Science.gov

Sample records for increased laser power

  1. Investigation into the absorptivity change in metals with increased laser power

    NASA Astrophysics Data System (ADS)

    Blidegn, M. Sc. K.; Olsen, Flemming O.

    1997-04-01

    At first glance the low absorptivity of metals in the infrared (IR) makes the use of YAG or carbon-dioxide lasers in metal processing very inefficient. However, it has been demonstrated that the absorptivity can reach significantly higher levels during the high power laser interaction. An increase which cannot be explained by the increase in temperature only. The interaction between laser light and metals is a major physical phenomena in laser material processing and when modeling processes the Drude free electron model or simplifications, such as the Hagen-Rubens relation, have often been used. This paper discusses the need to extend the Drude model taking into account interband transitions and anormal skin effect at low light intensities and a multiphoton absorption model in order to describe the increase in the absorptivity at high intensities. The model is compared with experimental results carried out at low power, and tested on experimental absorptivity measurements at high power YAG laser pulses, found in literature.

  2. Progress in increasing the maximum achievable output power of broad area diode lasers

    NASA Astrophysics Data System (ADS)

    Crump, P.; Wenzel, H.; Erbert, G.; Tränkle, G.

    2012-03-01

    High power broad area diode lasers provide the optical energy for all high performance laser systems, either directly or as pump sources for solid-state lasers. Continuous improvement is required in the peak achievable output power of these diode laser devices in order to enable performance improvements in full laser systems. In recent years, device technology has advanced to the point where the main limit to optical power is no longer device failure, but is instead power saturation due to various physical effects within the semiconductor device itself. For example, the combination of large optical cavity designs with advanced facet passivation means that facet failure is no longer the dominant limiting factor. Increases in the optical power therefore require firstly a clear identification of the limiting mechanisms, followed by design changes and material improvements to address these. Recent theoretical and experimental diagnostic studies at the Ferdinand-Braun-Institut have helped trace the saturation effects to three main effects: gain saturation, longitudinal-holeburning and current driven carrier leakage. Design changes based on these studies have enabled increases in the achievable emitted power density from broad area lasers. Recent experimental examples include ~100W from 100μm stripes under short-pulsed conditions, > 30W from 100μm stripes under quasi-continuous wave conditions and > 10W from 30μm stripes under continuous wave conditions. An overview of the results of the diagnostic studies performed at the FBH will be presented, and the design changes necessary to address the observed power saturation will be discussed.

  3. Significant increase in wavelength, power, and temperature operating envelopes for semiconductor laser diode bars for solid-state lasers

    NASA Astrophysics Data System (ADS)

    Haden, J.; Plano, B.; Major, J.; Harnagel, G.; Endriz, J.

    Attention is given to the substantial increase in the performance envelope of AlGaAs base semiconductor laser diode array bars (QCW bars) that are available to designers of diode pumped solid-state lasers. Reliable QCW bar performance includes operation to 100 W/cm with greater than 10 exp 9 pulse life, 65 C operation, and 780 to 980 nm wavelength availability (60 W/cm). Consideration is also given to 247-W QCW operation. At Nd:YAG, YLF wavelengths (798-807 nm), significant improvements have been achieved in allowable operating temperature (to 65 C) and operating power (to 100 W). These improvements offer the opportunity for the design of high-efficiency solid-state laser systems that need to operate in relatively severe environments.

  4. Systemic increase in blood flow in conditions of disturbed microcirculation after low-power laser irradiation

    NASA Astrophysics Data System (ADS)

    Schindl, Andreas; Schindl, Liesbeth

    1996-11-01

    As described earlier by our group, topical application of low power laser irradiation seems to have a systemic effect in terms of improving microcirculation in patients suffering from microangiopathic disorders. The aim of the presented study was to prove these clinical findings by measuring the skin temperature as a parameter of microcirculation suing an infrared-thermography-camera system. Patients who attended the Institute for Laser medicine between January and July 1996 and suffered from angiopathy of different origin were examined. The laser system used was a combined IR/HeNe- laser, power output 30mW, irradiation time was varied to keep the IED at a value of 20J/cm2. Irradiation was performed proximally to the affected area, the contralateral side being left untreated, IR-thermography was started after reaching adaption to the room temperature, with pictures of both extremities taken in 10 minute intervals during the irradiation and up to 45 minutes after stopping the irradiation. Results show a rise in temperature over the affected region as well as over the contralateral extremity, with maximal changes of up to + 3.0 degrees C. The improvement of blood flow started 15 min. after the onset of laser irradiation and persisted up to 45 min. after stopping the irradiation. The results obtained are in good accordance with findings of previously performed studies, undertaken with patients with autoimmune-angiopathies such as Buerger's disease. Therefore, we conclude that topical application of low power lasers is able to induce a systemic improvement of blood flow in conditions of disturbed microcirculation.

  5. Laser satellite power systems

    SciTech Connect

    Walbridge, E.W.

    1980-01-01

    A laser satellite power system (SPS) converts solar power captured by earth-orbiting satellites into electrical power on the earth's surface, the satellite-to-ground transmission of power being effected by laser beam. The laser SPS may be an alternative to the microwave SPS. Microwaves easily penetrate clouds while laser radiation does not. Although there is this major disadvantage to a laser SPS, that system has four important advantages over the microwave alternative: (1) land requirements are much less, (2) radiation levels are low outside the laser ground stations, (3) laser beam sidelobes are not expected to interfere with electromagnetic systems, and (4) the laser system lends itself to small-scale demonstration. After describing lasers and how they work, the report discusses the five lasers that are candidates for application in a laser SPS: electric discharge lasers, direct and indirect solar pumped lasers, free electron lasers, and closed-cycle chemical lasers. The Lockheed laser SPS is examined in some detail. To determine whether a laser SPS will be worthy of future deployment, its capabilities need to be better understood and its attractiveness relative to other electric power options better assessed. First priority should be given to potential program stoppers, e.g., beam attenuation by clouds. If investigation shows these potential program stoppers to be resolvable, further research should investigate lasers that are particularly promising for SPS application.

  6. Increased power, pulse length, and spectral purity free-electron laser for inverse-Compton X-ray production and laser induced breakdown spectroscopy of thin film photovoltaics

    NASA Astrophysics Data System (ADS)

    Kowalczyk, Jeremy M.

    The free-electron laser (FEL) system can be configured to produce X-ray or extreme ultraviolet (EUV) light via Compton backscattering and to perform many types of spectroscopy including laser induced breakdown spectroscopy (LIBS). In it's most common incarnation, the FEL is limited by three major factors: average laser power, laser spectral purity, and laser pulse length. Some examples of the limitations that these shortcomings give rise to include limiting the range of remote spectroscopy, degrading spectroscopic precision, and lowering the attainable x-ray flux, respectively. In this work, we explored three methods of improving the FEL. First, a beam expanding optic dubbed the TIRBBE was designed, built, and tested to prevent laser damage to the resonator mirrors and allow for higher average power. This optic had the added benefit of increasing the spectral purity. Second, a intra-cavity etalon filter dubbed the FROZEN FISH was designed, built, and tested to increase spectral purity and eliminate the frequency pulling (tendency of an FEL to pull towards longer wavelengths during a macropulse) all in a high damage threshold, fully wavelength adjustable package. Finally, a laser cooling scheme which allows for extension of the electron beam macropulse used to create the FEL light by counter-acting electron back-heating was explored. The first measurements of the back-heating temperature rise were taken, calculations of the required laser parameters were made, design of the full system was completed, and construction has begun. Experimental work using LIBS to characterize thin film solar cells was also completed in anticipation of using the improved FEL to better characterize such materials. The frequency tunability and picosecond micropulse width of the FEL will allow for exploration of the frequency response of LIBS ablation and fine resolution of the make up of these materials with depth unattainable with a conventional fixed frequency nanosecond pulse laser.

  7. Laser power transmission

    NASA Technical Reports Server (NTRS)

    Conway, Edmund J.

    1992-01-01

    An overview of previous studies related to laser power transmission is presented. Particular attention is given to the use of solar pumped lasers for space power applications. Three general laser mechanisms are addressed: photodissociation lasing driven by sunlight, photoexcitation lasing driven directly by sunlight, and photoexcitation lasing driven by thermal radiation.

  8. High power laser dump

    NASA Astrophysics Data System (ADS)

    Hsu, M. S.; Hsu, J. P.

    1985-08-01

    A high power laser dump has defined laser beam introduction angles to the internal surface of a cylinder to maximize energy dispersion and absorption and, has two zones formed of distinctive reflective and absorbing materials.

  9. Laser power transmission.

    NASA Technical Reports Server (NTRS)

    Ahlstrom, H. G.; Christiansen, W. H.; Hertzberg, A.

    1971-01-01

    Description of studies which have led to the design of a conceptual device in which the limitation of transforming heat into coherent radiation can be examined. By exploring the basic thermodynamic relationships controlling the operation of this device, it is concluded that a closed-cycle gasdynamic laser is possible in which all of the shaft energy supplied can be turned into laser radiation. Hence, it is possible in principle to convert heat into coherent radiation with approximately the same efficiency with which heat may be converted into electricity. By modifying the closed-cycle-gasdynamic-laser system, this system can be operated in reverse and the incoming radiation may be used to pump the gas in the loop so that shaft power can be extracted. By carefully controlling the temperature distribution in this machine, laser energy can be converted into useful shaft energy with an efficiency approaching 1 .

  10. Solar driven lasers for power satellite applications

    NASA Technical Reports Server (NTRS)

    Taussio, R.; Cassady, P.; Klosterman, E.

    1980-01-01

    The technological feasibility of using multimagawatt lasers for space power transmission is discussed. Candidate lasers include electric discharge lasers, direct optically pumped lasers, and free electron lasers.

  11. 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.

  12. Power Play, Laser Style

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Under a NASA SBIR (Small Business Innovation Research) SDL, Inc., has developed the TC40 Single-Frequency Continuously Tunable 500 mw Laser Diode System. This is the first commercially available single frequency diode laser system that offers the broad tunability and the high powers needed for atomic cooling and trapping as well as a variety of atomic spectroscopy techniques. By greatly decreasing both the equipment and the costs of entry, the TC40 enables researchers to pursue some of the most interesting areas of physical chemistry, biochemistry, and atomic physics.

  13. Gas-laser power monitor

    NASA Technical Reports Server (NTRS)

    Russ, C. E., Jr.

    1981-01-01

    Device attaches simply to front of laser housing for continuous monitoring of power output. Monitor is calibrated to read either total output or power generated in test volume. It is fabricated from four black-anodized aluminum parts; crown glass positioned at Brewster angle reflects 0.33 percent of beam onto photodiode calibrated for electrical output proportional to laser power. Unlike conventional calorimeter, monitor does not interrupt laser beams, and fast-response diode allows instantaneous tracking of power fluctuations.

  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. Laser powered interorbital vehicle

    NASA Technical Reports Server (NTRS)

    Clarke, M. T.; Cooper, J. J.; Eggleston, G. P.; Farkas, M. A.; Hunt, D. C.; King, J.; Nguyen, H.; Rahal, G.; Saw, K.; Tipton, R.

    1989-01-01

    A preliminary design of a low-thrust Laser Powered Interorbital Vehicle (LPIV) intended for cargo transportation between an Earth space station and a lunar base is presented. The selected mission utilizes a spiral trajectory, characteristic of a low-thrust spacecraft, requiring eight days for a lunar rendezvous and an additional nine days for return. The ship's configuration consists primarily of an optical train, two hydrogen plasma engines, a 37.1 m box-beam truss, a payload module, and propellant tanks. The total mass of the vehicle, fully loaded, is 63,300 kg. A single plasma, regeneratively cooled engine design is incorporated into the two 500 N engines. These are connected to the spacecraft by turntables that allow the vehicle to thrust tangential to the flight path. Proper collection and transmission of the laser beam to the thrust chambers is provided through the optical train. This system consists of a 23-m-diameter primary mirror, a convex parabolic secondary mirror, a beam splitter, and two concave parabolic tertiary mirrors. The payload bay is capable of carrying 18,000 kg of cargo and is located opposite the primary mirror on the main truss. Fuel tanks carrying a maximum of 35,000 kg of liquid hydrogen are fastened to tracks that allow the tanks to be moved perpendicular to the main truss. This capability is required to prevent the center of mass from moving out of the thrust vector line. The laser beam is located and tracked by means of an acquisition, pointing, and tracking system that can be locked onto the space-based laser station. Correct orientation of the spacecraft with the laser beam is maintained by control moment gyros and reaction control rockets. In addition, an aerobrake configuration was designed to provide the option of using the atmospheric drag in place of propulsion for a return trajectory.

  16. Laser-powered lunar base

    NASA Technical Reports Server (NTRS)

    Costen, R.; Humes, Donald H.; Walker, G. H.; Williams, M. D.; Deyoung, Russell J.

    1989-01-01

    The objective was to compare a nuclear reactor-driven Sterling engine lunar base power source to a laser-to-electric converter with orbiting laser power station, each providing 1 MW of electricity to the lunar base. The comparison was made on the basis of total mass required in low-Earth-orbit for each system. This total mass includes transportation mass required to place systems in low-lunar orbit or on the lunar surface. The nuclear reactor with Sterling engines is considered the reference mission for lunar base power and is described first. The details of the laser-to-electric converter and mass are discussed. The next two solar-driven high-power laser concepts, the diode array laser or the iodine laser system, are discussed with associated masses in low-lunar-orbit. Finally, the payoff for laser-power beaming is summarized.

  17. Laser power dependence of mechanoluminescence in metals.

    PubMed

    Sonwane, V D; Gour, Anubha S; Jha, Piyush

    2016-12-01

    Mechanoluminescence (ML) glow is produced on the back side when the front of a metal sample is irradiated with infrared Nd:YAG laser pulses. An incident laser beam with a power density below the plasma-flare onset threshold causes a rise in temperature in the studied metal. As the incident laser power density increases, the intensity of the ML glow signal also increases. On the basis of the laser power density-induced temperature, an expression is derived for the temperature-induced thermal stress. An expression is derived for the correlation between thermal stress and laser power density, which indicates that the temperature-induced thermal stress is directly related to the incident laser power density. In the region of plastic deformation, temperature-induced thermal stress is related to the strain and, consequently, to the emitted ML intensity. Finally, an expression is derived for the laser power dependence of the ML intensity, and good agreement is found between the theoretical and experimental results. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  18. Direct nuclear-powered lasers

    NASA Technical Reports Server (NTRS)

    Jalufka, N. W.

    1983-01-01

    The development of direct nuclear pumped lasers is reviewed. Theoretical and experimental investigations of various methods of converting the energy of nuclear fission fragments to laser power are summarized. The development of direct nuclear pumped lasers was achieved. The basic processes involved in the production of a plasma by nuclear radiation were studied. Significant progress was accomplished in this area and a large amount of basic data on plasma formation and atomic and molecular processes leading to population inversions is available.

  19. 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.

  20. 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.

  1. 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

  2. Laser-powered Martian rover

    NASA Technical Reports Server (NTRS)

    Harries, W. L.; Meador, W. E.; Miner, G. A.; Schuster, Gregory L.; Walker, G. H.; Williams, M. D.

    1989-01-01

    Two rover concepts were considered: an unpressurized skeleton vehicle having available 4.5 kW of electrical power and limited to a range of about 10 km from a temporary Martian base and a much larger surface exploration vehicle (SEV) operating on a maximum 75-kW power level and essentially unrestricted in range or mission. The only baseline reference system was a battery-operated skeleton vehicle with very limited mission capability and range and which would repeatedly return to its temporary base for battery recharging. It was quickly concluded that laser powering would be an uneconomical overkill for this concept. The SEV, on the other hand, is a new rover concept that is especially suited for powering by orbiting solar or electrically pumped lasers. Such vehicles are visualized as mobile habitats with full life-support systems onboard, having unlimited range over the Martian surface, and having extensive mission capability (e.g., core drilling and sampling, construction of shelters for protection from solar flares and dust storms, etc.). Laser power beaming to SEV's was shown to have the following advantages: (1) continuous energy supply by three orbiting lasers at 2000 km (no storage requirements as during Martian night with direct solar powering); (2) long-term supply without replacement; (3) very high power available (MW level possible); and (4) greatly enhanced mission enabling capability beyond anything currently conceived.

  3. Laser-powered Martian rover

    NASA Astrophysics Data System (ADS)

    Harries, W. L.; Meador, W. E.; Miner, G. A.; Schuster, Gregory L.; Walker, G. H.; Williams, M. D.

    1989-07-01

    Two rover concepts were considered: an unpressurized skeleton vehicle having available 4.5 kW of electrical power and limited to a range of about 10 km from a temporary Martian base and a much larger surface exploration vehicle (SEV) operating on a maximum 75-kW power level and essentially unrestricted in range or mission. The only baseline reference system was a battery-operated skeleton vehicle with very limited mission capability and range and which would repeatedly return to its temporary base for battery recharging. It was quickly concluded that laser powering would be an uneconomical overkill for this concept. The SEV, on the other hand, is a new rover concept that is especially suited for powering by orbiting solar or electrically pumped lasers. Such vehicles are visualized as mobile habitats with full life-support systems onboard, having unlimited range over the Martian surface, and having extensive mission capability (e.g., core drilling and sampling, construction of shelters for protection from solar flares and dust storms, etc.). Laser power beaming to SEV's was shown to have the following advantages: (1) continuous energy supply by three orbiting lasers at 2000 km (no storage requirements as during Martian night with direct solar powering); (2) long-term supply without replacement; (3) very high power available (MW level possible); and (4) greatly enhanced mission enabling capability beyond anything currently conceived.

  4. High power disk lasers: advances and applications

    NASA Astrophysics Data System (ADS)

    Havrilla, David; Holzer, Marco

    2011-02-01

    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 well over 1000 high power disk lasers installations, 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 important details of the TruDisk laser series and process relevant features of the system, 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. Power beaming with FEL lasers

    NASA Astrophysics Data System (ADS)

    Lampel, Michael C.; Curtin, Mark S.; Burke, Robert J.; Cover, Ralph A.; Rakowsky, George; Bennett, Glenn T.

    1993-06-01

    FEL power beaming has broad application to space operations. The Rocketdyne Division of Rockwell International Corporation has examined the commercial applications of beamed power from Earth to space using the Radio Frequency LINAC Free Electron Laser (RF FEL) and has determined that there is a substantial addressable market. Rocketdyne's experience in developing and demonstrating FEL technologies, optics and atmospheric compensation and advanced power and power distribution systems ideally positions the Division to conduct the initial demonstration to prove the feasibility of using a FEL to beam power to space platforms.

  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. 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.

  9. CONFOCAL MICROSCOPY SYSTEM PERFORMANCE: LASER POWER MEASUREMENTS

    EPA Science Inventory

    Laser power abstract
    The reliability of the confocal laser-scanning microscope (CLSM) to obtain intensity measurements and quantify fluorescence data is dependent on using a correctly aligned machine that contains a stable laser power. The laser power test appears to be one ...

  10. CONFOCAL MICROSCOPY SYSTEM PERFORMANCE: LASER POWER MEASUREMENTS

    EPA Science Inventory

    Laser power abstract
    The reliability of the confocal laser-scanning microscope (CLSM) to obtain intensity measurements and quantify fluorescence data is dependent on using a correctly aligned machine that contains a stable laser power. The laser power test appears to be one ...

  11. High Power Fiber Lasers

    DTIC Science & Technology

    2012-08-02

    was measured using a Fabry Perot interferometer. Resonance wavelength output varied from 1975 to 1989 nm with an average value of 1983 nm while...wavefront sensor ,” Directed Energy Professional Society (DEPS) Solid State Diode Laser Technology Review (SSDLTR) 2011. 45. R.A. Sims, P. Kadwani, C.C.C...for all fiber diameters, pressure driven coating system using pressures from 0.8 to 1.0 bar with coating head die sizes; 375 m (entrance die) with

  12. 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.

  13. Laser Powered Aircraft Takes Flight

    NASA Technical Reports Server (NTRS)

    2003-01-01

    A team of NASA researchers from Marshall Space Flight Center (MSFC) and Dryden Flight Research center have proven that beamed light can be used to power an aircraft, a first-in-the-world accomplishment to the best of their knowledge. Using an experimental custom built radio-controlled model aircraft, the team has demonstrated a system that beams enough light energy from the ground to power the propeller of an aircraft and sustain it in flight. Special photovoltaic arrays on the plane, similar to solar cells, receive the light energy and convert it to electric current to drive the propeller motor. In a series of indoor flights this week at MSFC, a lightweight custom built laser beam was aimed at the airplane `s solar panels. The laser tracks the plane, maintaining power on its cells until the end of the flight when the laser is turned off and the airplane glides to a landing. The laser source demonstration represents the capability to beam more power to a plane so that it can reach higher altitudes and have a greater flight range without having to carry fuel or batteries, enabling an indefinite flight time. The demonstration was a collaborative effort between the Dryden Center at Edward's, California, where the aircraft was designed and built, and MSFC, where integration and testing of the laser and photovoltaic cells was done. Laser power beaming is a promising technology for consideration in new aircraft design and operation, and supports NASA's goals in the development of revolutionary aerospace technologies. Photographed with their invention are (from left to right): David Bushman and Tony Frackowiak, both of Dryden; and MSFC's Robert Burdine.

  14. Social Power Increases Interoceptive Accuracy

    PubMed Central

    Moeini-Jazani, Mehrad; Knoeferle, Klemens; de Molière, Laura; Gatti, Elia; Warlop, Luk

    2017-01-01

    Building on recent psychological research showing that power increases self-focused attention, we propose that having power increases accuracy in perception of bodily signals, a phenomenon known as interoceptive accuracy. Consistent with our proposition, participants in a high-power experimental condition outperformed those in the control and low-power conditions in the Schandry heartbeat-detection task. We demonstrate that the effect of power on interoceptive accuracy is not explained by participants’ physiological arousal, affective state, or general intention for accuracy. Rather, consistent with our reasoning that experiencing power shifts attentional resources inward, we show that the effect of power on interoceptive accuracy is dependent on individuals’ chronic tendency to focus on their internal sensations. Moreover, we demonstrate that individuals’ chronic sense of power also predicts interoceptive accuracy similar to, and independent of, how their situationally induced feeling of power does. We therefore provide further support on the relation between power and enhanced perception of bodily signals. Our findings offer a novel perspective–a psychophysiological account–on how power might affect judgments and behavior. We highlight and discuss some of these intriguing possibilities for future research. PMID:28824501

  15. Phased laser array for generating a powerful laser beam

    DOEpatents

    Holzrichter, John F.; Ruggiero, Anthony J.

    2004-02-17

    A first injection laser signal and a first part of a reference laser beam are injected into a first laser element. At least one additional injection laser signal and at least one additional part of a reference laser beam are injected into at least one additional laser element. The first part of a reference laser beam and the at least one additional part of a reference laser beam are amplified and phase conjugated producing a first amplified output laser beam emanating from the first laser element and an additional amplified output laser beam emanating from the at least one additional laser element. The first amplified output laser beam and the additional amplified output laser beam are combined into a powerful laser beam.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Potential converter for laser-power beaming

    NASA Technical Reports Server (NTRS)

    Walker, Gilbert H.; Williams, Michael D.; Schuster, Gregory L.; Iles, Peter A.

    1991-01-01

    Future space missions, such as those associated with the Space Exploration Initiative (SEI), will require large amounts of power for operation of bases, rovers, and orbit transfer vehicles. One method for supplying this power is to beam power from a spaced based or Earth based laser power station to a receiver where laser photons can be converted to electricity. Previous research has described such laser power stations orbiting the Moon and beaming power to a receiver on the surface of the Moon by using arrays of diode lasers. Photovoltaic converters that can be efficiently used with these diode lasers are described.

  2. 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.

  3. A laser-powered flight transportation system

    NASA Technical Reports Server (NTRS)

    Hertzberg, A.; Sun, K. C.; Jones, W. S.

    1978-01-01

    Laser energy transmitted from a solar-power satellite via a set of relay satellites is used to power a cruising air transport; i.e., a laser-powered airplane. The result is a nearly fuelless pollution-free flight transportation system which is cost competitive with the fuel-conservative airplane of the future. The major components of this flight system include a laser-power satellite, relay satellites, laser-powered turbofans, and a conventional airframe. The relay satellites are orbiting optical systems which intercept the beam from a power satellite and refocus and redirect the beam to its next target.

  4. A laser-powered flight transportation system

    NASA Technical Reports Server (NTRS)

    Hertzberg, A.; Sun, K. C.; Jones, W. S.

    1978-01-01

    Laser energy transmitted from a solar-power satellite via a set of relay satellites is used to power a cruising air transport; i.e., a laser-powered airplane. The result is a nearly fuelless pollution-free flight transportation system which is cost competitive with the fuel-conservative airplane of the future. The major components of this flight system include a laser-power satellite, relay satellites, laser-powered turbofans, and a conventional airframe. The relay satellites are orbiting optical systems which intercept the beam from a power satellite and refocus and redirect the beam to its next target.

  5. Laser power conversion system analysis, volume 2

    NASA Technical Reports Server (NTRS)

    Jones, W. S.; Morgan, L. L.; Forsyth, J. B.; Skratt, J. P.

    1979-01-01

    The orbit-to-ground laser power conversion system analysis investigated the feasibility and cost effectiveness of converting solar energy into laser energy in space, and transmitting the laser energy to earth for conversion to electrical energy. The analysis included space laser systems with electrical outputs on the ground ranging from 100 to 10,000 MW. The space laser power system was shown to be feasible and a viable alternate to the microwave solar power satellite. The narrow laser beam provides many options and alternatives not attainable with a microwave beam.

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

    NASA Astrophysics Data System (ADS)

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

    1996-04-01

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

  7. Master-Oscillator/Power-Amplifier Laser System

    NASA Technical Reports Server (NTRS)

    Yu, Anthony W.; Krainak, Michael A.; Unger, Glenn L.

    1994-01-01

    Master-oscillator/power-amplifier (MOPA) laser system operates in continuous-wave mode or in amplitude-modulation (e.g., pulse) mode by modulation of oscillator current. Power amplifier is laser-diode-pumped neodymium:yttrium lithium fluoride (Nd:YLF) laser; oscillator is laser diode. Offers relatively high efficiency and power. Because drive current to oscillator modulated, external electro-optical modulator not needed. Potential uses include free-space optical communications, coded laser ranging, and generation of high-power, mode-locked pulses.

  8. Master-Oscillator/Power-Amplifier Laser System

    NASA Technical Reports Server (NTRS)

    Yu, Anthony W.; Krainak, Michael A.; Unger, Glenn L.

    1994-01-01

    Master-oscillator/power-amplifier (MOPA) laser system operates in continuous-wave mode or in amplitude-modulation (e.g., pulse) mode by modulation of oscillator current. Power amplifier is laser-diode-pumped neodymium:yttrium lithium fluoride (Nd:YLF) laser; oscillator is laser diode. Offers relatively high efficiency and power. Because drive current to oscillator modulated, external electro-optical modulator not needed. Potential uses include free-space optical communications, coded laser ranging, and generation of high-power, mode-locked pulses.

  9. 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.

  10. Green lasers are beyond power limits mandated by safety standards.

    PubMed

    Lee, M H; Fox, K; Goldwasser, S; Lau, D W M; Aliahmad, B; Sarossy, M

    2016-08-01

    There has been an increasing number of reports of people losing vision from laser exposure from pocket laser pointers despite the safety limit of 1 milliwatt (1mW) imposed by the Australian government. We hypothesize that this is because commercially available red and green laser pointers are exceeding their labeled power outputs. We tested the power outputs of 4 red and 4 green lasers which were purchased for less than AUD$30 each. The average of 10 measurements was recorded for each laser. We found that 3 out of 4 red lasers conformed to the 1mW safety standard; in contrast, all of the green lasers exceeded this limit, with one of the lasers recording an output of 127.9 mW. This contrast in compliance is explained by the construction of these lasers - green lasers are typically Diode Pumped Solid State (DPSS) lasers that can emit excessive infrared (IR) radiation with poor workmanship or inconsistent adherence to practices of safe design and quality control; red lasers are diode lasers which have limited power outputs due to `Catastrophic Optical Damage' (COD). Relevant professional bodies ought to advocate more strongly for stringent testing, quality control and licensing of DPSS lasers with a view towards government intervention to banning green laser pointer use.

  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. 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.

  13. Independent assessment of laser power beaming options

    NASA Technical Reports Server (NTRS)

    Ponikvar, Donald R.

    1992-01-01

    Technical and architectural issues facing a laser power beaming system are discussed. Issues regarding the laser device, optics, beam control, propagation, and lunar site are examined. Environmental and health physics aspects are considered.

  14. Metal vapor lasers with increased reliability

    NASA Astrophysics Data System (ADS)

    Soldatov, A. N.; Sabotinov, N. V.; Polunin, Yu. P.; Shumeiko, A. S.; Kostadinov, I. K.; Vasilieva, A. V.; Reimer, I. V.

    2015-12-01

    Results of investigation and development of an excitation pulse generator with magnetic pulse compression by saturation chokes for pumping of active media of CuBr, Sr, and Ca vapor lasers are presented. A high-power IGBT transistor is used as a commutator. The generator can operate at excitation pulse repetition frequencies up to 20 kHz. The total average power for all laser lines of the CuBr laser pumped by this generator is ~6.0 W; it is ~1.3-1.7 W for the Sr and Ca lasers.

  15. Laser power transmission concepts for Martian applications

    NASA Technical Reports Server (NTRS)

    De Young, R. J.; Conway, E. J.; Meador, W. E.; Humes, D. H.

    1989-01-01

    Long-term, highly reliable, flexible power will be required to support many diverse activities on Mars and for rapid development of the Mars environment. The potential of laser power transmission for supporting science, materials processing, transportation, and human habitats is discussed. Some advantageous locations for laser power stations in Mars orbit are developed.

