an output power of more than 300 W for a 200 μm NA 0.22 fiber with a weight vs. power ratio of only 0.9 kg/kW.

  18. Compact high-brightness and high-power diode laser source for materials processing

    NASA Astrophysics Data System (ADS)

    Treusch, Hans-Georg; Harrison, Jim; Morris, Robert; Powers, Jeff J.; Brown, Dennis; Martin, Joey

    2000-03-01

    A compact, reliable semiconductor laser source for materials processing, medical and pumping applications is described. This industrial laser source relies on a combination of technologies that have matured in recent years. In particular, effective means of stacking and imaging monolithic semiconductor laser arrays (a.k.a., bars), together with advances in the design and manufacture of the bars, have enabled the production of robust sources at market-competitive costs. Semiconductor lasers are presently the only lasers known that combine an efficiency of about 50% with compact size and high reliability. Currently the maximum demonstrated output power of a 10-mm-wide semiconductor laser bar exceeds the 260 W level when assembled on an actively cooled heat sink. (The rated power is in the range of 50 to 100 W.) Power levels in the kW range can be reached by stacking such devices. The requirements on the stacking technique and the optic assembly to achieve high brightness are discussed. Optics for beam collimation in fast and slow axis are compared. An example for an optical setup to use in materials processing will be shown. Spot sizes as low as 0.4 mm X 1.2 mm at a numerical aperture of 0.3 and output power of 1 kW are demonstrated. This results in a power density of more than 200 kW/cm2. A setup for further increase in brightness by wavelength and polarization coupling will be outlined. For incoherent coupling of multiple beams into a single core optical fiber, a sophisticated beam-shaping device is needed to homogenize the beam quality of stacked semiconductor lasers.

  19. Semiconductor Laser Tracking Frequency Distance Gauge

    NASA Technical Reports Server (NTRS)

    Phillips, James D.; Reasenberg, Robert D.

    2009-01-01

    Advanced astronomical missions with greatly enhanced resolution and physics missions of unprecedented accuracy will require a spaceworthy laser distance gauge of substantially improved performance. The Tracking Frequency Gauge (TFG) uses a single beam, locking a laser to the measurement interferometer. We have demonstrated this technique with pm (10(exp -12) m) performance. We report on the version we are now developing based on space-qualifiable, fiber-coupled distributed-feedback semiconductor lasers.

  20. Photoconductive Semiconductor Switch Technology for Short Pulse Electromagnetics and Lasers

    SciTech Connect

    Denison, Gary J.; Helgeson, Wesley D.; Hjalmarson, Harold P.; Loubriel, Guillermo M.; Mar, Alan; O'Malley, Martin W.; Zutavern, Fred J.

    1999-08-05

    High gain photoconductive semiconductor switches (PCSS) are being used to produce high power electromagnetic pulses foc (1) compact, repetitive accelerators, (2) ultra-wide band impulse sources, (3) precision gas switch triggers, (4) optically-activated firesets, and (5) high power optical pulse generation and control. High power, sub-nanosecond optical pulses are used for active optical sensors such as compact optical radars and range-gated hallistic imaging systems. Following a brief introduction to high gain PCSS and its general applications, this paper will focus on PCSS for optical pulse generation and control. PCSS technology can be employed in three distinct approaches to optical pulse generation and control: (1) short pulse carrier injection to induce gain-switching in semiconductor lasers, (2) electro-optical Q-switching, and (3) optically activated Q-switching. The most significant PCSS issues for these applications are switch rise time, jitter, and longevity. This paper will describe both the requirements of these applications and the most recent results from PCSS technology. Experiments to understand and expand the limitations of high gain PCSS will also be described.

  1. Homogenization of high power diode laser beams for pumping and direct applications

    NASA Astrophysics Data System (ADS)

    Traub, Martin; Hoffmann, Hans-Dieter; Plum, Heinz-Dieter; Wieching, Kristin; Loosen, Peter; Poprawe, Reinhart

    2006-02-01

    High power diode lasers have become an established source for numerous direct applications like metal hardening and polymer welding due to their high efficiency, small size, low cost and high reliability. These laser sources are also used for efficient pumping of solid state lasers as Nd:YAG lasers. To increase the output power of diode lasers up to several kilowatts, the emitters are scaled laterally by forming a diode laser bar and vertically by forming a diode laser stack. For most applications like hardening and illumination, though, the undefined far field distribution of most commercially available high power diode laser stacks states a major drawback of these devices. As single emitters and bars can fail during their lifetime, the near field distribution does not remain constant. To overcome these problems, the intensity distribution can be homogenized by a waveguide or by microoptic devices. The waveguide segments the far field distribution by several total internal reflections, and these segments are overlaid at the waveguide's exit surface. By the microoptic device, the near field is divided into beamlets which are overlaid by a field lens. Both approaches are presented, and realized systems are described.

  2. New horizons for high-power lasers: applications in civil engineering

    NASA Astrophysics Data System (ADS)

    Wignarajah, Sivakumaran

    2000-01-01

    Although material processing with high power lasers has found widespread use in a variety of industries such as the automotive industry, electrical and electronics industries, aerospace industry etc., civil engineering construction is one field that has lagged behind in the use of lasers for material processing. This is in spite of the fact that a large variety of materials including ceramics, metals and plastics are used in very large quantities for civil engineering construction. The main reasons for the delay in the adopting of laser for processing construction material seem to be the high costs involved and the lack of sufficient power for processing heavy and thick materials. However, with the advent of more compact lasers with higher powers, higher efficiencies and lower photon costs, greater interest has been shown in recent years in the possible uses of high power lasers for material processing in the construction industry. The author traces some of the past work carried out both in Japan and abroad on the use of lasers in civil engineering, specially with respect to the processing of inorganic material such as concrete, natural stones, tiles and rocks. Recent developments regarding laser decontamination and laser assisted rock excavation are also introduced.

  3. Forward voltage short-pulse technique for measuring high power laser array junction temperature

    NASA Technical Reports Server (NTRS)

    Meadows, Byron L. (Inventor); Amzajerdian, Frazin (Inventor); Barnes, Bruce W. (Inventor); Baker, Nathaniel R. (Inventor)

    2012-01-01

    The present invention relates to a method of measuring the temperature of the P-N junction within the light-emitting region of a quasi-continuous-wave or pulsed semiconductor laser diode device. A series of relatively short and low current monitor pulses are applied to the laser diode in the period between the main drive current pulses necessary to cause the semiconductor to lase. At the sufficiently low current level of the monitor pulses, the laser diode device does not lase and behaves similar to an electronic diode. The voltage across the laser diode resulting from each of these low current monitor pulses is measured with a high degree of precision. The junction temperature is then determined from the measured junction voltage using their known linear relationship.

  4. Finite element analysis of space debris removal by high-power lasers

    NASA Astrophysics Data System (ADS)

    Xue, Li; Jiang, Guanlei; Yu, Shuang; Li, Ming

    2015-08-01

    With the development of space station technologies, irradiation of space debris by space-based high-power lasers, can locally generate high-temperature plasmas and micro momentum, which may achieve the removal of debris through tracking down. Considered typical square-shaped space debris of material Ti with 5cm×5cm size, whose thermal conductivity, density, specific heat capacity and emissivity are 7.62W/(m·°C), 4500kg/m3, 0.52J/(kg·°C) and 0.3,respectively, based on the finite element analysis of ANSYS, each irradiation of space debris by high-power lasers with power density 106W/m2 and weapons-grade lasers with power density 3000W/m2 are simulated under space environment, and the temperature curves due to laser thermal irradiation are obtained and compared. Results show only 2s is needed for high-power lasers to make the debris temperature reach to about 10000K, which is the threshold temperature for plasmas-state conversion. While for weapons-grade lasers, it is 13min needed. Using two line elements (TLE), and combined with the coordinate transformation from celestial coordinate system to site coordinate system, the visible period of space debris is calculated as 5-10min. That is, in order to remove space debris by laser plasmas, the laser power density should be further improved. The article provides an intuitive and visual feasibility analysis method of space debris removal, and the debris material and shape, laser power density and spot characteristics are adjustable. This finite element analysis method is low-cost, repeatable and adaptable, which has an engineering-prospective applications.

  5. Watt-class high-power, high-beam-quality photonic-crystal lasers

    NASA Astrophysics Data System (ADS)

    Hirose, Kazuyoshi; Liang, Yong; Kurosaka, Yoshitaka; Watanabe, Akiyoshi; Sugiyama, Takahiro; Noda, Susumu

    2014-05-01

    The applications of surface-emitting lasers, in particular vertical-cavity surface-emitting lasers (VCSELs), are currently being extended to various low-power fields including communications and interconnections. However, the fundamental difficulties in increasing their output power by more than several milliwatts while maintaining single-mode operation prevent their application in high-power fields such as material processing, laser medicine and nonlinear optics, despite their advantageous properties of circular beams, the absence of catastrophic optical damage, and their suitability for two-dimensional integration. Here, we demonstrate watt-class high-power, single-mode operation by a two-dimensional photonic-crystal surface-emitting laser under room-temperature, continuous-wave conditions. The two-dimensional band-edge resonant effect of a photonic crystal formed by metal-organic chemical vapour deposition enables a 1,000 times broader coherent-oscillation area, which results in a high beam quality of M2 <= 1.1, narrowing the focus spot by two orders of magnitude compared to VCSELs. Our demonstration promises to realize innovative high-power applications for surface-emitting lasers.

  6. Single-mode and high power waveguide lasers fabricated by ion-exchange.

    PubMed

    Della Valle, G; Festa, A; Sorbello, G; Ennser, K; Cassagnetes, C; Barbier, D; Taccheo, S

    2008-08-04

    We report on a single-end diode-pumped waveguide laser providing output power in excess of 20 mW with 17% slope efficiency in robust single longitudinal and transverse mode operation at 1533.5 nm. The active medium was an Er:Yb-doped waveguide only 9-mm long fabricated by Ag-Na ion-exchange in a phosphate glass. The overall cavity length including butt-coupled fiber-Bragg-grating mirrors was <60 mm. We also report on high power waveguide lasers providing more than 160 mW output power and 46% slope efficiency in multimode operation. Feasibility of high power single mode waveguide lasers based on ion-exchange technology in phosphate glasses is also experimentally investigated by using a 50-mm long active waveguide specially designed for efficient single-end pumping.

  7. Simulation of the wavefront distortion and beam quality for a high-power zigzag slab laser

    NASA Astrophysics Data System (ADS)

    Shin, Jae Sung; Cha, Yong-Ho; Cha, Byung Heon; Lee, Hyeon Cheor; Kim, Hyun Tae; Lee, Jung Hwan

    2016-12-01

    A simulation method of the beam quality for a high-power zigzag slab laser has been developed. This method can predict the wavefront distortion and beam quality for various optical arrangements and optimize the design effectively. A Nd:YAG zigzag slab laser amplifier was designed as an application. The optimized design shows a beam quality of 1.20 corresponding to the minimized wavefront distortion with a peak-to-valley of 0.568 μm and root mean square of 0.115 μm even under high-power operation with a total pump power of 14 kW. Although there are some effects other than the optical design error that incur wavefront distortions, this method can help to determine the first optical design of the zigzag slab laser without the need for many experimental studies.

  8. Perspectives for neutron and gamma spectroscopy in high power laser driven experiments at ELI-NP

    NASA Astrophysics Data System (ADS)

    Negoita, F.; Gugiu, M.; Petrascu, H.; Petrone, C.; Pietreanu, D.; Fuchs, J.; Chen, S.; Higginson, D.; Vassura, L.; Hannachi, F.; Tarisien, M.; Versteegen, M.; Antici, P.; Balabanski, D.; Balascuta, S.; Cernaianu, M.; Dancus, I.; Gales, S.; Neagu, L.; Petcu, C.; Risca, M.; Toma, M.; Turcu, E.; Ursescu, D.

    2015-02-01

    The measurement of energy spectra of neutrons and gamma rays emitted by nuclei, together with charge particles spectroscopy, are the main tools for understanding nuclear phenomena occurring also in high power laser driven experiments. However, the large number of particles emitted in a very short time, in particular the strong X-rays flash produced in laser-target interaction, impose adaptation of technique currently used in nuclear physics experiment at accelerator based facilities. These aspects are discussed (Section 1) in the context of proposed studies at high power laser system of ELI-NP. Preliminary results from two experiments performed at Titan (LLNL) and ELFIE (LULI) facilities using plastic scintillators for neutron detection (Section 2) and LaBr3(Ce) scintillators for gamma detection (Section 3) are presented demonstrating the capabilities and the limitations of the employed methods. Possible improvements of these spectroscopic methods and their proposed implementation at ELI-NP will be discussed as well in the last section.

  9. Method for beam steering compensation in an ultra-high power liquid laser

    DOEpatents

    Ault, Earl R.

    2002-01-01

    Thermally induced distortion of the optical wavefront caused by heating of the laser media by waste heat from the excitation process and absorption of laser radiation creates optical phase errors. A system generates an error signal derived from the optical phase errors. The error signal is fed back to the power supplies driving semiconductor diodes that excite the lasing liquid thereby introducing an electrically controllable wedge into the optical cavity to correct the optical phase errors.

  10. High-power thulium fiber laser Q switched with single-layer graphene.

    PubMed

    Tang, Yulong; Yu, Xuechao; Li, Xiaohui; Yan, Zhiyu; Wang, Qi Jie

    2014-02-01

    We report high-power 2 μm Tm3+ fiber lasers passively Q switched by double-piece single-layer graphene transferred onto a glass plate. Through manipulating intracavity laser beam size and increasing pump ratios, an average power of 5.2 W is directly achieved from the laser oscillator with an optical-to-optical slope efficiency of 26%. The laser pulse energy can be as high as ∼18  μJ, comparable to that from actively Q-switched fiber lasers. The narrowest pulse width is 320 ns, and the pulse repetition rate can be tuned from tens of kilohertz to 280 kHz by changing the pump power. To the best of our knowledge, this is the highest average power and pulse energy, as well as the narrowest pulse width, from graphene-based Q-switched 2 μm fiber lasers.

  11. High power high repetition rate VCSEL array side-pumped pulsed blue laser

    NASA Astrophysics Data System (ADS)

    van Leeuwen, Robert; Zhao, Pu; Chen, Tong; Xu, Bing; Watkins, Laurence; Seurin, Jean-Francois; Xu, Guoyang; Miglo, Alexander; Wang, Qing; Ghosh, Chuni

    2013-03-01

    High power, kW-class, 808 nm pump modules based on the vertical-cavity surface-emitting laser (VCSEL) technology were developed for side-pumping of solid-state lasers. Two 1.2 kW VCSEL pump modules were implemented in a dual side-pumped Q-switched Nd:YAG laser operating at 946 nm. The laser output was frequency doubled in a BBO crystal to produce pulsed blue light. With 125 μs pump pulses at a 300 Hz repetition rate 6.1 W QCW 946 nm laser power was produced. The laser power was limited by thermal lensing in the Nd:YAG rod.

  12. High-power narrow-vertical-divergence photonic band crystal laser diodes with optimized epitaxial structure

    SciTech Connect

    Liu, Lei; Qu, Hongwei; Liu, Yun; Zhang, Yejin; Zheng, Wanhua; Wang, Yufei; Qi, Aiyi

    2014-12-08

    900 nm longitudinal photonic band crystal (PBC) laser diodes with optimized epitaxial structure are fabricated. With a same calculated fundamental-mode divergence, stronger mode discrimination is achieved by a quasi-periodic index modulation in the PBC waveguide than a periodic one. Experiments show that the introduction of over 5.5 μm-thick PBC waveguide contributes to only 10% increment of the internal loss for the laser diodes. For broad area PBC lasers, output powers of 5.75 W under continuous wave test and over 10 W under quasi-continuous wave test are reported. The vertical divergence angles are 10.5° at full width at half maximum and 21.3° with 95% power content, in conformity with the simulated angles. Such device shows a prospect for high-power narrow-vertical-divergence laser emission from single diode laser and laser bar.