  16. High Power CO Lasers And Their Application Potential

    NASA Astrophysics Data System (ADS)

    Maisenhalder, F.

    Comparing the state of development of high power gas lasers for civil applications, it can be seen that the CO2 laser is a well established tool; the CO laser, however, essentially remained a laboratory device. Hence, the question arises whether there will be an advantage to develop high power CO lasers for industrial applications, too. After a brief recapitulation of the typical CO-related properties, to help answering this question, the application potential of the CO laser, will be discussed. There are several wavelength-related advantages of the CO laser like increased absorption depth in glasses and crystals increased focal power density, and reduced plasma shielding. Furthermore, transmissive optical materials have considerably improved values for absorption and damage threshold, and finally power transmission through optical fibers is much more realistic in the near future for the 5 μm spectral range. In contrast to the variety of promising applications is the number of experimentally verified ones. This is due to the fact that only a few lasers are existing in the power range and in the developmental stage to be used for applications. In experiments CO lasers demonstrated advantages in the field of cutting and drilling metals and uranium isotope separation. Lasers in the high power range are developed in Japan, in the Soviet Union and in Germany. The types of lasers investigated in these countries differ from each other by the methods of gas cooling and excitation. Comparisons between Co- and CO2 lasers show that the system efficiencies of CO lasers are slightly higher by a factor of 1.3; the operation costs of CO lasers are reduced by the same factor. Investment and operation costs can be reduced considerably if for the planned application a high focal power density is used. Furthermore, the volumes of CO and CO2 lasers are comparable at present and in the future.

  17. Optimized high-power diode laser, laser arrays, and bars for pump applications

    NASA Astrophysics Data System (ADS)

    Hülsewede, R.; Schulze, H.; Sebastian, J.; Schröder, D.; Meusel, J.; Wolf, J.; Hennig, P.

    2009-02-01

    Broad area diode laser and diode laser bars are the most efficient light sources. In comparison to solid state laser or gas laser systems the over all beam quality of the diode laser is poor. Thus most application of diode laser bars is high efficient pumping of solid state lasers converting the beam quality and scaling the power of laser systems within the kW range. The pump efficiency and the beam coupling efficiency of the diode laser pumped systems has to be increased to meet the increasing laser market demands for reduced costs. JENOPTIK Diode Lab GmbH (JDL) has optimized their high power brilliance bars to enable reliable high power operation especially, for the 9xx nm wavelength range and low far field divergences. Superior reliability with long operation time of 13,000 hours and high power operation of 200 W are demonstrated for high power bars high filling factor mounted on passively cooled heat sinks. Smaller far field divergence at high power levels requires longer cavity length and higher efficiencies in the beam coupling needs requires lower filling factors. The new high brilliance bars and arrays with 20% filling factor are showing high power operation up to 95 W and a slow axis beam divergence of less than 8° (95% power content).

  18. High average power solid state laser power conditioning system

    SciTech Connect

    Steinkraus, R.F.

    1987-03-03

    The power conditioning system for the High Average Power Laser program at Lawrence Livermore National Laboratory (LLNL) is described. The system has been operational for two years. It is high voltage, high power, fault protected, and solid state. The power conditioning system drives flashlamps that pump solid state lasers. Flashlamps are driven by silicon control rectifier (SCR) switched, resonant charged, (LC) discharge pulse forming networks (PFNs). The system uses fiber optics for control and diagnostics. Energy and thermal diagnostics are monitored by computers.

  19. Laser energy converted into electric power

    NASA Technical Reports Server (NTRS)

    Shimada, K.

    1973-01-01

    Apparatus verifies concepts of converting laser energy directly into electric energy. Mirror, placed in beam and inclined at angle to it, directs small amount of incident radiation to monitor which establishes precise power levels and other beam characteristics. Second mirror and condensing lens direct bulk of laser energy into laser plasmadynamic converter.

  20. Piezoelectric measurement of laser power

    DOEpatents

    Deason, Vance A.; Johnson, John A.; Telschow, Kenneth L.

    1991-01-01

    A method for measuring the energy of individual laser pulses or a series of laser pulses by reading the output of a piezoelectric (PZ) transducer which has received a known fraction of the total laser pulse beam. An apparatus is disclosed that reduces the incident energy on the PZ transducer by means of a beam splitter placed in the beam of the laser pulses.

  1. Laser Powered Launch Vehicle Performance Analyses

    NASA Technical Reports Server (NTRS)

    Chen, Yen-Sen; Liu, Jiwen; Wang, Ten-See (Technical Monitor)

    2001-01-01

    The purpose of this study is to establish the technical ground for modeling the physics of laser powered pulse detonation phenomenon. Laser powered propulsion systems involve complex fluid dynamics, thermodynamics and radiative transfer processes. Successful predictions of the performance of laser powered launch vehicle concepts depend on the sophisticate models that reflects the underlying flow physics including the laser ray tracing the focusing, inverse Bremsstrahlung (IB) effects, finite-rate air chemistry, thermal non-equilibrium, plasma radiation and detonation wave propagation, etc. The proposed work will extend the base-line numerical model to an efficient design analysis tool. The proposed model is suitable for 3-D analysis using parallel computing methods.

  2. Potential of laser for SPS power transmission

    NASA Technical Reports Server (NTRS)

    Bain, C. N.

    1978-01-01

    Research on the feasibility of using a laser subsystem as an additional option for the transmission of the satellite power system (STS) power is presented. Current laser work and predictions for future laser performance provide a level of confidence that the development of a laser power transmission system is technologically feasible in the time frame required to develop the SBS. There are significant economic advantages in lower ground distribution costs and a reduction of more than two orders of magnitude in real estate requirements for ground based receiving/conversion sites.

  3. 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.

  4. 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.

  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.

    2007-02-01

    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.

  6. 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.

  7. 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.

  8. 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.

  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. Ceramics for High Power Lasers

    DTIC Science & Technology

    2011-12-01

    easily extracted by a TEM00 . The figure below shows the relevant geometry. For standard edge- pumped lasers , a gain medium with a uniform doping... Pump laser @808nm HR Planar Mirror HR mirror ROC 20cm Gain Medium Attenuator Photo- Diode 20cm Fig. 30 Schematic of the laser set-up with a...application for doping profiles is to simplify edge pumping of slab lasers by clustering more dopant in the center of the gain medium where it can be

  11. 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.

  12. Laser power beaming for satellite applications

    SciTech Connect

    Friedman, H.W.

    1993-09-22

    A serious consideration of laser power beaming for satellite applications appears to have grown out of a NASA mission analysis for transmitting power to lunar bases during the two week dark period. System analyses showed that laser power beaming to the moon in conjunction with efficient, large area solar cell collection panels, were an attractive alternative to other schemes such as battery storage and nuclear generators, largely because of the high space transportation costs. The primary difficulty with this scheme is the need for very high average power visible lasers. One system study indicated that lasers in excess of 10 MW at a wavelength of approximately 850 nm were required. Although such lasers systems have received much attention for military applications, their realization is still a long term goal.

  13. Diode laser power module for beamed power transmission

    NASA Technical Reports Server (NTRS)

    Choi, S. H.; Williams, M. D.; Lee, J. H.; Conway, E. J.

    1991-01-01

    Recent progress with powerful, efficient, and coherent monolithic diode master-oscillator/power-amplifier (M-MOPA) systems is promising for the development of a space-based diode laser power station. A conceptual design of a 50-kW diode laser power module was made for space-based power stations capable of beaming coherent power to the moon, Martian rovers, or other satellites. The laser diode power module consists of a solar photovoltaic array or nuclear power source, diode laser arrays (LDAs), a phase controller, beam-steering optics, a thermal management unit, and a radiator. Thermal load management and other relevant aspects of the system (such as power requirements and system mass) are considered. The 50-kW power module described includes the highest available efficiency of LD M-MOPA system to date. However, the overall efficiency of three amplifier stages, including the coupling efficiency, turns out to be 55.5 percent. Though a chain of PA stages generates a high-power coherent beam, there is a penalty due to the coupling loss between stages. The specific power of the 50-kW module using solar power is 6.58 W/kg.

  14. Diode laser power module for beamed power transmission

    NASA Technical Reports Server (NTRS)

    Choi, S. H.; Williams, M. D.; Lee, J. H.; Conway, E. J.

    1991-01-01

    Recent progress with powerful, efficient, and coherent monolithic diode master-oscillator/power-amplifier (M-MOPA) systems is promising for the development of a space-based diode laser power station. A conceptual design of a 50-kW diode laser power module was made for space-based power stations capable of beaming coherent power to the moon, Martian rovers, or other satellites. The laser diode power module consists of a solar photovoltaic array or nuclear power source, diode laser arrays (LDAs), a phase controller, beam-steering optics, a thermal management unit, and a radiator. Thermal load management and other relevant aspects of the system (such as power requirements and system mass) are considered. The 50-kW power module described includes the highest available efficiency of LD M-MOPA system to date. However, the overall efficiency of three amplifier stages, including the coupling efficiency, turns out to be 55.5 percent. Though a chain of PA stages generates a high-power coherent beam, there is a penalty due to the coupling loss between stages. The specific power of the 50-kW module using solar power is 6.58 W/kg.

  15. Average power meter for laser radiation

    NASA Astrophysics Data System (ADS)

    Shevnina, Elena I.; Maraev, Anton A.; Ishanin, Gennady G.

    2016-04-01

    Advanced metrology equipment, in particular an average power meter for laser radiation, is necessary for effective using of laser technology. In the paper we propose a measurement scheme with periodic scanning of a laser beam. The scheme is implemented in a pass-through average power meter that can perform continuous monitoring during the laser operation in pulse mode or in continuous wave mode and at the same time not to interrupt the operation. The detector used in the device is based on the thermoelastic effect in crystalline quartz as it has fast response, long-time stability of sensitivity, and almost uniform sensitivity dependence on the wavelength.

  16. 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.

  17. Solar powered blackbody-pumped lasers

    NASA Astrophysics Data System (ADS)

    Christiansen, Walter H.; Sirota, J. M.

    1991-02-01

    A concept for a solar-powered laser is presented which utilizes an intermediate blackbody cavity to provide a uniform optical pumping environment for the lasant, typically CO or CO2 or possibly a solid state laser medium. High power cw blackbody- pumped lasers with efficiencies on the order of 20 percent or more are feasible. The physical basis of this idea is reviewed. Small scale experiments using a high temperature oven as the optical pump have been carried out with gas laser mixtures. Detailed calculations showing a potential efficiency of 35 percent for blackbody pumped Nd:YAG system are discussed.

  18. Temporal response of laser power standards with natural convective cooling.

    PubMed

    Xu, Tao; Gan, Haiyong; Yu, Jing; Zang, Erjun

    2016-01-25

    Laser power detectors with natural convective cooling are convenient to use and hence widely applicable in a power range below 150 W. However, the temporal response characteristics of the laser power detectors need to be studied in detail for accurate measurement. The temporal response based on the absolute laser power standards with natural convective cooling is studied through theoretical analysis, numerical simulations, and experimental verifications. Our results show that the response deviates from a single exponential function and that an ultimate response balance is difficult to achieve because the temperature rise of the heat sink leads to continuous increase of the response. To determine the measurement values, an equal time reading method is proposed and validated by the laser power calibrations.

  19. Laser power conversion system analysis, volume 1

    NASA Technical Reports Server (NTRS)

    Jones, W. S.; Morgan, L. L.; Forsyth, J. B.; Skratt, J. P.

    1979-01-01

    The orbit-to-orbit laser energy conversion system analysis established a mission model of satellites with various orbital parameters and average electrical power requirements ranging from 1 to 300 kW. The system analysis evaluated various conversion techniques, power system deployment parameters, power system electrical supplies and other critical supplies and other critical subsystems relative to various combinations of the mission model. The analysis show that the laser power system would not be competitive with current satellite power systems from weight, cost and development risk standpoints.

  20. Workshop summary: Receivers for laser power beaming

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.

    1993-01-01

    At the Space Photovoltaics Research and Technology (SPRAT) conference at NASA Lewis Research Center, a workshop session was held to discuss issues involved in using photovoltaic arrays ('solar cells') to convert laser power into electrical power for use as receiving elements for beamed power.

  1. Deformable mirror for high power laser applications

    NASA Astrophysics Data System (ADS)

    Mrň; a, Libor; Sarbort, Martin; Hola, Miroslava

    2015-01-01

    The modern trend in high power laser applications such as welding, cutting and surface hardening lies in the use of solid-state lasers. The output beam of these lasers is characterized by a Gaussian intensity distribution. However, the laser beams with different intensity distributions, e.g. top-hat, are preferable in various applications. In this paper we present a new type of deformable mirror suitable for the corresponding laser beam shaping. The deformation of the mirror is achieved by an underlying array of actuators and a pressurized coolant that also provides the necessary cooling. We describe the results of the surface shape measurement using a 3D scanner for different settings of actuators. Further, we show the achieved intensity distributions measured by a beam profiler for a low power laser beam reflected from the mirror.

  2. 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.

  3. 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.

  4. Reduced Power Laser Designation Systems

    DTIC Science & Technology

    2009-01-10

    circuit of choice; and comparing the performance of this circuit against that of a basic transconductance amplifier . 15. SUBJECT TERMS Laser...Guided Weapons; Laser designation; laser rangefinders; infrared photodiodes; transconductance amplifiers . 16. SECURITY CLASSIFICATION OF: a. REPORT U...current-to-voltage amplifier ( transconductance amplifier ), the basic form of which is illustrated in Figure 2. ^>J 1—*£o p- Figure 2. Basic photodiode

  5. 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.

  6. 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.

  7. Gain switching in high power lasers

    NASA Astrophysics Data System (ADS)

    Druehl, K.; Scully, M. O.; Overhauser, A. W.

    1981-09-01

    Consideration is given to situations in which energy could be stored in a metastable state of a high-power laser and then dumped by applying a strong electric field to enhance coupling to the lower state. The electric dipole transitions induced by an external field are compared with magnetic dipole and electric quadrupole radiation due to other types of allowed transitions, and it is noted that in order for the application of the external field to increase the gain coefficient by at least an order of magnitude, the transitions in question must be forbidden for magnetic dipole radiation and occur at wavelengths of 1 to 10 microns. Field-induced transition rates are then calculated for the homonuclear diatomic molecules H2 and N2, along with the gain coefficient for H2. It is pointed out that stronger applied fields capable of increasing the gain may be produced by high-power laser pulses, resulting in gains of several per cent per cm.

  8. 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.

  9. Satellites Would Transmit Power By Laser Beams

    NASA Technical Reports Server (NTRS)

    Williams, M. D.; Walker, Gilbert H.; HUMES D. H.; Kwon, J. H.

    1995-01-01

    Arrays of diode lasers concentrate power into narrow beams. Baseline design of system formulated with regard to two particular missions that differ greatly in power requirements, thus showing scalability and attributes of basic system. Satellite system features large-scale array amplifier of high efficiency, injection-locked amplifiers, coherent combination of beams, and use of advanced lithographic technology to fabricate diode lasers in array. Extremely rapid development of applicable technologies make features realizable within decade.

  10. 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.

  11. System requirements for laser power beaming to geosynchronous satellites

    SciTech Connect

    Neal, R.D.; McKechnie, T.S.; Neal, D.R.

    1994-03-01

    Geosynchronous satellites use solar arrays as their primary source of electrical power. During earth eclipse, which occurs 90 times each year, the satellites are powered by batteries, but the heavy charge-discharge cycle decreases their life expectancy. By beaming laser power to satellites during the eclipses, satellite life expectancy can be significantly increased. In this paper, the authors investigate the basic system parameters and trade-offs of using reactor pumped laser technology to beam power from the Nevada Test Site. A first order argument is used to develop a consistent set of requirements for such a system.

  12. System requirements for laser power beaming to geosynchronous satellites

    SciTech Connect

    Neal, R.D.; McKechnie, T.S.; Neal, D.R.

    1994-12-31

    Geosynchronous satellites use solar arrays as their primary source of electrical power. During earth eclipse, which occurs 90 times each year, the satellites are powered by batteries, but the heavy charge-discharge cycle decreases their life expectancy. By beaming laser power to satellites during the eclipses, satellite life expectancy can be significantly increased. In this paper, the authors investigate the basic system parameters and trade-offs of using reactor pumped laser technology to beam power from the Nevada Test Site. A first order argument is used to develop a consistent set of requirements for such a system.

  13. Laser beamed power: Satellite demonstration applications

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Westerlund, Larry H.

    1992-01-01

    It is possible to use a ground-based laser to beam light to the solar arrays of orbiting satellites, to a level sufficient to provide all or some of the operating power required. Near-term applications of this technology for providing supplemental power to existing satellites are discussed. Two missions with significant commercial pay-off are supplementing solar power for radiation-degraded arrays and providing satellite power during eclipse for satellites with failed batteries.

  14. Laser beamed power: Satellite demonstration applications

    SciTech Connect

    Landis, G.A.; Westerlund, L.H.

    1992-08-01

    It is possible to use a ground-based laser to beam light to the solar arrays of orbiting satellites, to a level sufficient to provide all or some of the operating power required. Near-term applications of this technology for providing supplemental power to existing satellites are discussed. Two missions with significant commercial pay-off are supplementing solar power for radiation-degraded arrays and providing satellite power during eclipse for satellites with failed batteries.

  15. New laser power sensor using diamagnetic levitation.

    PubMed

    Pinot, P; Silvestri, Z

    2017-08-01

    This paper presents a preliminary study of an elementary device consisting of a small plate made from pyrolytic carbon levitated above a magnet array which is sensitive to any irradiating laser power. This device might provide an interesting alternative to power meters based on thermal measurement techniques via the Stefan-Boltzmann law or the photon-electron interaction. We show that the photo-response of a pyrolytic carbon plate in terms of levitation height versus irradiation power in the range of 20 mW to 1 W is sufficiently linear, sensitive, and reproducible to be used as a laser power sensor. The elevation height change as a function of irradiance time appears to be a suitable measurement parameter for establishing a relation with the irradiating laser power. The influence of some quantities affecting the measurement results has been highlighted. The study demonstrates that such a device should prove useful for applications in metrology, industry, or emerging technologies.

  16. New laser power sensor using diamagnetic levitation

    NASA Astrophysics Data System (ADS)

    Pinot, P.; Silvestri, Z.

    2017-08-01

    This paper presents a preliminary study of an elementary device consisting of a small plate made from pyrolytic carbon levitated above a magnet array which is sensitive to any irradiating laser power. This device might provide an interesting alternative to power meters based on thermal measurement techniques via the Stefan-Boltzmann law or the photon-electron interaction. We show that the photo-response of a pyrolytic carbon plate in terms of levitation height versus irradiation power in the range of 20 mW to 1 W is sufficiently linear, sensitive, and reproducible to be used as a laser power sensor. The elevation height change as a function of irradiance time appears to be a suitable measurement parameter for establishing a relation with the irradiating laser power. The influence of some quantities affecting the measurement results has been highlighted. The study demonstrates that such a device should prove useful for applications in metrology, industry, or emerging technologies.

  17. 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.

  18. Moderate-power cw fibre lasers

    SciTech Connect

    Kurkov, Andrei S; Dianov, Evgenii M

    2004-10-31

    A review of the development and investigation of moderate-power (10{sup -1}-10{sup 2} W) cw fibre lasers is presented. The properties of optical fibres doped with rare-earth ions and methods for fabricating double-clad fibres are considered. The methods for fabrication of fibre Bragg gratings used as selective reflectors are discussed and the grating properties are analysed. The main pump schemes for double-clad fibre lasers are described. The properties of fibre lasers doped with neodymium, ytterbium, erbium, thulium, and holmium ions are also considered. The principles of fabrication of Raman converters of laser radiation based on optical fibres of different compositions are discussed and the main results of their studies are presented. It is concluded that fibre lasers described in the review can produce moderate-power radiation at any wavelength in the spectral range from 0.9 to 2 {mu}m. (review)

  19. High average power lasers for future particle accelerators

    NASA Astrophysics Data System (ADS)

    Dawson, Jay W.; Crane, John K.; Messerly, Michael J.; Prantil, Matthew A.; Pax, Paul H.; Sridharan, Arun K.; Allen, Graham S.; Drachenberg, Derrek R.; Phan, Henry H.; Heebner, John E.; Ebbers, Christopher A.; Beach, Raymond J.; Hartouni, Edward P.; Siders, Craig W.; Spinka, Thomas M.; Barty, C. P. J.; Bayramian, Andrew J.; Haefner, Leon C.; Albert, Felicie; Lowdermilk, W. Howard; Rubenchik, Alexander M.; Bonanno, Regina E.

    2012-12-01

    Lasers are of increasing interest to the accelerator community and include applications as diverse as stripping electrons from hydrogen atoms, sources for Compton scattering, efficient high repetition rate lasers for dielectric laser acceleration, peta-watt peak power lasers for laser wake field and high energy, short pulse lasers for proton and ion beam therapy. The laser requirements for these applications are briefly surveyed. State of the art of laser technologies with the potential to eventually meet those requirements are reviewed. These technologies include diode pumped solid state lasers (including cryogenic), fiber lasers, OPCPA based lasers and Ti:Sapphire lasers. Strengths and weakness of the various technologies are discussed along with the most important issues to address to get from the current state of the art to the performance needed for the accelerator applications. Efficiency issues are considered in detail as in most cases the system efficiency is a valuable indicator of the actual ability of a given technology to deliver the application requirements.

  20. Ceramics for High Power Lasers

    DTIC Science & Technology

    2013-07-01

    ICP-MS) on 25 elements ranging from transition metals , rare earths, alkali , alkaline earths and silicon on a set of selected YAG ceramics and...component to UCF, this work has been delayed. Laser Properties The laser performance of the Nd:YAG sample Z-714 was tested in a simple planar...entering the amplifier with anomalous GVD. The end of the 11-m Tm-doped fiber amplifier was angle-cleaved to reduce the reflection. 26 Fiber

  1. The Mercury Laser Advances Laser Technology for Power Generation

    SciTech Connect

    Ebbers, C A; Caird, J; Moses, E

    2009-01-21

    The National Ignition Facility (NIF) at Lawrence Livermore Laboratory is on target to demonstrate 'breakeven' - creating as much fusion-energy output as laser-energy input. NIF will compress a tiny sphere of hydrogen isotopes with 1.8 MJ of laser light in a 20-ns pulse, packing the isotopes so tightly that they fuse together, producing helium nuclei and releasing energy in the form of energetic particles. The achievement of breakeven will culminate an enormous effort by thousands of scientists and engineers, not only at Livermore but around the world, during the past several decades. But what about the day after NIF achieves breakeven? NIF is a world-class engineering research facility, but if laser fusion is ever to generate power for civilian consumption, the laser will have to deliver pulses nearly 100,000 times faster than NIF - a rate of perhaps 10 shots per second as opposed to NIF's several shots a day. The Mercury laser (named after the Roman messenger god) is intended to lead the way to a 10-shots-per-second, electrically-efficient, driver laser for commercial laser fusion. While the Mercury laser will generate only a small fraction of the peak power of NIF (1/30,000), Mercury operates at higher average power. The design of Mercury takes full advantage of the technology advances manifest in its behemoth cousin (Table 1). One significant difference is that, unlike the flashlamp-pumped NIF, Mercury is pumped by highly efficient laser diodes. Mercury is a prototype laser capable of scaling in aperture and energy to a NIF-like beamline, with greater electrical efficiency, while still running at a repetition rate 100,000 times greater.

  2. Pulsed Power for Solid-State Lasers

    SciTech Connect

    Gagnon, W; Albrecht, G; Trenholme, J; Newton, M

    2007-04-19

    Beginning in the early 1970s, a number of research and development efforts were undertaken at U.S. National Laboratories with a goal of developing high power lasers whose characteristics were suitable for investigating the feasibility of laser-driven fusion. A number of different laser systems were developed and tested at ever larger scale in pursuit of the optimum driver for laser fusion experiments. Each of these systems had associated with it a unique pulsed power option. A considerable amount of original and innovative engineering was carried out in support of these options. Ultimately, the Solid-state Laser approach was selected as the optimum driver for the application. Following this, the Laser Program at the Lawrence Livermore National Laboratory and the University of Rochester undertook aggressive efforts directed at developing the technology. In particular, at Lawrence Livermore National Laboratory, a series of laser systems beginning with the Cyclops laser and culminating in the present with the National Ignition Facility were developed and tested. As a result, a large amount of design information for solid-state laser pulsed power systems has been documented. Some of it is in the form of published papers, but most of it is buried in internal memoranda, engineering reports and LLNL annual reports. One of the goals of this book is to gather this information into a single useable format, such that it is easily accessed and understood by other engineers and physicists for use with future designs. It can also serve as a primer, which when seriously studied, makes the subsequent reading of original work and follow-up references considerably easier. While this book deals only with the solid-state laser pulsed power systems, in the bibliography we have included a representative cross section of papers and references from much of the very fine work carried out at other institutions in support of different laser approaches. Finally, in recent years, there has

  3. 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.

  4. Systems analysis on laser beamed power

    NASA Technical Reports Server (NTRS)

    Zeiders, Glenn W., Jr.

    1993-01-01

    The NASA SELENE power beaming program is intended to supply cost-effective power to space assets via Earth-based lasers and active optics systems. Key elements of the program are analyzed, the overall effort is reviewed, and recommendations are presented.

  5. 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.

  6. 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.

  7. High power phase locked laser oscillators

    NASA Technical Reports Server (NTRS)

    Hayes, C. L.; Telk, C. L.; Soohoo, J.; Davis, W. C.

    1979-01-01

    The feasibility of mechanizing an adaptive array of independent laser oscillators for generation of a high power coherent output was experimentally investigated. Tests were structured to evaluate component/system requirements for delivery of energy to a low-earth orbit satellite. Initial experiments addressed the control issues of phase locking unstable resonators at low power levels. A successful phase lock demonstration formed the basis for the design and fabrication of the high power, water-cooled, control mirror subsequently installed in the NASA LeRC high power laser. Tests were performed to characterize the operational limits of the laser system and included quantitative assessment of the frequency stability, noise sources, and optical properties of the beam.

  8. Optical fiber transmission of high power excimer laser radiation.

    PubMed

    Pini, R; Salimbeni, R; Vannini, M

    1987-10-01

    An experimental investigation of optical fiber transmission of high power excimer laser radiation is presented. Different types of commercially available UV fiber have been tested, measuring energy handling capabilities and transmission losses of short samples at the XeCl (308-nm) and KrF (249-nm) wavelengths by using a standard excimer laser. A power density dependent damage process has been observed over 1 GW/cm(2). Fiber losses due to different radii of curvature are also reported. Experimental results have been examined to evaluate the effectiveness of excimer laser transmission through optical fibers for such medical uses as laser angioplasty, including also a comparison between the use of KrF or XeCl emission lines for this purpose. Finally, optimum excimer laser characteristics to increase the energy coupling in fibers are discussed.

  9. 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.

  10. 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.

  11. 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.

  12. Advanced Rock Drilling Technologies Using High Laser Power

    NASA Astrophysics Data System (ADS)

    Buckstegge, Frederik; Michel, Theresa; Zimmermann, Maik; Roth, Stephan; Schmidt, Michael

    Drilling through hard rock formations causes high mechanical wear and most often environmental disturbance. For the realization of an Advanced Adiabatic Compressed Air Energy Storage (AA-CAES) power plant a new and efficient method for tunneling utilising laser technology to support mechanical ablation of rock formations will be developed. Laser irradiation of inhomogeneous rock surfaces causes irregular thermal expansion leading to the formation of cracks and splintering as well as melting and slag-formation. This study focuses on the interaction of laser irradiation with calcite, porphyrite and siderite rock formations. A high power disc laser system at 1030nm wavelength is used to investigate the specific energy necessary to remove a unit volume depending on interaction times and applied power. Specific energies have been measured and an increase of fragility and brittleness of the rock surface has been observed.

  13. High Power Lasers And Their Application In Materials Processing

    NASA Astrophysics Data System (ADS)

    Bohn, W. L.

    1985-02-01

    The idea of using a laser for materials processing is more than 20 years old. Although the concept of a non-contact method for processing with a beam of light has been pursued with great interest and enthusiasm, the practical use of laser beam processing was slow to develop. The lasers available in the 1960's were fragile and of relatively low power. In the 1970's lasers in the multi-kilowatt range were developed but the problem of laser acceptance by the customer had to be overcome. Today, reliable Nd-Yag and CO2-lasers are available and laser processing is a fast growing market. An additional boost is expected with the development of the next generation of lasers and with increased knowledge of the physical phenomena that underlie laser material processing. This paper will review latest developments in laser technology and laser-workpiece interaction with special emphasis on the impact of high speed photography on the research work in these areas.

  14. 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.

  15. 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.

  16. 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.

  17. Magnetically switched power supply system for lasers

    NASA Technical Reports Server (NTRS)

    Pacala, Thomas J. (Inventor)

    1987-01-01

    A laser power supply system is described in which separate pulses are utilized to avalanche ionize the gas within the laser and then produce a sustained discharge to cause the gas to emit light energy. A pulsed voltage source is used to charge a storage device such as a distributed capacitance. A transmission line or other suitable electrical conductor connects the storage device to the laser. A saturable inductor switch is coupled in the transmission line for containing the energy within the storage device until the voltage level across the storage device reaches a predetermined level, which level is less than that required to avalanche ionize the gas. An avalanche ionization pulse generating circuit is coupled to the laser for generating a high voltage pulse of sufficient amplitude to avalanche ionize the laser gas. Once the laser gas is avalanche ionized, the energy within the storage device is discharged through the saturable inductor switch into the laser to provide the sustained discharge. The avalanche ionization generating circuit may include a separate voltage source which is connected across the laser or may be in the form of a voltage multiplier circuit connected between the storage device and the laser.

  18. Power versus stabilization for laser satellite communication.

    PubMed

    Arnon, S

    1999-05-20

    To establish optical communication between any two satellites, the lines of sight of their optics must be aligned for the duration of the communication. The satellite pointing and tracking systems perform the alignment. The satellite pointing systems vibrate because of tracking noise and mechanical impacts (such as thruster operation, the antenna pointing mechanism, the solar array driver, navigation noise, tracking noise). These vibrations increase the bit error rate (BER) of the communication system. An expression is derived for adaptive transmitter power that compensates for vibration effects in heterodyne laser satellite links. This compensation makes it possible to keep the link BER performance constant for changes in vibration amplitudes. The motivation for constant BER is derived from the requirement for future satellite communication networks with high quality of service. A practical situation of a two-low-Earth-orbit satellite communication link is given. From the results of the example it is seen that the required power for a given BER increases almost exponentially for linear increase in vibration amplitude.

  19. Retrospective analysis of the treatment of melasma lesions exhibiting increased vascularity with the 595-nm pulsed dye laser combined with the 1927-nm fractional low-powered diode laser.

    PubMed

    Geddes, Elizabeth R C; Stout, Ashlyn B; Friedman, Paul M

    2017-01-01

    Melasma presents a significant challenge to laser surgeons. Aggressive treatments often result in rebound melasma or post-inflammatory pigmentary alteration. Recent reports suggest melasma pathogenesis may have a vascular component. Spectrocolorimetry can detect subtle or sub-clinical telangiectatic erythema within melasma lesions. For certain patients identified by spectrocolorimetry, effective melasma treatment may include vascular-targeted therapy together with pigment-specific treatment modalities. Such combined therapies may reduce the likelihood of melasma recurrence. To evaluate the efficacy of treating melasma lesions exhibiting subtle or sub-clinical telangiectatic erythema with the 595-nm pulsed dye laser (PDL) combined with the 1927-nm fractional low-powered diode laser (FDL). A retrospective review was performed over a 2-year period as follows. Evaluated patients (n = 11) include 10 women and 1 man, average age of 38.7 years, and Fitzpatrick skin types II-IV. Each patient exhibited melasma lesions with subtle or sub-clinical telangiectatic erythema identified by spectrocolorimetry. Each underwent a series of treatments (average of four) at approximate 4-6 week intervals of the PDL followed by the FDL. Treatments were performed same-day, sequentially, with 10-15 minute interim time allowance for skin cooling. The following PDL parameters were utilized: 10 mm spot, 10-20 ms pulse duration, 7.5-8.5 J/cm(2) fluence, 30/30 DCD. Eight passes with the FDL (Clear + Brilliant(®) Permea™, Solta Medical, Hayward, CA) were then performed utilizing a "low" treatment level. Clinical endpoint was mild erythema and edema. Patients were encouraged to practice strict photoprotection and apply topical skin lightening agents, but compliance was not measured. An independent physician evaluated photographs taken at baseline and at follow-up after last treatment session (average follow-up of 96 days). A quartile improvement score was used to grade the

  20. Development of on-line laser power monitoring system

    NASA Astrophysics Data System (ADS)

    Ding, Chien-Fang; Lee, Meng-Shiou; Li, Kuan-Ming

    2016-03-01

    Since the laser was invented, laser has been applied in many fields such as material processing, communication, measurement, biomedical engineering, defense industries and etc. Laser power is an important parameter in laser material processing, i.e. laser cutting, and laser drilling. However, the laser power is easily affected by the environment temperature, we tend to monitor the laser power status, ensuring there is an effective material processing. Besides, the response time of current laser power meters is too long, they cannot measure laser power accurately in a short time. To be more precisely, we can know the status of laser power and help us to achieve an effective material processing at the same time. To monitor the laser power, this study utilize a CMOS (Complementary metal-oxide-semiconductor) camera to develop an on-line laser power monitoring system. The CMOS camera captures images of incident laser beam after it is split and attenuated by beam splitter and neutral density filter. By comparing the average brightness of the beam spots and measurement results from laser power meter, laser power can be estimated. Under continuous measuring mode, the average measuring error is about 3%, and the response time is at least 3.6 second shorter than thermopile power meters; under trigger measuring mode which enables the CMOS camera to synchronize with intermittent laser output, the average measuring error is less than 3%, and the shortest response time is 20 millisecond.

  1. High Power Continuous Wave Semiconductor Injection Laser

    DTIC Science & Technology

    1978-12-01

    hejunction rc~gion can be best accomplished in narro 7/,. laeswt width near 50 micrometers. Further optimization nnf FORM AWN2 AfI,~Jf~~’~ .* .~f’~W...high power CW operation. Trends in output powerwith varying laser length, width, reflectivity, and cavitythickness are presented graphically. LI ,N...J1 I H I I , THSI I ..... IU HIGH POWER CONTINUOUS WAVE ____________ SEMICONDUCTOR INJECTION LASER THESIS ’AIFIT/GEO/PH/78-.Z John1 C. Griffin, XIII

  2. Materials working with low power CO2 lasers

    NASA Astrophysics Data System (ADS)

    Fry, S. M.

    1980-01-01

    While the application of high power (50-5000 W) lasers to materials working is well known, the use of low power (1-5w) CO2 lasers has received little attention. This paper presents methods of utilizing low power CO2 lasers in materials processing, such as cutting, drilling, and welding of small organic (e.g., plastic) parts. Laser hardware is discussed and the waveguide laser is presented as an example of low-power materials working hardware. This paper also reports some of the applications which are ideally-handled by low power CO2 lasers, and reviews the factors which contribute to the successful use of these lasers.

  3. Laser beamed power - Satellite demonstration applications

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Westerlund, Larry H.

    1992-01-01

    Feasibility of using a ground-based laser to beam light to the solar arrays of orbiting satellites to a level sufficient to provide the operating power required is discussed. An example case of a GEO communications satellite near the end of life due to radiation damage of the solar arrays or battery failure is considered. It is concluded that the commercial satellite industry should be able to reap significant economic benefits through the use of power beaming which is capable of providing supplemental power for satellites with failing arrays, or primary power for failed batteries.

  4. 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.

  5. 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.

  6. Comparison of electrically driven lasers for space power transmission

    NASA Technical Reports Server (NTRS)

    Deyoung, R. J.; Lee, J. H.; Williams, M. D.; Schuster, G.; Conway, E. J.

    1988-01-01

    High-power lasers in space could provide power for a variety of future missions such as spacecraft electric power requirements and laser propulsion. This study investigates four electrically pumped laser systems, all scaled to 1-MW laser output, that could provide power to spacecraft. The four laser systems are krypton fluoride, copper vapor, laser diode array, and carbon dioxide. Each system was powered by a large solar photovoltaic array which, in turn, provided power for the appropriate laser power conditioning subsystem. Each system was block-diagrammed, and the power and efficiency were found for each subsystem block component. The copper vapor system had the lowest system efficiency (6 percent). The CO2 laser was found to be the most readily scalable but has the disadvantage of long laser wavelength.

  7. 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.

  8. Mid-infrared high-power diode lasers and modules

    NASA Astrophysics Data System (ADS)

    Kelemen, Márc T.; Gilly, Juergen; Rattunde, Marcel; Wagner, Joachim; Ahlert, Sandra; Biesenbach, Jens

    2010-02-01

    High-power diode lasers in the mid-infrared wavelength range between 1.8μm and 2.3μm have emerged new possibilities for applications like processing and accelerated drying of materials, medical surgery, infrared countermeasures or for pumping of solid-state and semiconductor disc lasers. We will present results on MBE grown (AlGaIn)(AsSb) quantum-well diode laser single emitters with emitter widths between 90μm and 200μm. In addition laser bars with 20% or 30% fill factor have been processed. More than 30% maximum wall-plug efficiency in cw operation for single emitters and laser bars has been reached. Even at 2200nm more than 15W have been demonstrated with a 30% fill factor bar. Due to an increasing interest in pulsed operation modes for these mid-infrared lasers, we have investigated single emitters and laser bars at 1940nm for different pulse times and duty cycles. More than 9W have been measured at 30A with 500ns pulse time and 1% duty cycle without COMD for a single emitter. Most applications mentioned before need fiber coupled output power, therefore fiber coupled modules based on single emitters or laser bars have been developed. Single-emitter based modules show 600mW out of a 200μm core fiber with NA=0.22 at different wavelengths between 1870nm and 1940nm. At 2200nm an output power of 450mW ex fiber impressively demonstrates the potential of GaSb based diode lasers well beyond wavelengths of 2μm. Combining several laser bars, 20W out of a 600μm core fiber have been established at 1870nm. Finally for a 7 bar stack at 1870nm we have demonstrated more than 85W at 50A in qcw mode.

  9. Transmission Of Power Via Combined Laser Beams

    NASA Technical Reports Server (NTRS)

    Kwon, Jin H.; Lee, Ja H.

    1992-01-01

    Laser Diode Array (LDA) appears to be most efficient means of transferring power from Earth to satellites and between satellites, in terms of mass and size, of various laser configurations. To form large-scale-array amplifier (LSAA), element LDA's must generate well-defined diffraction-limited beams. Coherent matching of phases among LDA's enables system to generate good beam pattern in far field over thousands of kilometers. By passing beam from master laser through number of LDA amplifiers simultaneously, one realizes coherence among amplified output beams. LSAA used for transmission of power with efficiency of approximately 80 percent into receiver of moderate size at 5,000 km. Also transmits data at high rates by line-of-sight rather than fiber optics.

  10. Excimer laser lead extraction catheter with increased laser parameters

    NASA Astrophysics Data System (ADS)

    Coe, M. Sean; Taylor, Kevin D.; Lippincott, Rebecca A.; Sorokoumov, Oleg; Papaioannou, Thanassis

    2001-05-01

    A fiber optic catheter connected to a pulsed excimer laser (308 nm) is currently used to extract chronically implanted pacemaker and defibrillator leads at Fluence of 60 mJ/mm2 and repetition rate of 40 Hz. The object of this study was to determine the effect of higher repetition rates (80 Hz) in the catheter's cutting performance. The penetration rate (micrometers /sec), and the associated mechanical and thermal effects were measured in soft (porcine myocardium) and hard tissue (bovine tendon) at 60 mJ/mm2-80 Hz, and were compared to the corresponding values at commercially available laser parameters (60 mJ/mm2-40 Hz). Ablation rates were measured with perforation experiments and the extent of thermal and mechanical damage was measured under polarized light microscopy. For hard (soft) tissue, the laser catheter demonstrated penetration speed of 106 +/- 32 (302 +/- 101) micrometers /sec at 40 Hz and 343 +/- 120 (830 +/- 364) micrometers /sec at 80 Hz. Maximum extent of thermal effects at 40 Hz and 80 Hz was 114 +/- 35 micrometers (72 +/- 18) and 233 +/- 63 micrometers (71 +/- 16) respectively. Maximum extent of mechanical effects at 40 Hz and 80 Hz was 188 +/- 63 micrometers (590 +/- 237) and 386 +/- 100 micrometers (767 +/- 160) respectively. In vitro testing of the laser catheter with 80 Hz laser parameters has demonstrated increased penetration speed in both soft and hard fibrous tissue, while maintaining associated thermal and mechanical effects within limited ranges.

  11. 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

  12. 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.

  13. Effect of low power laser irradiation on macrophage phagocytic capacity

    NASA Astrophysics Data System (ADS)

    Lu, Cuixia; Song, Sheng; Tang, Yu; Zhou, Feifan

    2011-03-01

    Phagocytosis and subsequent degradation of pathogens by macrophages play a pivotal role in host innate immunity in mammals. Laser irradiation has been found to produce photobiological effects with evidence of interference with immunological functions. However, the effects of laser on the immune response have not been extensively characterized. In this study, we focused our attention on the effects of He-Ne laser on the phagocytic activity of macrophages by using flow cytometry (FCM). After irradiating at fluence of 0, 1, 2 J/cm2 with He-Ne laser (632.8 nm, 3mw), the cells were incubated with microsphere and then subjected to FACS analysis. The results showed that Low-power laser irradiation (LPLI) leads to an increase in phagocytosis on both mouse peritoneal macrophages and the murine macrophage-like cell line RAW264.7. In addition, we demonstrated that LPLI increased phagocytosis of microsphere in a dose-dependent manner, reaching a maximum at fluence of 2 J/cm2. Taken together, our results indicated that Low-power laser irradiation with appropriate dosage can enhance the phagocytosis of macrophage, and provided a theoretical base for the clinical use of the He-Ne laser.

  14. 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.

  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. Coherent beam combining architectures for high power tapered laser arrays

    NASA Astrophysics Data System (ADS)

    Schimmel, G.; Janicot, S.; Hanna, M.; Decker, J.; Crump, P.; Erbert, G.; Witte, U.; Traub, M.; Georges, P.; Lucas-Leclin, G.

    2017-02-01

    Coherent beam combining (CBC) aims at increasing the spatial brightness of lasers. It consists in maintaining a constant phase relationship between different emitters, in order to combine them constructively in one single beam. We have investigated the CBC of an array of five individually-addressable high-power tapered laser diodes at λ = 976 nm, in two architectures: the first one utilizes the self-organization of the lasers in an interferometric extended-cavity, which ensures their mutual coherence; the second one relies on the injection of the emitters by a single-frequency laser diode. In both cases, the coherent combining of the phase-locked beams is ensured on the front side of the array by a transmission diffractive grating with 98% efficiency. The passive phase-locking of the laser bar is obtained up to 5 A (per emitter). An optimization algorithm is implemented to find the proper currents in the five ridge sections that ensured the maximum combined power on the front side. Under these conditions we achieve a maximum combined power of 7.5 W. In the active MOPA configuration, we can increase the currents in the tapered sections up to 6 A and get a combined power of 11.5 W, corresponding to a combining efficiency of 76%. It is limited by the beam quality of the tapered emitters and by fast phase fluctuations between emitters. Still, these results confirm the potential of CBC approaches with tapered lasers to provide a high-power and high-brightness beam, and compare with the current state-of-the-art with laser diodes.

  17. 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.

  18. The Way to Increased Airplane Engine Power

    NASA Technical Reports Server (NTRS)

    Vohrer, Eugen

    1939-01-01

    The purpose of this paper is to give an outline of the present state of development and point out the possibilities available for the further increase in the power/displacement ratio, the economy, and the reliability of the engine. Some of the aspects discussed are methods of increasing take-off power, the various methods of preparation of the fuel mixture and their effect on power, economy, and safety.

  19. 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.

  20. 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.

  1. Application of Laser Ablation Processing in Electric Power System Industries

    NASA Astrophysics Data System (ADS)

    Konagai, Chikara; Sano, Yuji; Nittoh, Koichi; Kuwako, Akira

    The present status of laser ablation processing applied in electric power system industries is reviewed. High average power LD-pumped Nd:YAG lasers with Q-switch have been developed and currently introduced into various applications. Optical fiber based laser beam delivery systems for Q-switched pulse laser are also being developed these years. Based on such laser and beam delivery technology, laser ablation processes are gradually introduced in maintenance of nuclear power plant, thermal power plant and electrical power distribution system. Cost effectiveness, robustness and reliability of the process is highly required for wide utilization in these fields.

  2. Laser power beaming system analyses

    NASA Technical Reports Server (NTRS)

    Zeiders, Glenn W., Jr.

    1993-01-01

    The successful demonstration of the PAMELA adaptive optics hardware and the fabrication of the BTOS truss structure were identified by the program office as the two most critical elements of the NASA power beaming program, so it was these that received attention during this program. Much of the effort was expended in direct program support at MSFC, but detailed technical analyses of the AMP deterministic control scheme and the BTOS truss structure (both the JPL design and a spherical one) were prepared and are attached, and recommendations are given.

  3. 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

  4. High power laser with focusing mirror sets

    SciTech Connect

    Hobart, J.L.; Sasnett, M.W.; Mefferd, W.S.; Allen, P.N.

    1991-06-11

    This patent describes a laser system producing a high power laser beam which propogates along a path. It comprises an optical resonator cavity enclosing a lasing medium through which the laser beam propagates along a first portion of the path within the optical resonator cavity; wherein the laser beam emerges from the cavity and propogates along a second portion of the path outside the cavity; and a first mirror set positioned along the first portion of the path within the cavity, the first set having effective focal length providing sufficient focal power to compensate for distributed thermally-induced lensing in the lasing medium and to maintain substantially constant laser beam diameter along a region of the path adjacent the first set, wherein each mirror in the first set is shaped and oriented so that the first set is substantially astigmatism- free, wherein the first set includes a spherical mirror and a cylindrical mirror, and wherein the spherical mirror has a radius of curvature equal to R and the cylindrical mirror has a radius of curvature substantially equal to R, and the first set has an effective focal length substantially equal to f = {radical}2R/4.

  5. 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.

  6. 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.

  7. Laser-Material Interaction of Powerful Ultrashort Laser Pulses

    SciTech Connect

    Komashko, A

    2003-01-06

    Laser-material interaction of powerful (up to a terawatt) ultrashort (several picoseconds or shorter) laser pulses and laser-induced effects were investigated theoretically in this dissertation. Since the ultrashort laser pulse (USLP) duration time is much smaller than the characteristic time of the hydrodynamic expansion and thermal diffusion, the interaction occurs at a solid-like material density with most of the light energy absorbed in a thin surface layer. Powerful USLP creates hot, high-pressure plasma, which is quickly ejected without significant energy diffusion into the bulk of the material, Thus collateral damage is reduced. These and other features make USLPs attractive for a variety of applications. The purpose of this dissertation was development of the physical models and numerical tools for improvement of our understanding of the process and as an aid in optimization of the USLP applications. The study is concentrated on two types of materials - simple metals (materials like aluminum or copper) and wide-bandgap dielectrics (fused silica, water). First, key physical phenomena of the ultrashort light interaction with metals and the models needed to describe it are presented. Then, employing one-dimensional plasma hydrodynamics code enhanced with models for laser energy deposition and material properties at low and moderate temperatures, light absorption was self-consistently simulated as a function of laser wavelength, pulse energy and length, angle of incidence and polarization. Next, material response on time scales much longer than the pulse duration was studied using the hydrocode and analytical models. These studies include examination of evolution of the pressure pulses, effects of the shock waves, material ablation and removal and three-dimensional dynamics of the ablation plume. Investigation of the interaction with wide-bandgap dielectrics was stimulated by the experimental studies of the USLP surface ablation of water (water is a model of

  8. Space power by laser illumination of PV arrays

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.

    1991-01-01

    There has recently been a resurgence of interest in the use of beamed power to support space exploration activities. The utility is examined of photovoltaics and problem and research areas are identified for photovoltaics in two beamed-power applications: to convert incident laser radiation to power at a remote receiving station, and as a primary power source on space based power station transmitting power to a remote user. A particular application of recent interest is to use a ground-based free electron laser as a power source for space applications. Specific applications include: night power for a moonbase by laser illumination of the moonbase solar arrays; use of a laser to provide power for satellites in medium and geosynchronous Earth orbit, and a laser powered system for an electrical propulsion orbital transfer vehicle. These and other applications are currently being investigated at NASA Lewis as part of a new program to demonstrate the feasibility of laser transmission of power for space.

  9. 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.

  10. 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.

  11. Methods for determining optical power, for power-normalizing laser measurements, and for stabilizing power of lasers via compliance voltage sensing

    DOEpatents

    Taubman, Matthew S; Phillips, Mark C

    2015-04-07

    A method is disclosed for power normalization of spectroscopic signatures obtained from laser based chemical sensors that employs the compliance voltage across a quantum cascade laser device within an external cavity laser. The method obviates the need for a dedicated optical detector used specifically for power normalization purposes. A method is also disclosed that employs the compliance voltage developed across the laser device within an external cavity semiconductor laser to power-stabilize the laser mode of the semiconductor laser by adjusting drive current to the laser such that the output optical power from the external cavity semiconductor laser remains constant.

  12. Effects of low-power diode lasers on flap survival

    SciTech Connect

    Kami, T.; Yoshimura, Y.; Nakajima, T.; Ohshiro, T.; Fujino, T.

    1985-03-01

    The authors investigated the effect of low-power laser irradiation on the survival of experimental skin flaps in rats. A gallium-aluminum-arsenide diode laser that was developed by the Japan Medical Laser Laboratory was used. The laser power was 15 mW and the wavelength 830 nm. Irradiation was carried out, either before or after flap elevation, in two groups of 20 Wistar strain rats. A third group of 20 rats served as controls. A caudally based skin flap, 3 X 9 cm, was designed on the back of each rat. Laser irradiation therapy was performed for 5 consecutive days for 6 minutes per flap per day, preoperatively in one group and postoperatively in the other. Seven days postoperatively, the survival areas of the flaps were measured and compared. The survival area was increased significantly in both groups receiving laser therapy, probably due to the observed proliferation of blood vessels around the irradiated points and an increase in blood flow.

  13. 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.

  14. Subpicosecond high power UV—laser system

    NASA Astrophysics Data System (ADS)

    Schwarzenbach, A. P.; Luk, T. S.; Johann, U.; McIntyre, I.; McPherson, A.; Boyer, K.; Rhodes, C. K.

    1986-08-01

    A synchronously pumped dye laser with saturable absorber jet and cavity dumper is used as the source for producing a seed beam for excimer amplifiers. An optical fiber after the dye laser and a grating pair are used to compress the dye laser pulse to 250 fsec. A two stage dye amplifier brings the pulse to about 0.1 mJ at 745.2 nm. Frequency doubling followed by summing the second harmonic with the fundamental in two KDP crystals produces radiation at 248.4 nm to be amplified in two KrF amplifiers. The UV pulse duration was measured after the first amplifier to be 450±150 fsec. The pulse energy was 23±2 mJ, and the power therefore, was nominally ˜50 GW.

  15. 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.

  16. Laser beam characterization results for a high power CW Nd:YAG laser

    SciTech Connect

    Keicher, D.M.

    1994-12-31

    In an effort to understand multimode laser beam propagation characteristics for better development of laser material processing applications, beam diagnostic experiments were performed on a 1800 watt CW Nd:YAG laser. Beam diameter data were acquired at approximately 12 positions along the beam optical axis about the minimum waist created by a long focal length single element lens at several power levels. These data were then used to evaluate the laser output beam characteristics using two differing techniques. For the ISO technique, two data points from the beam diameter data were used in determining the output laser beam characteristics. These points were the beam minimum waist diameter and the diameter at a point along the beam optical axis where the beam diameter had increased to approximately 0.7 times that of the beam minimum waist diameter. The second analysis technique involved fitting the entire data set to theoretical equations used to describe the multimode laser beam propagation and points from the fitted curve fit were then used to determine the output beam characteristics from the laser. For all power levels evaluated, calculated results predicting the laser beam minimum waist location were in agreement with measured values and more consistent using the curve-fit technique than the two-point evaluation technique.

  17. Design investigation of solar powered lasers for space applications

    NASA Technical Reports Server (NTRS)

    Taussig, R.; Bruzzone, C.; Quimby, D.; Nelson, L.; Christiansen, W.; Neice, S.; Cassady, P.; Pindroh, A.

    1979-01-01

    The feasibility of solar powered lasers for continuous operation in space power transmission was investigated. Laser power transmission in space over distances of 10 to 100 thousand kilometers appears possible. A variety of lasers was considered, including solar-powered GDLs and EDLs, and solar-pumped lasers. An indirect solar-pumped laser was investigated which uses a solar-heated black body cavity to pump the lasant. Efficiencies in the range of 10 to 20 percent are projected for these indirect optically pumped lasers.

  18. 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.

  19. Powerful narrow linewidth random fiber laser

    NASA Astrophysics Data System (ADS)

    Ye, Jun; Xu, Jiangming; Zhang, Hanwei; Zhou, Pu

    2017-03-01

    In this paper, we demonstrate a narrow linewidth random fiber laser, which employs a tunable pump laser to select the operating wavelength for efficiency optimization, a narrow-band fiber Bragg grating (FBG) and a section of single mode fiber to construct a half-open cavity, and a circulator to separate pump light input and random lasing output. Spectral linewidth down to 42.31 GHz is achieved through filtering by the FBG. When 8.97 W pump light centered at the optimized wavelength 1036.5 nm is launched into the half-open cavity, 1081.4 nm random lasing with the maximum output power of 2.15 W is achieved, which is more powerful than the previous reported results.

  20. Powerful narrow linewidth random fiber laser

    NASA Astrophysics Data System (ADS)

    Ye, Jun; Xu, Jiangming; Zhang, Hanwei; Zhou, Pu

    2016-11-01

    In this paper, we demonstrate a narrow linewidth random fiber laser, which employs a tunable pump laser to select the operating wavelength for efficiency optimization, a narrow-band fiber Bragg grating (FBG) and a section of single mode fiber to construct a half-open cavity, and a circulator to separate pump light input and random lasing output. Spectral linewidth down to 42.31 GHz is achieved through filtering by the FBG. When 8.97 W pump light centered at the optimized wavelength 1036.5 nm is launched into the half-open cavity, 1081.4 nm random lasing with the maximum output power of 2.15 W is achieved, which is more powerful than the previous reported results.

  1. 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.

  2. Moonbase night power by laser illumination

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.

    1992-01-01

    Moonbase solar-power concepts must somehow address the energy storage problem posed by the 354-hour lunar night. Attention is presently given to the feasibility of laser-array illumination of a lunar base, using technology that is projected to be available in the near term. Beam-spreading due to atmospheric distortions could be reduced through the use of adaptive optics to compensate for atmospheric turbulence.

  3. 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.

  4. Improve power conversion efficiency of slab coupled optical waveguide lasers.

    PubMed

    Fan, Jiahua; Zhu, Lin; Dogan, Mehmet; Jacob, Jonah

    2014-07-28

    The slab coupled optical waveguide laser (SCOWL) is a promising candidate for high power, single mode emitter for a number of reasons, including its near diffraction limited optical quality, large modal size and near circular output pattern. Current SCOWL designs have limited electrical-optical power conversion efficiency (PCE) around 40%, which is lower than conventional RWG laser and broad area laser that are known to have much higher PCEs. To improve the SCOWL PCE, we theoretically optimize its structure by reducing Al content, increasing doping concentration and introducing a GRIN layer to prevent carrier leakage. Numerical simulations predict that an optimized SCOWL design has a maximum PCE of about 57% at room temperature.

  5. Comparison of laser and power bleaching techniques in tooth color change

    PubMed Central

    Fekrazad, Reza; Alimazandarani, Shervin; Kalhori, Katayoun AM; Assadian, Hadi

    2017-01-01

    Background Laser-assisted bleaching uses laser beam to accelerate release of free radicals within the bleaching gel to decrease time of whitening procedure. The aim of this study was to compare the efficacy of power bleaching using Opalescence Xtra Boost® and laser bleaching technique using LaserSmile gel and diode laser as an activator in their tooth whitening capacity. Material and Methods Student t test showed that the laser bleaching group significantly outperformed the power bleaching group in changing ∆E (p=0.977). Results Similarly, while comparing the groups in changing ∆L, the laser bleaching group indicated significantly superior results (p=0.953). Statistical data from student t test while comparing the groups in changing the parameter of yellowness indicated that samples in laser bleaching group underwent a more significant reduction than power-bleached samples (p=0.85). Correspondingly, changes in whiteness were statistically tested through student t test, showing that laser bleaching technique increased whiteness of the samples significantly more than those treated by power bleaching (p=0.965). The digital color evaluation data was in accordance with spectrophotometry and showed that laser bleaching outperformed power bleaching technique. Both techniques were able to increase whiteness and decrease yellowness ratio of the samples. ΔE decrease for laser bleaching and power bleaching groups were 3.05 and 1.67, respectively. Tooth color change in laser bleaching group was 1.88 times more than that of power bleaching group (p<0.001). Conclusions It could be concluded that under the conditions of this study, both laser-assisted and power bleaching techniques were capable of altering tooth color change, but laser bleaching was deemed a more efficient technique in this regard. Key words:Laser, power bleaching, tooth color introduction. PMID:28469814

  6. Enabling lunar and space missions by laser power transmission

    NASA Technical Reports Server (NTRS)

    Deyoung, R. J.; Nealy, J. E.; Humes, D. H.; Meador, W. E.

    1992-01-01

    Applications are proposed for laser power transmission on the Moon. A solar-pumped laser in lunar orbit would beam power to the lunar surface for conversion into either electricity or propulsion needs. For example, lunar rovers could be much more flexible and lighter than rovers using other primary power sources. Also, laser power could be absorbed by lunar soil to create a hard glassy surface for dust-free roadways and launch pads. Laser power could also be used to power small lunar rockets or orbital transfer vehicles, and finally, photovoltaic laser converters could power remote excavation vehicles and human habitats. Laser power transmission is shown to be a highly flexible, enabling primary power source for lunar missions.

  7. Enabling lunar and space missions by laser power transmission

    NASA Astrophysics Data System (ADS)

    De Young, R. J.; Nealy, J. E.; Humes, D. H.; Meador, W. E.

    1992-09-01

    Applications are proposed for laser power transmission on the Moon. A solar-pumped laser in lunar orbit would beam power to the lunar surface for conversion into either electricity or propulsion needs. For example, lunar rovers could be much more flexible and lighter than rovers using other primary power sources. Also, laser power could be absorbed by lunar soil to create a hard glassy surface for dust-free roadways and launch pads. Laser power could also be used to power small lunar rockets or orbital transfer vehicles, and finally, photovoltaic laser converters could power remote excavation vehicles and human habitats. Laser power transmission is shown to be a highly flexible, enabling primary power source for lunar missions.

  8. 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.