  13. Prototype of a high-power, high-energy industrial XeCl laser

    NASA Astrophysics Data System (ADS)

    Borisov, V. M.; Demin, A. I.; Khristoforov, O. B.

    2015-03-01

    We discuss the results of fabrication and experimental study of a high-power excimer XeCl laser for industrial applications. Compactness of the laser is achieved by the employment of a laser chamber based on a ceramic tube made of Al2O3. High laser output energy (1.5 - 2.5 J pulse-1) is obtained using a wide-aperture (up to 55 × 30 mm) volume discharge with pre-ionisation by a creeping discharge. The pre-ionisation is realised through a semitransparent electrode by the UV radiation of a creeping discharge in the form of uniform plasma sheet on a surface of a plane sapphire plate. The operating lifetime of the gas mixture amounts to ~57 × 106 pulses at a stabilised average laser power of 450 W. The results obtained demonstrate real prospects for developing a new class of excimer XeCl lasers with an average power of ~1 kW.

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

    PubMed

    Liang, Dawei; Almeida, Joana; Garcia, Dário

    2014-03-20

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

  15. High-power spectral beam combining of linearly polarized Tm:fiber lasers.

    PubMed

    Shah, Lawrence; Sims, R Andrew; Kadwani, Pankaj; Willis, Christina C C; Bradford, Joshua B; Sincore, Alex; Richardson, Martin

    2015-02-01

    To date, high-power scaling of Tm:fiber lasers has been accomplished by maximizing the power from a single fiber aperture. In this work, we investigate power scaling by spectral beam combination of three linearly polarized Tm:fiber MOPA lasers using dielectric mirrors with a steep transition from highly reflective to highly transmissive that enable a minimum wavelength separation of 6 nm between individual laser channels within the wavelength range from 2030 to 2050 nm. Maximum output power is 253 W with M(2)<2, ultimately limited by thermal lensing in the beam combining elements.

  16. Improving Reliability of High Power Quasi-CW Laser Diode Arrays Operating in Long Pulse Mode

    NASA Technical Reports Server (NTRS)

    Amzajerdian, Farzin; Meadows, Byron L.; Barnes, Bruce W.; Lockard, George E.; Singh, Upendra N.; Kavaya, Michael J.; Baker, Nathaniel R.

    2006-01-01

    Operating high power laser diode arrays in long pulse regime of about 1 msec, which is required for pumping 2-micron thulium and holmium-based lasers, greatly limits their useful lifetime. This paper describes performance of laser diode arrays operating in long pulse mode and presents experimental data of the active region temperature and pulse-to-pulse thermal cycling that are the primary cause of their premature failure and rapid degradation. This paper will then offer a viable approach for determining the optimum design and operational parameters leading to the maximum attainable lifetime.

  17. Stabilized high-power laser system for the gravitational wave detector advanced LIGO.

    PubMed

    Kwee, P; Bogan, C; Danzmann, K; Frede, M; Kim, H; King, P; Pöld, J; Puncken, O; Savage, R L; Seifert, F; Wessels, P; Winkelmann, L; Willke, B

    2012-05-07

    An ultra-stable, high-power cw Nd:YAG laser system, developed for the ground-based gravitational wave detector Advanced LIGO (Laser Interferometer Gravitational-Wave Observatory), was comprehensively characterized. Laser power, frequency, beam pointing and beam quality were simultaneously stabilized using different active and passive schemes. The output beam, the performance of the stabilization, and the cross-coupling between different stabilization feedback control loops were characterized and found to fulfill most design requirements. The employed stabilization schemes and the achieved performance are of relevance to many high-precision optical experiments.

  18. High-power CO[sub 2] laser with coaxial waveguide and diffusion cooling

    SciTech Connect

    Ehrlichmann, D.; Habich, U.; Plum, H.D. )

    1993-07-01

    A diffusion-cooled CO[sub 2] laser using a coaxial waveguide is analyzed theoretically and experimentally. The resonator extracting the laser beam consists of two annular plane mirrors enclosing the two ends of the waveguide. The beam exits through an aperture in one of these annular mirrors. The mirror tilt is shown to provide efficient beam extraction through this aperture. A theoretical resonator model based on the vector modes of propagation in a dielectric coaxial waveguide is presented. Experimental data show the feasibility of coaxial waveguide lasers and their ability to supply beams of high power and quality. Experimental data are discussed with respect to the presented theory.

  19. Characterization of mechanical shock waves in aluminum 6061-T6 using a high power laser pulse

    NASA Astrophysics Data System (ADS)

    Gonzalez Romero, J. R.; García-Torales, G.; Gómez Rosas, G.; Ocaña, J. L.; Flores, Jorge L.

    2016-09-01

    Strengthening techniques allows enhance metal physical properties. Laser shock peening (LSP) technique consist in a surface treatment which a high power laser pulse induces a compressive residual stress field through mechanical shock waves, increasing hardness, corrosion resistance, fatigue resistance. In comparison with the shot peening technique, LSP is a method that allows precision controlling the laser incidence on the surface under treatment increasing the surface quality in the surface under treatment. In this work, mechanical shock waves are induced in aluminum and measure using two different experimental approaches. First, using a PVDZ sensors and secondly, strain gauges are used. Experimental results are presented.

  20. Narrow linewidth single-mode semiconductor laser development for coherent detection lidar

    NASA Technical Reports Server (NTRS)

    Mansour, Kamjou; Ksendzov, Alexander; Menzies, Robert T.; Maker, Paul D.; Muller, Richard E.; Manfra, M. J.; Turner, George W.

    2003-01-01

    High power, tunable, single mode, narrow linewidth semiconductor lasers in the 2.05-(micro)m wavelength region are needed to develop semiconductor laser reference oscillators for optical remote sensing from Earth orbit. 2.05-I1/4m narrow linewidth monolithic distributed feedback (DFB) and distributed Bragg reflector (DBR) with the external grating ridge waveguide lasers fabricated from epitaxially grown InGaAs/InGaAsP/InP and in InGaAsSb/AlGaAsSb/GaSb heterostructures are reported.

  1. Saturation of light – current characteristics of high-power lasers (λ = 1.0 – 1.1 mm) in pulsed regime

    SciTech Connect

    Veselov, D A; Kapitonov, V A; Pikhtin, N A; Lyutetskiy, A V; Nikolaev, D N; Slipchenko, S O; Sokolova, Z N; Shamakhov, V V; Shashkin, I S; Tarasov, I S

    2014-11-30

    Semiconductor lasers based on MOVPE-grown asymmetric separate-confinement heterostructures with a broadened waveguide and emitting in the wavelength range 1.0 – 1.1 μm are studied. It is found that the intensity of spontaneous emission from the active region increases with increasing pump current above the lasing threshold and that this is caused by a growth in the concentration of charge carriers in the active region due to the modal gain enhancement needed to compensate for the growing internal optical loss at high pulsed pump currents. It is shown that the increase in the internal optical loss with increasing pulsed pump current is one of the main reasons for saturation of the light – current characteristics of high-power semiconductor lasers. (lasers)

  2. Thermal investigation on high power dfb broad area lasers at 975 nm, with 60% efficiency

    NASA Astrophysics Data System (ADS)

    Mostallino, R.; Garcia, M.; Deshayes, Y.; Larrue, A.; Robert, Y.; Vinet, E.; Bechou, L.; Lecomte, M.; Parillaud, O.; Krakowski, M.

    2016-03-01

    The demand of high power diode lasers in the range of 910-980nm is regularly growing. This kind of device for many applications, such as fiber laser pumping [1], material processing [1], solid-state laser pumping [1], defense and medical/dental. The key role of this device lies in the efficiency (𝜂𝐸) of converting input electrical power into output optical power. The high value of 𝜂𝐸 allows high power level and reduces the need in heat dissipation. The requirement of wavelength stabilization with temperature is more obvious in the case of multimode 975nm diode lasers used for pumping Yb, Er and Yb/Er co-doped solid-state lasers, due to the narrow absorption line close to this wavelength. Such spectral width property (<1 nm), combined with wavelength thermal stabilization (0.07 𝑛𝑚 • °𝐶-1), provided by a uniform distributed feedback grating (DFB) introduced by etching and re-growth process techniques, is achievable in high power diode lasers using optical feedback. This paper reports on the development of the diode laser structure and the process techniques required to write the gratings taking into account of the thermal dissipation and optical performances. Performances are particularly determined in terms of experimental electro-optical characterizations. One of the main objectives is to determine the thermal resistance of the complete assembly to ensure the mastering of the diode laser temperature for operating condition. The classical approach to determine junction temperature is based on the infrared thermal camera, the spectral measurement and the pulse electrical method. In our case, we base our measurement on the spectral measurement but this approach is not well adapted to the high power diodes laser studied. We develop a new measurement based on the pulse electrical method and using the T3STERequipment. This method is well known for electronic devices and LEDs but is weakly developed for the high

  3. Laser Assisted Semiconductor Device Processing

    DTIC Science & Technology

    1980-11-30

    In strongly absorbing semiconductors, the dominant absorption mechanism at frequencies higher than the bandgap frequency is interband transitions. The...current). The solution for miconductors. In strongly absorbing semiconductors, the n(x,t ) is a closed-form expression consisting of complemen- dominant 0...representative profles are shown in Fis. $-12. o -- For Nd: YAG in silicon. E, _0.99hv and the profiks are therefore and-gap recombination dominated

  4. The use of a high-power laser on swine mitral valve chordae tendineae.

    PubMed

    Pinto, Nathali Cordeiro; Chavantes, M Cristina; Zezell, Denise; Deana, Alessandro; Benetti, Carolina; Marcos, Rodrigo Labat; Lopes, Luciana Almeida; Martins, Rodrigo A B Lopes; Aiello, Vera Demarchi; Jatene, Fabio Biscegli; Pomerantzeff, Pablo M A

    2016-08-01

    Worldwide, rheumatic fever remains a significant cause of mitral valve insufficiency. It is responsible for approximately 90 % of early childhood valvular surgeries in Brazil. Elongated or flail chordae are frequently responsible and require surgical correction. The purpose of this study was to analyze and compare the histological tissues of the mitral valve chordae and the mechanical resistance generated by the chordae, both with and without the application of a high-power laser. Twenty normal porcine mitral valve chordae were measured and divided randomly into the following two groups: control group (not subjected to a high-power laser) and laser group (subjected to photonic irradiation). Laser surgery was performed under controlled conditions, using following parameters: λ = 980-nm wavelength, power = 3 W, and energy = 60 J. A mechanical test machine was used in combination with a subsequent histological study to measure chordae tensile properties. A histological analysis demonstrated a typical collagen bundle arrangement in the control group; however, under a particular reached temperature range (48), the collagen bundles assumed different arrangements in the laser group. Significant reductions in the chordae tendineae lengths and changes in their resistance in the laser group were observed, as these chordae exhibited less rigid fibers. The chordae tendineae of normal porcine valves subjected to a high-power laser exhibited its length reduction and less stiffness compared to the control group. A histological analysis of the laser treatment specimens demonstrated differences in collagen bundle spatial organization, following slight changes into tissue temperature.

  5. Wavefront control of high power laser beams for the National Ignition Facility (NIF)

    SciTech Connect

    Bliss, E; Feldman, M; Grey, A; Koch, J; Lund, L; Sacks, R; Smith, D; Stolz, C; Van Atta, L; Winters, S; Woods, B; Zacharias, R

    1999-09-22

    The use of lasers as the driver for inertial confinement fusion and weapons physics experiments is based on their ability to produce high-energy short pulses in a beam with low divergence. Indeed, the focus ability of high quality laser beams far exceeds alternate technologies and is a major factor in the rationale for building high power lasers for such applications. The National Ignition Facility (NIF) is a large, 192-beam, high-power laser facility under construction at the Lawrence Livermore National Laboratory for fusion and weapons physics experiments. Its uncorrected minimum focal spot size is limited by laser system aberrations. The NIF includes a Wavefront Control System to correct these aberrations to yield a focal spot small enough for its applications. Sources of aberrations to be corrected include prompt pump-induced distortions in the laser amplifiers, previous-shot thermal distortions, beam off-axis effects, and gravity, mounting, and coating-induced optic distortions. Aberrations from gas density variations and optic manufacturing figure errors are also partially corrected. This paper provides an overview of the NIF Wavefront Control System and describes the target spot size performance improvement it affords. It describes provisions made to accommodate the NIF's high fluence (laser beam and flashlamp), large wavefront correction range, wavefront temporal bandwidth, temperature and humidity variations, cleanliness requirements, and exception handling requirements (e.g. wavefront out-of-limits conditions).

  6. Bidirectional chaos communication between two outer semiconductor lasers coupled mutually with a central semiconductor laser.

    PubMed

    Li, Ping; Wu, Jia-Gui; Wu, Zheng-Mao; Lin, Xiao-Dong; Deng, Dao; Liu, Yu-Ran; Xia, Guang-Qiong

    2011-11-21

    Based on a linear chain composed of a central semiconductor laser and two outer semiconductor lasers, chaos synchronization and bidirectional communication between two outer lasers have been investigated under the case that the central laser and the two outer lasers are coupled mutually, whereas there exists no coupling between the two outer lasers. The simulation results show that high-quality and stable isochronal synchronization between the two outer lasers can be achieved, while the cross-correlation coefficients between the two outer lasers and the central laser are very low under proper operation condition. Based on the high performance chaos synchronization between the two outer lasers, message bidirectional transmissions of bit rates up to 20 Gbit/s can be realized through adopting a novel decoding scheme which is different from that based on chaos pass filtering effect. Furthermore, the security of bidirectional communication is also analyzed.

  7. Theory, Modeling, and Simulation of Semiconductor Lasers

    NASA Technical Reports Server (NTRS)

    Ning, Cun-Zheng; Saini, Subbash (Technical Monitor)

    1998-01-01

    Semiconductor lasers play very important roles in many areas of information technology. In this talk, I will first give an overview of semiconductor laser theory. This will be followed by a description of different models and their shortcomings in modeling and simulation. Our recent efforts in constructing a fully space and time resolved simulation model will then be described. Simulation results based on our model will be presented. Finally the effort towards a self-consistent and comprehensive simulation capability for the opto-electronics integrated circuits (OEICs) will be briefly reviewed.

  8. Studies of High Power Density, Pico-Second Rise-Time Light Activated Semiconductor Switch

    DTIC Science & Technology

    1988-12-31

    34 Proceedings of the IEEE, vol.55, pp.2192-2193, 1967. 3. McKay, K., K. McAfee, "Electron Multiplication in Silicon and Germanium ," Physical Review...Conwell, E., "Properties of Silicon and Germanium : II," Proceedings of the Institute of Radio Engineers. vol.46, pp.1281-1300, 1958. 6. Zucker, 0...light activated semiconductor switches made of silicon junction diode have been demonstrated. A novel optical delay line has been designed in sampling

  9. Comparison of ALD and IBS Al2O3 films for high power lasers

    NASA Astrophysics Data System (ADS)

    Liu, Hao; Jensen, Lars; Becker, Jürgen; Wurz, Marc Christopher; Ma, Ping; Ristau, Detlev

    2016-12-01

    Atomic layer deposition (ALD) has been widely studied in Micro-electronics due to its self-terminating property. ALD also grows film coatings with precise thickness and nodular-free structure, which are desirable properties for high power coatings. The depositing process was studied to produce uniform, stable and economic Al2O3 single layers. The layer properties relevant to high power laser industry were studied and compared with IBS Al2O3 single layers. ALD Al2O3 showed a stable growth of 0.104 nm/cycle, band gap energy of 6.5 eV and tensile stress of about 480 MPa. It also showed a low absorption at wavelength 1064 nm within several ppm, and LIDT above 30 J/cm2. These properties are superior to the reference IBS Al2O3 single layers and indicate a high versatility of ALD Al2O3 for high power coatings.