  9. A lunar rover powered by an orbiting laser diode array

    NASA Technical Reports Server (NTRS)

    De Young, R. J.; Williams, M. D.; Walker, G. H.; Schuster, G. L.; Lee, J. H.

    1991-01-01

    A conceptual design of a high-power, long-duration lunar rover powered by a laser beam is proposed. The laser transmitter in lunar orbit consists of an SP-100 nuclear reactor prime power source providing 100 kW of electricity to a laser array that emits 50 kW of laser radiation. The laser radiation is beamed to the lunar surface where it is received by a GaAlAs solid-state, laser-to-electric converter. This converter provides 22 kW of electrical power to the rover vehicle for science, locomotion, and crew needs. The mass of the laser transmitter is approximately 5000 kg, whereas the mass of the rover power supply is 520 kg. The rover power unit is significantly less massive than alternative rover power units.

  10. 2013 R&D 100 Award: New tech could mean more power for fiber lasers

    ScienceCinema

    Dawson, Jay

    2016-07-12

    An LLNL team of six physicists has developed a new technology that is a stepping stone to enable some of the limitations on high-power fiber lasers to be overcome. Their technology, dubbed "Efficient Mode-Converters for High-Power Fiber Amplifiers," allows the power of fiber lasers to be increased while maintaining high beam quality. Currently, fiber lasers are used in machining, on factory floors and in a number of defense applications and can produce tens of kilowatts of power.The conventional fiber laser design features a circular core and has fundamental limitations that make it impractical to allow higher laser power unless the core area is increased. LLNL researchers have pioneered a design to increase the laser's core area along the axis of the ribbon fiber. Their design makes it difficult to use a conventional laser beam, so the LLNL team converted the beam into a profile that propagates into the ribbon fiber and is converted back once it is amplified. The use of this LLNL technology will permit the construction of higher power lasers for lower costs and increase the power of fiber lasers from tens of kilowatts of power to about 100 kilowatts and potentially even higher.

  11. 2013 R&D 100 Award: New tech could mean more power for fiber lasers

    SciTech Connect

    Dawson, Jay

    2014-04-03

    An LLNL team of six physicists has developed a new technology that is a stepping stone to enable some of the limitations on high-power fiber lasers to be overcome. Their technology, dubbed "Efficient Mode-Converters for High-Power Fiber Amplifiers," allows the power of fiber lasers to be increased while maintaining high beam quality. Currently, fiber lasers are used in machining, on factory floors and in a number of defense applications and can produce tens of kilowatts of power.The conventional fiber laser design features a circular core and has fundamental limitations that make it impractical to allow higher laser power unless the core area is increased. LLNL researchers have pioneered a design to increase the laser's core area along the axis of the ribbon fiber. Their design makes it difficult to use a conventional laser beam, so the LLNL team converted the beam into a profile that propagates into the ribbon fiber and is converted back once it is amplified. The use of this LLNL technology will permit the construction of higher power lasers for lower costs and increase the power of fiber lasers from tens of kilowatts of power to about 100 kilowatts and potentially even higher.

  12. 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.

  13. Satellite Power Systems (SPS) laser studies. Volume 1: Laser environmental impact study

    NASA Technical Reports Server (NTRS)

    Beverly, R. E., III

    1980-01-01

    The environmental impact of space to Earth power transmission using space borne laser subsystems is emphasized. A laser system is defined, estimates of relevant efficiencies for laser power generation and atmospheric transmission are developed, and a comparison is made to a microwave system. Ancillary issues, such as laser beam spreading, safety and security, mass and volume estimates and technology growth are considered.

  14. LASER BIOLOGY AND MEDICINE: Medical instruments based on high-power diode and fibre lasers

    NASA Astrophysics Data System (ADS)

    Gapontsev, V. P.; Minaev, V. P.; Savin, V. I.; Samartsev, I. E.

    2002-11-01

    The characteristics and possible applications of scalpels based on diode and fibre lasers emitting at 0.97, 1.06, 1.56, and 1.9 μm, which are produced and developed by the IRE-Polyus Co., are presented. The advantages of such devices and the possibilities for increasing their output power and extending their spectral range are shown.

  15. 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.

  16. Laser ablation of borosilicate glass with high power shaped UV nanosecond laser pulses

    NASA Astrophysics Data System (ADS)

    von Witzendorff, Philipp; Bordin, Andrea; Suttmann, Oliver; Patel, Rajesh S.; Bovatsek, James; Overmeyer, Ludger

    2016-03-01

    The application of thin borosilicate glass as interposer material requires methods for separation and drilling of this material. Laser processing with short and ultra-short laser pulses have proven to enable high quality cuts by either direct ablation or internal glass modification and cleavage. A recently developed high power UV nanosecond laser source allows for pulse shaping of individual laser pulses. Thus, the pulse duration, pulse bursts and the repetition rate can be set individually at a maximum output power of up to 60 W. This opens a completely new process window, which could not be entered with conventional Q-switched pulsed laser sources. In this study, the novel pulsed UV laser system was used to study the laser ablation process on 400 μm thin borosilicate glass at different pulse durations ranging from 2 - 10 ns and a pulse burst with two 10 ns laser pulses with a separation of 10 ns. Single line scan experiments were performed to correlate the process parameters and the laser pulse shape with the ablation depth and cutting edge chipping. Increasing the pulse duration within the single pulse experiments from 2 ns to longer pulse durations led to a moderate increase in ablation depth and a significant increase in chipping. The highest material removal was achieved with the 2x10 ns pulse burst. Experimental data also suggest that chipping could be reduced, while maintaining a high ablation depth by selecting an adequate pulse overlap. We also demonstrate that real-time combination of different pulse patterns during drilling a thin borosilicate glass produced holes with low overall chipping at a high throughput rate.

  17. Suppression of stimulated brillouin scattering in high power narrow linewidth fiber laser

    NASA Astrophysics Data System (ADS)

    Zhang, Liming; Yan, Chuping; Feng, Jinjun; Zhang, Kun; Zhu, Chen; Zhang, Dayong; Zhao, Hong; Zhou, Shouhuan

    2017-05-01

    In this paper, limitation factor of high power narrow linewidth fiber laser is analyzed. The influence of Stimulated Brillouin Scattering and its suppressing theory are discussed. Influences of frequency number and frequency spacing to Stimulated Brillouin Scattering are analyzed respectively by simulation. The results indicate that increasing frequency number and controlling frequency spacing can reduce the power spectrum density in fiber. Then the Stimulated Brillouin Scattering threshold is increased. Finally, the fiber laser output power is increased a lot.

  18. Extraction of power lines from mobile laser scanning data

    NASA Astrophysics Data System (ADS)

    Xiang, Qing; Li, Jonathan; Wen, Chenglu; Huang, Pengdi

    2016-03-01

    Modern urban life is becoming increasingly more dependent on reliable electric power supply. Since power outages cause substantial financial losses to producers, distributors and consumers of electric power, it is in the common interest to minimize failures of power lines. In order to detect defects as early as possible and to plan efficiently the maintenance activities, distribution networks are regularly inspected. Carrying out foot patrols or climbing the structures to visually inspect transmission lines and aerial surveys (e.g., digital imaging or most recent airborne laser scanning (ALS) are the two most commonly used methods of power line inspection. Although much faster in comparison to the foot patrol inspection, aerial inspection is more expensive and usually less accurate, in complex urban areas particularly. This paper presents a scientific work that is done in the use of mobile laser scanning (MLS) point clouds for automated extraction of power lines. In the proposed method, 2D power lines are extracted using Hough transform in the projected XOY plane and the 3D power line points are visualized after the point searching. Filtering based on an elevation threshold is applied, which is combined with the vehicle's trajectory in the horizontal section.

  19. 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.

  20. 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.

  1. 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.

  2. 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%.

  3. 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).

  4. 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.

  5. 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.

  6. Laser power beaming applications and technology

    NASA Astrophysics Data System (ADS)

    Burke, Robert J.; Cover, Ralph A.; Curtin, Mark S.; Dinius, R.; Lampel, Michael C.

    1994-05-01

    Beaming laser energy to spacecraft has important economic potential. It promises significant reduction in the cost of access to space, for commercial and government missions. While the potential payoff is attractive, existing technologies perform the same missions and the keys to market penetration for power beaming are a competitive cost and a schedule consistent with customers' plans. Rocketdyne is considering these questions in the context of a commercial enterprise -- thus, evaluation of the requirements must be done based on market assessments and recognition that significant private funding will be involved. It is in the context of top level business considerations that the technology requirements are being assessed and the program being designed. These considerations result in the essential elements of the development program. Since the free electron laser is regarded as the `long pole in the tent,' this paper summarizes Rocketdyne's approach for a timely, cost-effective program to demonstrate an FEL capable of supporting an initial operating capability.

  7. Laser power beaming: an emerging technology for power transmission and propulsion in space

    NASA Astrophysics Data System (ADS)

    Bennett, Harold E.

    1997-05-01

    A ground based laser beam transmitted to space can be used as an electric utility for satellites. It can significantly increase the electric power available to operate a satellite or to transport it from low earth orbit (LEO) to mid earth or geosynchronous orbits. The increase in electrical power compared to that obtainable from the sun is as much as 1000% for the same size solar panels. An increase in satellite electric power is needed to meet the increasing demands for power caused by the advent of 'direct to home TV,' for increased telecommunications, or for other demands made by the burgeoning 'space highway.' Monetary savings as compared to putting up multiple satellites in the same 'slot' can be over half a billion dollars. To obtain propulsion, the laser power can be beamed through the atmosphere to an 'orbit transfer vehicle' (OTV) satellite which travels back and forth between LEO and higher earth orbits. The OTV will transport the satellite into orbit as does a rocket but does not require the heavy fuel load needed if rocket propulsion is used. Monetary savings of 300% or more in launch costs are predicted. Key elements in the proposed concept are a 100 to 200 kW free- electron laser operating at 0.84 m in the photographic infrared region of the spectrum and a novel adaptive optic telescope.

  8. Fabrication of microchannels on PMMA using a low power CO2 laser

    NASA Astrophysics Data System (ADS)

    Imran, Muhammad; Rahman, Rosly A.; Ahmad, Mukhtar; Akhtar, Majid N.; Usman, Arslan; Sattar, Abdul

    2016-09-01

    This study presents a cheap and quick method for the formation of microchannels on poly methyl methacrylate (PMMA). A continuous wave CO2 laser with a wavelength of 10.6 μm was used to inscribe periodic ripple structures on a PMMA substrate. A direct writing technique was employed for micromachining. As PMMA is very sensitive to such laser irradiations, a slightly low power CO2 laser was effective in inscribing such periodic structures. The results show that smooth and fine ripple structures can be fabricated by controlling the input laser parameters and interaction time of the laser beam. This direct laser writing technique is promising enough to prevent us from using complex optical arrangements. Laser power was tested starting from the ablation threshold and was gradually increased, together with the variation in scanning speed of the xy-translational stage, to observe the effects on the target surface in terms of depth and width of trenches. It was observed that the depth of the trenches increases on increasing the laser power, and the bulge formation on the outer sides of the trenches was also studied. It was evident that the formation of bulges across the trenches is dependent on the scanning speed and input laser power. The results depict that a focused laser beam with optimized parameters, such as controlling the scanning speed and laser power, results in fine, regular and tidy periodic structures.

  9. Effects of low-power laser irradiation on the mitosis rate of the corneal epithelium

    NASA Astrophysics Data System (ADS)

    Chen, Varda; Landshman, Nahum; Belkin, Michael

    1995-05-01

    The effect of repeated low power He-Ne laser on rabbit's corneal epithelium was studied after 3 daily sessions. Under certain irradiation parameters, low power He-Ne laser irradiation was found to change the mitotic rate in the basal layer of intact corneal epithelium. Three daily irradiations for 3 or 10 minutes increased the mitotic index while 30 minutes irradiations decreased it.

  10. Effects of laser power on the microstructure and mechanical properties of 316L stainless steel prepared by selective laser melting

    NASA Astrophysics Data System (ADS)

    Zheng, Zeng; Wang, Lianfeng; Yan, Biao

    2017-07-01

    Selective laser melting (SLM) was used to prepare 316L stainless steel parts and the effects of laser power on the microstructure and mechanical properties of the final products were studied. With increasing applied laser power, the defects of as-built parts were reduced greatly and the as-built parts presented a highest relative density of 99.1%. The tensile strength of samples was significantly improved from 321 ± 10 MPa to 722 ± 10 MPa. The microhardness was homogeneous; the residual stresses in the samples were tensile, which were higher in the section perpendicular to the laser scanning strategy. The probable reasons for this phenomenon were proposed.

  11. Beamed laser power in support of near-earth missions

    NASA Technical Reports Server (NTRS)

    Conway, Edmund J.; Schuster, Gregory L.; Weaver, Willard; Humes, Donald H.

    1989-01-01

    It was found that solar-pumped laser-beamed power is lighter than photovoltaic for power requirements of 150 KWe and above, and is competitive with combined photovoltaic/solar-dynamic over the entire power range investigated. A space station supported by laser-beamed power can be a lower-g facility (reduced drag) than with PV or PV + SD power; has greater freedom of orientation (small receiver moves rather than large arrays or concentrators); and requires less structure (arrays, alpha joints, booms) permitting easier control and fewer vibrational modes. Laser power beaming offers a revolutionary concept for planning designing, and powering large orbiting spacecraft.

  12. ["Power bleaching" with the KTP laser].

    PubMed

    Vanderstricht, K; Nammour, S; De Moor, R

    2009-01-01

    The most important constituent of the bleaching process is the hydrogen peroxyde. The bleaching effect is the result of a change in the chemical structure of organic molecules in the teeth. Different bleaching techniques are described on the basis of the concentration of the hydrogen peroxyde used and on the basis of the different methods of application. It has been demonstrated that a faster change in colour can be obtained when bleaching is performed in combination with a light source i.e. power bleaching aiming for a more in depth change of colour. Different investigations have demonstrated that negative effects associated with bleaching agents are seen earlier when light sources have been used as accelerators. So, light activation may not lead to 'heating of the pulp'. Different types of laser bleaching have been described, though, not all of them will lead to the desired result. There is only one exception at present and this is the KTP-laser bleaching with the Smart Bleach gel. The specific laser-tissue interaction is the result of different activation processes of the hydrogen peroxyde in the gel: as a result of the interaction with the laser a photocatalytic effect is induced (i.e. the activation of the gel by means of light--this is also referred to as a photochemical reaction), a limited photothermal effect (light absorption may result in a certain heating of the gel). The light activated gel also has an alkaline pH, which favours the ionisation of the hydrogen peroxyde into perhydroxyl ions (these are the most reactive free radicals). It is also possible to directly cut the tetracycline molecules (a good absorption of light by the tetracycline molecules at 532 nm). This will result in better decolouration of tetracycline stained teeth. This last process is described as direct photobleaching. It also needs to be emphasized that bleaching with a laser can only be performed by a dentist who has acquired a substantial knowledge on laser-tissue interaction

  13. High average power diamond Raman laser.

    PubMed

    Feve, Jean-Philippe M; Shortoff, Kevin E; Bohn, Matthew J; Brasseur, Jason K

    2011-01-17

    We report a pulsed Raman laser at 1193 nm based on synthetic diamond crystals with a record output power of 24.5 W and a slope efficiency of 57%. We compared the performance of an anti-reflection coated crystal at normal incidence with a Brewster cut sample. Raman oscillation was achieved at both room temperature and under cryogenic operation at 77 K. Modeling of these experiments allowed us to confirm the value of Raman gain coefficient of diamond, which was found to be 13.5 ± 2.0 cm/GW for a pump wavelength of 1030 nm.

  14. Collimation optics for high power blue laser diodes

    NASA Astrophysics Data System (ADS)

    Huber, M.; Forrer, H.; Wuest, P.; Moser, H.; Forrer, M.

    2017-02-01

    Similar to the well-established high power laser diodes in the infrared wavelength range, the laser diodes in the blue wavelength range require tailored optics for beam shaping, to make the light usable for a variety of applications. High power laser diode arrays or single emitters require fast and slow axis optical collimation for further transport or photonics applications using high power laser radiation. With increasing requirements in higher brightness for slow axis collimation different engineering solutions exist. By using novel production technologies, e.g. precision molding, approaches that were considered too expensive for mass production become available to broad application fields. Here we report about the benefits of molded refractive, freeform slow axis collimation optics and compare them to the ubiquitous standard circular cylindrical, as well as acircular cylindrical slow axis collimation optics. By using refractive free form slow axis collimation optics it is possible to achieve significantly better brightness compared to circular cylindrical or acircular cylindrical slow axis collimation optics.

  15. Near-term feasibility demonstration of laser power beaming

    NASA Astrophysics Data System (ADS)

    Friedman, Herbert W.

    1994-05-01

    A mission to recharge batteries of satellites in geostationary orbits (geosats) may be a commercially viable application which could be achieved with laser systems somewhat larger than present state-of-the-art. The lifetime of batteries on geosats is limited by repetitive discharge cycles which occur when the satellites are eclipsed by the earth during the spring and fall equinoxes. By coupling high power lasers with modern, large aperture telescopes and laser guide star adaptive optics systems, present day communications satellites could be targeted. It is important that a near term demonstration of laser power beaming be accomplished using lasers in the kilowatt range so that issues associated with high average power be addressed. The Laser Guide Star Facility at LLNL has all the necessary subsystems needed for such a near term demonstration, including high power lasers for both the power beam and guide star, beam directors and satellite tracking system.

  16. Near-term feasibility demonstration of laser power beaming

    SciTech Connect

    Friedman, H.W.

    1994-01-01

    A mission to recharge batteries of satellites in geostationary orbits (geosats) may be a commercially viable application which could be achieved with laser systems somewhat larger than present state-of-the-art. The lifetime of batteries on geosats is limited by repetitive discharge cycles which occur when the satellites are eclipsed by the earth during the spring and fall equinoxes. By coupling high power lasers with modern, large aperture telescopes and laser guide star adaptive optics systems, present day communications satellites could be targeted. It is important that a near term demonstration of laser power beaming be accomplished using lasers in the kilowatt range so that issues associated with high average power be addressed. The Laser Guide Star Facility at LLNL has all the necessary subsystems needed for such a near term demonstration, including high power lasers for both the power beam and guide star, beam directors and satellite tracking system.

  17. 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.

  18. 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.

  19. Analysis of the scalability of diffraction-limited fiber lasers and amplifiers to high average power.

    PubMed

    Dawson, Jay W; Messerly, Michael J; Beach, Raymond J; Shverdin, Miroslav Y; Stappaerts, Eddy A; Sridharan, Arun K; Pax, Paul H; Heebner, John E; Siders, Craig W; Barty, C P J

    2008-08-18

    We analyze the scalability of diffraction-limited fiber lasers considering thermal, non-linear, damage and pump coupling limits as well as fiber mode field diameter (MFD) restrictions. We derive new general relationships based upon practical considerations. Our analysis shows that if the fiber's MFD could be increased arbitrarily, 36 kW of power could be obtained with diffraction-limited quality from a fiber laser or amplifier. This power limit is determined by thermal and non-linear limits that combine to prevent further power scaling, irrespective of increases in mode size. However, limits to the scaling of the MFD may restrict fiber lasers to lower output powers.

  20. Low-power laser therapy for carpal tunnel syndrome: effective optical power.

    PubMed

    Chen, Yan; Zhao, Cheng-Qiang; Ye, Gang; Liu, Can-Dong; Xu, Wen-Dong

    2016-07-01

    Low-power laser therapy has been used for the non-surgical treatment of mild to moderate carpal tunnel syndrome, although its efficacy has been a long-standing controversy. The laser parameters in low-power laser therapy are closely related to the laser effect on human tissue. To evaluate the efficacy of low-power laser therapy, laser parameters should be accurately measured and controlled, which has been ignored in previous clinical trials. Here, we report the measurement of the effective optical power of low-power laser therapy for carpal tunnel syndrome. By monitoring the backside reflection and scattering laser power from human skin at the wrist, the effective laser power can be inferred. Using clinical measurements from 30 cases, we found that the effective laser power differed significantly among cases, with the measured laser reflection coefficient ranging from 1.8% to 54%. The reflection coefficient for 36.7% of these 30 cases was in the range of 10-20%, but for 16.7% of cases, it was higher than 40%. Consequently, monitoring the effective optical power during laser irradiation is necessary for the laser therapy of carpal tunnel syndrome.

  1. 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.

  2. 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.

  3. High average power scaleable thin-disk laser

    DOEpatents

    Beach, Raymond J.; Honea, Eric C.; Bibeau, Camille; Payne, Stephen A.; Powell, Howard; Krupke, William F.; Sutton, Steven B.

    2002-01-01

    Using a thin disk laser gain element with an undoped cap layer enables the scaling of lasers to extremely high average output power values. Ordinarily, the power scaling of such thin disk lasers is limited by the deleterious effects of amplified spontaneous emission. By using an undoped cap layer diffusion bonded to the thin disk, the onset of amplified spontaneous emission does not occur as readily as if no cap layer is used, and much larger transverse thin disks can be effectively used as laser gain elements. This invention can be used as a high average power laser for material processing applications as well as for weapon and air defense applications.

  4. 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.

  5. High-average-power Nd:YAG planar waveguide laser that is face pumped by 10 laser diode bars.

    PubMed

    Lee, J R; Baker, H J; Friel, G J; Hilton, G J; Hall, D R

    2002-04-01

    A planar waveguide Nd:YAG laser is pumped with 430 W of power from 10 laser diode bars to produce a multimode output power of 150 W at an optical efficiency of 35%. Use of a hybrid resonator of the positive-branch confocal unstable type for the lateral axis and of one of the near-case I waveguide type for the transverse axis increased the laser brightness by a factor of ~26 with only 12% less power than in the multimode case.

  6. High Average Power Diode Pumped Solid State Lasers: Power Scaling With High Spectral and Spatial Coherence

    DTIC Science & Technology

    2009-03-30

    TEM00 -mode, diode - laser - pumped , Nd:YAG miniature-slab laser ,” Opt. Lett...30-Sep-2008 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER High Average Power Diode - Pumped Solid-State Lasers : Power DAAD19-02-1-0184 Scaling with High...documentation. 14. ABSTRACT The main program objective was the development ofa kilowatt class, cw Nd:YAG diode - laser - pumped solid-state laser (DPSSL)

  7. Semiconductor Laser Diodes and the Design of a D.C. Powered Laser Diode Drive Unit

    DTIC Science & Technology

    1988-06-01

    i FILE c(OP!; NAVAL POSTGRADUATE SCHOOL Monterey, California 00 ,, STAES THESIS SEMICONDUCTOR LASER DIODES AND THE DESIGN OF A D.C. POWERED LASER...the design of a laser diode modulation circuit is the determination of the input imped- ence and equivalent circuit of the laser diode and packag- ing...current source with a high internal impedance as compared to the input imped- ance of the laser. [Ref. l:p. 33] Summarizing the above, laser diodes

  8. 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)

  9. Scalable high-power optically pumped GaAs laser

    NASA Astrophysics Data System (ADS)

    Le, H. Q.; di Cecca, S.; Mooradian, A.

    1991-05-01

    The use of disk geometry, optically pumped semiconductor gain elements for high-power scalability and good transverse mode quality has been studied. A room-temperature TEM00 transverse mode, external-cavity GaAs disk laser has been demonstrated with 500 W peak-power output and 40-percent slope efficiency, when pumped by a Ti:Al2O3 laser. The conditions for diode laser pumping are shown to be consistent with available power level.

  10. Advanced Optical Fibers for High power Fiber lasers

    DTIC Science & Technology

    2015-08-24

    0704-0188 3. DATES COVERED (From - To) - UU UU UU UU 24-08-2015 Approved for public release; distribution is unlimited. Advanced Optical Fibers for...0946 ABSTRACT Advanced Optical Fibers for High power Fiber lasers Report Title A review of recent fiber developement for high power fiber lasers...Chapter 7 Advanced Optical Fibers for High Power Fiber Lasers Liang Dong Additional information is available at the end of the chapter http://dx.doi.org

  11. High-Power Laser Oscillation Test Using Ceramic Waveguide

    DTIC Science & Technology

    2013-07-01

    pumping beam can generate laser output power effectively (high-gain and high-efficiency). For this purpose, sapphire was used for cladding the...1 Final Short Report for AOARD Grant Number FA2386-11-1-4082 Title of proposed project: “High-power laser oscillation test using ceramic...01 JUL 2013 2. REPORT TYPE Final 3. DATES COVERED 19-09-2011 to 01-01-2013 4. TITLE AND SUBTITLE High-power laser oscillation test using

  12. Application of reactor-pumped lasers to power beaming

    SciTech Connect

    Repetti, T.E.

    1991-10-01

    Power beaming is the concept of centralized power generation and distribution to remote users via energy beams such as microwaves or laser beams. The power beaming community is presently performing technical evaluations of available lasers as part of the design process for developing terrestrial and space-based power beaming systems. This report describes the suitability of employing a nuclear reactor-pumped laser in a power beaming system. Although there are several technical issues to be resolved, the power beaming community currently believes that the AlGaAs solid-state laser is the primary candidate for power beaming because that laser meets the many design criteria for such a system and integrates well with the GaAs photodiode receiver array. After reviewing the history and physics of reactor-pumped lasers, the advantages of these lasers for power beaming are discussed, along with several technical issues which are currently facing reactor-pumped laser research. The overriding conclusion is that reactor-pumped laser technology is not presently developed to the point of being technially or economically competitive with more mature solid-state technologies for application to power beaming. 58 refs.

  13. Application of reactor-pumped lasers to power beaming

    SciTech Connect

    Repetti, T.E.

    1991-10-01

    Power beaming is the concept of centralized power generation and distribution to remote users via energy beams such as microwaves or laser beams. The power beaming community is presently performing technical evaluations of available lasers as part of the design process for developing terrestrial and space-based power beaming systems. This report describes the suitability of employing a nuclear reactor-pumped laser in a power beaming system. Although there are several technical issues to be resolved, the power beaming community currently believes that the AlGaAs solid-state laser is the primary candidate for power beaming because that laser meets the many design criteria for such a system and integrates well with the GaAs photodiode receiver array. After reviewing the history and physics of reactor-pumped lasers, the advantages of these lasers for power beaming are discussed, along with several technical issues which are currently facing reactor-pumped laser research. The overriding conclusion is that reactor-pumped laser technology is not presently developed to the point of being technially or economically competitive with more mature solid-state technologies for application to power beaming. 58 refs.

  14. 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].

  15. 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.

  16. Wind Power Ramping Product for Increasing Power System Flexibility

    SciTech Connect

    Cui, Mingjian; Zhang, Jie; Wu, Hongyu; Hodge, Bri-Mathias; Ke, Deping; Sun, Yuanzhang

    2016-05-05

    With increasing penetrations of wind power, system operators are concerned about a potential lack of system flexibility and ramping capacity in real-time dispatch stages. In this paper, a modified dispatch formulation is proposed considering the wind power ramping product (WPRP). A swinging door algorithm (SDA) and dynamic programming are combined and used to detect WPRPs in the next scheduling periods. The detected WPRPs are included in the unit commitment (UC) formulation considering ramping capacity limits, active power limits, and flexible ramping requirements. The modified formulation is solved by mixed integer linear programming. Numerical simulations on a modified PJM 5-bus System show the effectiveness of the model considering WPRP, which not only reduces the production cost but also does not affect the generation schedules of thermal units.

  17. 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.

  18. 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.

  19. Laser power beaming for rocket propulsion and airbreathing propulsion

    NASA Technical Reports Server (NTRS)

    Hertzberg, A.

    1980-01-01

    The developing technology of laser power beaming is introduced, and two systems are used as examples of the capabilities of the laser for beamed energy. In the first system, the potential of the laser to power flight systems ranging from hypersonic air-breathing launch vehicles to commercial jet transports is examined. Attention is given to the possibility of an air-breathing propulsion which offers the promise of a global air transportation network independent of kerosene and powered by solar energy. In addition, consideration is given to a new type of rocket propulsion based on the laser's ability to concentrate coherent laser energy to high power densities. Focused laser beams would heat the propellants directly to produce specific impulses approaching ion and MHD rocket levels, and would do so without the burden of a heavy electrical power supply.

  20. 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.

  1. 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.

  2. Non-intrusive beam power monitor for high power pulsed or continuous wave lasers

    DOEpatents

    Hawsey, Robert A.; Scudiere, Matthew B.

    1993-01-01

    A system and method for monitoring the output of a laser is provided in which the output of a photodiode disposed in the cavity of the laser is used to provide a correlated indication of the laser power. The photodiode is disposed out of the laser beam to view the extraneous light generated in the laser cavity whose intensity has been found to be a direct correlation of the laser beam output power level. Further, the system provides means for monitoring the phase of the laser output beam relative to a modulated control signal through the photodiode monitor.

  3. 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.

  4. 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.

  5. 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).

  6. 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.

  7. Laser Ablation Increases PEM/Catalyst Interfacial Area

    NASA Technical Reports Server (NTRS)

    Whitacre, Jay; Yalisove, Steve

    2009-01-01

    An investigational method of improving the performance of a fuel cell that contains a polymer-electrolyte membrane (PEM) is based on the concept of roughening the surface of the PEM, prior to deposition of a thin layer of catalyst, in order to increase the PEM/catalyst interfacial area and thereby increase the degree of utilization of the catalyst. The roughening is done by means of laser ablation under carefully controlled conditions. Next, the roughened membrane surface is coated with the thin layer of catalyst (which is typically platinum), then sandwiched between two electrode/catalyst structures to form a membrane/ele c t - rode assembly. The feasibility of the roughening technique was demonstrated in experiments in which proton-conducting membranes made of a perfluorosulfonic acid-based hydrophilic, protonconducting polymer were ablated by use of femtosecond laser pulses. It was found that when proper combinations of the pulse intensity, pulse-repetition rate, and number of repetitions was chosen, the initially flat, smooth membrane surfaces became roughened to such an extent as to be converted to networks of nodules interconnected by filaments (see Figure 1). In further experiments, electrochemical impedance spectroscopy (EIS) was performed on a pristine (smooth) membrane and on two laser-roughened membranes after the membranes were coated with platinum on both sides. Some preliminary EIS data were interpreted as showing that notwithstanding the potential for laser-induced damage, the bulk conductivities of the membranes were not diminished in the roughening process. Other preliminary EIS data (see Figure 2) were interpreted as signifying that the surface areas of the laser-roughened membranes were significantly greater than those of the smooth membrane. Moreover, elemental analyses showed that the sulfur-containing molecular groups necessary for proton conduction remained intact, even near the laser-roughened surfaces. These preliminary results can be taken

  8. Improved low-power semiconductor diode lasers for photodynamic therapy in veterinary medicine

    NASA Astrophysics Data System (ADS)

    Lee, Susanne M.; Mueller, Eduard K.; Van de Workeen, Brian C.; Mueller, Otward M.

    2001-05-01

    Cryogenically cooling semiconductor diode lasers provides higher power output, longer device lifetime, and greater monochromaticity. While these effects are well known, such improvements have not been quantified, and thus cryogenically operated semiconductor lasers have not been utilized in photodynamic therapy (PDT). We report quantification of these results from laser power meter and photospectrometer data. The emission wavelengths of these low power multiple quantum well semiconductor lasers were found to decrease and become more monochromatic with decreasing temperature. Significant power output improvements also were obtained at cryogenic temperatures. In addition, the threshold current, i.e. the current at which lasing begins, decreased with decreasing temperature. This lower threshold current combined with the increased power output produced dramatically higher device efficiencies. It is proposed that cryogenic operation of semiconductor diode lasers will reduce the number of devices needed to produce the requisite output for many veterinary and medical applications, permitting significant cost reductions.

  9. 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

  10. Bone fracture consolidates faster with low-power laser

    SciTech Connect

    Trelles, M.A.; Mayayo, E.

    1987-01-01

    Low-power laser radiation is currently used in the treatment of pain and osteoarticular inflammation. However, the mechanisms of the laser biostimulating effects on tissue are still not completely understood. With laser treatment, we have achieved activation of osseous regeneration in human bone fractures. After 7 years of positive clinical control in human beings, we decided to start an experimental study of fractures in the tibia of mice, histologically controlling its reparation after exposure to 632 nm. He/Ne laser in doses of 2.4 Joules in one point was used. The radiation was directly applied to the area of fracture in a series of 12 treatments (one treatment every second day). By optic microscope we observed, in the treated animals, an important increase in vascularization and faster formation of osseous tissue with a dense trabecular net compared to the control group, which presented only chondroid tissue and poor vascularization corresponding to an earlier stage of bone consolidation (controls were also analyzed by electron microscopy). Potentially, the laser effect might modulate the function of osteocytes, promoting faster metabolism and reaction of bone callus.

  11. Industrial CO laser with tens of kilowatt power: technical offer

    NASA Astrophysics Data System (ADS)

    Baranov, Igor Y.

    2005-09-01

    The laser with power tens of kilowatt would be essential for dismantlement of obsolete nuclear-power reactors, laser-hardening the surfaces of railway rails and etc. The production of high power, high efficiency, high specific energy and high optical beam quality can be obtained in the experimental systems of a quasi-cw electroionization CO laser with cooling a CO mixture by its expansion in the nozzles. The way of transfer to industrial high-power CO lasers is proposed through the continuous formation of a CO laser mixture during laser operation. CO laser mixture is formed by using air as a buffer gas (about 90%). CO molecules are generated in oxidation reaction of oxygen-containing molecules with carbon. The carbon arises from a decomposition of hydrocarbon fuel on the catalyst surface. CO mixture is excited by radio-frequency (RF) electric discharge in a supersonic gas flow without an electron gun. The given conception was used on a small-scale model system to demonstrate that the laser radiation was possible in a CO mixture with combustion products and air, which are excited by RF discharge in a supersonic flow. The industrial CO laser with tens of kilowatt power is offer with open working cycle without ejecting toxic CO into the atmosphere by converting CO molecules to C02 ones. The estimated cost of a laser is several hundred thousand and the small sizes of laser give possibility to install its on manipulator without fiber-optic delivery.

  12. Laboratory modeling of big bang nucleosynthesis using powerful laser facilities

    NASA Astrophysics Data System (ADS)

    Belyaev, V. S.; Zagreev, B. V.; Kedrov, A. Yu; Kovkov, D. V.; Lobanov, A. V.; Matafonov, A. P.; Savel'ev, A. B.; Mordvincev, I. M.; Tsymbalov, I. N.; Shulyapov, S. A.; Paskhalov, A. A.; Eremin, N. V.; Krainov, V. P.

    2017-06-01

    The processes and problems of big bang nucleosynthesis are considered. Powerful laser pulses allow us to obtain high energy density in matter. Thus, laboratory modeling of big bang nucleosynthesis becomes feasible. Results of experiments on the picosecond laser facility ‘Neodymium’ and on the femtosecond terawatt laser are reported. Further investigations of this topic are discussed.

  13. 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.

  14. Lasers for industrial production processing: tailored tools with increasing flexibility

    NASA Astrophysics Data System (ADS)

    Rath, Wolfram

    2012-03-01

    High-power fiber lasers are the newest generation of diode-pumped solid-state lasers. Due to their all-fiber design they are compact, efficient and robust. Rofin's Fiber lasers are available with highest beam qualities but the use of different process fiber core sizes enables the user additionally to adapt the beam quality, focus size and Rayleigh length to his requirements for best processing results. Multi-mode fibers from 50μm to 600μm with corresponding beam qualities of 2.5 mm.mrad to 25 mm.mrad are typically used. The integrated beam switching modules can make the laser power available to 4 different manufacturing systems or can share the power to two processing heads for parallel processing. Also CO2 Slab lasers combine high power with either "single-mode" beam quality or higher order modes. The wellestablished technique is in use for a large number of industrial applications, processing either metals or non-metallic materials. For many of these applications CO2 lasers remain the best choice of possible laser sources either driven by the specific requirements of the application or because of the cost structure of the application. The actual technical properties of these lasers will be presented including an overview over the wavelength driven differences of application results, examples of current industrial practice as cutting, welding, surface processing including the flexible use of scanners and classical optics processing heads.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Photovoltaic receivers for laser beamed power in space

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.

    1991-01-01

    There has recently been a resurgence of interest in the use of beamed power to support space exploration activities. One of the most promising beamed power concepts uses a laser beam to transmit power to a remote photovoltaic array. Large lasers can be located on cloud-free sites at one or more ground locations and illuminate solar arrays to a level sufficient to provide operating power. Issues involved in providing photovoltaic receivers for such applications are discussed.

  20. 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.

  1. Measuring laser power as a force: a new paradigm to accurately monitor optical power during laser-based machining operations

    NASA Astrophysics Data System (ADS)

    Williams, Paul; Simonds, Brian; Sowards, Jeffrey; Hadler, Joshua

    2016-03-01

    In laser manufacturing operations, accurate measurement of laser power is important for product quality, operational repeatability, and process validation. Accurate real-time measurement of high-power lasers, however, is difficult. Typical thermal power meters must absorb all the laser power in order to measure it. This constrains power meters to be large, slow and exclusive (that is, the laser cannot be used for its intended purpose during the measurement). To address these limitations, we have developed a different paradigm in laser power measurement where the power is not measured according to its thermal equivalent but rather by measuring the laser beam's momentum (radiation pressure). Very simply, light reflecting from a mirror imparts a small force perpendicular to the mirror which is proportional to the optical power. By mounting a high-reflectivity mirror on a high-sensitivity force transducer (scale), we are able to measure laser power in the range of tens of watts up to ~ 100 kW. The critical parameters for such a device are mirror reflectivity, angle of incidence, and scale sensitivity and accuracy. We will describe our experimental characterization of a radiation-pressure-based optical power meter. We have tested it for modulated and CW laser powers up to 92 kW in the laboratory and up to 20 kW in an experimental laser welding booth. We will describe present accuracy, temporal response, sources of measurement uncertainty, and hurdles which must be overcome to have an accurate power meter capable of routine operation as a turning mirror within a laser delivery head.

  2. 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.

  3. High-powered CO2 -lasers and noise control

    NASA Astrophysics Data System (ADS)

    Honkasalo, Antero; Kuronen, Juhani

    High-power CO2 -lasers are being more and more widely used for welding, drilling and cutting in machine shops. In the near future, different kinds of surface treatments will also become routine practice with laser units. The industries benefitting most from high power lasers will be: the automotive industry, shipbuilding, the offshore industry, the aerospace industry, the nuclear and the chemical processing industries. Metal processing lasers are interesting from the point of view of noise control because the working tool is a laser beam. It is reasonable to suppose that the use of such laser beams will lead to lower noise levels than those connected with traditional metal processing methods and equipment. In the following presentation, the noise levels and possible noise-control problems attached to the use of high-powered CO2 -lasers are studied.

  4. Low power-consumption quantum cascade lasers

    NASA Astrophysics Data System (ADS)

    Katsuyama, Tsukuru; Hashimoto, Jun-ichi; Yoshinaga, Hiroyuki; Mori, Hiroki; Tsuji, Yukihiro; Murata, Makoto; Ekawa, Mitsuru; Tanahashi, Toshiyuki

    2015-01-01

    Quantum cascade lasers (QCLs) are promising light sources for real time high-sensitivity gas sensing in the mid-infrared region. For the practical use of QCLs as a compact and portable gas sensor, their power-consumption needs to be reduced. We report a successful operation of a low power-consumption distributed feedback (DFB) QCL. For the reduction of power consumption, we introduced a vertical-transition structure in a core region to improve carrier transition efficiency and reduced the core volume. DFB-QCL epitaxial structure was grown by low-pressure OMVPE. The core region consists of AlInAs/GaInAs superlattices lattice-matched to InP. A first-order Bragg-grating was formed near the core region to obtain a large coupling coefficiency. A mesa-strip was formed by reactive ion etching and a buried-heterostructure was fabricated by the regrowth of semi-insulating InP. High-reflective facet coatings were also performed to decrease the mirror loss for the reduction of the threshold current. A device (5x500μm) operated with a single mode in the wavelength region from 7.23μm to 7.27μm. The threshold current and threshold voltage under CW operation at 20 °C were 52mA and 8.4V respectively. A very low threshold power-consumption as low as 0.44 W was achieved, which is among the lowest values at room temperature to our knowledge.

  5. Supplemental Task-High Power Lasers

    DTIC Science & Technology

    2011-12-20

    first task involved the growth and characterization of 1040 nm vertical external cavity surface emitting lasers ( VECSELs ). These devices have been... VECSEL research at CHTM. Vertical external cavity surface emitting lasers, crystal growth, semiconductor laser epi-structure design, quantum wells...involved the growth and characterization of 1040 nm vertical external cavity surface emitting lasers ( VECSELs ). These devices have been grown by MOCVD

  6. Hybrid Laser Would Combine Power With Efficiency

    NASA Technical Reports Server (NTRS)

    Sipes, Donald L., Jr

    1986-01-01

    Efficient laser system constructed by using two semiconductor lasers to pump neodymium yttrium aluminum garnet (Nd:YAG) device. Hybrid concept allows digital transmission at data rates of several megabits per second with reasonably sized optical aperture of 20 cm. Beams from two GaAs lasers efficiently coupled for pumping Nd:YAG crystal. Combination of lasers exploits best features of each.

  7. 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.

  8. 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.

  9. 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.

  10. Power blue and green laser diodes and their applications

    NASA Astrophysics Data System (ADS)

    Hager, Thomas; Strauß, Uwe; Eichler, Christoph; Vierheilig, Clemens; Tautz, Sönke; Brüderl, Georg; Stojetz, Bernhard; Wurm, Teresa; Avramescu, Adrian; Somers, André; Ristic, Jelena; Gerhard, Sven; Lell, Alfred; Morgott, Stefan; Mehl, Oliver

    2013-03-01

    InGaN based green laser diodes with output powers up to 50mW are now well established for variety of applications ranging from leveling to special lighting effects and mobile projection of 12lm brightness. In future the highest market potential for visible single mode profile lasers might be laser projection of 20lm. Therefore direct green single-mode laser diodes with higher power are required. We found that self heating was the limiting factor for higher current operation. We present power-current characteristics of improved R and D samples with up to 200mW in cw-operation. An optical output power of 100mW is reached at 215mA, a current level which is suitable for long term operation. Blue InGaN laser diodes are also the ideal source for phosphor based generation of green light sources of high luminance. We present a light engine based on LARP (Laser Activated Remote Phosphor) which can be used in business projectors of several thousand lumens on screen. We discuss the advantages of a laser based systems in comparison with LED light engines. LARP requires highly efficient blue power laser diodes with output power above 1W. Future market penetration of LARP will require lower costs. Therefore we studied new designs for higher powers levels. R and D chips with power-current characteristics up to 4W in continuous wave operation on C-mount at 25°C are presented.

  11. 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.

  12. 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.

  13. 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.

  14. Advantages of ground-to-space laser power beaming

    NASA Technical Reports Server (NTRS)

    Rather, John D. G.

    1992-01-01

    NASA's current research activities to evaluate laser power beaming systems are reviewed. Applications of such systems are considered, including communications satellites, radar and direct broadcast satellites, space transfer vehicles lunar base operations and exploration, and optical technologies. The current laser power beaming program within the NASA Headquarters Office of Aeronautics and Space Technology is addressed.

  15. Preliminary comparison of laser and solar space power systems

    NASA Technical Reports Server (NTRS)

    Deyoung, R. J.; Tepper, W. D.; Conway, E. J.; Humes, D. H.

    1983-01-01

    Four laser receiver systems are compared to onboard solar photovoltaic power generation for spacecraft electrical requirements. The laser photovoltaic and laser MHD receivers were found to be lighter than a comparable planar solar photovoltaic system. The laser receiver also shows less drag at lower altitudes. Panel area is also reduced for the laser receiver allowing fewer Shuttle trips for construction. Finally, it is shown that a 1 megawatt laser and receiver system might be constructed with less weight than a comparable planar solar photovoltaic system.

  16. Development of High Average Power Lasers for the Photon Collider

    SciTech Connect

    Gronberg, Jeff; Stuart, Brent; Seryi, Andrei; /SLAC

    2012-07-05

    The laser and optics system for the photon collider seeks to minimize the required laser power by using an optical stacking cavity to recirculate the laser light. An enhancement of between 300 to 400 is desired. In order to achieve this the laser pulses which drive the cavity must precisely match the phase of the pulse circulating within the cavity. We report on simulations of the performance of a stacking cavity to various variations of the drive laser in order to specify the required tolerances of the laser system.

  17. 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.

  18. 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

  19. High Average Power Lasers for the Photon Collider

    SciTech Connect

    Stuart, B; Gronberg, J; Seryi, A

    2009-04-29

    The idea to convert an electron collider into a high energy photon collider has existed for several decades. A key technological limitation to realizing this idea is the need to create a large amount of laser power to drive the Compton back-scattering. A concept to reduce the required laser power using a recirculating cavity has been proposed. We describe a concept for a laser architecture that could drive such a cavity.

  20. 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.

  1. High-power laser diodes at various wavelengths

    SciTech Connect

    Emanuel, M.A.

    1997-02-19

    High power laser diodes at various wavelengths are described. First, performance and reliability of an optimized large transverse mode diode structure at 808 and 941 nm are presented. Next, data are presented on a 9.5 kW peak power array at 900 nm having a narrow emission bandwidth suitable for pumping Yb:S-FAP laser materials. Finally, results on a fiber-coupled laser diode array at {approx}730 nm are presented.

  2. 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.

  3. Active cooling of pulse compression diffraction gratings for high energy, high average power ultrafast lasers

    SciTech Connect

    Alessi, David A.; Rosso, Paul A.; Nguyen, Hoang T.; Aasen, Michael D.; Britten, Jerald A.; Haefner, Constantin

    2016-12-26

    Laser energy absorption and subsequent heat removal from diffraction gratings in chirped pulse compressors poses a significant challenge in high repetition rate, high peak power laser development. In order to understand the average power limitations, we have modeled the time-resolved thermo-mechanical properties of current and advanced diffraction gratings. We have also developed and demonstrated a technique of actively cooling Petawatt scale, gold compressor gratings to operate at 600W of average power - a 15x increase over the highest average power petawatt laser currently in operation. As a result, combining this technique with low absorption multilayer dielectric gratings developed in our group would enable pulse compressors for petawatt peak power lasers operating at average powers well above 40kW.

  4. Active cooling of pulse compression diffraction gratings for high energy, high average power ultrafast lasers

    DOE PAGES

    Alessi, David A.; Rosso, Paul A.; Nguyen, Hoang T.; ...

    2016-12-26

    Laser energy absorption and subsequent heat removal from diffraction gratings in chirped pulse compressors poses a significant challenge in high repetition rate, high peak power laser development. In order to understand the average power limitations, we have modeled the time-resolved thermo-mechanical properties of current and advanced diffraction gratings. We have also developed and demonstrated a technique of actively cooling Petawatt scale, gold compressor gratings to operate at 600W of average power - a 15x increase over the highest average power petawatt laser currently in operation. As a result, combining this technique with low absorption multilayer dielectric gratings developed in ourmore » group would enable pulse compressors for petawatt peak power lasers operating at average powers well above 40kW.« less

  5. Active cooling of pulse compression diffraction gratings for high energy, high average power ultrafast lasers.

    PubMed

    Alessi, David A; Rosso, Paul A; Nguyen, Hoang T; Aasen, Michael D; Britten, Jerald A; Haefner, Constantin

    2016-12-26

    Laser energy absorption and subsequent heat removal from diffraction gratings in chirped pulse compressors poses a significant challenge in high repetition rate, high peak power laser development. In order to understand the average power limitations, we have modeled the time-resolved thermo-mechanical properties of current and advanced diffraction gratings. We have also developed and demonstrated a technique of actively cooling Petawatt scale, gold compressor gratings to operate at 600W of average power - a 15x increase over the highest average power petawatt laser currently in operation. Combining this technique with low absorption multilayer dielectric gratings developed in our group would enable pulse compressors for petawatt peak power lasers operating at average powers well above 40kW.

  6. Space Solar Power Technology Demonstration for Lunar Polar Applications: Laser-Photovoltaic Wireless Power Transmission

    NASA Technical Reports Server (NTRS)

    Henley, M. W.; Fikes, J. C.; Howell, J.; Mankins, J. C.; Howell, Joe T. (Technical Monitor)

    2002-01-01

    Space Solar Power technology offers unique benefits for near-term NASA space science missions, which can mature this technology for other future applications. "Laser-Photo-Voltaic Wireless Power Transmission" (Laser-PV WPT) is a technology that uses a laser to beam power to a photovoltaic receiver, which converts the laser's light into electricity. Future Laser-PV WPT systems may beam power from Earth to satellites or large Space Solar Power satellites may beam power to Earth, perhaps supplementing terrestrial solar photo-voltaic receivers. In a near-term scientific mission to the moon, Laser-PV WPT can enable robotic operations in permanently shadowed lunar polar craters, which may contain ice. Ground-based technology demonstrations are proceeding, to mature the technology for this initial application, in the moon's polar regions.

  7. Highly-efficient high-power pumps for fiber lasers

    NASA Astrophysics Data System (ADS)

    Gapontsev, V.; Moshegov, N.; Berezin, I.; Komissarov, A.; Trubenko, P.; Miftakhutdinov, D.; Berishev, I.; Chuyanov, V.; Raisky, O.; Ovtchinnikov, A.

    2017-02-01

    We report on high efficiency multimode pumps that enable ultra-high efficiency high power ECO Fiber Lasers. We discuss chip and packaged pump design and performance. Peak out-of-fiber power efficiency of ECO Fiber Laser pumps was reported to be as high as 68% and was achieved with passive cooling. For applications that do not require Fiber Lasers with ultimate power efficiency, we have developed passively cooled pumps with out-of-fiber power efficiency greater than 50%, maintained at operating current up to 22A. We report on approaches to diode chip and packaged pump design that possess such performance.

  8. Power scaling of cryogenic Yb:LiYF(4) lasers.

    PubMed

    Zapata, Luis E; Ripin, Daniel J; Fan, Tso Yee

    2010-06-01

    We demonstrate a cryogenically cooled Yb:LiYF(4) (Yb:YLF) laser with 224W linearly polarized output power (pump-power limited) and a slope efficiency of 68%. The beam quality is characterized by an M(2) approximately 1.1 at 60W output and M(2) approximately 2.6 at 180W output. This level of average laser power is approximately 2 orders of magnitude higher than demonstrated previously in cryogenic Yb:YLF. Yb:YLF is attractive for femtosecond pulse generation because of its wide gain bandwidth, and this demonstration shows the potential for high-average-power subpicosecond pulse lasers.

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

    PubMed

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

    2015-07-01

    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.

  11. Macro-channel cooled high power fiber coupled diode lasers exceeding 1.2kW of output power

    NASA Astrophysics Data System (ADS)

    Koenning, Tobias; Alegria, Kim; Wang, Zuolan; Segref, Armin; Stapleton, Dean; Faßbender, Wilhelm; Flament, Marco; Rotter, Karsten; Noeske, Axel; Biesenbach, Jens

    2011-03-01

    We report on a new series of fiber coupled diode laser modules exceeding 1.2kW of single wavelength optical power from a 400um / 0.2NA fiber. The units are constructed from passively cooled laser bars as opposed to other comparably powered, commercially available modules that use micro-channel heat-sinks. Micro-channel heat sinks require cooling water to meet demanding specifications and are therefore prone to failures due to contamination and increase the overall cost to operate and maintain the laser. Dilas' new series of high power fiber coupled diode lasers are designed to eliminate micro channel coolers and their associated failure mechanisms. Low-smile soldering processes were developed to maximize the brightness available from each diode laser bar. The diode laser brightness is optimally conserved using Dilas' recently developed propriety laser bar stacking geometry and optics. A total of 24 bars are coupled into a single fiber core using a polarization multiplexing scheme. The modular design permits further power scaling through wavelength multiplexing. Other customer critical features such as industrial grade fibers, pilot beams, fiber interlocks and power monitoring are standard features on these modules. The optical design and the beam parameter calculations will be presented to explain the inherit design trade offs. Results for single and dual wavelengths modules will be presented.

  12. 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.

  13. Solar power satellite system definition study. Volume 3: Laser SPS analysis, phase 3

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The potential use of lasers for transmitting power to Earth from Solar Power Satellites was examined. Free electron lasers appear most promising and would have some benefits over microwave power transmission. Further research in laser technology is needed.

  14. Space power by ground-based laser transmission

    SciTech Connect

    Landis, G.A. NASA, Lewis Research Center, Cleveland, OH )

    1992-07-01

    A new method for providing power to space vehicles consists of using high-power CW lasers on the ground to beam power to photovoltaic receivers in space. Such large lasers could be located at cloud-free sites at one or more ground locations, and use large mirrors with adaptive optical correction to reduce the beam spread due to diffraction or atmospheric turbulence. This can result in lower requirements for battery storage, due to continuous illumination of arrays even during periods of shadow by the earth, and higher power output, due to the higher efficiency of photovoltaic arrays under laser illumination compared to solar and the ability to achieve higher intensities of illumination. Applications include providing power for satellites during eclipse, providing power to resurrect satellites which are failing due to solar array degradation, powering orbital transfer vehicles or lunar transfer shuttles, and providing night power to a solar array on the moon. 22 refs.

  15. Illuminating the Hazards of Powerful Laser Products

    MedlinePlus

    ... must also be manufactured with permission from FDA. Green lasers are particularly troubling to FDA, says CDR ... FDA’s Center for Devices and Radiological Health. “A green laser beam could cause a larger startling or ...

  16. 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.

  17. High-power cw operation of diode laser transversely-pumped Nd:YAG lasers

    NASA Astrophysics Data System (ADS)

    Golla, Dirk; Knoke, S.; Schoene, Wolfram; Ernst, G.; Tuennermann, Andreas; Welling, Herbert

    1995-04-01

    We report on diode laser side-pumped, cw Nd:YAG rod lasers operating at pump powers up to 1 kW. With linear diode laser arrays as pump sources a pump power of 90 W/cm is realized. In multimode operation at 1064 nm, output powers of more than 300 W cw are observed. Applying a dynamically stable resonator design, an output power of more than 45 W in TEM00 mode operation is realized with an optical-to-optical efficiency of more than 11%. Higher pump powers up to several 100 W/cm can be achieved by using fiber-coupled diode lasers as pump sources. Laser performance, thermal properties and possible applications of these laser systems will be discussed.

  18. Redistribution of the laser beam power using diffractive optical elements

    NASA Astrophysics Data System (ADS)

    Murzin, Serguei P.; Liedl, Gerhard; Bielak, Robert

    2017-04-01

    The use of laser technologies in the production of optical fiber requires a careful choice of optical systems for positioning and transforming the laser beam. The purpose of this research is to determine a possibility of the redistribution of the laser beam power using diffractive optical elements. It was determined that for a radius of the focusable beam Rf = rf =2.2×10-2 m, the length of the focal spot will be increased to a value L =13.6×10-3 m, which is 1.2 times larger than Rf = rf =1.8×10-2 m. In this case, the intensity of the laser beam at the centre of the focal spot, q0 , and the maximum value, qmax , decreased by 1.1 times. An approximation of function q(x, y) by polynomials of degree n =5and m =3 was performed. It is shown that the maximal relative error of approximation does not exceed 4%, and the relative error of approximation in the centre of the focal spot does not exceed 3%. Presented equations can be used to calculate the intensity distribution in the focal plane of diffractive optical elements.

  19. 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.

  20. Ground-based and space-based laser beam power applications

    SciTech Connect

    Bozek, J.M.

    1995-02-01

    A space power system based on laser beam power is sized to reduce mass, increase operational capabilities, and reduce complexity. The advantages of laser systems over solar-based systems are compared as a function of application. Power produced from the conversion of a laser beam that has been generated on the Earth`s surface and beamed into cislunar space resulted in decreased round-trip time for Earth satellite electric propulsion tugs and a substantial landed mass savings for a lunar surface mission. The mass of a space-based laser system (generator in space and receiver near user) that beams down to an extraterrestrial airplane, orbiting spacecraft, surface outpost, or rover is calculated and compared to a solar system. In general, the advantage of low mass for these space-based laser systems is limited to high solar eclipse time missions at distances inside Jupiter. The power system mass is less in a continuously moving Mars rover or surface outpost using space-based laser technology than in a comparable solar-based power system, but only during dust storm conditions. Even at large distances from the Sun, the user-site portion of a space-based laser power system (e.g., the laser receiver component) is substantially less massive than a solar-based system with requisite on-board electrochemical energy storage.

  1. Ground-Based and Space-Based Laser Beam Power Applications

    NASA Technical Reports Server (NTRS)

    Bozek, John M.

    1995-01-01

    A space power system based on laser beam power is sized to reduce mass, increase operational capabilities, and reduce complexity. The advantages of laser systems over solar-based systems are compared as a function of application. Power produced from the conversion of a laser beam that has been generated on the Earth's surface and beamed into cislunar space resulted in decreased round-trip time for Earth satellite electric propulsion tugs and a substantial landed mass savings for a lunar surface mission. The mass of a space-based laser system (generator in space and receiver near user) that beams down to an extraterrestrial airplane, orbiting spacecraft, surface outpost, or rover is calculated and compared to a solar system. In general, the advantage of low mass for these space-based laser systems is limited to high solar eclipse time missions at distances inside Jupiter. The power system mass is less in a continuously moving Mars rover or surface outpost using space-based laser technology than in a comparable solar-based power system, but only during dust storm conditions. Even at large distances for the Sun, the user-site portion of a space-based laser power system (e.g., the laser receiver component) is substantially less massive than a solar-based system with requisite on-board electrochemical energy storage.

  2. Molecular Dynamics Simulations of Laser Powered Carbon Nanotube Gears

    NASA Technical Reports Server (NTRS)

    Srivastava, Deepak; Globus, Al; Han, Jie; Chancellor, Marisa K. (Technical Monitor)

    1997-01-01

    Dynamics of laser powered carbon nanotube gears is investigated by molecular dynamics simulations with Brenner's hydrocarbon potential. We find that when the frequency of the laser electric field is much less than the intrinsic frequency of the carbon nanotube, the tube exhibits an oscillatory pendulam behavior. However, a unidirectional rotation of the gear with oscillating frequency is observed under conditions of resonance between the laser field and intrinsic gear frequencies. The operating conditions for stable rotations of the nanotube gears, powered by laser electric fields are explored, in these simulations.

  3. 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

  4. Molecular Dynamics Simulations of Laser Powered Carbon Nanotube Gears

    NASA Technical Reports Server (NTRS)

    Srivastava, Deepak; Globus, Al; Han, Jie; Chancellor, Marisa K. (Technical Monitor)

    1997-01-01

    Dynamics of laser powered carbon nanotube gears is investigated by molecular dynamics simulations with Brenner's hydrocarbon potential. We find that when the frequency of the laser electric field is much less than the intrinsic frequency of the carbon nanotube, the tube exhibits an oscillatory pendulam behavior. However, a unidirectional rotation of the gear with oscillating frequency is observed under conditions of resonance between the laser field and intrinsic gear frequencies. The operating conditions for stable rotations of the nanotube gears, powered by laser electric fields are explored, in these simulations.

  5. Laser photovoltaic power system synergy for SEI applications

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Hickman, J. M.