  10. High-Power Laser Pulse Recirculation for Inverse Compton Scattering-Produced Gamma-Rays

    SciTech Connect

    Jovanovic, I; Shverdin, M; Gibson, D; Brown, C

    2007-04-17

    Inverse Compton scattering of high-power laser pulses on relativistic electron bunches represents an attractive method for high-brightness, quasi-monoenergetic {gamma}-ray production. The efficiency of {gamma}-ray generation via inverse Compton scattering is severely constrained by the small Thomson scattering cross section. Furthermore, repetition rates of high-energy short-pulse lasers are poorly matched with those available from electron accelerators, resulting in low repetition rates for generated {gamma}-rays. Laser recirculation has been proposed as a method to address those limitations, but has been limited to only small pulse energies and peak powers. Here we propose and experimentally demonstrate an alternative method for laser pulse recirculation that is uniquely capable of recirculating short pulses with energies exceeding 1 J. Inverse Compton scattering of recirculated Joule-level laser pulses has a potential to produce unprecedented peak and average {gamma}-ray brightness in the next generation of sources.

  11. High-power disordered Nd:CaYAlO(4)lasers at 1.08 microm.

    PubMed

    Yu, Haohai; Xu, Xiaodong; Li, Dongzhen; Wang, Zhengping; Xu, Jun

    2010-08-01

    We demonstrate the high-power laser performance with a disordered Na:CaYAlO(4) crystal at a wavelength of about 1.08microm. Continuous-wave output power of 5.16W is achieved with a laser diode as the pump source. For the first time to our knowledge, the passively Q-switched Na:CaYAlO(4) laser is obtained with the maximum average output power of 2.39W, shortest pulse width of 5.7ns, and highest peak power of 15.47kW. By spectral analysis, the Nd:CaAlO(4) laser wavelength is centered at about 1.08microm. We propose that, by suitable tuning, the Na:CaYAlO(4) laser should be an excellent source for helium optical pumping.

  12. MOVPE growth of laser structures for high-power applications at different ambient temperatures

    NASA Astrophysics Data System (ADS)

    Bugge, F.; Crump, P.; Frevert, C.; Knigge, S.; Wenzel, H.; Erbert, G.; Weyers, M.

    2016-10-01

    Laser structures for different operating temperatures were developed. Higher temperatures need an increase in barrier height to reduce carrier leakage. Best results for an emission wavelength of ≈800 nm were obtained using an asymmetric structure containing an n-InGaP and a p-Al0.5Ga0.5As waveguide. Such structures show 10 W output power for a single laser diode and >100 W for a laser bar at 50 °C ambient temperature and also a good aging behavior. Lower operating temperatures permit lower barrier heights which results in a lower series resistance and therefore higher conversion efficiency at high power. Carrier concentration and mobility for different AlxGa1-xAs compositions were estimated in dependence on temperature. An optimized structure reached 20 W for a single laser diode and 2 kW for a laser bar in QCW mode at -70 °C.

  13. High-power cw laser bars of the 750 - 790-nm wavelength range

    SciTech Connect

    Degtyareva, N S; Kondakov, S A; Mikayelyan, G T; Gorlachuk, P V; Ladugin, M A; Marmalyuk, Aleksandr A; Ryaboshtan, Yu L; Yarotskaya, I V

    2013-06-30

    We have developed the effective design of semiconductor heterostructures, which allow one to fabricate cw laser diodes emitting in the 750 - 790-nm spectral range. The optimal conditions for fabrication of GaAsP/AlGaInP/GaAs heterostructures by MOCVD have been determined. It is shown that the use of quantum wells with a precisely defined quantity mismatch reduces the threshold current density and increases the external differential efficiency. The results of studies of characteristics of diode laser bars fabricated from these heterostructures are presented. (lasers)

  14. Research of silicon solar cells' performance after being irradiated by high power laser

    NASA Astrophysics Data System (ADS)

    Zhang, Yu; Li, Yunfei; Li, Yanjie; Zhao, Guomin; Chen, Minsun

    2016-11-01

    Compared with traditional methods of energy supply, there is a great possibility to get a more remarkable enhancement of conversion efficiency for laser power (of proper wavelength and intensity) beaming to silicon solar cells. However, it should be noticed that cells may be damaged by high power laser. Based on the background, this essay explores high-power-laser's possible damage to silicon solar cells by analyzing IV curves (obtained by IV tester) and minority-carrier lifetime (measured by open-circuit-voltage-decay method). Research shows that, for 30s irradiation, minority-carrier lifetime decreases to some extent when irradiated by laser of over 5.5W/cm2 and the higher laser power density, the more degradation. Similarly, IV curves see a downward trend under laser of over 5.5W/cm2. In addition, there is a roughly linear relationship between lifetime and the decrease amount of short circuit current. Moreover, the degradation degree has a close relation with the maximum temperature. The prolonged illumination would not bring about more serious damage if one cell had already reached an equilibrium temperature.

  15. Advances in 808nm high power diode laser bars and single emitters

    NASA Astrophysics Data System (ADS)

    Morales, J.; Lehkonen, S.; Liu, G.; Schleuning, D.; Acklin, B.

    2016-03-01

    Key applications for 780-830nm high power diode lasers include the pumping of various gas, solid state, and fiber laser media; medical and aesthetic applications including hair removal; direct diode materials processing; and computer-to-plate (CtP) printing. Many of these applications require high brightness fiber coupled beam delivery, in turn requiring high brightness optical output at the bar and chip level. Many require multiple bars per system, with aggregate powers on the order of kWs, placing a premium on high power and high power conversion efficiency. This paper presents Coherent's recent advances in the production of high power, high brightness, high efficiency bars and chips at 780-830nm. Results are presented for bars and single emitters of various geometries. Performance data is presented demonstrating peak power conversion efficiencies of 63% in CW mode. Reliability data is presented demonstrating <50k hours lifetime for products including 60W 18% fill factor and 80W 28% fill factor conduction cooled bars, and <1e9 shots lifetime for 500W QCW bars.

  16. Apply high-power fiber laser in oil/gas wells drilling

    NASA Astrophysics Data System (ADS)

    Jiang, Houman; Guo, Shaofeng; Chen, Minsun; Wang, Wenliang

    2015-05-01

    The concept of using lasers to drill through rock has been discussed in the oil and gas industries since the development of the high-power laser. To evaluate the possibility of fielding a laser drilling system, two laser-related problems have to be investigated. The first is the irradiation effects of laser upon rocks; the second is the effects in laser transmission from the source to the rock deep in the well. This transmission includes two stages: the first stage is the transmission inside a fiber, which is packaged in a cable and has about the same length with the well depth; the second stage refers to the transmission process when the laser leaves the fiber and some transforming optics and transmits to the rock surface, during which the well conditions may impose tough restrictions. In this paper, experiment results of laser irradiation upon siliceous sandstone and granite are reported, and the fiber transmission loss is simulated, considering the main absorbing or scattering mechanisms inside fiber. And the laser transmission from the fiber end to the rock surface, in my view, may impose great challenge on the laser drilling technology.

  17. Development of high-brightness high-power fiber laser pump sources

    NASA Astrophysics Data System (ADS)

    Priest, J. A.; Faircloth, Brian O.; Swint, Reuel B.; Coleman, James J.; Forbes, David V.; Zediker, Mark S.

    2004-06-01

    High power fiber lasers have strong potential for use in both commercial and military applications. Improved wall plug efficiency over Nd:YAG and CO2 lasers combined with up to a 10-fold improvement in beam quality, make fiber lasers extremely attractive for industrial applications such as welding and cutting. In military applications, fiber lasers offer a simplified logistic train, a deep magazine limited only by electric power, and a compact footprint, allowing theater defense and self-protection of combat platforms with speed of light engagement and flexible response. Commercial viability of these systems, however, is limited by the availability of compact, cost effective, and reliable diode laser pump sources in the multi-kilowatt regime. The relatively low brightness of diode laser sources has complicated the task of building high power pumps at a reasonable cost. In response to this need, Nuvonyx, Inc. in conjunction with the University of Illinois at Urbana-Champaign, has been developing a new technology for producing high power, single lateral mode devices which do not suffer form the instabilities mentioned above. The waveguide consists of a narrow section, approximately 2 μm wide, which flares to approximately 12 μm wide at the output facet. The flaring of the waveguide increases the gain volume and reduces the optical power density at the facet allowing for higher output power capability. The index guide is defined using an epitaxial process which allows the confinement of the mode to be reduced as the width of the guide expands. Thus, the mode is confined in a single mode waveguide throughout the cavity maintaining stability of the mode to the emitting facet. In November 2002, Nuvonyx, Inc. was awarded a contract with the Air Force Research Lab, Kirtland AFB, Albuquerque, NM, to transition these devices to production quality for use in high-power fiber laser pumps. Partnered with Alfalight, Inc. and the University of Illinois, we have begun initial

  18. About Losses in Pumping Generators of High-Power Electrodischarge Excimer Lasers

    NASA Astrophysics Data System (ADS)

    Ivanov, N. G.; Losev, V. F.

    2015-04-01

    Energy losses in pumping systems of discharge high-power lasers are investigated. To estimate the losses, the discharge circuit operation was modeled, and its calculation was performed using the program PSpice. Results of measurements and calculations demonstrate that the resistance of a rail gap with electric field distortion exceeds several times the resistance of a single-channel gap without field distortion. A difference in the resistances is explained by different mechanisms of discharge burning: in the first case diffusion mechanism and in the second case the spark mechanism. The low efficiency of the high-power excimer lasers (~1%) is explained by high energy losses in the rail gap that reach more than 50% of the initially stored energy.

  19. High power double-scale pulses from a gain-guided double-clad fiber laser

    NASA Astrophysics Data System (ADS)

    Zhang, Haitao; Gao, Gan; Li, Qinghua; Gong, Mali

    2017-03-01

    Generation of high power double-scale pulses from a gain-guided double-clad fiber laser is experimentally demonstrated. By employing the Yb-doped 10/130 double-clad fiber as the gain medium, the laser realizes an output power of 5.1 W and pulse energy of 0.175 µJ at repetition rate of 29.14 MHz. To the best of our knowledge, this average output power is the highest among the reported double-scale pulse oscillators. The autocorrelation trace of pulses contains the short (98 fs) and long (29.5 ps) components, and the spectral bandwidth of the pulse is 27.3 nm. Such double-scale pulses are well suited for seeding the high power MOPA (master oscillator power amplifier) systems, nonlinear frequency conversion and optical coherence tomography.

  20. Third user workshop on high-power lasers at the Linac Coherent Light Source

    SciTech Connect

    Bolme, Cynthia Anne; Glenzer, Sigfried; Fry, Alan

    2016-03-24

    On October 5–6, 2015, the third international user workshop focusing on high-power lasers at the Linac Coherent Light Source (LCLS) was held in Menlo Park, CA, USA [1 R. Falcone, S. Glenzer, and S. Hau-Riege, Synchrotron Radiation News 27(2), 56–58 (2014)., 2 P. Heimann and S. Glenzer, Synchrotron Radiation News 28(3), 54–56 (2015).]. Here, the workshop was co-organized by Los Alamos National Laboratory and SLAC National Accelerator Laboratory. More than 110 scientists attended from North America, Europe, and Asia to discuss high-energy-density (HED) science that is enabled by the unique combination of high-power lasers with the LCLS X-rays at the LCLS-Matter in Extreme Conditions (MEC) endstation.

  1. Third user workshop on high-power lasers at the Linac Coherent Light Source

    DOE PAGES

    Bolme, Cynthia Anne; Glenzer, Sigfried; Fry, Alan

    2016-03-24

    On October 5–6, 2015, the third international user workshop focusing on high-power lasers at the Linac Coherent Light Source (LCLS) was held in Menlo Park, CA, USA [1 R. Falcone, S. Glenzer, and S. Hau-Riege, Synchrotron Radiation News 27(2), 56–58 (2014)., 2 P. Heimann and S. Glenzer, Synchrotron Radiation News 28(3), 54–56 (2015).]. Here, the workshop was co-organized by Los Alamos National Laboratory and SLAC National Accelerator Laboratory. More than 110 scientists attended from North America, Europe, and Asia to discuss high-energy-density (HED) science that is enabled by the unique combination of high-power lasers with the LCLS X-rays at themore » LCLS-Matter in Extreme Conditions (MEC) endstation.« less

  2. Procedure for pressure contact on high-power semiconductor devices free of thermal fatigue

    NASA Technical Reports Server (NTRS)

    Knobloch, J.

    1979-01-01

    To eliminate thermal fatigue, a procedure for manufacturing semiconductor power devices with pure pressure contact without solid binding was developed. Pressure contact without the use of a solid binding to avoid a limitation of the maximum surface in the contact was examined. A silicon wafer covered with a relatively thick metal layer is imbedded with the aid of a soft silver foil between two identically sized hard contact discs (molybdenum or tungsten) which are rotationally symmetrical. The advantages of this concept are shown for large diameters. The pressure contact was tested successfully in many devices in a large variety of applications.

  3. Semiconductor Laser With Multilayer Dielectric Reflector

    NASA Technical Reports Server (NTRS)

    Lang, Robert J.

    1991-01-01

    Multilayer dielectric reflector included in proposed surface-emitting, distributed-feedback, grating semiconductor laser (e.g., a GaAlAs device). Contributes to efficiency and output power of laser by reducing amount of light entering substrate, where wasted by absorption. Index of refraction in reflector sublayers alternates between higher and lower value. Higher value less than effective index of refraction of waveguide layer.

  4. Pump-probe photoelectron spectroscopy by a high-power 90 nm vacuum-ultraviolet laser

    NASA Astrophysics Data System (ADS)

    Sato, Motoki; Suzuki, Yoshi-ichi; Suzuki, Toshinori; Adachi, Shunsuke

    2016-02-01

    We present pump-probe photoelectron spectroscopy of Kr and NO using a high-power vacuum-ultraviolet (VUV) laser at a wavelength of 90 nm. Clear quantum beats are observed in the photoelectron angular distributions as well as in the photoelectron yields, resulting from the coherent excitation of two Kr Rydberg states by the VUV pump. The entire Franck-Condon envelope of the NO A(2Σ+) excited state is also successfully captured by the VUV probe.

  5. Initial High-Power-CW-Laser Testing of Liquid-Crystal Optical Phased Arrays

    DTIC Science & Technology

    2010-02-01

    AFRL-RY-WP-TR-2010-1043 INITIAL HIGH-POWER-CW-LASER TESTING OF LIQUID-CRYSTAL OPTICAL PHASED ARRAYS Bert Whitaker OptiMetrics, Inc...Bert Whitaker (OptiMetrics, Inc.) Scott Harris (Flatiron Research, LLC) 5d. PROJECT NUMBER 2003 5e. TASK NUMBER 11 5f. WORK UNIT NUMBER...to a Carl Zeiss petrographic microscope. The crossed polarizers in this microscope highlighted the presence of LC material due to its birefringence

  6. High-power and highly efficient Tm3+-doped silica fiber lasers pumped with diode lasers operating at 1150 nm.

    PubMed

    Jackson, Stuart D; Bugge, Frank; Erbert, Götz

    2007-10-01

    An output power of 1.74 W at 2.03 microm was generated at a slope efficiency of 51% when a double-clad Tm(3+)-doped silica fiber laser was pumped with high-power 1150 nm diode lasers. Pump excited state absorption from the upper laser level populates higher energy levels allowing cross relaxation to repopulate the upper laser level at a quantum efficiency greater than unity and to limit losses relating to additional pump excited state absorption. The output power was scaled to 4.77 W when both ends of the fiber were pumped.

  7. Analysis of the light-field intensity dependence of catastrophic optical damage in high-power AlGaInP lasers using an asymmetrical tapered laser

    NASA Astrophysics Data System (ADS)

    Bou Sanayeh, Marwan

    2016-04-01

    Catastrophic optical damage (COD) in semiconductor lasers is a major limiting effect for high-power operation. Several techniques like microphotoluminescence (μPL) mapping, focused ion beam (FIB) microscopy, and micro- Raman spectroscopy were employed to reveal the physics behind catastrophic optical damage, its related temperature dynamics, as well as associated defect and near-field patterns. High-resolution μPL images demonstrated that during COD, nonradiative dark line defects (DLDs) originate from the front mirror of the laser and propagate deep inside the cavity. Furthermore, FIB microscopy identified the epitaxial layers affected by COD, revealing that the DLDs are confined to the active region. In addition, deep-etching uncovered the DLDs by making them visible, and showed that they are composed of complex dislocation networks. Lasers that underwent a spontaneous breakdown where also studied. One missing piece to complete the characterization of COD is to analyze if the DLDs actually follow certain crystal direction lines inside the laser cavity, which are in general perpendicular to the output facet, or follow the path of the light-field intensity-maximum. Using a specially designed innovative device, namely an asymmetrical AlGaInP tapered laser, it is proven in this study that the COD is strongly dependent on the light-field intensity inside the laser cavity and not on certain crystal direction lines.

  8. The outgassing characteristic research of the silicone rubber in high power laser system

    NASA Astrophysics Data System (ADS)

    Wu, Qipeng; Lv, Haibing; Dong, Meng; Fu, Zhaohui

    2016-11-01

    The outgassing characteristic of the silicone rubber which is the main material of non-metallic materials in high power laser system was studied outgassing rates of the silicone rubber and the baked-out silicone rubber which was performed at 80°C4 hours were measured by the constant volume process method and outgassing properties of them were analyzed by the quadrupole mass spectrometer. The results show that the outgassing rate of the silicone rubber and the baked-out silicone rubber is 2.69×10-7 Pa·m3s-1cm-2 and 6.47×10-8 Pa·m3s-1cm-2 respectively. All of them give out condensable volatile matter in vacuum. The outgassing rate and condensable volatile matter of the baked-out silicone rubber are less an order of magnitude compared with the silicone rubber, and the outgassing rate of the silicone rubber is less than 1×10-7 Pa·m3s-1cm-2, which is fit for non-metallic material of the high power laser system. This paper also discusses the method of reducing the outgassing rate and condensable volatile matter of the silicone rubber in high power laser system.

  9. High-power air-cooled SiC-clad Nd:YVO4 slab lasers.

    PubMed

    Zhang, Rui; Niu, Jinfu; Xu, Jianqiu; Xu, Jingzhong

    2011-05-15

    We demonstrate a diode-pumped, air-cooled, 100 W class SiC-clad Nd:YVO(4) active slab laser based on diffusion bonding of two SiC plates to a thin Nd:YVO(4) slab. We obtained 83 W of cw output power with a slope efficiency of 27% without water cooling. This demonstration initiates a novel (to the best of our knowledge) cooling design for efficient removal of waste heat generated from the diode edge-pumped high-power slab laser at room temperature.

  10. The causes of high power diode laser brazed seams fractures of dissimilar materials

    NASA Astrophysics Data System (ADS)

    Adamiak, Marcin; Czupryński, Artur; Janicki, Damian; Górka, Jacek

    2016-12-01

    Presented in this article are the results of experiments carried out to determine the causes of braze cracking of dissimilar materials brazed with a ROFIN DL 020 high power diode laser with the use of additional powdered EN AW-1070A aluminium alloy to bond thin aluminium sheets with soft, low alloy DC04+ZE75/75 steel plate which was electrolytically coated with zinc on both sides. Presented are the results of metallographic, macroscopic, microscopic, diffractometric phase analyses of the weld joints. Metallurgical problems arising during processing as well as suggestions regarding technical aspects of laser brazing dissimilar materials in regards to their physical characteristics and chemical composition are explored.

  11. Diffractive optical elements fabricated for beam shaping of high-power diode lasers

    NASA Astrophysics Data System (ADS)

    Vogt, Helge; Biertümpfel, Ralf; Pawlowski, Edgar

    2008-02-01

    This paper discusses the use of diffractive optical elements (DOEs) and micro-optics fabricated by precise pressing in glass for beam shaping of high-power diode lasers. The DOEs are used to diffract the light into the point of interest and to improve the laser beam quality. We have realized circular, flat-top and multi-beam intensity profiles. The highest measured diffraction efficiency was higher than 95 %. The new established fabrication process has potential for mass production of DOEs. SCHOTT's precision glass molding process guarantees a very constant quality over the complete production chain.

  12. High-Power γ-Ray Flash Generation in Ultraintense Laser-Plasma Interactions

    NASA Astrophysics Data System (ADS)

    Nakamura, Tatsufumi; Koga, James K.; Esirkepov, Timur Zh.; Kando, Masaki; Korn, Georg; Bulanov, Sergei V.

    2012-05-01

    When high-intensity laser interaction with matter enters the regime of dominated radiation reaction, the radiation losses open the way for producing short pulse high-power γ-ray flashes. The γ-ray pulse duration and divergence are determined by the laser pulse amplitude and by the plasma target density scale length. On the basis of theoretical analysis and particle-in-cell simulations with the radiation friction force incorporated, optimal conditions for generating a γ-ray flash with a tailored overcritical density target are found.

  13. Dual Wavelength High Power Double-Clad Ytterbium-Doped Fiber Laser

    NASA Astrophysics Data System (ADS)

    Moghaddam, M. R. A.; Harun, S. W.; Shahi, S.; Ahmad, H.

    A dual wavelength high power double-clad erbium/ytterbium-doped fiber laser with a narrowest spacing of 0.4 nm and a M2 value of close to unity is presented in the region of 1565 nm. This result can be realized with a significant improvement of the mode competition problem using a loop mirror as a comb filter. The wavelength region can also be varied using polarization controllers in the loop mirror. This dual-wavelength fiber laser with side mode suppression ratio (SMSR) of 40 dB is quite stable, and the output power variance is as low as 0.46 dB.

  14. High-temperature operation of 640 nm wavelength high-power laser diode arrays

    NASA Astrophysics Data System (ADS)

    Imanishi, Daisuke

    2017-03-01

    We realized the fabrication of a red semiconductor laser array with high optical power and reliability using an AlGaInP-based compound semiconductor. To obtain a high optical output, the semiconductor laser requires high-quality quantum wells. In this work, we improved quantum well layer abruptness by applying high-temperature growth condition to quantum wells. We obtained a very high optical power of 20.1 W with a wavelength of 644 nm under this growth condition using magnesium as a dopant for a p-type layer. As a results, we achieved a high characteristic temperature of 68 K and a high electrical-to-optical (E–O) conversion efficiency 37% at 15 W optical output. When the laser lifetime at a temperature of 35 °C and an optical output power of 6.6 W for operation is defined as the time when the output power decreases to 50%, which is usually used for defining the lifetime of ultra high-pressure (UHP) lamps in projection display, we can estimate the lifetime of this laser to be longer than 10000 h or more.

  15. Waveform agile high-power fiber laser illuminators for directed-energy weapon systems

    NASA Astrophysics Data System (ADS)

    Engin, Doruk; Lu, Wei; Kimpel, Frank; Gupta, Shantanu

    2012-06-01

    A kW-class fiber-amplifier based laser illuminator system at 1030nm is demonstrated. At 125 kHz pulse repetition rate, 1.9mJ energy per pulse (235W average power) is achieved for 100nsec pulses with >72% optical conversion efficiency, and at 250kHz repetition, >350W average power is demonstrated, limited by the available pumps. Excellent agreement is established between the experimental results and dynamic fiber amplifier simulation, for predicting the pulse shape, spectrum and ASE accumulation throughout the fiber-amplifier chain. High pulse-energy, high power fiber-amplifier operation requires careful engineering - minimize ASE content throughout the pre-amplifier stages, use of large mode area gain fiber in the final power stage for effective pulse energy extraction, and pulse pre-shaping to compensate for the laser gain-saturation induced intra-pulse and pulse-pattern dependent distortion. Such optimization using commercially available (VLMA) fibers with core size in the 30-40μm range is estimated to lead to >4mJ pulse energy for 100nsec pulse at 50kHz repetition rate. Such waveform agile high-power, high-energy pulsed fiber laser illuminators at λ=1030nm satisfies requirements for active-tracking/ranging in high-energy laser (HEL) weapon systems, and in uplink laser beacon for deep space communication.

  16. Rapid prototyping process using linear array of high-power laser diodes

    NASA Astrophysics Data System (ADS)

    Zhu, Linquan; Cheng, Jun; Zhou, Hanchang

    2000-02-01

    Because of the weak points of the SLS spot Scanning process, a new rapid prototyping process -- SLS line scan using linear array of high power laser diodes regarded as energy sources is researched in this paper. A linear array with requisite length is formed by some high power laser diodes that can be derived individually. Beams of the linear array are transferred to the workplace and imaged some short and light lines by the corresponding optical collimators. They are lined up in a linear laser beam without separation whose length is equal to that of the linear array diodes. When sintering powdered material, the linear laser beam scans in one direction along x axis only. Only if the maximum line length is less than the y axial size of the workpiece, it is necessary that linear laser beam is lapped for some times in the y axis. The Scanning mode of x-y simultaneous guideways are used in this new system which differs entirely from the vibrating mirror scan. The scanning trace of the latter is an arc that will influence processing quality. This new process has higher efficiency and better quality than the traditional spot scanning method.

  17. Far-field beam quality evaluation of high-power unstable resonators TEA CO2 Laser

    NASA Astrophysics Data System (ADS)

    Guo, Ruhai; Chen, Ning; Shi, Kui; Wang, Bing

    2013-05-01

    High average power pulsed TEA CO2 lasers have many important applications, such as laser manufacturing, military applications, but there rarely have reports about the theoretical and experimental studies on the virtual confocus resonator of pulsed TEA CO2 laser, especially its far field optical quality. Based on the real date of the unstable resonator modified by the stable resonator of high power TEA CO2, three common theoretical evaluations and analyzes were conducted and compared with the measured results of far field light intensity distribution with 2 kW designed unstable resonator laser with the block ratio is ɛ=0.404. The results show that the unstable resonator can obtain near diffraction limitation and high optical quality beam. The β factor is smaller than 4 times than the stable resonator. Furthermore, the smaller block factor can make higher power in bucket for the unstable resonator. The comprehensive prediction and evaluation of designed unstable resonator need to synthetically use these three theoretical methods of the evaluations. The simulation results, with considering the optical aberration, heat distortion and atmospheric effect, agree well with the real recording image by the infrared imaging system in the distance of 300m. The research of this paper has very important reference value for evaluating the tactical effectiveness and optimization design of high power TEA CO2 laser system with different unstable resonators.

  18. High Power Laser Welding. [of stainless steel and titanium alloy structures

    NASA Technical Reports Server (NTRS)

    Banas, C. M.

    1972-01-01

    A review of recent developments in high power, carbon dixoide laser welding is presented. Deep penetration welding in stainless steel to 0.5-in. thick, high speed welding in thin gage rimmed steel and gas shielded welding in Ti-6Al-4V alloy are described. The effects of laser power, power density, focusing optics, gas-shielding techniques, material properties and weld speed on weld quality and penetration are discussed. It is shown that laser welding performance in thin materials is comparable to that of electron beams. It is further shown that high quality welds, as evidenced by NDT, mechanical and metal-lographic tests, can be achieved. The potential of the laser for industrial welding applications is indicated.

  19. 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.

  20. High-power dual-wavelength laser with disordered Nd:CNGG crystals.

    PubMed

    Yu, Haohai; Zhang, Huaijin; Wang, Zhengping; Wang, Jiyang; Yu, Yonggui; Shi, Zibin; Zhang, Xingyu; Jiang, Minhua

    2009-01-15

    We demonstrate the high-power dual-wavelength laser output with disordered Nd:CNGG laser crystals. Continuous-wave output power of 4.03 W was obtained under the incident pump power of 15.62 W. In the passively Q-switched operation, the shortest pulse width, largest pulse energy, and highest peak power were achieved to be 12.9 ns, 173.16 microJ, and 12.3 kW, respectively, with Cr(4+):YAG crystals as the saturable absorbers. By spectral analysis, the output lasers were found to have dual wavelengths. We believed that the passively Q-switched dual-wavelength laser should be possible to be used as a source for the generation of terahertz radiation.

  1. High-power continuous-wave cladding-pumped Raman fiber laser.

    PubMed

    Codemard, C A; Dupriez, P; Jeong, Y; Sahu, J K; Ibsen, M; Nilsson, J

    2006-08-01

    We demonstrate a high-power single-mode cladding-pumped Raman fiber laser. The Raman fiber laser consists of a 1.2 km long germanium-doped double-clad fiber in a linear cavity, which is spliced to a single-mode fiber. The laser is end pumped by a multimode erbium-ytterbium-doped fiber, which is coupled to the inner cladding of the Raman fiber. The embedded core was designed to be single mode at the Raman Stokes wavelength, and up to 10 W of power was obtained at 1660 nm from the single-mode fiber end. The laser has a slope efficiency of 67% and a threshold of 6.5 W.

  2. Three-dimensional welding and cutting using high-power CO2 or YAG laser

    NASA Astrophysics Data System (ADS)

    Zuo, Tiechuan; Chen, Jiming; Xiao, Rongshi; Bao, Yong

    2000-10-01

    In this paper, the theory of 3D laser welding and cutting was established firstly. Then the expert system for 3D laser processing and software of 3D laser processing CAD/CAM were developed, respectively. Under the guidance of these software, with high power CO2 laser, the 3D covers of a car have been cut and edge smoothed, which decrease the number of models and shorten the period of production. With adoption of this technology, the covers of extended Hong Qi cars and furthermore Da Hong Qi cars have been processed successfully, which will bring out the innovation of production design and the revolution of processing technology in manufacture industry.

  3. Formation of ultracold molecules induced by a high-power single-frequency fiber laser

    NASA Astrophysics Data System (ADS)

    Fernandes Passagem, Henry; Colín-Rodríguez, Ricardo; Ventura da Silva, Paulo Cesar; Bouloufa-Maafa, Nadia; Dulieu, Olivier; Marcassa, Luis Gustavo

    2017-02-01

    The influence of a high-power single-frequency fiber laser on the formation of ultracold 85Rb2 molecules is investigated as a function of its frequency (in the 1062–1070 nm range) in a magneto-optical trap. We find evidence for the formation of ground-state 85Rb2 molecules in low vibrational levels (v≤slant 20) with a maximal rate of 104 s‑1, induced by short-range photoassociation by the fiber laser followed by spontaneous emission. When this laser is used to set up a dipole trap, we measure an atomic loss rate at a wavelength far from the PA resonances, only four times smaller than that observed at a PA resonance wavelength. This work may have important consequences for atom trapping using lasers around the conventional 1064 nm wavelength.

  4. High-power in-band pumped Er:YAG laser at 1617 nm.

    PubMed

    Kim, J W; Shen, D Y; Sahu, J K; Clarkson, W A

    2008-04-14

    High-power room-temperature operation of an Er:YAG laser at 1617 nm in-band pumped by a cladding-pumped Er,Yb fiber laser at 1532 nm is reported. The Er:YAG laser yielded 31 W of continuous-wave output in a beam with M(2) approximately = 2.2 for 72 W of incident pump power. The threshold pump power was 4.1 W and the slope efficiency with respect to incident pump power was approximately 47%. The influence of erbium doping level and resonator design on laser performance is discussed, and the prospects for further increase in output power and improvement in lasing efficiency are considered.