    1991-01-01

    Solar arrays can provide reliable space power, but do not operate when there is no solar energy. Photovoltaic arrays can also convert laser energy with high efficiency. One proposal to reduce the required mass of energy storage required is to illuminate the photovoltaic arrays by a ground laser system. It is proposed to locate large lasers on cloud-free sites at one or more ground locations, and use large lenses or mirrors with adaptive optical correction to reduce the beam spread due to diffraction or atmospheric turbulence. During the eclipse periods or lunar night, the lasers illuminate the solar arrays to a level sufficient to provide operating power.

  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. 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.

  8. 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.

  9. 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.

  10. Lasers of All Sizes

    NASA Astrophysics Data System (ADS)

    Balcou, Philippe; Forget, Sébastien Robert-Philip, Isabelle

    2015-10-01

    * Introduction * The Laser in All Its Forms * Gas lasers * Dye lasers * Solid-state lasers * Lasers for Every Taste * The rise of lasers * Lasers of all sizes * The colors of the rainbow... and beyond * Shorter and shorter lasers * Increasingly powerful lasers * Lasers: A Universal Tool? * Cutting, welding, and cleaning * Communicating * Treating illnesses * Measuring * Supplying energy? * Entertaining * Understanding * Conclusion

  11. High power low cost drive laser for LPP source

    NASA Astrophysics Data System (ADS)

    Fomenkov, Igor V.; Hansson, Björn A. M.; Böwering, Norbert R.; Ershov, Alex I.; Partlo, William N.; Fleurov, Vladimir B.; Khodykin, Oleh V.; Bykanov, Alexander N.; Rettig, Curtis L.; Hoffman, Jerzy R.; Vargas L., Ernesto; Chavez, Juan A.; Marx, William F.; Brandt, David C.

    2006-03-01

    We report on the approach for a high-power high-beam-quality drive laser system that is used for a laser-produced plasma (LPP) EUV source. Cymer has conducted research on a number of solutions for a multi-kW drive laser system that satisfy high volume production requirements. Types of lasers to be presented include XeF at 351 nm and CO II at 10.6 micron. We report on a high efficiency XeF amplifier with a 3rd harmonic Nd:YLF master oscillator operated in the 6 to 8 kHz range and a CO II laser system with Q-switched cavity dumped master oscillator and RF pumped fast axial flow amplifiers operated in the 10 to 100 kHz range. CO II laser short pulse gain and optical isolation techniques are reported. Optical performance data and design features of the drive laser system are discussed, as well as a path to achieve output power scaling to meet high volume manufacturing (HVM) requirements and beyond. Additionally, the electrical efficiency as a component of cost of operation is presented. Development of a drive laser with sufficient output power, high beam quality, and economical cost of operation is critical to the successful implementation of a laser-produced-plasma (LPP) EUV source for HVM applications. Cymer has conducted research on a number of solutions to this critical need. We report our progress on development of a high power system with two gas-discharge power amplifiers to produce high output power with high beam quality. We provide optical performance data and design features of the drive laser as well as a path to output power scaling to meet HVM requirements. Development of a drive laser for LPP EUV source is a challenging task. It requires multi-kW laser output power with short pulse duration and diffraction limited beam quality. In addition, this system needs to be very reliable and cost-efficient to satisfy industry requirements for high volume integrated circuit manufacturing. Feasibility studies of high power laser solutions that utilize proven laser

  12. Multichip Vertical-External-Cavity Surface-Emitting Lasers: A Coherent Power Scaling Scheme (Postprint)

    DTIC Science & Technology

    2006-12-01

    emitting laser ( VECSEL ), in which the waste heat generated in the active region is distributed on multi- VECSEL chips such that the pump level at the...thermal rollover is significantly increased. The advantages of this laser are discussed, and the development and demonstration of a two-chip VECSEL ...published November 22, 2006 We propose an efficient coherent power scaling scheme, the multichip vertical-external-cavity surface- emitting laser ( VECSEL ), in

  13. 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.

  14. Using structural power sources to increase influence.

    PubMed

    Hoezel, C B

    1989-11-01

    To be more effective in the health care system of the 1990s, nursing administrators must understand organizational sources of structural power. After analyzing structural power sources, the nursing administrator must develop a plan to use them and, finally, must be willing to acquire that power which is available. The author explores three sources of structural power: centrality, control of uncertainty and control over resources, and analyzes their relevance for nursing administrators.

  15. Design and characterization of a novel power over fiber system integrating a high power diode laser

    NASA Astrophysics Data System (ADS)

    Perales, Mico; Yang, Mei-huan; Wu, Cheng-liang; Hsu, Chin-wei; Chao, Wei-sheng; Chen, Kun-hsein; Zahuranec, Terry

    2017-02-01

    High power 9xx nm diode lasers along with MH GoPower's (MHGP's) flexible line of Photovoltaic Power Converters (PPCs) are spurring high power applications for power over fiber (PoF), including applications for powering remote sensors and sensors monitoring high voltage equipment, powering high voltage IGBT gate drivers, converters used in RF over Fiber (RFoF) systems, and system power applications, including powering UAVs. In PoF, laser power is transmitted over fiber, and is converted to electricity by photovoltaic cells (packaged into Photovoltaic Power Converters, or PPCs) which efficiently convert the laser light. In this research, we design a high power multi-channel PoF system, incorporating a high power 976 nm diode laser, a cabling system with fiber break detection, and a multichannel PPC-module. We then characterizes system features such as its response time to system commands, the PPC module's electrical output stability, the PPC-module's thermal response, the fiber break detection system response, and the diode laser optical output stability. The high power PoF system and this research will serve as a scalable model for those interested in researching, developing, or deploying a high power, voltage isolated, and optically driven power source for high reliability utility, communications, defense, and scientific applications.

  16. 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.

  17. Possibility of increasing the efficiency of laser-induced tattoo removal by optical skin clearing

    NASA Astrophysics Data System (ADS)

    Genina, E. A.; Bashkatov, A. N.; Tuchin, V. V.; Altshuler, G. B.; Yaroslavskii, I. V.

    2008-06-01

    The possibility of selective laser photothermolysis improvement for the removal of tattoo pigments due to the optical clearing of human skin is investigated. It is shown experimentally that the optical skin clearing increases the tattoo image contrast. Computer Monte Carlo simulations show that by decreasing the laser beam scattering in upper skin layers, it is possible to reduce the radiation power required for tattoo removal by 30%—40% and, therefore, to increase the the photothermolysis efficiency.

  18. Apparatus for increasing the resolution of a laser gyroscope

    SciTech Connect

    Dorsman, A.K.

    1987-05-12

    This patent describes a laser gyroscope output signal generator for increasing a laser gyroscope output resolution. The signal generator is responsive to a sequence of pairs of phase shifted first and second laser gyroscope output pulses each being characterized to have a first and second logic state. The first and second output pulses in each pair have a leading or lagging phase relationship determined by the direction of rotation the laser gyroscope sourcing the pairs of phase shifted output pulses. The laser gyroscope output signal generator comprises: a first exclusive OR gate having inputs coupled to respective first and second laser gyroscope output pulses; and a first one-shot multivibrator having at least one input responsive to any state change at the output of the first exclusive OR gate to produce an output signal having a pulse recurrent frequency of four times that of the first laser gyroscope output pulse.

  19. Terahertz master-oscillator power-amplifier quantum cascade lasers

    NASA Astrophysics Data System (ADS)

    Zhu, Huan; Wang, Fangfang; Yan, Quan; Yu, Chenren; Chen, Jianxin; Xu, Gangyi; He, Li; Li, Lianhe; Chen, Li; Giles Davies, A.; Linfield, Edmund H.; Hao, Jiaming; Vigneron, Pierre-Baptiste; Colombelli, Raffaele

    2016-12-01

    We report on the realization of a monolithically integrated master-oscillator power-amplifier architecture in a terahertz quantum cascade laser (THz-QCL) with a metal-metal waveguide. The master-oscillator section is a first-order distributed feedback (DFB) laser. Instead of using a thick anti-reflection coating, we exploit a diffraction grating together with an absorbing boundary in the power-amplifier section to efficiently extract the laser radiation and suppress the self-lasing in it. The devices demonstrate a stable generation and power amplification of single-mode emission. The amplification factor is about 5, and the output power is approximately twice that of the standard second-order DFB lasers fabricated from the same material. Emission beam pattern with a divergence angle of ˜18 × 40° is achieved. Our work provides an avenue for the realization of single-mode THz-QCLs with high output power and good beam quality.

  20. Advances in fiber laser spectral beam combining for power scaling

    NASA Astrophysics Data System (ADS)

    Honea, Eric; Afzal, Robert S.; Savage-Leuchs, Matthias; Henrie, Jason; Brar, Khush; Kurz, Nathan; Jander, Don; Gitkind, Neil; Hu, Dan; Robin, Craig; Jones, Andrew M.; Kasinadhuni, Ravi; Humphreys, Richard

    2016-03-01

    Spectral Beam Combining (SBC) of fiber lasers provides a simple, robust architecture for high brightness power scaling beyond the limit of a single fiber. We review recent progress in power scaling and describe what we believe is the highest power SBC fiber demonstration and largest number of fiber lasers combined to date. Here we report results on a fiber SBC system where we achieved > 30 kW by combining 96 individual fiber lasers into a single high brightness beam with a beam quality of M2 = 1.6 x 1.8. The potential for further power scaling at the system level is highlighted with examples of beam combinable fiber laser power scaling.

  1. 1047 nm laser diode master oscillator Nd:YLF power amplifier laser system

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

  2. 1047 nm laser diode master oscillator Nd:YLF power amplifier laser system

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

  3. High average power diode pumped solid state lasers for CALIOPE

    SciTech Connect

    Comaskey, B.; Halpin, J.; Moran, B.

    1994-07-01

    Diode pumping of solid state media offers the opportunity for very low maintenance, high efficiency, and compact laser systems. For remote sensing, such lasers may be used to pump tunable non-linear sources, or if tunable themselves, act directly or through harmonic crystals as the probe. The needs of long range remote sensing missions require laser performance in the several watts to kilowatts range. At these power performance levels, more advanced thermal management technologies are required for the diode pumps. The solid state laser design must now address a variety of issues arising from the thermal loads, including fracture limits, induced lensing and aberrations, induced birefringence, and laser cavity optical component performance degradation with average power loading. In order to highlight the design trade-offs involved in addressing the above issues, a variety of existing average power laser systems are briefly described. Included are two systems based on Spectra Diode Laboratory`s water impingement cooled diode packages: a two times diffraction limited, 200 watt average power, 200 Hz multi-rod laser/amplifier by Fibertek, and TRW`s 100 watt, 100 Hz, phase conjugated amplifier. The authors also present two laser systems built at Lawrence Livermore National Laboratory (LLNL) based on their more aggressive diode bar cooling package, which uses microchannel cooler technology capable of 100% duty factor operation. They then present the design of LLNL`s first generation OPO pump laser for remote sensing. This system is specified to run at 100 Hz, 20 nsec pulses each with 300 mJ, less than two times diffraction limited, and with a stable single longitudinal mode. The performance of the first testbed version will be presented. The authors conclude with directions their group is pursuing to advance average power lasers. This includes average power electro-optics, low heat load lasing media, and heat capacity lasers.

  4. Optimal laser wavelength for efficient laser power converter operation over temperature

    SciTech Connect

    Höhn, O. Walker, A. W.; Bett, A. W.; Helmers, H.

    2016-06-13

    A temperature dependent modeling study is conducted on a GaAs laser power converter to identify the optimal incident laser wavelength for optical power transmission. Furthermore, the respective temperature dependent maximal conversion efficiencies in the radiative limit as well as in a practically achievable limit are presented. The model is based on the transfer matrix method coupled to a two-diode model, and is calibrated to experimental data of a GaAs photovoltaic device over laser irradiance and temperature. Since the laser wavelength does not strongly influence the open circuit voltage of the laser power converter, the optimal laser wavelength is determined to be in the range where the external quantum efficiency is maximal, but weighted by the photon flux of the laser.

  5. Micro-scanning mirrors for high-power laser applications in laser surgery

    NASA Astrophysics Data System (ADS)

    Sandner, Thilo; Kimme, Simon; Grasshoff, Thomas; Todt, Ulrich; Graf, Alexander; Tulea, Cristian; Lenenbach, Achim; Schenk, Harald

    2014-03-01

    We present two novel micro scanning mirrors with large aperture and HR dielectric coatings suitable for high power laser applications in a miniaturized laser-surgical instrument for neurosurgery to cut skull tissue. An electrostatic driven 2D-raster scanning mirror with 5x7.1mm aperture is used for dynamic steering of a ps-laser beam of the laser cutting process. A second magnetic 2D-beam steering mirror enables a static beam correction of a hand guided laser instrument. Optimizations of a magnetic gimbal micro mirror with 6 mm x 8 mm mirror plate are presented; here static deflections of 3° were reached. Both MEMS devices were successfully tested with a high power ps-laser at 532nm up to 20W average laser power.

  6. Novel concepts for laser-plasma-based acceleration of electrons using ultrahigh power laser pulses

    NASA Astrophysics Data System (ADS)

    Kim, Joon-Koo

    Analytical and numerical studies of plasma physics in ultra-intense plasma wave generation, electron injection, and wavebreaking are performed, which are relevant to the subject of plasma wake-field accelerators. A method for generating large-amplitude nonlinear plasma waves, which utilizes an optimized train of independently adjustable, intense laser pulses, is analyzed in one dimension both theoretically and numerically (using both Maxwell-fluid and particle-in-cell codes). Optimal pulse widths and interpulse spacings are computed for pulses with either square or finite-rise-time sine shapes. A resonant region of the plasma-wave phase space is found where the plasma wave is driven most efficiently by the laser pulses. Resonant excitation is found to be superior for electron acceleration to either beatwave or single- pulse excitation because comparable plasma wave amplitudes may be generated at lower plasma densities, reducing electron-phase detuning, or at lower laser intensities, reducing laser-plasma instabilities. The idea of all-optical acceleration of electrons in the wakefield is also discussed. It is shown that the injection of background plasma electrons can be accomplished using the large ponderomotive force of an injection laser pulse in either collinear or transverse geometry with respect to the direction of pump propagation, thus removing the necessity of an expensive first-stage linac system for injection of electrons. Detailed nonlinear analysis of the trapping and acceleration of electrons inside the separatrix of the wakefield is formulated and compared with PIC (Particle- In-Cell) and fluid simulations. The three-dimensional wave-breaking of relativistic plasma waves driven by a ultrashort high-power lasers, is described within a framework of cold 2-D fluid theory. It is shown that the transverse nonlinearity of the plasma wave results in temporally increasing transverse plasma oscillation in the wake of the laser pulse, inevitably inducing wave

  7. 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.

  8. Comparisons of selected laser beam power missions to conventionally powered missions

    NASA Technical Reports Server (NTRS)

    Bozek, John M.; Oleson, Steven R.; Landis, Geoffrey A.; Stavnes, Mark W.

    1993-01-01

    Earth-based laser sites beaming laser power to space assets have shown benefits over competing power system concepts for specific missions. Missions analyzed in this report that show benefits of laser beam power are low Earth orbit (LEO) to geosynchronous Earth orbit (GEO) transfer, LEO to low lunar orbit (LLO) cargo missions, and lunar-base power. Both laser- and solar-powered orbit-transfer vehicles (OTV's) make a 'tug' concept viable, which substantially reduces cumulative initial mass to LEO in comparison to chemical propulsion concepts. Lunar cargo missions utilizing laser electric propulsion from Earth-orbit to LLO show substantial mass saving to LEO over chemical propulsion systems. Lunar-base power system options were compared on a landed-mass basis. Photovoltaics with regenerative fuel cells, reactor-based systems, and laser-based systems were sized to meet a generic lunar-base power profile. A laser-based system begins to show landed mass benefits over reactor-based systems when proposed production facilities on the Moon require power levels greater than approximately 300 kWe. Benefit/cost ratios of laser power systems for an OTV, both to GEO and LLO, and for a lunar base were calculated to be greater than 1.

  9. Comparisons of selected laser beam power missions to conventionally powered missions

    SciTech Connect

    Bozek, J.M.; Oleson, S.R.; Landis, G.A.; Stavnes, M.W.

    1993-02-01

    Earth-based laser sites beaming laser power to space assets have shown benefits over competing power system concepts for specific missions. Missions analyzed in this report that show benefits of laser beam power are low Earth orbit (LEO) to geosynchronous Earth orbit (GEO) transfer, LEO to low lunar orbit (LLO) cargo missions, and lunar-base power. Both laser- and solar-powered orbit-transfer vehicles (OTV's) make a tug concept viable, which substantially reduces cumulative initial mass to LEO in comparison to chemical propulsion concepts. Lunar cargo missions utilizing laser electric propulsion from Earth-orbit to LLO show substantial mass saving to LEO over chemical propulsion systems. Lunar-base power system options were compared on a landed-mass basis. Photovoltaics with regenerative fuel cells, reactor-based systems, and laser-based systems were sized to meet a generic lunar-base power profile. A laser-based system begins to show landed mass benefits over reactor-based systems when proposed production facilities on the Moon require power levels greater than approximately 300 kWe. Benefit/cost ratios of laser power systems for an OTV, both to GEO and LLO, and for a lunar base were calculated to be greater than 1.

  10. Comparisons of selected laser beam power missions to conventionally powered missions

    NASA Astrophysics Data System (ADS)

    Bozek, John M.; Oleson, Steven R.; Landis, Geoffrey A.; Stavnes, Mark W.

    1993-02-01

    Earth-based laser sites beaming laser power to space assets have shown benefits over competing power system concepts for specific missions. Missions analyzed in this report that show benefits of laser beam power are low Earth orbit (LEO) to geosynchronous Earth orbit (GEO) transfer, LEO to low lunar orbit (LLO) cargo missions, and lunar-base power. Both laser- and solar-powered orbit-transfer vehicles (OTV's) make a 'tug' concept viable, which substantially reduces cumulative initial mass to LEO in comparison to chemical propulsion concepts. Lunar cargo missions utilizing laser electric propulsion from Earth-orbit to LLO show substantial mass saving to LEO over chemical propulsion systems. Lunar-base power system options were compared on a landed-mass basis. Photovoltaics with regenerative fuel cells, reactor-based systems, and laser-based systems were sized to meet a generic lunar-base power profile. A laser-based system begins to show landed mass benefits over reactor-based systems when proposed production facilities on the Moon require power levels greater than approximately 300 kWe. Benefit/cost ratios of laser power systems for an OTV, both to GEO and LLO, and for a lunar base were calculated to be greater than 1.

  11. 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.

  12. Ex vivo efficacy evaluation of laser vaporization for treatment of benign prostatic hyperplasia using a 300-W high-power laser diode with a wavelength of 980 nm

    PubMed Central

    Takada, Junya; Honda, Norihiro; Hazama, Hisanao

    2014-01-01

    Background and Objective: Laser vaporization of the prostate is considered to be a promising treatment for benign prostatic hyperplasia (BPH), and efficiency of vaporization and hemostasis are both important parameters for such treatment. In this study, we used a high-power laser diode with a wavelength of 980 nm to obtain high vaporization efficiency with good hemostasis. The objective of this study is to evaluate the efficacy of laser vaporization for treatment of BPH in ex vivo experiments using a 300-W high-power laser diode with a wavelength of 980 nm quantitatively. Materials and Methods: An ex vivo experimental setup simulating clinical treatment situation was constructed. Bovine prostate tissue was used as a sample. The power setting was 100, 150, 200, 250, or 300 W, and the irradiation time was 0.5, 1, or 2 s. After laser irradiation, vaporized and coagulated depths were measured. Results: The vaporized depth increased with the laser power and irradiation time, and the results confirmed that the high-power laser diode could efficiently vaporize the prostate tissue. Coagulated depth increased as the laser power became higher. Conclusions: Laser vaporization of prostate tissue using a high-power laser diode with a wavelength of 980 nm represents a promising treatment for BPH; this method exhibits high vaporization efficiency and good hemostasis. However, operators must be aware of the risk of postoperative perforation of the prostatic capsule caused by coagulation of deep regions that cannot be visualized by endoscopic observation. PMID:25368442

  13. 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.

  14. Influence of laser power on microstructure of laser metal deposited 17-4 ph stainless steel

    NASA Astrophysics Data System (ADS)

    Adeyemi, A. A.; Akinlabi, ET; Mahamood, R. M.; Sanusi, K. O.; Pityana, S.; Tlotleng, M.

    2017-08-01

    The influence of laser power on the microstructure of 17-4 PH stainless steel produced by laser metal deposition was investigated. Multiple-trackof 17-4 stainless steel powder was deposited on 316 stainless steel substrate using laser metal deposition, an additive manufacturing process. In this research, laser power was varied between 1.0 kW and 2.6 kW with scanning speed fixed at 1.2 m/s. The powder flow rate and the gas flow rate were also kept constant at values of 5 g/min and 2 l/min respectively. The microstructure was studied under optical microscope and it revealed that the microstructure was dendritic in structure with finer and lesser δ-ferriteat low laser power while the appearance of coarse and more δ-ferriteare seen at higher laser power.

  15. High-power cw visible lasers pumped by Raman fibre lasers

    NASA Astrophysics Data System (ADS)

    Surin, A. A.; Larin, S. V.; Borisenko, T. E.; Prusakov, K. Yu.; Stirmanov, Yu. S.

    2016-12-01

    This paper describes cw visible lasers having an output power above 10 {\\text{W}} and emitting at wavelengths of 561, 589 and 623 {\\text{nm}}. An approach is proposed for obtaining single-mode cw visible laser light with a power above 10 {\\text{W}} at any wavelength in the range 560 - 660 {\\text{nm}}.

  16. Laser plasma influence on the space-time structure of powerful laser radiation

    NASA Astrophysics Data System (ADS)

    Ananyin, O. B.; Bogdanov, G. S.; Vovchenko, E. D.; Gerasimov, I. A.; Kuznetsov, A. P.; Melekhov, A. P.

    2016-01-01

    This paper deals with the influence of laser plasma on the structure of the radiation field of a powerful Nd-glass laser with pulse energy up to 30 J and with the diameter of the output beam 45 mm. Laser plasma is generated by focusing the laser radiation on a low-density target such as nylon mesh and teflon or mylar films. Temporal profile of the laser pulse with a total duration of 25 ns consists of a several short pulse train. Duration of each pulse is about 2 ns. Notable smoothing of spatially non-uniform radiation structure was observed in the middle of the laser pulse.

  17. High-power compact laser with segmented longitudinal pumping of coupled laser channels

    SciTech Connect

    Mamonov, D N; Il'ichev, N N; Sirotkin, A A; Pivovarov, P A; Derzhavin, S I; Klimentov, S M; Rebrov, S G

    2015-06-30

    The characteristics of a compact Nd:YAG/Cr:YAG laser with segmented end pumping using a bundle of seven optical fibres are presented. In the regime of optical coupling of thus formed seven laser channels, 3-ns pulses with an energy up to 20 mJ, as well as their trains, are obtained. The used method makes it possible to scale the energy and power of lasers of this type with controlled spatial beam profile. (lasers)

  18. Multichip vertical-external-cavity surface-emitting lasers: a coherent power scaling scheme.

    PubMed

    Fan, Li; Fallahi, Mahmoud; Hader, Jörg; Zakharian, Aramais R; Moloney, Jerome V; Murray, James T; Bedford, Robert; Stolz, Wolfgang; Koch, Stephan W

    2006-12-15

    We propose an efficient coherent power scaling scheme, the multichip vertical-external-cavity surface-emitting laser (VECSEL), in which the waste heat generated in the active region is distributed on multi-VECSEL chips such that the pump level at the thermal rollover is significantly increased. The advantages of this laser are discussed, and the development and demonstration of a two-chip VECSEL operating around 970 nm with over 19 W of output power is presented.

  19. Support for High Power Laser Ablation 2010

    DTIC Science & Technology

    2010-04-16

    Femtosecond Pulsed laser Ablation and Deposition Marta Castillejo Instituto de Quimica Fisica Rocasolano, CSIC, Serrano 119, 28006 Madrid, Spain Tel:+34...system to transition the laser cavity’s low pressure to the ambient pressure outside the device. Diffusers use a series of shocks in a duct to...especially the incident laser fluence and ambient pressure. New results highlight the influence of the ambient pressure on ablation physics from the

  20. 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.

  1. Low Power Consumption Lasers for Miniature Optical Spectrometers for Trace Gas Analysis

    NASA Technical Reports Server (NTRS)

    Forouhar, S.; Frez, C.; Franz, K. J.; Ksendzov, A.; Qiu, Y.; Soibel, K. A.; Chen, J.; Hosoda, T.; Kipshidze, G.; Shterengas, L.; Belenky, G.

    2011-01-01

    The air quality of any manned spacecraft needs to be continuously monitored in order to safeguard the health of the crew. Air quality monitoring grows in importance as mission duration increases. Due to the small size, low power draw, and performance reliability, semiconductor laser-based instruments are viable candidates for this purpose. Achieving a minimum instrument size requires lasers with emission wavelength coinciding with the absorption of the fundamental absorption lines of the target gases, which are mostly in the 3.0-5.0 micron wavelength range. In this paper we report on our progress developing high wall plug efficiency type-I quantum-well GaSb-based diode lasers operating at room temperatures in the spectral region near 3.0-3.5 micron and quantum cascade (QC) lasers in the 4.0-5.0 micron range. These lasers will enable the development of miniature, low-power laser spectrometers for environmental monitoring of the spacecraft.

  2. Low Power Consumption Lasers for Miniature Optical Spectrometers for Trace Gas Analysis

    NASA Technical Reports Server (NTRS)

    Forouhar, S.; Frez, C.; Franz, K. J.; Ksendzov, A.; Qiu, Y.; Soibel, K. A.; Chen, J.; Hosoda, T.; Kipshidze, G.; Shterengas, L.; hide

    2011-01-01

    The air quality of any manned spacecraft needs to be continuously monitored in order to safeguard the health of the crew. Air quality monitoring grows in importance as mission duration increases. Due to the small size, low power draw, and performance reliability, semiconductor laser-based instruments are viable candidates for this purpose. Achieving a minimum instrument size requires lasers with emission wavelength coinciding with the absorption of the fundamental absorption lines of the target gases, which are mostly in the 3.0-5.0 micron wavelength range. In this paper we report on our progress developing high wall plug efficiency type-I quantum-well GaSb-based diode lasers operating at room temperatures in the spectral region near 3.0-3.5 micron and quantum cascade (QC) lasers in the 4.0-5.0 micron range. These lasers will enable the development of miniature, low-power laser spectrometers for environmental monitoring of the spacecraft.

  3. 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.

  4. Solid state laser media driven by remote nuclear powered fluorescence

    DOEpatents

    Prelas, Mark A.

    1992-01-01

    An apparatus is provided for driving a solid state laser by a nuclear powered fluorescence source which is located remote from the fluorescence source. A nuclear reaction produced in a reaction chamber generates fluorescence or photons. The photons are collected from the chamber into a waveguide, such as a fiber optic waveguide. The waveguide transports the photons to the remote laser for exciting the laser.

  5. Ceramic tile grout removal & sealing using high power lasers

    SciTech Connect

    Lawrence, J.; Li, L.; Spencer, J.T.

    1996-12-31

    Work has been conducted using a Nd:YAG laser, a CO{sub 2} laser and a high power diode laser (HPDL) in order to determine the feasibility of removing contaminated tile grout from the void between adjoining vitrified ceramic tiles, and to seal the void permanently with a material having an impermeable surface glaze. Reported on in the paper are; the basic process phenomena, the process effectiveness, suitable vitrifiable material development, a heat affect study and a morphological and compositional analysis.

  6. 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.

  7. 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.

  8. Diode laser satellite systems for beamed power transmission

    NASA Technical Reports Server (NTRS)

    Williams, M. D.; Kwon, J. H.; Walker, G. H.; Humes, D. H.

    1990-01-01

    A power system composed of an orbiting laser satellite and a surface-based receiver/converter is described. Power is transmitted from the satellite to the receiver/converter by laser beam. The satellite components are: (1) solar collector; (2) blackbody; (3) photovoltaic cells; (4) heat radiators; (5) laser system; and (6) transmission optics. The receiver/converter components are: receiver dish; lenticular lens; photocells; and heat radiator. Although the system can be adapted to missions at many locations in the solar system, only two are examined here: powering a lunar habitat; and powering a lunar rover. Power system components are described and their masses, dimensions, operating powers, and temperatures, are estimated using known or feasible component capabilities. The critical technologies involved are discussed and other potential missions are mentioned.

  9. 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.

  10. 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.

  11. High Power Laser Hybrid Welding - Challenges and Perspectives

    NASA Astrophysics Data System (ADS)

    Nielsen, Steen Erik

    High power industrial lasers at power levels up to 100 kW is now available on the market. Therefore, welding of thicker materials has become of interest for the heavy metal industry e.g. shipyards and wind mill producers. Further, the power plant industry, producers of steel pipes, heavy machinery and steel producers are following this new technology with great interest. At Lindø Welding Technology (LWT), which is a subsidiary to FORCE Technology, a 32-kwatt disc laser is installed. At this laser facility, welding procedures related to thick section steel applications are developed. Material thicknesses between 40 and 100 mm are currently of interest. This paper describes some of the challenges that are related to the development of the high power hybrid laser welding process as well as to the perspectives for the technology as a production tool for the heavy metal industry.

  12. Power Enhancement Cavity for Burst-Mode Laser Pulses

    SciTech Connect

    Liu, Yun

    2015-01-01

    We demonstrate a novel optical cavity scheme and locking method that can realize the power enhancement of picosecond UV laser pulses operating at a burst mode with arbitrary burst (macropulse) lengths and repetition rates.