  5. High-power 1300-nm Fabry-Perot and DFB ridge-waveguide lasers

    NASA Astrophysics Data System (ADS)

    Garbuzov, Dmitri Z.; Maiorov, Mikhail A.; Menna, Raymond J.; Komissarov, Anatoly V.; Khalfin, V.; Kudryashov, Igor V.; Lunev, Alexander V.; DiMarco, Louis A.; Connolly, John C.

    2002-05-01

    In this paper we summarize the results on the development of high power 1300 nm ridge waveguide Fabry-Perot and distributed-feedback (DFB) lasers. Improved performance of MOCVD grown InGaAsP/InP laser structures and optimization of the ridge waveguide design allowed us to achieve more than 800 mW output power from 1300 nm single mode Fabry-Perot lasers. Despite the fact that the beam aspect ratio for ridge lasers (30 degree(s) x 12 degree(s)) is higher than that for buried devices, our modeling and experiments demonstrated that the fiber coupling efficiency of about 75-80% could be routinely achieved using a lensed fiber or a simple lens pair. Fiber power of higher than 600 mW was displayed. Utilizing similar epitaxial structures and device geometry, the 1300 nm DFB lasers with output power of 500 mW have been fabricated. Analysis of the laser spectral characteristics shows that the high power DFB lasers can be separated into several groups. The single frequency spectral behavior was exhibited by about 20% of all studied DFB lasers. For these lasers, side-mode suppression increases from 45 dB at low current up to 60 dB at maximum current. About 30% of DFB lasers, at all driving currents, demonstrate multi-frequency spectra consisting of 4-8 longitudinal modes with mode spacing larger than that for Fabry-Perot lasers of the same cavity length. Both single frequency and multi frequency DFB lasers exhibit weak wavelength-temperature dependence and very low relative intensity noise (RIN) values. Fabry-Perot and both types of DFB lasers can be used as pump sources for Raman amplifiers operating in the 1300 nm wavelength range where the use of EDFA is not feasible. In addition, the single-mode 1300 nm DFB lasers operating in the 500 mW power range are very attractive for new generation of the cable television transmission and local communication systems.

  6. EFFECT OF LASER LIGHT ON MATTER. LASER PLASMAS: Multiphoton coloration of lead silicate glasses by high-power laser radiation

    NASA Astrophysics Data System (ADS)

    Efimov, O. M.; Matveev, Yu A.; Mekryukov, A. M.

    1994-04-01

    A study was made of the mechanism of the formation of colour centres by the exposure of lead silicate glasses to high-power laser radiation. The long-wavelength mobility edge (>5.8 eV) of charge carriers in these glasses was located well above the fundamental absorption edge (3.5 eV), so that coloration was observed only when the glass matrix experienced multiphoton ionisation. The newly formed colour centres make the main contribution to the change in the transmission directly during the action of nanosecond laser pulses. An estimate was obtained of the three-photon absorption coefficient of TF10 glass at the wavelength of 527 nm.

  7. Method and system for powering and cooling semiconductor lasers

    SciTech Connect

    Telford, Steven J; Ladran, Anthony S

    2014-02-25

    A semiconductor laser system includes a diode laser tile. The diode laser tile includes a mounting fixture having a first side and a second side opposing the first side and an array of semiconductor laser pumps coupled to the first side of the mounting fixture. The semiconductor laser system also includes an electrical pulse generator thermally coupled to the diode bar and a cooling member thermally coupled to the diode bar and the electrical pulse generator.

  8. Performance of passive Q-switched solar-pumped high-power Nd:YAG lasers

    NASA Astrophysics Data System (ADS)

    Noter, Yoram; Naftali, Nir; Pe'er, Idit L.; Yogev, Amnon; Lando, Mordechai; Shimony, Yehoshua

    1997-09-01

    Q-switched, solar-pumped, high power Nd:YAG lasers are attractive for a variety of applications requiring high instantaneous peak power density. The Q-switching can be obtained by an acousto-optic, electro-optic or passive device. Passive Q-switching seems an excellent choice for space as well as for other applications since it neither requires an external driver nor an electrical power supply. In recent years Cr+4:YAG single crystals were extensively used as passive Q-switches for flashlamp-pumped high power Nd:YAG lasers, demonstrating their superior thermal superior thermal characteristics and durability. In this work we report the first operation of passive Q- switched, solar-pumped, high power Nd:YAG lasers. The concentrated solar energy for he optical pumping of the laser was obtained by a 3-stage combination of imaging and non-imaging optics. It included: i) Weizmann Institute solar tower heliostats, ii) 3D compound parabolic concentrator, and iii) 2D compound parabolic concentrator in which the laser rod was placed. 72 mm long laser rods with either 3 mm or 4 mm diameter were used. The passive Q-switch was made from a Cr$=+4):YAG single crystal having a low- intensity transmission of 72 percent at 1.06 (mu) . Its rear surface was coated by a high reflectivity coating, serving as the rear mirror of the cavity. Output coupling mirrors with various reflectivities were used. The passive Q-switch demonstrated excellent durability and reliability during all the experiments. Repetition rates of 6-39 kHz were measured, showing higher repetition rates at higher laser power levels. The pulses demonstrated shorter full width at half maximum (FWHM) time for higher laser power elves, and the FWHM time range was 190-310 nsec. The maximal measured average power was 14 W. Thermal lensing was measured as a function of the absorbed solar power in the laser rod. It is estimated that laser peak power densities of approximately 100 kW/cm2 were achieved in the experiments. It is

  9. Numerical investigation on high power mid-infrared supercontinuum fiber lasers pumped at 3 µm.

    PubMed

    Wei, Chen; Zhu, Xiushan; Norwood, Robert A; Song, Feng; Peyghambarian, N

    2013-12-02

    High power mid-infrared (mid-IR) supercontinuum (SC) laser sources in the 3-12 µm region are of great interest for a variety of applications in many fields. Although various mid-IR SC laser sources have been proposed and investigated experimentally and theoretically in the past several years, power scaling of mid-IR SC lasers beyond 3 μm with infrared edges extending beyond 7 μm are still challenges because the wavelengths of most previously used pump sources are below 2 μm. These problems can be solved with the recent development of mode-locked fiber lasers at 3 μm. In this paper, high power mid-IR SC laser sources based on dispersion engineered tellurite and chalcogenide fibers and pumped by ultrafast lasers at 3 µm are proposed and investigated. Our simulation results show that, when a W-type tellurite fiber with a zero dispersion wavelength (ZDW) of 2.7 µm is pumped at 2.78 μm, the power proportion of the SC laser beyond 3 µm can exceed 40% and the attainable SC output power of the proposed solid-cladding tellurite fiber is one order of magnitude higher than that of existing microstructured tellurite fibers. Our calculation also predicts that a very promising super-broadband mid-IR SC fiber laser source covering two atmospheric windows and molecules' "fingerprint" region can be obtained with a microstructured As2Se3 chalcogenide fiber pumped at 2.78 μm.

  10. Ultralow noise miniature external cavity semiconductor laser

    PubMed Central

    Liang, W.; Ilchenko, V. S.; Eliyahu, D.; Savchenkov, A. A.; Matsko, A. B.; Seidel, D.; Maleki, L.

    2015-01-01

    Advanced applications in optical metrology demand improved lasers with high spectral purity, in form factors that are small and insensitive to environmental perturbations. While laboratory-scale lasers with extraordinarily high stability and low noise have been reported, all-integrated chip-scale devices with sub-100 Hz linewidth have not been previously demonstrated. Lasers integrated with optical microresonators as external cavities have the potential for substantial reduction of noise. However, stability and spectral purity improvements of these lasers have only been validated with rack-mounted support equipment, assembled with fibre lasers to marginally improve their noise performance. In this work we report on a realization of a heterogeneously integrated, chip-scale semiconductor laser featuring 30-Hz integral linewidth as well as sub-Hz instantaneous linewidth. PMID:26104321

  11. Subwavelength metal-optic semiconductor nanopatch lasers.

    PubMed

    Yu, Kyoungsik; Lakhani, Amit; Wu, Ming C

    2010-04-26

    We report on near infrared semiconductor nanopatch lasers with subwavelength-scale physical dimensions (0.019 cubic wavelengths) and effective mode volumes (0.0017 cubic wavelengths). We observe lasing in the two most fundamental optical modes which resemble oscillating electrical and magnetic dipoles. The ultra-small laser volume is achieved with the presence of nanoscale metal patches which suppress electromagnetic radiation into free-space and convert a leaky cavity into a highly-confined subwavelength optical resonator. Such ultra-small lasers with metallodielectric cavities will enable broad applications in data storage, biological sensing, and on-chip optical communication.

  12. Semiconductor laser applications in rheumatology

    NASA Astrophysics Data System (ADS)

    Pascu, Mihail-Lucian; Suteanu, S.

    1996-01-01

    Two types of laser diode (LD) based equipment for rheumatology are introduced. The first is a portable device which contains single LD emitting at 890 nm laser pulses (time full width 100 nsec) of reprate tunable within (0.5 - 1.5) kHz; the laser beam average power is 0.7 mW at 1 kHz reprate. The second is computer controlled, contains one HeNe laser and 5 LD allowing 6 modes of patient irradiation (placebo effect evaluation included). HeNe laser works in cw at 632.8 nm; the LD works each as described for the portable equipment. HeNe and LD beams are superposed so that HeNe laser spot in the irradiation plane has a 60 mm diameter and the LD spots covers a 50 mm diameter disc centered on the HeNe laser spot. Clinical applications using the second type of equipment are reported; 1287 patients were treated between October 1991 and October 1994. Female/male ratio was 4:1 and their age distribution was between 18 and 85 years. The average number of exposures was 10 and the mean exposure time was 7 minutes. Studies were made on the treatment of rheumatoid arthritis, seronegative arthritis, degenerative joint diseases, abarticular rheumatism, osteoporosis pain and pains and edema after fractures.

  13. Finite-Element Simulation for Electrothermal Characterization of High-Power Diode Laser Bars

    DTIC Science & Technology

    2010-03-31

    materials. The single electron, time-independent Schrodinger equation is, ( − h̄ 2 2m ∇2 + V ) ψn = Enψn, (37) where m is the appropriate effective...Snowden, and T Boettcher. Solution of the coupled Poisson- Schrodinger equations using the multigrid method. Interna- tional Journal of Numerical Modelling...Simulation of semiconductor diode laser performance involves interaction between multiple physics domains. This report presents the governing equations and

  14. Formation of short high-power laser radiation pulses in excimer mediums

    NASA Astrophysics Data System (ADS)

    Losev, V. F., Sr.; Ivanov, N. G.; Panchenko, Yu. N.

    2007-06-01

    Presently an excimer mediums continue are examined as one of variants for formation of powerful and over powerful pulses of laser radiation with duration from units of nanosecond up to tens femtosecond. The researches on such powerful installations as "NIKE" (USA) and << SUPER ASHURA >>, Japan) proceed in this direction. The main advantage of excimer mediums is the opportunity to work in a frequency mode, absence of restriction on the size of active area, high uniformity of a gas working medium, high efficiency (up to 10 %) and wide spectral range of laser radiation (KrF, XeCl ~ 2nm, XeF (C-A), Xe IICl ~ 50-100 nanometers). Research in area of high quality laser beams formation in excimer mediums and its amplification in high power amplifiers are carried out the long time in Institute of High Current Electronics SB RAS, Tomsk, Russia. The wide aperture XeCl laser system of MELS-4k is used for these investigations. Last time we take part in program on development of high power excimer laser system with a petawatt level of power. This system supposes the formation and amplification high quality laser beams with different pulse duration from units of nanosecond up to tens femtosecond. We research the possibility of laser beams formation in excimer mediums with ps-ns pulse duration having the low noise and divergence near to diffraction limit. In other hand, we are developing the wide aperture XeF(C-A) amplifier with optical pump on base electron accelerator. According to our estimations of the XeF(C-A) amplifier based on the converter of e-beam energy to the Xe II* fluorescence at 172 nm will allow to obtain up to 100 TW peak power in a 30 fs pulse.

  15. Laser processes and analytics for high power 3D battery materials

    NASA Astrophysics Data System (ADS)

    Pfleging, W.; Zheng, Y.; Mangang, M.; Bruns, M.; Smyrek, P.

    2016-03-01

    Laser processes for cutting, modification and structuring of energy storage materials such as electrodes, separator materials and current collectors have a great potential in order to minimize the fabrication costs and to increase the performance and operational lifetime of high power lithium-ion-batteries applicable for stand-alone electric energy storage devices and electric vehicles. Laser direct patterning of battery materials enable a rather new technical approach in order to adjust 3D surface architectures and porosity of composite electrode materials such as LiCoO2, LiMn2O4, LiFePO4, Li(NiMnCo)O2, and Silicon. The architecture design, the increase of active surface area, and the porosity of electrodes or separator layers can be controlled by laser processes and it was shown that a huge impact on electrolyte wetting, lithium-ion diffusion kinetics, cell life-time and cycling stability can be achieved. In general, the ultrafast laser processing can be used for precise surface texturing of battery materials. Nevertheless, regarding cost-efficient production also nanosecond laser material processing can be successfully applied for selected types of energy storage materials. A new concept for an advanced battery manufacturing including laser materials processing is presented. For developing an optimized 3D architecture for high power composite thick film electrodes electrochemical analytics and post mortem analytics using laser-induced breakdown spectroscopy were performed. Based on mapping of lithium in composite electrodes, an analytical approach for studying chemical degradation in structured and unstructured lithium-ion batteries will be presented.

  16. High-power highly reliable single emitter laser diodes at 808 nm

    NASA Astrophysics Data System (ADS)

    Gao, Wei; Xu, Zuntu; Cheng, Lisen; Luo, Kejian; Mastrovito, Andre; Shen, Kun

    2007-02-01

    High power laser diodes and diode arrays emitting at the wavelength of 808nm are widely used for pumping neodymium (Nd+) doped solid state lasers and fiber lasers, medical surgery, dental treatment and material processing. In general, the power is limited by catastrophic optical mirror damage (COMD) and heat dissipation. In this paper we demonstrate 29W CW output power at 808 nm from a 400 μm single emitter with 2mm cavity length. The device thermally rolls over due to the excess heat. The L-I curve rolls over at 29.5W, the laser is still alive, and we can repeat the test again and again without catastrophic optical mirror-damage (COMD). The device consists of an InAlGaAs/AlGaAs/GaAs, optimized special graded-index separated-confinement heterostructure (GRINSCH) broad waveguide (BW), single quantum well (SQW) and barriers between waveguide and cladding layers. A weak temperature dependence characteristic, which is desirable for high power and reliable operation, is obtained from these devices.

  17. Anti-Reflective and Waterproof Hard Coating for High Power Laser Optical Elements

    NASA Astrophysics Data System (ADS)

    Murahara, Masataka; Yabe, Takashi; Uchida, Shigeaki; Yoshida, Kunio; Okamoto, Yoshiaki

    2006-05-01

    A hard coating method of single crystalline porous silica film is widely used for high power laser optical elements in the air. However, there is no protective hard coating method for the elements to survive high power laser irradiance while in the water. We, thus, developed a new method for a waterproof coating with photo-oxidation of silicone oil. The silicone oil was spin-coated onto the surface of optical elements, and then irradiated with a xenon excimer lamp in the air. In this treatment, a protective coating for plastic lenses, mirrors, and nonlinear optical crystals, which are highly deliquescent, was developed by taking advantage of the phenomenon in which organic silicone oil is transformed to inorganic amorphous glass by a process of photo-oxidation. This technique has enabled an optical thin coating film to transmit ultraviolet rays of wavelengths under 200 nm and possess the characteristics of homogeneity, high density, resistance to environment, anti-reflectiveness, resistance to water, and Mohs' scale of 5, which is comparable to apatite. This allows us to cool a slab laser head and use as a mirror for underwater laser welding.

  18. Highly reliable high-power AlGaAs/GaAs 808 nm diode laser bars

    NASA Astrophysics Data System (ADS)

    Hülsewede, R.; Schulze, H.; Sebastian, J.; Schröder, D.; Meusel, J.; Hennig, P.

    2007-02-01

    There are strong demands at the market to increase power and reliability for 808 nm diode laser bars. Responding to this JENOPTIK Diode Lab GmbH developed high performance 808 nm diode laser bars in the AlGaAs/GaAs material system with special emphasis to high power operation and long term stability. Optimization of the epitaxy structure and improvements in the diode laser bar design results in very high slope efficiency of >1.2 W/A, low threshold current and small beam divergence in slow axis direction. Including low serial resistance the overall wall plug efficiency is up to 65% for our 20%, 30% and 50% filling factor 10 mm diode laser bars. With the JENOPTIK Diode Lab cleaving and coating technique the maximum output power is 205 W in CW operation and 377 W in QCW operation (200 μs, 2% duty cycle) for bars with 50% filling factor. These bars mounted on micro channel cooled package are showing a very high reliability of >15.000 h. Mounted on conductive cooled package high power operation at 100 W is demonstrated for more than 5000h.

  19. Spectral combining of high-power fiber laser beams using Bragg grating in PTR glass

    NASA Astrophysics Data System (ADS)

    Ciapurin, Igor V.; Glebov, Leonid B.; Smirnov, Vadim I.

    2004-06-01

    High-efficient volume Bragg gratings (VBG) in inorganic photo-thermo-refractive (PTR) glass were recently reported for the use in high-power laser systems. Both transmission and reflection gratings have shown diffraction efficiency greater than 95% from visible to near IR spectra in a wide range of spatial frequencies. Those gratings have exhibited perfect thermal, optical and mechanical stability. Spectral beam combining (SBC) using PTR Bragg grating with efficiency more than 92% for two 100 W Yb-fiber-laser beams with the 11 nm wavelength separation between them is reported. The paper presents results of modeling and experimental study of a beam combiner for high-power lasers with the only passive PTR grating component in it. Two laser beams illuminate a thick Bragg grating which has only two symmetric resonant angles providing total diffraction of a beam with a certain wavelength. Incidence angle for all transmitting beams should correspond to the Bragg angle for the diffracted beam. Transmitting beams are not diffracted by grating if spectral sift corresponds to zeros in a spectral selectivity curve, and propagate in the same direction as a diffracted beam. It is shown the efficient trade-off between grating period and refractive index modulation allows modeling of high-efficient combining setup for each of arbitrary chosen grating thickness. Comparison between calculation results and experimental data is given.

  20. Feasibility of High-Power Diode Laser Array Surrogate to Support Development of Predictive Laser Lethality Model

    SciTech Connect

    Lowdermilk, W H; Rubenchik, A M; Springer, H K

    2011-01-13

    Predictive modeling and simulation of high power laser-target interactions is sufficiently undeveloped that full-scale, field testing is required to assess lethality of military directed-energy (DE) systems. The cost and complexity of such testing programs severely limit the ability to vary and optimize parameters of the interaction. Thus development of advanced simulation tools, validated by experiments under well-controlled and diagnosed laboratory conditions that are able to provide detailed physics insight into the laser-target interaction and reduce requirements for full-scale testing will accelerate development of DE weapon systems. The ultimate goal is a comprehensive end-to-end simulation capability, from targeting and firing the laser system through laser-target interaction and dispersal of target debris; a 'Stockpile Science' - like capability for DE weapon systems. To support development of advanced modeling and simulation tools requires laboratory experiments to generate laser-target interaction data. Until now, to make relevant measurements required construction and operation of very high power and complex lasers, which are themselves costly and often unique devices, operating in dedicated facilities that don't permit experiments on targets containing energetic materials. High power diode laser arrays, pioneered by LLNL, provide a way to circumvent this limitation, as such arrays capable of delivering irradiances characteristic of De weapon requires are self-contained, compact, light weight and thus easily transportable to facilities, such as the High Explosives Applications Facility (HEAF) at Lawrence Livermore National Laboratory (LLNL) where testing with energetic materials can be performed. The purpose of this study was to establish the feasibility of using such arrays to support future development of advanced laser lethality and vulnerability simulation codes through providing data for materials characterization and laser-material interaction

  1. Alexandrite laser pumped by semiconductor lasers

    SciTech Connect

    Scheps, R.; Gately, B.M.; Myers, J.F. ); Krasinski, J.S. ); Heller, D.F. )

    1990-06-04

    We report the first operation of a direct diode-pumped tunable chromium-doped solid-state laser. A small alexandrite (Cr:BeAl{sub 2}O{sub 4}) crystal was longitudinally pumped by two visible laser diodes. The threshold pump power was 12 mW using the {ital R}{sub 1} line at 680.4 nm for the pump transition, and the slope efficiency was 25%. The measured laser output bandwidth was 2.1 nm.

  2. Alexandrite laser pumped by semiconductor lasers

    NASA Astrophysics Data System (ADS)

    Scheps, Richard; Gately, Bernard M.; Myers, Joseph F.; Krasinski, Jerzy S.; Heller, Donald F.

    1990-06-01

    We report the first operation of a direct diode-pumped tunable chromium-doped solid-state laser. A small alexandrite (Cr:BeAl2O4) crystal was longitudinally pumped by two visible laser diodes. The threshold pump power was 12 mW using the R1 line at 680.4 nm for the pump transition, and the slope efficiency was 25%. The measured laser output bandwidth was 2.1 nm.

  3. Electronically-Steerable, Coherent Laser Arrays: REALLY Small, Lightweight, High Power Lasers for DoD Applications (BRIEFING CHARTS)

    DTIC Science & Technology

    2007-03-07

    Optics Element LiNO3 Electric Field Controller • Intensity • Phase • Polarization APPLET SPGD Algorithm implemented on FPGA Fiber Laser Amplifier...Need High Power Fiber Laser Amplifiers – 2 kW – Single Transverse Mode – Single Polarization – < λ/20 Phase Noise – No SBS/SRS - Narrowline These 2...limiting factor Fiber Laser Technology – 100 kW • Explore Ultimate Fiber Amplifier Array Scaling Limits – Single-Mode (M2 < 1.5) – Single-

  4. Temperature evaluation of dental implant surface irradiated with high-power diode laser.

    PubMed

    Rios, F G; Viana, E R; Ribeiro, G M; González, J C; Abelenda, A; Peruzzo, D C

    2016-09-01

    The prevalence of peri-implantitis and the absence of a standard approach for decontamination of the dental implant surface have led to searches for effective therapies. Since the source of diode lasers is portable, has reduced cost, and does not cause damage to the titanium surface of the implant, high-power diode lasers have been used for this purpose. The effect of laser irradiation on the implants is the elevation of the temperature surface. If this elevation exceeds 47 °C, the bone tissue is irreversibly damaged, so for a safety therapy, the laser parameters should be controlled. In this study, a diode laser of GaAsAl was used to irradiate titanium dental implants, for powers 1.32 to 2.64 W (real) or 2.00 to 4.00 W (nominal), in continuous/pulsed mode DC/AC, with exposure time of 5/10 s, with/without air flow for cooling. The elevation of the temperature was monitored in real time in two positions: cervical and apical. The best results for decontamination using a 968-nm diode laser were obtained for a power of 1.65 and 1.98 W (real) for 10 s, in DC or AC mode, with an air flow of 2.5 l/min. In our perspective in this article, we determine a suggested approach for decontamination of the dental implant surface using a 968-nm diode laser.

  5. Prototype of a high-power, high-energy industrial XeCl laser

    SciTech Connect

    Borisov, V M; Demin, A I; Khristoforov, O B

    2015-03-31

    We discuss the results of fabrication and experimental study of a high-power excimer XeCl laser for industrial applications. Compactness of the laser is achieved by the employment of a laser chamber based on a ceramic tube made of Al{sub 2}O{sub 3}. High laser output energy (1.5 – 2.5 J pulse{sup -1}) is obtained using a wide-aperture (up to 55 × 30 mm) volume discharge with pre-ionisation by a creeping discharge. The pre-ionisation is realised through a semitransparent electrode by the UV radiation of a creeping discharge in the form of uniform plasma sheet on a surface of a plane sapphire plate. The operating lifetime of the gas mixture amounts to ∼57 × 10{sup 6} pulses at a stabilised average laser power of 450 W. The results obtained demonstrate real prospects for developing a new class of excimer XeCl lasers with an average power of ∼1 kW. (lasers)

  6. Passive and Active Protective Clothing against High-Power Laser Radiation

    NASA Astrophysics Data System (ADS)

    Hennigs, C.; Hustedt, M.; Kaierle, S.; Wenzel, D.; Markstein, S.; Hutter, A.

    The main objective of the work described in this paper was the development of passive and active protective clothing for the protection of the human skin against accidental laser irradiation and of active protective curtains. Here, the passive systems consist of functional multi-layer textiles, providing a high level of passive laser resistance. In addition, the active functional multi-layer textiles incorporate sensors that detect laser exposure and are, by means of a safety control, able to deactivate the laser beam automatically.Due to the lack of regulations for testing and qualifying textiles to be used as laser PPE, test methods were defined and validated. Additionally, corresponding testing set-ups were developed.Finally, the gap with respect to standardization was bridged by the definition of a test procedure and the requirements with respect to laser PPE.The developments were demonstrated by a set of tailored functional passive and active laser-protective clothing prototypes (gloves, jackets, aprons, trousers) and active curtains as well as by a prototype testing rig, providing the possibility to perform the specified low-power and high-power textile test procedure.

  7. Damage Resistant Optical Glasses for High Power Lasers: A Continuing Glass Science and Technology Challenge

    SciTech Connect

    Campbell, J H

    2002-08-28

    A major challenge in the development of optical glasses for high-power lasers is reducing or eliminating laser-induced damage to the interior (bulk) and the polished surface of the glass. Bulk laser damage in glass generally originates from inclusions. With the development of novel glass melting and forming processes it is now possible to make both fused silica and a suit of meta-phosphate laser glasses in large sizes ({approx}>0.5-lm diameter), free of inclusions and with high optical homogeneity ({approx} 10{sup -6}). Considerable attention also has been focused on improving the laser damage resistance to polished optical glass surfaces. Studies have shown that laser-induced damage to surfaces grows exponentially with the number of shots when illuminated with nano-second pulses at 351-nm above a given fluence threshold. A new approach for reducing and eliminating laser-induced surface damage relies on a series of post-polishing treatment steps. This damage improvement method is briefly reviewed.

  8. Plasma-based amplification and manipulation of high-power laser pulses

    NASA Astrophysics Data System (ADS)

    Lehmann, Goetz

    2016-10-01

    In the last decade the increasing availability of Tera- and Petawatt class lasers with ps to fs pulse duration has intensified the interest in the relativistic interaction between laser radiation and matter. Today laser intensities up to 1022 W/cm2 can be achieved. Most high intensity lasers today rely on amplification schemes that can only hardly be scaled to higher power levels due to material damage thresholds. An alternative approach that allows circumventing these issues is the use of plasma as an amplification medium. Langmuir or ion waves may be used as optical components, scattering the energy from a long pump pulse into a short seed pulse. Damage thresholds of solid-state materials are not only limiting the generation of high power laser light, but also its subsequent manipulation. Again, plasma can provide an alternative approach to light manipulation. We recently proposed the concept of transient plasma photonic crystals, which aims at transferring and extending the concept of photonic crystals to the realm of plasma physics in the range of optical frequencies. In my presentation I will discuss Brillouin type plasma-based laser amplifiers and show that the ion plasma waves, driven by the two laser pulses, eventually form photonic crystals. The properties and possible future applications of these plasma photonic crystals as efficient Bragg type mirrors or polarizers will be discussed.

  9. Frequency doubled high-power disk lasers in pulsed and continuous-wave operation

    NASA Astrophysics Data System (ADS)

    Weiler, Sascha; Hangst, Alexander; Stolzenburg, Christian; Zawischa, Ivo; Sutter, Dirk; Killi, Alexander; Kalfhues, Steffen; Kriegshaeuser, Uwe; Holzer, Marco; Havrilla, David

    2012-03-01

    The disk laser with multi-kW output power in infrared cw operation is widely used in today's manufacturing, primarily in the automotive industry. The disk technology combines high power (average and/or peak power), excellent beam quality, high efficiency and high reliability with low investment and operating costs. Additionally, the disk laser is ideally suited for frequency conversion due to its polarized output with negligible depolarization losses. Laser light in the green spectral range (~515 nm) can be created with a nonlinear crystal. Pulsed disk lasers with green output of well above 50 W (extracavity doubling) in the ps regime and several hundreds of Watts in the ns regime with intracavity doubling are already commercially available whereas intracavity doubled disk lasers in continuous wave operation with greater than 250 W output are in test phase. In both operating modes (pulsed and cw) the frequency doubled disk laser offers advantages in existing and new applications. Copper welding for example is said to show much higher process reliability with green laser light due to its higher absorption in comparison to the infrared. This improvement has the potential to be very beneficial for the automotive industry's move to electrical vehicles which requires reliable high-volume welding of copper as a major task for electro motors, batteries, etc.

  10. Effect of laser cavity parameters on saturation of light – current characteristics of high-power pulsed lasers

    SciTech Connect

    Veselov, D A; Pikhtin, N A; Lyutetskiy, A V; Nikolaev, D N; Slipchenko, S O; Sokolova, Z N; Shamakhov, V V; Shashkin, I S; Kapitonov, V A; Tarasov, I S

    2015-07-31

    We report an experimental study of power characteristics of semiconductor lasers based on MOVPE-grown asymmetric separate-confinement heterostructures with a broadened waveguide as functions of cavity length, stripe contact width and mirror reflectivities. It is shown that at high current pump levels, the variation of the cavity parameters of a semiconductor laser (width, length and mirror reflectivities) influences the light – current (L – I) characteristic saturation and maximum optical power by affecting such laser characteristics, as the current density and the optical output loss. A model is elaborated and an optical power of semiconductor lasers is calculated by taking into account the dependence of the internal optical loss on pump current density and concentration distribution of charge carriers and photons along the cavity axis of the cavity. It is found that only introduction of the dependence of the internal optical loss on pump current density to the calculation model provides a good agreement between experimental and calculated L – I characteristics for all scenarios of variations in the laser cavity parameters. (lasers)

  11. High-power passively mode-locked Nd:YVO(4) laser using SWCNT saturable absorber fabricated by dip coating method.

    PubMed

    Tang, Chun Yin; Chai, Yang; Long, Hui; Tao, Lili; Zeng, Long Hui; Tsang, Yuen Hong; Zhang, Ling; Lin, Xuechun

    2015-02-23

    Passive mode locked laser is typically achieved by the Semiconductor Saturable absorber Mirror, SESAM, saturable absorber, which is produced by expensive and complicated metal organic chemical vapor deposition method. Carbon based single wall carbon nanotube (SWCNT), saturable absorber, is a promising material which is capable to produce stable passive mode-locking in the high power laser cavity over a wide operational wavelength range. This study has successfully demonstrated the high power mode locking laser system operating at 1 micron by using SWCNT based absorbers fabricated by dip coating method. The proposed fabrication method is practical, simple and cost effective for fabricating SWCNT saturable absorber. The demonstrated high power Nd:YVO(4) mode-locked laser operating at 1064nm have maximum output power up to 2.7W,with the 167MHz repetition rate and 3.1 ps pulse duration, respectively. The calculated output pulse energy and peak power are 16.1nJ and 5.2kW, respectively.