  13. Possibility of increasing the efficiency of laser-induced tattoo removal by optical skin clearing

    SciTech Connect

    Genina, E A; Bashkatov, A N; Tuchin, V V; Yaroslavskii, I V; Altshuler, G B

    2008-06-30

    The possibility of selective laser photothermolysis improvement for the removal of tattoo pigments due to the optical clearing of human skin is investigated. It is shown experimentally that the optical skin clearing increases the tattoo image contrast. Computer Monte Carlo simulations show that by decreasing the laser beam scattering in upper skin layers, it is possible to reduce the radiation power required for tattoo removal by 30%-40% and, therefore, to increase the the photothermolysis efficiency. (special issue devoted to application of laser technologies in biophotonics and biomedical studies)

  14. Compact, 17W average power, 100kW peak power, nanosecond fiber laser system

    NASA Astrophysics Data System (ADS)

    Saracco, Matthieu J.; Logan, David; Green, Jared; Balsley, David; Nelson, Mike; Small, Jay; Mettlen, Scott; Lowder, Tyson L.; McComb, Timothy S.; Kutscha, Tim; Burkholder, Gary; Smith, Michael R.; Kliner, Dahv A. V.; Randall, Matthew; Fanning, Geoff; Bell, Jake

    2013-03-01

    We demonstrate a robust, compact, low-cost, pulsed, linearly polarized, 1064 nm, Yb:fiber laser system capable of generating ~100 kW peak power pulses and >17 W average power at repetition rates of 80 - 285 kHz. The system employs a configurable microchip seed laser that provides nanosecond (~1.0 - 1.5 ns) pulse durations. The seed pulses are amplified in an all-fiber, polarization maintaining, large mode area (LMA) fiber amplifier optimized for high peak power operation. The LMA Yb:fiber amplifier enables near diffraction limited beam quality at 100 kW peak power. The seed laser, fiber amplifier, and beam delivery optics are packaged into an air-cooled laser head of 152×330×87 mm3 with pump power provided from a separate air-cooled laser controller. Due to the high peak power, high beam quality, spectral purity, and linearly polarized nature of the output beam, the laser is readily frequency doubled to 532 nm. Average 532 nm powers up to 7 W and peak powers exceeding 40 kW have been demonstrated. Potential for scaling to higher peak and average powers in both the green and infrared (IR) will be discussed. This laser system has been field tested and demonstrated in numerous materials processing applications in both the IR and green, including scribing and marking. We discuss recent results that demonstrate success in processing a diverse array of representative industrial samples.

  15. Increased diffraction efficiencies of DBR gratings in diode lasers with adiabatic ridge waveguides

    NASA Astrophysics Data System (ADS)

    Müller, André; Fricke, Jörg; Brox, Olaf; Erbert, Götz; Sumpf, Bernd

    2016-12-01

    The influence of the lateral layout on the diffraction efficiency of gratings in DBR lasers is presented. In this experimental study DBR ridge waveguide (RW) lasers with different ridge widths as well as straight and adiabatic waveguides are compared. The lasers are based on a vertical layer structure with an asymmetric super large optical cavity. DBR gratings of 3rd and 7th order are manufactured using electron beam lithography and dry etching. Their diffraction efficiencies are determined by measuring the optical output power emitted through the rear and front facets of unmounted devices. In comparison to a laser with a 30 μm ridge, the DBR diffraction efficiency in a laser with a 4 μm ridge is reduced by 46 percentage points. Implementing an adiabatic widening of the ridge width increases the diffraction efficiency from 35% to 72%. The latter is close to 81% achieved for the laser with 30 μm ridge. The new layout with enhanced DBR diffraction efficiency increases the optical output power of the narrow RW laser by a factor of 1.3. Similar results are obtained with 7th order gratings. All devices provide single-mode emission with spectral widths of 30 pm and side mode suppressions >60 dΒ. According to these results, implementing adiabatic waveguides is beneficial in terms of diffraction efficiency and performance of narrow RW lasers based on the applied vertical structure.

  16. 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.

  17. Impact of laser power density on tribological properties of Pulsed Laser Deposited DLC films

    SciTech Connect

    Gayathri, S.; Sridharan, M. E-mail: m.sridharan@ece.sastra.edu; Kumar, N.; Krishnan, R. E-mail: m.sridharan@ece.sastra.edu; AmirthaPandian, S.; Ravindran, T. R.; Dash, S.; Tyagi, A. K.

    2013-12-15

    Fabrication of wear resistant and low friction carbon films on the engineered substrates is considered as a challenging task for expanding the applications of diamond-like carbon (DLC) films. In this paper, pulsed laser deposition (PLD) technique is used to deposit DLC films on two different types of technologically important class of substrates such as silicon and AISI 304 stainless steel. Laser power density is one of the important parameter used to tailor the fraction of sp{sup 2} bonded amorphous carbon (a-C) and tetrahedral amorphous carbon (ta-C) made by sp{sup 3} domain in the DLC film. The I(D)/I(G) ratio decreases with the increasing laser power density which is associated with decrease in fraction of a-C/ta-C ratio. The fraction of these chemical components is quantitatively analyzed by EELS which is well supported to the data obtained from the Raman spectroscopy. Tribological properties of the DLC are associated with chemical structure of the film. However, the super low value of friction coefficient 0.003 is obtained when the film is predominantly constituted by a-C and sp{sup 2} fraction which is embedded within the clusters of ta-C. Such a particular film with super low friction coefficient is measured while it was deposited on steel at low laser power density of 2 GW/cm{sup 2}. The super low friction mechanism is explained by low sliding resistance of a-C/sp{sup 2} and ta-C clusters. Combination of excellent physical and mechanical properties of wear resistance and super low friction coefficient of DLC films is desirable for engineering applications. Moreover, the high friction coefficient of DLC films deposited at 9GW/cm{sup 2} is related to widening of the intergrain distance caused by transformation from sp{sup 2} to sp{sup 3} hybridized structure.

  18. 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.

  19. 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.

  20. A power ramped pulsed mode laser piercing technique for improved CO 2 laser profile cutting

    NASA Astrophysics Data System (ADS)

    Tirumala Rao, B.; Ittoop, M. O.; Kukreja, L. M.

    2009-11-01

    Laser piercing is one of the inevitable requirements of laser profile cutting process and it has a direct bearing on the quality of the laser cut profiles. We have developed a novel power ramped pulsed mode (PRPM) laser piercing technique to produce much finer pierced holes and to achieve a better control on the process parameters compared to the existing methodology based on normal pulsed mode (NPM). Experiments were carried out with both PRPM and NPM laser piercing on 1.5-mm-thick mild steel using an in-house developed high-power transverse flow continuous wave (CW)-CO 2 laser. Significant improvements in the spatter, circularity of the pierced hole and reproducibility were achieved through the PRPM technique. We studied, in detail, the dynamics of processes involved in PRPM laser piercing and compared that with those of the NPM piercing.

  1. 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.

  2. 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.

  3. Applications of high-power diode lasers for aluminum welding

    NASA Astrophysics Data System (ADS)

    Huber, Sonja; Merzkirch, Matthias; Zaeh, Michael F.; Schulze, Volker

    2009-02-01

    Industries worldwide are confronted with the need for an increased use of aluminum alloys in various applications. Therefore the requirements result in the necessity for a multitude of joining and welding innovations. Applications of modern aluminum alloys are not constricted to common components anymore. In fact, they are used in ever more complex lightweight structures. However, this complexity has to be fulfilled by a higher geometric flexibility in laser welding and represents a major challenge for new approaches in working lightweight structures. The present work includes the welding of aluminum utilizing Bifocal Hybrid Laser Welding (BHLW) and a 6 kW high power diode laser (HPDL) for welding. The welding setups allow for welded butt- and fillet-welds of tubes under consideration of the hardly fusion weldable alloy AA6060. Welded joints of AA6060 are investigated metallographically in regard to the influence of process parameters like intensity and the interconnected penetration. The weldability is characterized by qualitative investigations of the microstructure as well as the mechanical behavior under quasistatic loading. The investigations result in an adequate welding process for AA6060.

  4. Perspectives of powerful laser technique for medicine

    NASA Astrophysics Data System (ADS)

    Konov, Vitali I.; Prokhorov, Alexander M.; Shcherbakov, Ivan A.

    1991-11-01

    The optimum laser-system parameters are being selected for several types of surgical operations using ablation techniques. The choice is based on the specific demands of the operation performed, knowledge of the ablation laws, limitations on laser-beam intensity which come from the necessity to transport high-intensity light through flexible fiber, and the peculiarities of different laser systems. At present it is more expedient to develop laser medical setups oriented to the solution of one task or a limited number of problems. The choice of a concrete installation should be based on the investigation results of interaction of radiation with biological tissues and its transmission through the fiber, the analysis of the level of development of laser and fiber technique, specificity of the operation, and compatibility of laser facilitates and traditional medical equipment. The paper illustrates such an approach by way of several concrete examples and notes the corresponding laser systems, which were developed or are in the developmental stage in the General Physics Institute of the USSR Academy of Sciences and in organizations connected with the Institute.

  5. Solid-state power supply for gas lasers

    NASA Astrophysics Data System (ADS)

    Bertolini, A.; Beverini, N.; Carelli, G.; Francesconi, M.; Nannizzi, M.; Strumia, F.; Ioli, N.; Moretti, A.

    2004-08-01

    A novel pulsed power supply for gas lasers is presented. The device uses only solid state components and is based on a capacitor bank discharge. Fast switching of the discharge is triggered by an insulated gate bipolar transistor. The terminal section of the power supply is a transformer designed to match the reactive capacitance of a gas discharge. Strokes up to 30 kV and 30 mA are achieved across the secondary windings of this transformer. The power supply delivers high voltage pulses with a duration between 0.5 and 50 μs and a repetition rate up to some kHz. The power supply has been tested on a longitudinal discharge quasi-cw regime CO2 laser. Laser pulses were generated with a duration down to the microseconds region, a peak power exceeding some kilowatts, and a repetition rate ranging from 200 Hz to a few kHz.

  6. Application of laser bar code technology in power fitting evaluation

    NASA Astrophysics Data System (ADS)

    Yang, Xiaohong; Liu, Shuhuab

    2007-12-01

    In this work, an automatic encoding and management system on power fittings (PFEMS) is developed based on laser bar coding technology. The system can encode power fittings according to their types, structure, dimensions, materials, and technical characteristics. Both the character codes and the laser bar codes of power fittings can be produced from the system. The system can evaluate power fittings and search process-paper automatically. The system analyzes the historical values and technical information of congeneric fittings, and forms formulae of evaluation with recursive analytical method. And then stores the formulae and technical documents into the database for index. Scanning the bar code with a laser bar code reader, accurate evaluation and corresponding process-paper of the fittings can be produced. The software has already been applied in some power stations and worked very well.

  7. Scaling of solid state lasers for satellite power beaming applications

    SciTech Connect

    Friedman, H.W.; Albrecht, G.F.; Beach, R.J.

    1994-01-01

    The power requirements for a satellite power beaming laser system depend upon the diameter of the beam director, the performance of the adaptive optics system, and the mission requirements. For an 8 meter beam director and overall Strehl ratio of 50%, a 30 kW laser at 850 nm can deliver an equivalent solar flux to a satellite at geostationary orbit. Advances in Diode Pumped Solid State Lasers (DPSSL) have brought these small, efficient and reliable devices to high average power and they should be considered for satellite power beaming applications. Two solid state systems are described: a diode pumped Alexandrite and diode pumped Thulium doped YAG. Both can deliver high average power at 850 nm in a single aperture.

  8. Scaling of solid state lasers for satellite power beaming applications

    SciTech Connect

    Friedman, H.; Albrecht, G.; Beach, R.

    1994-12-31

    The power requirements for a satellite power beaming laser system depend upon the diameter of the beam director, the performance of the adaptive optics system, and the mission requirements. For an 8 meter beam director and overall Strehl ratio of 50%, a 30 kW laser at 850 nm can deliver an equivalent solar flux to a satellite at geostationary orbit. Advances in Diode Pumped Solid State Lasers (DPSSL) have brought these small, efficient and reliable devices to high average power and they should be considered for satellite power beaming applications. Two solid state systems are described: a diode pumped Alexandrite and diode pumped Thulium doped YAG. Both can deliver high average power at 850 nm in a single aperture.

  9. Excimer laser annealing for low-voltage power MOSFET

    NASA Astrophysics Data System (ADS)

    Chen, Yi; Okada, Tatsuya; Noguchi, Takashi; Mazzamuto, Fulvio; Huet, Karim

    2016-08-01

    Excimer laser annealing of lumped beam was performed to form the P-base junction for high-performance low-voltage-power MOSFET. An equivalent shallow-junction structure for the P-base junction with a uniform impurity distribution is realized by adopting excimer laser annealing (ELA). The impurity distribution in the P-base junction can be controlled precisely by the irradiated pulse energy density and the number of shots of excimer laser. High impurity activation for the shallow junction has been confirmed in the melted phase. The application of the laser annealing technology in the fabrication process of a practical low-voltage trench gate MOSFET was also examined.

  10. 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.

  11. High power, high contrast hybrid femtosecond laser systems

    NASA Astrophysics Data System (ADS)

    Dabu, Razvan

    2017-06-01

    For many research applications a very high laser intensity of more than 1022 W/cm2 in the focused beam is required. If a laser intensity of about 1011W/cm2 is reached on the target before the main laser pulse, the generated pre-plasma disturbs the experiment. High power femtosecond lasers must be tightly focused to get high intensity and in the same time must have a high enough intensity contrast of the temporally compressed amplified pulses. Reaching an intensity contrast in the range of 1012 represents a challenging task for a Ti:sapphire CPA laser. Hybrid femtosecond lasers combine optical parametric chirped pulsed amplification (OPCPA) in nonlinear crystals with the chirped pulse amplification (CPA) in laser active media. OPCPA provides large amplification spectral bandwidth and improves the intensity contrast of the amplified pulses. A key feature of these systems consists in the adaptation of the parametric amplification phase-matching bandwidth of nonlinear crystals to the spectral gain bandwidth of laser amplifying Ti:sapphire crystals. OPCPA in BBO crystals up to mJ energy level in the laser Front-End, followed by CPA up to ten/hundred Joules in large aperture Ti:sapphire crystals, represents a suitable solution for PW-class femtosecond lasers. The configuration and expected output beam characteristics of the hybrid amplification 2 × 10 PW ELI-NP laser are described.

  12. Next generation laser optics for a hybrid fusion-fission power plant

    SciTech Connect

    Stolz, C J; Latkowski, J T; Schaffers, K I

    2009-09-10

    The successful completion of the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL), followed by a campaign to achieve ignition, creates the proper conditions to begin exploring what development work remains to construct a power plant based on Inertial Confinement Fusion (ICF) technology. Fundamentally, two distinct NIF laser properties must be overcome. The repetition rate must increase from a shot every four hours to several shots per second. Additionally, the efficiency of converting electricity to laser light must increase by 20x to roughly 10 percent. Solid state diode pumped lasers, commercially available for table top applications, have adequate repetition rates and power conversion efficiencies, however, they operate at a tiny fraction of the required energy for an ICF power plant so would need to be scaled in energy and aperture. This paper describes the optics and coatings that would be needed to support this type of laser architecture.

  13. Laser-driven plasma photonic crystals for high-power lasers

    NASA Astrophysics Data System (ADS)

    Lehmann, G.; Spatschek, K. H.

    2017-05-01

    Laser-driven plasma density gratings in underdense plasma are shown to act as photonic crystals for high power lasers. The gratings are created by counterpropagating laser beams that trap electrons, followed by ballistic ion motion. This leads to strong periodic plasma density modulations with a lifetime on the order of picoseconds. The grating structure is interpreted as a plasma photonic crystal time-dependent property, e.g., the photonic band gap width. In Maxwell-Vlasov and particle-in-cell simulations it is demonstrated that the photonic crystals may act as a frequency filter and mirror for ultra-short high-power laser pulses.

  14. Prophylaxis and treatment of acute radiation ulcers in rats with low-power infrared laser radiation

    NASA Astrophysics Data System (ADS)

    Kursova, Larisa V.; Kaplan, Michael A.; Nikitina, Rosa G.; Maligina, Antonina I.

    1999-12-01

    Exposure of radiation ulcers in rats to low-power infrared laser radiation (LPLR) (wavelength--890 nm, pulse power--6 W, frequency--150 and 300 Hz, irradiation time--10 min) noticeably accelerates their healing, reduces exudative processes, increases number of specialized cells in wound. Application of LPLR prior to radiation damage decreases ulcer dimensions.

  15. Approaches to solar cell design for pulsed laser power receivers

    NASA Technical Reports Server (NTRS)

    Jain, Raj K.; Landis, Geoffrey A.

    1993-01-01

    Using a laser to beam power from Earth to a photovoltaic receiver in space could be a technology with applications to many space missions. Extremely high average-power lasers would be required in a wavelength range of 700-1000 nm. However, high-power lasers inherently operate in a pulsed format. Existing solar cells are not well designed to respond to pulsed incident power. To better understand cell response to pulsed illumination at high intensity, the PC-1D finite-element computer model was used to analyze the response of solar cells to continuous and pulsed laser illumination. Over 50 percent efficiency was calculated for both InP and GaAs cells under steady-state illumination near the optimum wavelength. The time-dependent response of a high-efficiency GaAs concentrator cell to a laser pulse was modeled, and the effect of laser intensity, wavelength, and bias point was studied. Three main effects decrease the efficiency of a solar cell under pulsed laser illumination: series resistance, L-C 'ringing' with the output circuit, and current limiting due to the output inductance. The problems can be solved either by changing the pulse shape or designing a solar cell to accept the pulsed input. Cell design possibilities discussed are a high-efficiency, light-trapping silicon cell, and a monolithic, low-inductance GaAs cell.

  16. Potential of high-average-power solid state lasers

    SciTech Connect

    Emmett, J.L.; Krupke, W.F.; Sooy, W.R.

    1984-09-25

    We discuss the possibility of extending solid state laser technology to high average power and of improving the efficiency of such lasers sufficiently to make them reasonable candidates for a number of demanding applications. A variety of new design concepts, materials, and techniques have emerged over the past decade that, collectively, suggest that the traditional technical limitations on power (a few hundred watts or less) and efficiency (less than 1%) can be removed. The core idea is configuring the laser medium in relatively thin, large-area plates, rather than using the traditional low-aspect-ratio rods or blocks. This presents a large surface area for cooling, and assures that deposited heat is relatively close to a cooled surface. It also minimizes the laser volume distorted by edge effects. The feasibility of such configurations is supported by recent developments in materials, fabrication processes, and optical pumps. Two types of lasers can, in principle, utilize this sheet-like gain configuration in such a way that phase and gain profiles are uniformly sampled and, to first order, yield high-quality (undistorted) beams. The zig-zag laser does this with a single plate, and should be capable of power levels up to several kilowatts. The disk laser is designed around a large number of plates, and should be capable of scaling to arbitrarily high power levels.

  17. High Average Power, High Energy Short Pulse Fiber Laser System

    SciTech Connect

    Messerly, M J

    2007-11-13

    Recently continuous wave fiber laser systems with output powers in excess of 500W with good beam quality have been demonstrated [1]. High energy, ultrafast, chirped pulsed fiber laser systems have achieved record output energies of 1mJ [2]. However, these high-energy systems have not been scaled beyond a few watts of average output power. Fiber laser systems are attractive for many applications because they offer the promise of high efficiency, compact, robust systems that are turn key. Applications such as cutting, drilling and materials processing, front end systems for high energy pulsed lasers (such as petawatts) and laser based sources of high spatial coherence, high flux x-rays all require high energy short pulses and two of the three of these applications also require high average power. The challenge in creating a high energy chirped pulse fiber laser system is to find a way to scale the output energy while avoiding nonlinear effects and maintaining good beam quality in the amplifier fiber. To this end, our 3-year LDRD program sought to demonstrate a high energy, high average power fiber laser system. This work included exploring designs of large mode area optical fiber amplifiers for high energy systems as well as understanding the issues associated chirped pulse amplification in optical fiber amplifier systems.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Method for splitting low power laser beams

    SciTech Connect

    Pierscionek, B.K. )

    1990-04-01

    A new method for producing parallel rays from a laser beam using a cylindrical lens and pinholes is presented. This method can produce a greater number of emergent rays than using a {ital beam} {ital splitter}.

  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. 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.

  5. Power Beamed Photon Sails: New Capabilities Resulting From Recent Maturation Of Key Solar Sail And High Power Laser Technologies

    SciTech Connect

    Montgomery, Edward E. IV

    2010-05-06

    This paper revisits some content in the First International Symposium on Beamed Energy Propulsion in 2002 related to the concept of propellantless in-space propulsion utilizing an external high energy laser to provide momentum to an ultralightweight (gossamer) spacecraft. The design and construction of the NanoSail-D solar sail demonstration spacecraft has demonstrated in space flight hardware the concept of small, very light--yet capable--spacecraft. The results of the Joint High Power Solid State Laser (JHPSSL) have also increased the effectiveness and reduced the cost of an entry level laser source. This paper identifies the impact from improved system parameters on current mission applications.

  6. Inertial fusion with ultra-powerful lasers

    SciTech Connect

    Tabak, M.; Hammer, J.; Glinsky, M.; Kruer, W.; Wilks, S.; Woodworth, J.; Campbell, E.M.; Perry, M.D.; Mason, R.

    1993-10-01

    Ultra-high intensity lasers can be used to ignite ICF capsules with a few tens of kilojoules of light and can lead to high gain with as little as 100 kilojoules of incident laser light. We propose a scheme with three phases. First, a capsule is imploded as in the conventional approach to inertial fusion to assemble a high density fuel configuration. Second, a hole is bored through capsule corona composed of ablated material, pushing critical density close to the high density core of the capsule, by employing the ponderomotive force associated with high intensity laser light. Finally, the fuel is ignited by suprathermal electrons, produced in the high intensity laser plasma interactions, which propagate from critical density to this high density core. This paper reviews two models of energy gain in ICF capsules and explains why ultra-high intensity lasers allow access to the model producing the higher gains. This new scheme also drastically reduces the difficulty of the implosion and thereby allows lower quality fabrication and less stringent beam quality and symmetry requirements from the implosion driver. The difficulty of the fusion scheme is transferred to the technological difficulty of producing the ultra-high-intensity laser and of transporting this energy to the fuel.

  7. 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.

  8. 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)

  9. Plume attenuation of laser radiation during high power fiber laser welding

    NASA Astrophysics Data System (ADS)

    Shcheglov, P. Yu; Uspenskiy, S. A.; Gumenyuk, A. V.; Petrovskiy, V. N.; Rethmeier, M.; Yermachenko, V. M.

    2011-06-01

    The results of an in-situ plume-laser interaction measurement during welding of mild steel with a 5 kW ytterbium fiber laser are reported. A measurement of the attenuation of probe laser beam passing through the plume has allowed to estimate the plume characteristics like the size of the extinction area and the spatial distribution of the extinction coefficient. The power loss of the fiber laser radiation propagating through the whole plume length was calculated. Together with a measured temporal characteristics of extinction the result indicates a significant decreasing of the laser radiation stability, which can lead to the formation of the macroscopic welding defects.

  10. High-power ultralong-wavelength Tm-doped silica fiber laser cladding-pumped with a random distributed feedback fiber laser

    PubMed Central

    Jin, Xiaoxi; Du, Xueyuan; Wang, Xiong; Zhou, Pu; Zhang, Hanwei; Wang, Xiaolin; Liu, Zejin

    2016-01-01

    We demonstrated a high-power ultralong-wavelength Tm-doped silica fiber laser operating at 2153 nm with the output power exceeding 18 W and the slope efficiency of 25.5%. A random distributed feedback fiber laser with the center wavelength of 1173 nm was employed as pump source of Tm-doped fiber laser for the first time. No amplified spontaneous emissions or parasitic oscillations were observed when the maximum output power reached, which indicates that employing 1173 nm random distributed feedback fiber laser as pump laser is a feasible and promising scheme to achieve high-power emission of long-wavelength Tm-doped fiber laser. The output power of this Tm-doped fiber laser could be further improved by optimizing the length of active fiber, reflectivity of FBGs, increasing optical efficiency of pump laser and using better temperature management. We also compared the operation of 2153 nm Tm-doped fiber lasers pumped with 793 nm laser diodes, and the maximum output powers were limited to ~2 W by strong amplified spontaneous emission and parasitic oscillation in the range of 1900–2000 nm. PMID:27416893

  11. High-power ultralong-wavelength Tm-doped silica fiber laser cladding-pumped with a random distributed feedback fiber laser

    NASA Astrophysics Data System (ADS)

    Jin, Xiaoxi; Du, Xueyuan; Wang, Xiong; Zhou, Pu; Zhang, Hanwei; Wang, Xiaolin; Liu, Zejin

    2016-07-01

    We demonstrated a high-power ultralong-wavelength Tm-doped silica fiber laser operating at 2153 nm with the output power exceeding 18 W and the slope efficiency of 25.5%. A random distributed feedback fiber laser with the center wavelength of 1173 nm was employed as pump source of Tm-doped fiber laser for the first time. No amplified spontaneous emissions or parasitic oscillations were observed when the maximum output power reached, which indicates that employing 1173 nm random distributed feedback fiber laser as pump laser is a feasible and promising scheme to achieve high-power emission of long-wavelength Tm-doped fiber laser. The output power of this Tm-doped fiber laser could be further improved by optimizing the length of active fiber, reflectivity of FBGs, increasing optical efficiency of pump laser and using better temperature management. We also compared the operation of 2153 nm Tm-doped fiber lasers pumped with 793 nm laser diodes, and the maximum output powers were limited to ~2 W by strong amplified spontaneous emission and parasitic oscillation in the range of 1900-2000 nm.

  12. High-power ultralong-wavelength Tm-doped silica fiber laser cladding-pumped with a random distributed feedback fiber laser.

    PubMed

    Jin, Xiaoxi; Du, Xueyuan; Wang, Xiong; Zhou, Pu; Zhang, Hanwei; Wang, Xiaolin; Liu, Zejin

    2016-07-15

    We demonstrated a high-power ultralong-wavelength Tm-doped silica fiber laser operating at 2153 nm with the output power exceeding 18 W and the slope efficiency of 25.5%. A random distributed feedback fiber laser with the center wavelength of 1173 nm was employed as pump source of Tm-doped fiber laser for the first time. No amplified spontaneous emissions or parasitic oscillations were observed when the maximum output power reached, which indicates that employing 1173 nm random distributed feedback fiber laser as pump laser is a feasible and promising scheme to achieve high-power emission of long-wavelength Tm-doped fiber laser. The output power of this Tm-doped fiber laser could be further improved by optimizing the length of active fiber, reflectivity of FBGs, increasing optical efficiency of pump laser and using better temperature management. We also compared the operation of 2153 nm Tm-doped fiber lasers pumped with 793 nm laser diodes, and the maximum output powers were limited to ~2 W by strong amplified spontaneous emission and parasitic oscillation in the range of 1900-2000 nm.

  13. 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

  14. 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.

  15. 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.

  16. Biomedical effects of low-power laser controlled by electroacupuncture

    NASA Astrophysics Data System (ADS)

    Kalenchits, Nadezhda I.; Nicolaenko, Andrej A.; Shpilevoj, Boris N.

    1997-12-01

    The methods and technical facilities of testing the biomedical effects caused by the influence of low-power laser radiation in the process of laser therapy are presented. Described studies have been conducted by means of the complex of fireware facilities consisting of the system of electroacupuncture diagnostics (EA) and a system of laser therapy on the basis of multichannel laser and magneto-laser devices. The task of laser therapy was concluded in undertaking acupuncture anaesthetization, achievement of antioedemic and dispersional actions, raising tone of musculus and nervous system, normalization of immunity factors under the control of system EA. The 82 percent to 95 percent agreement of the result of an electroacupuncture diagnostics with clinical diagnoses were achieved.

  17. Average Power and Brightness Scaling of Diamond Raman Lasers

    DTIC Science & Technology

    2012-01-07

    on 1064 nm beam conversion of 50 W lasers in the ?external cavity? Raman cavity configuration in both pulsed and continuous wave modes of operation...scaling of  diamond Raman  lasers . The investigations focus on  1064  nm beam conversion of 50 W  lasers  in the “external  cavity” Raman cavity configuration... laser  pumped using a CW Nd  laser  at  1064  nm. The output  power is more than three times the highest for a CW crystalline Raman  laser , that being for a

  18. Influence of laser power on microstructure and mechanical properties of laser welded-brazed Mg to Ni coated Ti alloys

    NASA Astrophysics Data System (ADS)

    Tan, Caiwang; Lu, Qingshuang; Chen, Bo; Song, Xiaoguo; Li, Liqun; Feng, Jicai; Wang, Yang

    2017-03-01

    AZ31B Magnesium (Mg) and Ti-6Al-4V titanium (Ti) alloys with Ni coating were joined by laser welding-brazing process using AZ92 Mg based filler. The influence of laser power on microstructure and mechanical properties were investigated. Ni coating was found to significantly promote good wetting-spreading ability of molten filler on the Ti sheet. Acceptable joints without obvious defects were obtained within a relatively wide processing window. In the process metallurgical bonding was achieved by the formation of Ti3Al phase at direct irradiation zone and Al-Ni phase followed by a layer of Mg-Al-Ni ternary compound adjacent to the fusion zone at the intermediate zone. The thickness of reaction layers increased slowly with the increasing laser power. The tensile-shear test indicated that joints produced at the laser power of 1300 W reached 2387 N fracture load, representing 88.5% joint efficiency with respect to the Mg base metal. The corresponding failure occurred in the fusion zone of the Mg base metal, while joints fractured at the interface at lower/higher laser power due to the crack or excessive intermetallic compound (IMC) formation along the interface.