  12. High power, 1060-nm diode laser with an asymmetric hetero-waveguide

    SciTech Connect

    Li, T; Zhang, Yu; Hao, E

    2015-07-31

    By introducing an asymmetric hetero-waveguide into the epitaxial structure of a diode laser, a 6.21-W output is achieved at a wavelength of 1060 nm. A different design in p- and n-confinement, based on optimisation of energy bands, is used to reduce voltage loss and meet the requirement of high power and high wall-plug efficiency. A 1060-nm diode laser with a single quantum well and asymmetric hetero-structure waveguide is fabricated and analysed. Measurement results show that the asymmetric hetero-structure waveguide can be efficiently used for reducing voltage loss and improving the confinement of injection carriers and wall-plug efficiency. (lasers)

  13. Second user workshop on high-power lasers at the Linac Coherent Light Source

    DOE PAGES

    Heimann, Phil; Glenzer, Siegfried

    2015-05-28

    The second international workshop on the physics enabled by the unique combination of high-power lasers with the world-class Linac Coherent Light Source (LCLS) free-electron X-ray laser beam was held in Stanford, CA, on October 7–8, 2014. The workshop was co-organized by UC Berkeley, Lawrence Berkeley, Lawrence Livermore, and SLAC National Accelerator Laboratories. More than 120 scientists, including 40 students and postdoctoral scientists who are working in high-intensity laser-matter interactions, fusion research, and dynamic high-pressure science came together from North America, Europe, and Asia. The focus of the second workshop was on scientific highlights and the lessons learned from 16 newmore » experiments that were performed on the Matter in Extreme Conditions (MEC) instrument since the first workshop was held one year ago.« less

  14. Deformable mirrors for intra-cavity use in high-power thin-disk lasers.

    PubMed

    Piehler, Stefan; Dietrich, Tom; Wittmüss, Philipp; Sawodny, Oliver; Ahmed, Marwan Abdou; Graf, Thomas

    2017-02-20

    We present deformable mirrors for the intra-cavity use in high-power thin-disk laser resonators. The refractive power of these mirrors is continuously adaptable from -0.7 m-1 to 0.3 m-1, corresponding to radii of curvature ranging between 2.86 m (convex) and 6.67 m (concave). The optimized shape of the mirror membrane enables a very low peak-to-valley deviation from a paraboloid deformation over a large area. With the optical performance of our mirrors being equal to that of standard HR mirrors, we were able to demonstrate the tuning of the beam quality of a thin-disk laser in a range of M2 = 3 to M2 = 1 during laser operation at output powers as high as 1.1 kW.

  15. Applications of high power lasers. [using reflection holograms for machining and surface treatment

    NASA Technical Reports Server (NTRS)

    Angus, J. C.

    1979-01-01

    The use of computer generated, reflection holograms in conjunction with high power lasers for precision machining of metals and ceramics was investigated. The Reflection holograms which were developed and made to work at both optical wavelength (He-Ne, 6328 A) and infrared (CO2, 10.6) meet the primary practical requirement of ruggedness and are relatively economical and simple to fabricate. The technology is sufficiently advanced now so that reflection holography could indeed be used as a practical manufacturing device in certain applications requiring low power densities. However, the present holograms are energy inefficient and much of the laser power is lost in the zero order spot and higher diffraction orders. Improvements of laser machining over conventional methods are discussed and addition applications are listed. Possible uses in the electronics industry include drilling holes in printed circuit boards making soldered connections, and resistor trimming.

  16. Thermal modelling of high-power laser diodes mounted using various types of submounts

    SciTech Connect

    Bezotosnyi, V V; Krokhin, O N; Oleshchenko, V A; Pevtsov, V F; Popov, Yu M; Cheshev, E A

    2014-10-31

    Using three-dimensional thermal modelling of a highpower 980-nm laser diode with a stripe contact width of 100 μm as an example, we analyse the thermal parameters of high-power laser diodes mounted using submounts. We consider a range of thermal conductivities of submounts that includes parameters of widely used thermal compensators based on AlN, BeO and SiC, as well as on CuW and CuMo composites and polycrystalline and single-crystal synthetic diamond with high thermal conductivity. Taking into account experimental overall efficiency vs. pump current data, we calculate the temperature of the active layer as a function of the width, thickness and thermal conductivity of the submount at thermal loads corresponding to cw output powers of 10, 15 and 20 W. (lasers)

  17. Thermomechanical model for the plastic deformation in high power laser diodes during operation

    NASA Astrophysics Data System (ADS)

    Martín-Martín, A.; Avella, M.; Iñiguez, M. P.; Jiménez, J.; Oudart, M.; Nagle, J.

    2009-10-01

    A thermomechanical model for the mechanism of rapid degradation of AlGaAs based high power laser bars (808 nm) is presented. Thermal stresses induced in the device by local heating around a facet defect by nonradiative recombination and self-absorption of photons are calculated, as well as the conditions for the beginning of plastic deformation, when these thermal stresses overcome the yield strength. The values of the power density and of the local temperature at which the yield limit is surmounted are in agreement with the threshold values for the degradation of Al based lasers given in the literature. The present model can also elucidate the role played by the packaging stress, being able to explain how this stress reduces the optical power density threshold for failure of these lasers.

  18. Defects Induced in Fused Silica by High Power UV Laser Pulses at 355 nm

    SciTech Connect

    Stevens-Kalceff, M A; Stesmans, A; Wong, J

    2001-03-23

    Point defects induced in high quality optical-grade based silica by high power (>30 J/cm{sup 2}) 355 nm laser pulses have been investigated to elucidate the nature of laser damage in transparent optics designed for use at the National Ignition Facility (NIF). Six defects have been identified: the NBOHC (non-bridging oxygen hole center), a STE (self-trapped exciton), an ODC (oxygen-deficient center), interstitial oxygen, the E'{sub {gamma}}, and E'{sub 74}. The former four defects were identified and spatially resolved in the damage craters using cathodoluminescence (CL) microanalysis (spectroscopy and microscopy). The latter two defects were identified using ESR spectroscopy at cryogenic temperatures. These defects are unlikely to be a prime factor in damage growth by subsequent laser pulses. Their concentration is too low to effect a high enough temperature rise by a volume absorption mechanism.

  19. Novel technology and performance of a high-power CO2 wavelength laser

    NASA Astrophysics Data System (ADS)

    Conder, P. C.; Redding, J. R.; Jenkins, R. M.

    1985-02-01

    Two new methods for solving problems encountered in the design and construction of rugged, reliable, high-power, CO2 waveguide lasers in alumina are described. Both methods require the laser body to be manufactured in two halves with the waveguide profile machined into one or both pieces. The two halves are then precisely placed together and a vacuum-tight seal is created to complete the procedure. The first method involves applying a glass glaze to the seal surfaces and fusing the two halves together. In the second method, the two halves are thermodiffusion-bonded together without using any intervening seal material. The performance of a 10 W dc-excited CO2 waveguide laser is described.

  20. Study on folded resonator of high power transverse flow CO2 laser

    NASA Astrophysics Data System (ADS)

    Qin, Yingxiong; Tang, Xiahui; Liu, Juan; Peng, Hao; Deng, Qiansong

    2009-08-01

    A numerical model of the folded resonator is founded by using the eigenvector method. The beam characteristics and relative amplitude distribution of dominant mode of the N-shaped three-folded resonator with different aperture diameter are obtained by numerical simulation. The experiment of the resonator is done on HUST5000 high power transverse flow CO2 laser. The results show that the mode volume of the N-shaped three-folded resonator with the aperture diameter of 25mm can match the gain zone of the transverse flow CO2 laser well, the output power and beam mode are fit for industrial applications. The laser welding system based on this resonator is developed for gas generator of automobile safety airbag.

  1. Second user workshop on high-power lasers at the Linac Coherent Light Source

    SciTech Connect

    Heimann, Phil; Glenzer, Siegfried

    2015-05-28

    The second international workshop on the physics enabled by the unique combination of high-power lasers with the world-class Linac Coherent Light Source (LCLS) free-electron X-ray laser beam was held in Stanford, CA, on October 7–8, 2014. The workshop was co-organized by UC Berkeley, Lawrence Berkeley, Lawrence Livermore, and SLAC National Accelerator Laboratories. More than 120 scientists, including 40 students and postdoctoral scientists who are working in high-intensity laser-matter interactions, fusion research, and dynamic high-pressure science came together from North America, Europe, and Asia. The focus of the second workshop was on scientific highlights and the lessons learned from 16 new experiments that were performed on the Matter in Extreme Conditions (MEC) instrument since the first workshop was held one year ago.

  2. Robust cladding light stripper for high-power fiber lasers using soft metals.

    PubMed

    Babazadeh, Amin; Nasirabad, Reza Rezaei; Norouzey, Ahmad; Hejaz, Kamran; Poozesh, Reza; Heidariazar, Amir; Golshan, Ali Hamedani; Roohforouz, Ali; Jafari, S Naser Tabatabaei; Lafouti, Majid

    2014-04-20

    In this paper we present a novel method to reliably strip the unwanted cladding light in high-power fiber lasers. Soft metals are utilized to fabricate a high-power cladding light stripper (CLS). The capability of indium (In), aluminum (Al), tin (Sn), and gold (Au) in extracting unwanted cladding light is examined. The experiments show that these metals have the right features for stripping the unwanted light out of the cladding. We also find that the metal-cladding contact area is of great importance because it determines the attenuation and the thermal load on the CLS. These metals are examined in different forms to optimize the contact area to have the highest possible attenuation and avoid localized heating. The results show that sheets of indium are very effective in stripping unwanted cladding light.

  3. Ultra-flat supercontinuum generated from high-power, picosecond telecommunication fiber laser source.

    PubMed

    Liao, Ruoyu; Song, Youjian; Zhou, Xiaokang; Chai, Lu; Wang, Chingyue; Hu, Minglie

    2016-11-20

    An ultra-flat, high-power supercontinuum generated from a picosecond telecommunication fiber laser was presented. The pulse from a carbon nanotube mode-locked oscillator was amplified using an Er-Yb codoped fiber amplifier. The output of the system achieved an average power of 2.7 W, with the center wavelength at 1564 nm and a FWHM of 6 nm in the spectral domain. By passing this amplified high-power pulse through a 4.6 m highly nonlinear photonic crystal fiber, an ultra-flat supercontinuum spanning 1600-2180 nm is generated. And the average power of the supercontinuum achieves 1 W.

  4. Visible-wavelength semiconductor lasers and arrays

    DOEpatents

    Schneider, Jr., Richard P.; Crawford, Mary H.

    1996-01-01

    A visible semiconductor laser. The visible semiconductor laser includes an InAlGaP active region surrounded by one or more AlGaAs layers on each side, with carbon as the sole p-type dopant. Embodiments of the invention are provided as vertical-cavity surface-emitting lasers (VCSELs) and as edge-emitting lasers (EELs). One or more transition layers comprised of a substantially indium-free semiconductor alloy such as AlAsP, AlGaAsP, or the like may be provided between the InAlGaP active region and the AlGaAS DBR mirrors or confinement layers to improve carrier injection and device efficiency by reducing any band offsets. Visible VCSEL devices fabricated according to the invention with a one-wavelength-thick (1.lambda.) optical cavity operate continuous-wave (cw) with lasing output powers up to 8 mW, and a peak power conversion efficiency of up to 11%.

  5. Laser diode technology and applications V; Proceedings of the Meeting, Los Angeles, CA, Jan. 18-20, 1993

    NASA Astrophysics Data System (ADS)

    Renner, Daniel

    Various papers on laser diode technology and its applications are presented. The general topics addressed include: high-power coherent large-aperture sources, vertical-cavity lasers, quantum-well lasers, semiconductor laser reliability, high-power semiconductor lasers, surface-emitting lasers, laser dynamics, and visible and midinfrared semiconductor lasers.

  6. Centimeter-scale MEMS scanning mirrors for high power laser application

    NASA Astrophysics Data System (ADS)

    Senger, F.; Hofmann, U.; v. Wantoch, T.; Mallas, C.; Janes, J.; Benecke, W.; Herwig, Patrick; Gawlitza, P.; Ortega-Delgado, M.; Grune, C.; Hannweber, J.; Wetzig, A.

    2015-02-01

    A higher achievable scan speed and the capability to integrate two scan axes in a very compact device are fundamental advantages of MEMS scanning mirrors over conventional galvanometric scanners. There is a growing demand for biaxial high speed scanning systems complementing the rapid progress of high power lasers for enabling the development of new high throughput manufacturing processes. This paper presents concept, design, fabrication and test of biaxial large aperture MEMS scanning mirrors (LAMM) with aperture sizes up to 20 mm for use in high-power laser applications. To keep static and dynamic deformation of the mirror acceptably low all MEMS mirrors exhibit full substrate thickness of 725 μm. The LAMM-scanners are being vacuum packaged on wafer-level based on a stack of 4 wafers. Scanners with aperture sizes up to 12 mm are designed as a 4-DOF-oscillator with amplitude magnification applying electrostatic actuation for driving a motor-frame. As an example a 7-mm-scanner is presented that achieves an optical scan angle of 32 degrees at 3.2 kHz. LAMM-scanners with apertures sizes of 20 mm are designed as passive high-Q-resonators to be externally excited by low-cost electromagnetic or piezoelectric drives. Multi-layer dielectric coatings with a reflectivity higher than 99.9 % have enabled to apply cw-laser power loads of more than 600 W without damaging the MEMS mirror. Finally, a new excitation concept for resonant scanners is presented providing advantageous shaping of intensity profiles of projected laser patterns without modulating the laser. This is of interest in lighting applications such as automotive laser headlights.

  7. Semiconductor ring lasers as optical neurons

    NASA Astrophysics Data System (ADS)

    Coomans, W.; Gelens, L.; Mashal, L.; Beri, S.; Van der Sande, G.; Danckaert, J.; Verschaffelt, G.

    2012-06-01

    Semiconductor Ring Lasers (SRLs) are a modern class of semiconductor lasers whose active cavity is characterized by a circular geometry. This enables the laser to support two counterpropagating modes, referred to as the clockwise (CW) and the counterclockwise (CCW) mode. Semiconductor ring lasers have been shown to have a regime of operation in which they are excitable, when the linear coupling between the counterpropagating modes is asymmetric. This can be achieved by increasing the reflection of, for example, the CW mode into the CCW mode. This will stabilize lasing in the CCW mode. In the excitable regime, the SRL will fire optical pulses (spikes) in the CW mode as a response to noise perturbations. In this contribution we experimentally and theoretically characterize these spikes. Our experiments reveal a statistical distribution of the characteristics of the optical pulses that is not observed in regular excitable systems. In particular, an inverse correlation exists between the pulse amplitude and duration. Numerical simulations and an interpretation in an asymptotic phase space confirm and explain these experimentally observed pulse characteristics [L. Gelens et al., Phys. Rev. A 82 063841, 2010]. We will also theoretically consider asymmetric SRLs coupled through a single bus waveguide. This is a first step towards an integrated optical neural network using semiconductor ring lasers as building blocks. We will show that for weak coupling, excitatory excursions still persist due to the similar phase space structure. Moreover, the coupled SRLs can excite pulses in each other and can thus function as communicating neurons [W. Coomans et al., Phys. Rev. E 84 036209, 2011]. This type of neural network can be fully integrated on chip and does not suffer from the drawback of needing extra-cavity measures, such as optical injection or saturable absorbers.

  8. High Power Laser Diode Arrays for 2-Micron Solid State Coherent Lidars Applications

    NASA Technical Reports Server (NTRS)

    Amzajerdian, Farzin; Meadows, Byron; Kavaya, Michael J.; Singh, Upendra; Sudesh, Vikas; Baker, Nathaniel

    2003-01-01

    Laser diode arrays are critical components of any diode-pumped solid state laser systems, constraining their performance and reliability. Laser diode arrays (LDAs) are used as the pump source for energizing the solid state lasing media to generate an intense coherent laser beam with a high spatial and spectral quality. The solid state laser design and the characteristics of its lasing materials define the operating wavelength, pulse duration, and power of the laser diodes. The pump requirements for high pulse energy 2-micron solid state lasers are substantially different from those of more widely used 1-micron lasers and in many aspects more challenging [1]. Furthermore, the reliability and lifetime demanded by many coherent lidar applications, such as global wind profiling from space and long-range clear air turbulence detection from aircraft, are beyond the capability of currently available LDAs. In addition to the need for more reliable LDAs with longer lifetime, further improvement in the operational parameters of high power quasi-cw LDAs, such as electrical efficiency, brightness, and duty cycle, are also necessary for developing cost-effective 2-micron coherent lidar systems for applications that impose stringent size, heat dissipation, and power constraints. Global wind sounding from space is one of such applications, which is the main driver for this work as part of NASA s Laser Risk Reduction Program. This paper discusses the current state of the 792 nm LDA technology and the technology areas being pursued toward improving their performance. The design and development of a unique characterization facility for addressing the specific issues associated with the LDAs for pumping 2-micron coherent lidar transmitters and identifying areas of technological improvement will be described. Finally, the results of measurements to date on various standard laser diode packages, as well as custom-designed packages with potentially longer lifetime, will be reported.

  9. Energy coupling and plume dynamics during high power laser heating of metals

    SciTech Connect

    Jeong, S. |

    1997-05-01

    High power laser heating of metals was studied utilizing experimental and numerical methods with an emphasis on the laser energy coupling with a target and on the dynamics of the laser generated vapor flow. Rigorous theoretical modeling of the heating, melting, and evaporation of metals due to laser radiation with a power density below the plasma shielding threshold was carried out. Experimentally, the probe beam deflection technique was utilized to measure the propagation of a laser induced shock wave. The effects of a cylindrical cavity in a metal surface on the laser energy coupling with a solid were investigated utilizing photothermal deflection measurements. A numerical calculation of target temperature and photothermal deflection was performed to compare with the measured results. Reflection of the heating laser beam inside the cavity was found to increase the photothermal deflection amplitude significantly and to enhance the overall energy coupling between a heating laser beam and a solid. Next, unsteady vaporization of metals due to nanosecond pulsed laser heating with an ambient gas at finite pressure was analyzed with a one dimensional thermal evaporation model for target heating and one dimensional compressible flow equations for inviscid fluid for the vapor flow. Lastly, the propagation of a shock wave during excimer laser heating of aluminum was measured with the probe beam deflection technique. The transit time of the shock wave was measured at the elevation of the probe beam above the target surface; these results were compared with the predicted behavior using ideal blast wave theory. The propagation of a gaseous material plume was also observed from the deflection of the probe beam at later times.

  10. Ultrafast Modulation of Semiconductor Lasers Through a Terahertz Field

    NASA Technical Reports Server (NTRS)

    Ning, Cun-Zheng; Hughes, Steven; Citrin, David

    1998-01-01

    We demonstrate, by means of numerical simulation, a new mechanism to modulate and switch semiconductor lasers at THz and sub-THz frequency rates. A sinusoidal terahertz field applied to a semiconductor laser heats the electron-hole plasma and consequently modifies the optical susceptibility. This allows an almost linear modulation of the output power of tile semiconductor laser and leads to a faithful reproduction of the terahertz-field waveform in the emitted laser intensity.

  11. Simulation study of the lethality effect of high-power laser with supersonic air flow

    NASA Astrophysics Data System (ADS)

    Peng, Xin; Zhao, Guomin; Chen, Minsun

    2016-10-01

    The lethality effect of high power laser on target is simulated with CFD method under different conditions of supersonic air flow on the surface of the target. Materials used in the experiments are 2cm aluminum plate. With the Mach number changing from 1 to 5, the lethality effects of the high power laser can be obtained from the simulations under these conditions of supersonic air flow. The flow-structure-laser coupling impact on the failure time of the target is discussed based on the simulation. Results show that with the increase of mach number, the effect on the aluminum plate is increase first and then decrease by the pressure. Because that it is obvious that the maximum area of pressure is away from the center of deformation region when the mach number is bigger than 5 . At the same time, when mach number is increase, the aerodynamic heating play more important role than the convective heat transfer on the temperature field of aluminum plate. there are two impacts from the supersonic flow. Firstly , the flow can produce the pressure on the surface of the aluminum plate. Secondly, the flow can produce aerodynamic heat on the aluminum plate.

  12. High-power high-brightness 808nm QCW laser diode mini bars

    NASA Astrophysics Data System (ADS)

    Huang, Hua; Wang, Jun; DeVito, Mark; Bao, Ling; Hodges, Aaron; Zhang, Shiguo; Wise, Damian; Grimshaw, Mike; Xu, Dapeng; Bai, Chendong

    2010-02-01

    A new class of high power high brightness 808 nm QCW laser diode mini bars has been developed. With nLight's nXLT facet passivation technology and improvements in epitaxial structure, mini bars of 3 mm bar width with high efficiency design have tested to over 280 W peak power with peak efficiency over 64% on conduction cooled CS packages, equivalent to output power density near 130 mW/μm. These mini laser bars open up new applications as compact, portable, and low current pump sources. Liftests have been carried out on conduction cooled CS packages and on QCW stacks. Over 370 million (M) shots lifetest with high efficiency design has been demonstrated on CS so far without failure, and over 80 M shots on QCW stacks with accelerated stress lifetest have also proven high reliability on mini bars with high temperature design. Failure analysis determined that the failure mechanism was related to bulk defects, showing that mini laser bars are not prone to facet failure, which is consistent with the large current pulse test and failure analysis on high power single emitters.

  13. Perspectives for neutron and gamma spectroscopy in high power laser driven experiments at ELI-NP

    SciTech Connect

    Negoita, F. Gugiu, M. Petrascu, H. Petrone, C. Pietreanu, D.; Fuchs, J.; Chen, S.; Higginson, D.; Vassura, L.; Hannachi, F.; Tarisien, M.; Versteegen, M.; Antici, P.; Balabanski, D.; Balascuta, S.; Cernaianu, M.; Dancus, I.; Gales, S.; Neagu, L.; Petcu, C.; and others

    2015-02-24

    The measurement of energy spectra of neutrons and gamma rays emitted by nuclei, together with charge particles spectroscopy, are the main tools for understanding nuclear phenomena occurring also in high power laser driven experiments. However, the large number of particles emitted in a very short time, in particular the strong X-rays flash produced in laser-target interaction, impose adaptation of technique currently used in nuclear physics experiment at accelerator based facilities. These aspects are discussed (Section 1) in the context of proposed studies at high power laser system of ELI-NP. Preliminary results from two experiments performed at Titan (LLNL) and ELFIE (LULI) facilities using plastic scintillators for neutron detection (Section 2) and LaBr{sub 3}(Ce) scintillators for gamma detection (Section 3) are presented demonstrating the capabilities and the limitations of the employed methods. Possible improvements of these spectroscopic methods and their proposed implementation at ELI-NP will be discussed as well in the last section.

  14. Amorphous structure evolution of high power diode laser cladded Fe-Co-B-Si-Nb coatings

    NASA Astrophysics Data System (ADS)

    Zhu, Yanyan; Li, Zhuguo; Huang, Jian; Li, Min; Li, Ruifeng; Wu, Yixiong

    2012-11-01

    Fe-Co-B-Si-Nb coatings were fabricated on the surface of low carbon steel using high power diode laser cladding of [(Fe0.5Co0.5)0.75B0.2Si0.05]95.7Nb4.3 amorphous powders at three different scanning speeds of 6, 17 and 50 m/s. At each scanning speed, laser power was optimized to obtain low dilution ratio. Scanning electron microscopy, X-ray diffraction, transmission electron microscopy with energy dispersive spectrometer and electron probe micro analysis were carried out to characterize the microstructure and chemical composition of the cladded coatings. Differential scanning calorimetry was also carried out to investigate the fraction of the amorphous phase. The results showed that dilution ratio and scanning speed were the two main factors for fabricating Fe-Co-B-Si-Nb amorphous coating by high power diode laser cladding. Low dilution ratio was crucial for the formation of amorphous phase. When the dilution ratio was low, the fraction of amorphous phase in the cladded coatings increased upon increasing the scanning speed.

  15. High-power picosecond laser with 400W average power for large scale applications

    NASA Astrophysics Data System (ADS)

    Du, Keming; Brüning, Stephan; Gillner, Arnold

    2012-03-01

    Laser processing is generally known for low thermal influence, precise energy processing and the possibility to ablate every type of material independent on hardness and vaporisation temperature. The use of ultra-short pulsed lasers offers new possibilities in the manufacturing of high end products with extra high processing qualities. For achieving a sufficient and economical processing speed, high average power is needed. To scale the power for industrial uses the picosecond laser system has been developed, which consists of a seeder, a preamplifier and an end amplifier. With the oscillator/amplifier system more than 400W average power and maximum pulse energy 1mJ was obtained. For study of high speed processing of large embossing metal roller two different ps laser systems have been integrated into a cylinder engraving machine. One of the ps lasers has an average power of 80W while the other has 300W. With this high power ps laser fluencies of up to 30 J/cm2 at pulse repetition rates in the multi MHz range have been achieved. Different materials (Cu, Ni, Al, steel) have been explored for parameters like ablation rate per pulse, ablation geometry, surface roughness, influence of pulse overlap and number of loops. An enhanced ablation quality and an effective ablation rate of 4mm3/min have been achieved by using different scanning systems and an optimized processing strategy. The max. achieved volume rate is 20mm3/min.

  16. Developing high-power hybrid resonant gain-switched thulium fiber lasers.

    PubMed

    Yan, Shuo; Wang, Yao; Zhou, Yan; Yang, Nan; Li, Yue; Tang, Yulong; Xu, Jianqiu

    2015-10-05

    In this paper, we propose hybrid-pumped resonant gain-switched thulium fiber lasers to realize high-average-power and high-pulse-energy 2-μm laser emissions. Based on numerical simulation, laser dynamics (pulse peak power, pulse energy, pulse duration, etc.) of this kind of laser system are investigated in detail. By taking advantages of the 793 nm continuous wave pump and the 1900 nm pulsed pump, performance of the laser emission can be significantly improved, with the highest average power of 28 W, peak power of 3.5 kW, pulse energy of 281 μJ, and narrowest pulse duration of 92 ns, all of which can be further optimized through designing the cavity parameters and the pumping circumstance. Compared with the pump pulses, two times improvement in pulse energy and average power has been achieved. This hybrid resonant gain-switched system has an all-fiber configuration and high efficiency (low heat load), and can be steadily extended into the cladding pump scheme, thus paving a new way to realize high power (>100 W average power) and high pulse energy (>1 mJ) 2 μm thulium fiber lasers.

  17. High-power diode lasers operating around 1500-nm for eyesafe applications

    NASA Astrophysics Data System (ADS)

    Patterson, Steve; Leisher, Paul; Price, Kirk; Kennedy, Keith; Dong, Weimin; Grimshaw, Mike; Zhang, Shiguo; Patterson, Jason; Das, Suhit; Karlsen, Scott; Martinsen, Rob; Bell, Jake

    2008-04-01

    Er:YAG solid state lasers offer an "eye-safe" alternative to traditional Nd:YAG lasers for use in military and industrial applications such as range-finding, illumination, flash/scanning LADAR, and materials processing. These laser systems are largely based on diode pumped solid state lasers that are subsequently (and inefficiently) frequency-converted using optical parametric oscillators. Direct diode pumping of Er:YAG around 1.5 μm offers the potential for greatly increased system efficiency, reduced system complexity/cost, and further power scalability. Such applications have been driving the development of high-power diode lasers around these wavelengths. For end-pumped rod and fiber applications requiring high brightness, nLIGHT has developed a flexible package format, based on scalable arrays of single-emitter diode lasers and efficiently coupled into a 400 μm core fiber. In this format, a rated power of 25 W is reported for modules operating at 1.47 μm, with a peak electrical to optical conversion efficiency of 38%. In centimeter-bar on copper micro-channel cooler format, maximum continuous wave power in excess of 100 W at room temperature and conversion efficiency of 50% at 6C are reported. Copper heat sink conductively-cooled bars show a peak electrical-to-optical efficiency of 43% with 40 W of maximum continuous wave output power. Also reviewed are recent reliability results at 1907-nm.

  18. New generation high-power rare-earth-doped phosphate glass fiber and fiber laser

    NASA Astrophysics Data System (ADS)

    Wu, Ruikun; Myers, John D.; Myers, Michael J.

    2001-04-01

    High power, high brightness fiber lasers have numerous potential commercial and military applications. Fiber lasers with cladding pump designs represent a new generation of diode pumped configurations that are extremely efficient, have single mode output and may be operated with or without active cooling. Kigre has invented a new family of Er/Yb/Nd phosphate laser glass materials (designated QX) that promise to facilitate a quantum leap in fiber laser technology of this field. The new phosphate glass Rare-Earth doped fiber exhibit many advantages than Silica or Fluoride base fiber, see table.1. Instead of 30 to 50 meters of fused silica with a 50 mm bend radii; Kigre's phosphate glass fiber amplifiers may be designed to be less than 4 meters long .Laser performance and various design parameters, such as the fiber core diameter, NA, inner cladding shape and doping concentration are evaluated. Laser performances was demonstrated for an experimental QX/Er doubled clading fiber commissioned by MIT having 8 micron core, a 240 X 300 micron rectangle shaped inner cladding with 0.4 NA and 500 micron outer clading.. Kigre obtained approximately 2 dB/cm gain from 15cm long fiber under 940nm pumping The same fiber was evaluated by researcher at MIT. They used 975nm pump source. Maximum 270mW output was demonstrated by 30 cm long fiber with Fresnel reflection resonator mirrors. The slope efficiency of absorbed pump power s 47%.

  19. High-power thulium-doped fiber laser in an all-fiber configuration

    NASA Astrophysics Data System (ADS)

    Baravets, Yauhen; Todorov, Filip; Honzatko, Pavel

    2016-12-01

    High-power Tm-doped fiber lasers are greatly suitable for various applications, such as material processing, medicine, environmental monitoring and topography. In this work we present an all-fiber narrowband CW laser in near fundamental mode operation based on a Tm-doped double-clad active fiber pumped by 793 nm laser diodes with a central wavelength stabilized at 2039 nm by a fiber Bragg grating. The achieved output power is 60 W with a slope efficiency of 46%. The measured beam quality factor is less than 1.4. Further increasing of the output power is possible using various power scaling techniques, for example, coherent combination of several Tm-doped fiber lasers. The developed fiber laser could be employed for welding, cutting and marking of thermoplastics in industry, minimally invasive surgery in medicine or sensors in lidar systems. Future improvements of thulium fiber lasers are possible due to the extremely wide gain-bandwidth of the active medium and the rapid growth of 2-μm fiber components production.

  20. High-power GaN diode-pumped continuous wave Pr3+-doped LiYF4 laser.

    PubMed

    Hashimoto, Kohei; Kannari, Fumihiko

    2007-09-01

    A cw Pr(3+):LiYF(4) laser at 639 nm pumped by a high-power GaN laser diode (444 nm) is demonstrated. The highest laser power of 112 mW is achieved with an optical-optical conversion efficiency of 33.5%. Characteristics of this laser at elevated temperatures are also investigated for practical applications such as a laser projector.