  19. Advanced Receiver/Converter Experiments for Laser Wireless Power Transmission

    NASA Technical Reports Server (NTRS)

    Howell, Joe T.; ONeill, Mark; Fork, Richard

    2004-01-01

    For several years NASA Marshall Space Flight Center, UAH and ENTECH have been working on various aspects of space solar power systems. The current activity was just begun in January 2004 to further develop this new photovoltaic concentrator laser receiver/converter technology. During the next few months, an improved prototype will be designed, fabricated, and thoroughly tested under laser illumination. The final paper will describe the new concept, present its advantages over other laser receiver/converter approaches (including planar photovoltaic arrays), and provide the latest experiment results on prototype hardware (including the effects of laser irradiance level and cell temperature). With NASA's new human exploration plans to first return to the Moon, and then to proceed to Mars, the new photovoltaic concentrator laser receiver/converter technology could prove to be extremely useful in providing power to the landing sites and other phases of the missions. For example, to explore the scientifically interesting and likely resource-rich poles of the Moon (which may contain water) or the poles of Mars (which definitely contain water and carbon dioxide), laser power beaming could represent the simplest means of providing power to these regions, which receive little or no sunlight, making solar arrays useless there. In summary, the authors propose a paper on definition and experimental results of a novel photovoltaic concentrator approach for collecting and converting laser radiation to electrical power. The new advanced photovoltaic concentrator laser receiver/converter offers higher performance, lighter weight, and lower cost than competing concepts, and early experimental results are confirming the expected excellent Performance levels. After the small prototypes are successfully demonstrated, a larger array with even better performance is planned for the next phase experiments and demonstrations. Thereafter, a near-term flight experiment of the new technology

  20. Study on Interactions of Continuous Low Power CO2 Laser with Malaysian Molar Teeth

    NASA Astrophysics Data System (ADS)

    Ahmad, A. L.; Jaafar, M. S.; Ramzun, M. R.; Bermakai, M. Yahaya; Ismail, N. E.; Houssien, Hend A. A.

    2010-07-01

    Recent studies have shown that CO2 lasers can successfully be used at low-energy densities in dentistry. The CO2 laser is effective for a dental hard tissue since it strongly absorbs light in certain regions of the infrared spectrum because of the carbonate and hydroxyl groups in the structure. In this study, nineteen samples of molars extracted human teeth were irradiated with low power CO2 laser. Laser power of 3W, 6W, 9W, 12W, 15W and 18W, with exposure time of 5 s and 10 s, and distance between laser aperture and sample of 4 cm were used. Laser power above 18W is seen to damage the teeth. The teeth compositions were analyzed using the Fourier Transform Infrared Spectroscopy (FTIR). High laser power caused higher reflectance of the beam because the increased in temperature increasing the rate of chemical reaction, hence, the products after the irradiation. This situation can be explained by the Arrhenius equation [1].

  1. High power continuous-wave diode-laser-pumped Nd:YAG laser

    NASA Astrophysics Data System (ADS)

    Golla, D.; Knoke, S.; Schöne, W.; Tünnermann, A.; Schmidt, H.

    1994-05-01

    We report on a diode-laser-pumped cw Nd: YAG laser operating at a power level of 150 W. By using a transverse pump geometry, the radiation of 54 diode lasers with an output power of 10 W each is coupled into a Nd:YAG rod. In multimode operation, an optical slope efficiency of 32% and an optical to optical efficiency of 29% are obtained. In TEM00 operation, an output power of more than 30 W is realized with an optical to optical efficiency of 10%.

  2. Effects of low-power laser radiation on mice immunity.

    PubMed

    Novoselova, E G; Glushkova, O V; Cherenkov, D A; Chudnovsky, V M; Fesenko, E E

    2006-02-01

    Because of large interest in biological effects of laser radiation used in laser therapy, the effect of extremely low-level red laser light intensity on the immune cell activity has been studied in the animal model with well-characterized macrophage and T cell populations as responder cells producing cytokines, protective proteins, active oxygen, and nitric compounds. To study of the possible side effects of laser immunotherapy we monitored the productions of cytokines, nitric oxide (NO), and heat shock protein 70 (Hsp70) in mice subjected to a periodic laser exposure for 1 month. Helium-neon laser radiation with the power of 0.2 mW/cm2 and wavelength of 632.8 nm was applied on two different mouse skin surfaces, i.e. a thymus projection area or a hind limb. Healthy NMRI male mice were irradiated repeatedly with laser light for 1 min with 48-h intervals for 30 days. The animals were divided into three groups of 25 mice. The first and the second groups were exposed to laser light, on the thymus and hind limb area, respectively. The third, sham-irradiated group served as a control. Early and prolonged effects of laser radiation on the levels of NO (by Griess assay), Hsp70 (by Western blot assay), tumor necrosis factors (TNF-alpha and TNF-beta) (by cytotoxic assay using L929 cells as targets), and interleukin-2 (IL-2) (by ELISA assay) were determined. The dynamics of immune responses to low-power laser light intensity was shown to be dependent on two factors, i.e. the cumulative dose and the localization of the irradiated surface. Besides, various populations of cells demonstrated different sensitivity to laser radiation, with T cells being more responsive among examined populations of the cells. Low intensity laser light induced an immune cell activity when the exposure duration did not exceed 10 days, while a more prolonged period of treatment generated more severe changes in the immune system, up to immunosuppression. The treatment of the thymus zone resulted in

  3. Power-scalable subcycle pulses from laser filaments

    PubMed Central

    Voronin, A.A.; Zheltikov, A.M.

    2017-01-01

    Compression of optical pulses to ultrashort pulse widths using methods of nonlinear optics is a well-established technology of modern laser science. Extending these methods to pulses with high peak powers, which become available due to the rapid progress of laser technologies, is, however, limited by the universal physical principles. With the ratio P/Pcr of the peak power of an ultrashort laser pulse, P, to the critical power of self-focusing, Pcr, playing the role of the fundamental number-of-particles integral of motion of the nonlinear Schrödinger equation, keeping this ratio constant is a key principle for the power scaling of laser-induced filamentation. Here, we show, however, that, despite all the complexity of the underlying nonlinear physics, filamentation-assisted self-compression of ultrashort laser pulses in the regime of anomalous dispersion can be scaled within a broad range of peak powers against the principle of constant P/Pcr. We identify filamentation self-compression scaling strategies whereby subcycle field waveforms with almost constant pulse widths can be generated without a dramatic degradation of beam quality within a broad range of peak powers, varying from just a few to hundreds of Pcr. PMID:28367980

  4. Power-scalable subcycle pulses from laser filaments

    NASA Astrophysics Data System (ADS)

    Voronin, A. A.; Zheltikov, A. M.

    2017-04-01

    Compression of optical pulses to ultrashort pulse widths using methods of nonlinear optics is a well-established technology of modern laser science. Extending these methods to pulses with high peak powers, which become available due to the rapid progress of laser technologies, is, however, limited by the universal physical principles. With the ratio P/Pcr of the peak power of an ultrashort laser pulse, P, to the critical power of self-focusing, Pcr, playing the role of the fundamental number-of-particles integral of motion of the nonlinear Schrödinger equation, keeping this ratio constant is a key principle for the power scaling of laser-induced filamentation. Here, we show, however, that, despite all the complexity of the underlying nonlinear physics, filamentation-assisted self-compression of ultrashort laser pulses in the regime of anomalous dispersion can be scaled within a broad range of peak powers against the principle of constant P/Pcr. We identify filamentation self-compression scaling strategies whereby subcycle field waveforms with almost constant pulse widths can be generated without a dramatic degradation of beam quality within a broad range of peak powers, varying from just a few to hundreds of Pcr.

  5. Power-scalable subcycle pulses from laser filaments.

    PubMed

    Voronin, A A; Zheltikov, A M

    2017-04-03

    Compression of optical pulses to ultrashort pulse widths using methods of nonlinear optics is a well-established technology of modern laser science. Extending these methods to pulses with high peak powers, which become available due to the rapid progress of laser technologies, is, however, limited by the universal physical principles. With the ratio P/Pcr of the peak power of an ultrashort laser pulse, P, to the critical power of self-focusing, Pcr, playing the role of the fundamental number-of-particles integral of motion of the nonlinear Schrödinger equation, keeping this ratio constant is a key principle for the power scaling of laser-induced filamentation. Here, we show, however, that, despite all the complexity of the underlying nonlinear physics, filamentation-assisted self-compression of ultrashort laser pulses in the regime of anomalous dispersion can be scaled within a broad range of peak powers against the principle of constant P/Pcr. We identify filamentation self-compression scaling strategies whereby subcycle field waveforms with almost constant pulse widths can be generated without a dramatic degradation of beam quality within a broad range of peak powers, varying from just a few to hundreds of Pcr.

  6. 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.

  7. Power combining of semiconductor lasers: A review

    NASA Technical Reports Server (NTRS)

    Katz, J.

    1982-01-01

    Several methods of coherent power combining are described and compared. A comparison is also made between coherent and incoherent power combining, and important operational characteristics are considered. It is found that in communication links with demanding requirements coherent power combining is necessary.

  8. Recirculation of Laser Power in an Atomic Fountain

    NASA Technical Reports Server (NTRS)

    Enzer, Daphna G.; Klipstein, WIlliam M.; Moore, James D.

    2007-01-01

    A new technique for laser-cooling atoms in a cesium atomic fountain frequency standard relies on recirculation of laser light through the atom-collection region of the fountain. The recirculation, accomplished by means of reflections from multiple fixed beam-splitter cubes, is such that each of two laser beams makes three passes. As described below, this recirculation scheme offers several advantages over prior designs, including simplification of the laser system, greater optical power throughput, fewer optical and electrical connections, and simplification of beam power balancing. A typical laser-cooled cesium fountain requires the use of six laser beams arranged as three orthogonal pairs of counter-propagating beams to decelerate the atoms and hold them in a three-dimensional optical trap in vacuum. Typically, these trapping/cooling beams are linearly polarized and are positioned and oriented so that (1) counter-propagating beams in each pair have opposite linear polarizations and (2) three of the six orthogonal beams have the sum of their propagation directions pointing up, while the other three have the sum of their propagation directions pointing down. In a typical prior design, two lasers are used - one to generate the three "up" beams, the other to generate the three "down" beams. For this purpose, the output of each laser is split three ways, then the resulting six beams are delivered to the vacuum system, independently of each other, via optical fibers. The present recirculating design also requires two lasers, but the beams are not split before delivery. Instead, only one "up" beam and one oppositely polarized "down" beam are delivered to the vacuum system, and each of these beams is sent through the collection region three times. The polarization of each beam on each pass through the collection region is set up to yield the same combination of polarization and propagation directions as described above. In comparison with the prior design, the present

  9. 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.

  10. 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.

  11. Interaction of high-power laser radiation with low-density polymer aerogels

    NASA Astrophysics Data System (ADS)

    Kaur, Ch; Chaurasia, Sh; Borisenko, N. G.; Orekhov, A. S.; Leshma, P.; Pimenov, V. G.; Sklizkov, G. V.; Akunets, A. A.; Deo, M. N.

    2017-06-01

    The interaction of high-power subnanosecond laser pulses with low-density targets of cellulose triacetate polymer is considered. An Nd-glass laser setup provides a focal spot intensity of over 1014 W cm-2. An investigation is made of absorption of laser radiation, laser-to-X-ray energy conversion, spectra of ions emitted from the plasma, transmission of laser radiation through the target and plasma, as well as volume heating of the target material. It is experimentally determined that the laser energy conversion efficiency to X-rays with photon energies of a few kiloelectronvolts decreases with increasing target material density. With the use of targets of density 10 mg cm-3 this efficiency is two times lower in comparison to 2 mg cm-3 density targets. The duration and amplitude of laser pulses transmitted through the target decreases with increasing column target density (the product of target material density and its thickness). The spectra of ions emitted from low-density target plasmas are recorded using ion collectors positioned at different angles relative to the direction of laser beam propagation as well as a high-resolution Thomson mass spectrometer. The ion flux and ion energies are found to increase with increasing target material density. The peak of the ion energy spectrum is shifted towards higher energies with increasing laser radiation intensity.

  12. Department of Defense high power laser program guidance

    NASA Astrophysics Data System (ADS)

    Muller, Clifford H.

    1994-06-01

    The DoD investment of nominally $200 million per year is focused on four high power laser (HPL) concepts: Space-Based Laser (SBL), a Ballistic Missile Defense Organization effort that addresses boost-phase intercept for Theater Missile Defense and National Missile Defense; Airborne Laser (ABL), an Air Force effort that addresses boost-phase intercept for Theater Missile Defense; Ground-Based Laser (GBL), an Air Force effort addressing space control; and Anti-Ship Missile Defense (ASMD), a Navy effort addressing ship-based defense. Each organization is also supporting technology development with the goal of achieving less expensive, brighter, and lighter high power laser systems. These activities represent the building blocks of the DoD program to exploit the compelling characteristics of the high power laser. Even though DoD's HPL program are focused and moderately strong, additional emphasis in a few technical areas could help reduce risk in these programs. In addition, a number of options are available for continuing to use the High-Energy Laser System Test Facility (HELSTF) at White Sands Missile Range. This report provides a brief overview and guidance for the five efforts which comprise the DoD HPL program (SBL, ABL, GBL, ASMD, HELSTF).

  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. Laser Drilling - Drilling with the Power of Light

    SciTech Connect

    Brian C. Gahan; Samih Batarseh

    2004-09-28

    Gas Technology Institute (GTI) has been the leading investigator in the field of high power laser applications research for well construction and completion applications. Since 1997, GTI (then as Gas Research Institute) has investigated several military and industrial laser systems and their ability to cut and drill into reservoir type rocks. In this report, GTI continues its investigation with a recently acquired 5.34 kW ytterbium-doped multi-clad high power fiber laser (HPFL). The HPFL represents a potentially disruptive technology that, when compared to its competitors, is more cost effective to operate, capable of remote operations, and requires considerably less maintenance and repair. To determine how this promising laser compares with other lasers used in past experimental work, GTI performed a number of experiments with results directly comparable to previous data. Experiments were designed to investigate the effect of laser input parameters on representative reservoir rock types of sandstone and limestone. The focus of the experiments was on completion and perforation applications, although the results and techniques apply to well construction and other rock cutting applications. Variables investigated include laser power, beam intensity, external purging of cut materials, sample orientation, beam duration, beam shape, and beam frequency. The investigation also studied the thermal effects on the two sample rock types and their methods of destruction: spallation for sandstone, and thermal dissociation for limestone. Optimal operating conditions were identified for each rock type and condition. As a result of this experimental work, the HPFL has demonstrated a better capability of cutting and drilling limestone and sandstone when compared with other military and industrial lasers previously tested. Consideration should be given to the HPFL as the leading candidate for near term remote high power laser applications for well construction and completion.

  15. Laser power and Scanning Speed Influence on the Mechanical Property of Laser Metal Deposited Titanium-Alloy

    NASA Astrophysics Data System (ADS)

    Mahamood, Rasheedat M.; Akinlabi, Esther T.; Akinlabi, Stephen

    2015-03-01

    The influence of the laser power and the scanning speed on the microhardness of the Laser Metal Deposited Ti6Al4V, an aerospace Titanium-alloy, was studied. Ti6Al4V powder was deposited on the Ti6Al4V substrate using the Laser Metal Deposition (LMD) process, an Additive Manufacturing (AM) manufacturing technology. The laser power was varied between 1.8 kW 3 kW and the scanning speed was varied between 0.05 m/s and 0.1 m/s. The powder flow rate and the gas flow rate were kept at constant values of 2 g/min and 2 l/min respectively. The full factorial design of experiment was used to design the experiment and to also analyze the results in the Design Expert 9 software environment. The microhardness profiling was studied using Microhardness indenter performed at a load of 500 g and at a dwelling time of 15 s. The distance between indentations was maintained at a distance of 15 μm. The study revealed that as the laser power was increased, the microhardness was found to decrease and as the scanning speed was increased, the microhardness was found to also increase. The results are presented and fully discussed.

  16. High power tunable femtosecond ultraviolet laser source based on an Yb-fiber-laser pumped optical parametric oscillator.

    PubMed

    Gu, Chenglin; Hu, Minglie; Fan, Jintao; Song, Youjian; Liu, Bowen; Chai, Lu; Wang, Chingyue; Reid, Derryck T

    2015-03-09

    We report a high average power tunable 51 MHz femtosecond ultraviolet (UV) laser source based on an intra-cavity sum frequency mixing optical parametric oscillator (OPO) pumped by a fiber laser. The UV laser is generated by sum frequency generation (SFG) between the second harmonic of a mode-locked Yb-fiber laser and the signal of the OPO. A non-collinear configuration is used in the SFG to compensate the group velocity mismatch, and to increase the SFG conversion efficiency dramatically. Tunable ultraviolet pulses within the wavelength range from 385 to 400 nm have been produced with a maximum average power of 402 mW and a pulse width of 286 fs at 2 W Yb-fiber laser pump, corresponding to 20.1% near-infrared to UV conversion efficiency at 387 nm. To our knowledge, this is the first demonstration of tunable femtosecond UV pulse generation from a fiber laser pumped OPO, and is also the highest average power tunable UV femtosecond pulses from an OPO.

  17. Power transmission by laser beam from lunar-synchronous satellite

    NASA Technical Reports Server (NTRS)

    Williams, M. D.; Deyoung, R. J.; Schuster, G. L.; Choi, S. H.; Dagle, J. E.; Coomes, E. P.; Antoniak, Z. I.; Bamberger, J. A.; Bates, J. M.; Chiu, M. A.

    1993-01-01

    The possibility of beaming power from synchronous lunar orbits (the L1 and L2 Lagrange points) to a manned long-range lunar rover is addressed. The rover and two versions of a satellite system (one powered by a nuclear reactor, the other by photovoltaics) are described in terms of their masses, geometries, power needs, missions, and technological capabilities. Laser beam power is generated by a laser diode array in the satellite and converted to 30 kW of electrical power at the rover. Present technological capabilities, with some extrapolation to near future capabilities, are used in the descriptions. The advantages of the two satellite/rover systems over other such systems and over rovers with onboard power are discussed along with the possibility of enabling other missions.

  18. Power transmission by laser beam from lunar-synchronous satellite

    NASA Astrophysics Data System (ADS)

    Williams, M. D.; De Young, R. J.; Schuster, G. L.; Choi, S. H.; Dagle, J. E.; Coomes, E. P.; Antoniak, Z. I.; Bamberger, J. A.; Bates, J. M.; Chiu, M. A.

    1993-11-01

    The possibility of beaming power from synchronous lunar orbits (the L1 and L2 Lagrange points) to a manned long-range lunar rover is addressed. The rover and two versions of a satellite system (one powered by a nuclear reactor, the other by photovoltaics) are described in terms of their masses, geometries, power needs, missions, and technological capabilities. Laser beam power is generated by a laser diode array in the satellite and converted to 30 kW of electrical power at the rover. Present technological capabilities, with some extrapolation to near future capabilities, are used in the descriptions. The advantages of the two satellite/rover systems over other such systems and over rovers with onboard power are discussed along with the possibility of enabling other missions.

  19. Wavelength dependency in high power laser cutting and welding

    NASA Astrophysics Data System (ADS)

    Havrilla, David; Ziermann, Stephan; Holzer, Marco

    2012-03-01

    Laser cutting and welding have been around for more than 30 years. Within those three decades there has never been a greater variety of high power laser types and wavelengths to choose from than there is today. There are many considerations when choosing the right laser for any given application - capital investment, cost of ownership, footprint, serviceability, along with a myriad of other commercial & economic considerations. However, one of the most fundamental questions that must be asked and answered is this - "what type of laser is best suited for the application?". Manufacturers and users alike are realizing what, in retrospect, may seem obvious - there is no such thing as a universal laser. In many cases there is one laser type and wavelength that clearly provides the highest quality application results. This paper will examine the application fields of high power, high brightness 10.6 & 1 micron laser welding & cutting and will provide guidelines for selecting the laser that is best suited for the application. Processing speed & edge quality serve as key criteria for cutting. Whereas speed, seam quality & spatter ejection provide the paradigm for welding.

  20. High Power Mid Wave Infrared Semiconductor Lasers

    DTIC Science & Technology

    2006-06-15

    injected MWIR laser arrays using III-V antimonide based materials. In this approach, InGaSb quantum wells are grown on metamorphic layers on a GaSb or GaAs...also demonstrated room temperature photoluminescence up to 3 gm from InGaSb quantum wells grown on GaAs substrate. Using this approach we have...InAsSb/InAlAs quantum well lasers was reported with a To of 26K. Thus typically, the devices require thermoelectric or even cryogenic cooling to operate

  1. Long range laser propagation: power scaling and beam quality issues

    NASA Astrophysics Data System (ADS)

    Bohn, Willy L.

    2010-09-01

    This paper will address long range laser propagation applications where power and, in particular beam quality issues play a major role. Hereby the power level is defined by the specific mission under consideration. I restrict myself to the following application areas: (1)Remote sensing/Space based LIDAR, (2) Space debris removal (3)Energy transmission, and (4)Directed energy weapons Typical examples for space based LIDARs are the ADM Aeolus ESA mission using the ALADIN Nd:YAG laser with its third harmonic at 355 nm and the NASA 2 μm Tm:Ho:LuLiF convectively cooled solid state laser. Space debris removal has attracted more attention in the last years due to the dangerous accumulation of debris in orbit which become a threat to the satellites and the ISS space station. High power high brightness lasers may contribute to this problem by partially ablating the debris material and hence generating an impulse which will eventually de-orbit the debris with their subsequent disintegration in the lower atmosphere. Energy transmission via laser beam from space to earth has long been discussed as a novel long term approach to solve the energy problem on earth. In addition orbital transfer and stationkeeping are among the more mid-term applications of high power laser beams. Finally, directed energy weapons are becoming closer to reality as corresponding laser sources have matured due to recent efforts in the JHPSSL program. All of this can only be realized if he laser sources fulfill the necessary power requirements while keeping the beam quality as close as possible to the diffraction limited value. And this is the rationale and motivation of this paper.

  2. 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.

  3. High power, high efficiency, 2D laser diode arrays for pumping solid state lasers

    SciTech Connect

    Rosenberg, A.; McShea, J.C.; Bogdan, A.R.; Petheram, J.C.; Rosen, A.

    1987-11-01

    This document reports the current performance of 2D laser diode arrays operating at 770 nm and 808 nm for pumping promethium and neodymium solid state lasers, respectively. Typical power densities are in excess of 2kw/cm/sup 2/ with overall efficiencies greater than 30%.

  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. Interaction between the laser beam and keyhole wall during high power fiber laser keyhole welding.

    PubMed

    Zou, Jianglin; Ha, Na; Xiao, Rongshi; Wu, Qiang; Zhang, Qunli

    2017-07-24

    The crucial factor of laser welding is the laser energy conversion. For a better understanding of the process, the interaction process between the laser beam and keyhole wall was investigated by observing the keyhole wall evaporation during high-power fiber laser welding. The results show that the evaporation vapor, induced by the laser beam, discretely distributed on the keyhole wall. A tiny 'hollow' zone was observed at the spot center-action region on the FKW. The evaporation vapor induced by the spot center moved downward along the front keyhole wall (FKW) with a period of about 0.3~0.75 ms, which indicates that the keyhole formation is reminiscent of a periodical laser drilling process on the FKW. The evaporation vapor on the keyhole wall suggest the assumption that the laser energy coupling mode in the keyhole was multiple-reflection, and the keyhole depth was mainly determined by the drilling behavior induced by the first absorption on the FKW.

  6. Power scaling of a directly diode-laser-pumped Ti:sapphire laser.

    PubMed

    Roth, Peter W; Burns, David; Kemp, Alan J

    2012-08-27

    Improvements in the output power of a directly GaN diode-laser-pumped Ti:Al2O3 laser are achieved by using double-sided pumping. In continuous wave operation, an output power of 159 mW is reported. A tuning range of over 125 nm with output powers in excess of 100 mW is achieved. Pulses of 111 fs duration and an average power of 101 mW are demonstrated by mode locking the laser with a saturable Bragg reflector. Pumping with GaN diode lasers at wavelengths around 450 nm induces an additional parasitic crystal loss of about 1% per resonator roundtrip that is not observed at the conventional green pump wavelengths.

  7. 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.

  8. Hybrid modulation driving power technology for pulsed laser fuze

    NASA Astrophysics Data System (ADS)

    Xu, Xiaobin; Zhang, He

    2016-10-01

    According to the requirement of the long range detection of the circumferential detection system of the laser fuze, a hybrid modulated pulsed laser driving power supplying for APD avalanche photodiode is designed. The working principle of the laser circumferential detection system is analyzed, and the APD is selected as the photoelectric detector according to the measurement equation of the circumferential detection system. According to the different kinds of APD requirements for high voltage power supply, the principle of boost converter is analyzed. By using PWM and PFM hybrid modulation type power supply technology, PWM modulation is applied in low rising voltage. When the voltage is required to achieve more than 100V, PFM mode boost is chosen. Simulation of the output voltages which are 85V and 200V of the two modes respectively is made. The PCB circuit board is processed to verify the experiment. The experimental results show that the hybrid modulation pulse laser drive power supply can meet the requirements of all kinds of APD power supply. The circuit board can be used in the detection of laser fuze with different target distance, and has wide application prospect.

  9. Laser Microchemistry : A Powerful Tool For VLSI

    NASA Astrophysics Data System (ADS)

    Tonneau, Didier; Guern, Yves; Pelous, Gerard

    1989-01-01

    Interconnection direct writing on ICs is possible by localized laser-assisted Chemical Vapor Deposition. Recently we have developed and marketed a new laser microchemistry tool particularly designed for VLSI prototypes rewiring. By dissociating Ni(CO)4 molecules, Ni lines can be written at speeds higher than 5 gm/s under laser induced temperature as low as 400°C. At the same temperature tungsten stripes can be driven from decomposition of WF6-H2 mixtures. However the tungsten deposition rate is about two orders of magnitude lower than the nickel growth rate in the same temperature conditions. The resistivities of the deposits are in both cases around 10 μΩ.cm. Silicon dioxide layers can be promoted from dissociation of a Si2H6-N20 mixture under surface temperature around 500°C. These metal and insulator deposition basic steps have been integrated in a complete metal bridging process suitable for the last interconnection level of a VLSI circuit. This process has been firstly estimated from a functional point of view, by electrical characterizations realized on test patterns entirely drawn by laser chemistry. At least, by measuring the time necessary to perform a metal bridge, the process has been evaluated from an economical point of view.

  10. 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.

  11. 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.

  12. High-Power Diode Laser Technology and Characteristics

    NASA Astrophysics Data System (ADS)

    Behringer, Martin

    Laser operation relies on two conditions, stimulated emission of the amplifying medium and feedback by an optical resonator. The threshold of laser operation is obtained if the gain in the resonator compensates for the overall losses, i.e., the propagation losses and the apparent losses due to the extraction of light [2.1]. Both common laser conditions are satisfied in diode lasers in another way than in typical gas or solid-state lasers. The resonator is given by the semiconductor structure itself using the crystal facets as mirrors. The gain in diode lasers involves a whole crystal structure and not only excited single atoms, ions, or molecules. Modern semiconductor lasers restrict the excited volume to reduce the threshold current by applying quantum wells or quantum dots. Technically, this is achieved by growing very thin layers consisting of different crystal compositions for quantum wells or by applying two-dimensional growth for quantum dots. A scheme of a diode laser is shown in Fig. 2.1. The following chapter takes a short tour through the excitation of high-power semiconductor lasers by examining the current injection of carriers, the optical gain, and appropriate resonator structures. More detailed descriptions of several aspects can be found in several textbooks [2.2, 2.3].

  13. Low Power Laser Irradiation Stimulates the Proliferation of Adult Human Retinal Pigment Epithelial Cells in Culture

    PubMed Central

    Song, Qing; Uygun, Basak; Banerjee, Ipsita; Nahmias, Yaakov; Zhang, Quan; Berthiaume, François; Latina, Mark; Yarmush, Martin L.

    2015-01-01

    We investigated the effects of low power laser irradiation on the proliferation of retinal pigment epithelial (RPE) cells. Adult human RPE cells were artificially pigmented by preincubation with sepia melanin, and exposed to a single sublethal laser pulse (590 nm, 1 µs, <200 mJ/cm2). DNA synthesis, cell number, and growth factor activity in irradiated RPE cells were subsequently monitored. The effect of sublethal laser irradiation on the “wound” healing response of an RPE monolayer in an in vitro scratch assay was also investigated. Single pulsed laser irradiation increased DNA synthesis in pigmented RPE cells measured 6 h post-treatment. In the scratch assay, laser irradiation increased the rates of cell proliferation and wound closure. Conditioned medium, collected 48 h following laser treatment, increased cell proliferation of unirradiated cells. Irradiation increased RPE cell secretion of platelet-derived growth factor (PDGF)-B chain, and increased mRNA levels of several growth factors and their receptors, including PDGF, transforming growth factor-β1, basic fibroblast growth factor, epidermal growth factor, insulin-like growth factor, as well as heat shock proteins. This demonstrates, for the first time, that low power single pulsed laser irradiation stimulates the proliferation of RPE cells, and upregulates growth factors that are mitogenic for RPE cells. PMID:26740823

  14. Low-power-laser therapy used in tendon damage

    NASA Astrophysics Data System (ADS)

    Strupinska, Ewa

    1996-03-01

    The following paper covers evaluation of low-power laser therapy results in chronic Achilles tendon damage and external Epicondylalia (tennis elbow). Fifty patients with Achilles damage (18 women and 32 men, age average 30, 24 plus or minus 10, 39 years) and fifty patients having external Epicondyalgiae (31 women and 19 men, age average 44, 36 plus or minus 10, 88 years) have been examined. The patients were irradiated by semiconductor infrared laser wavelength 904 nm separately or together with helium-neon laser wavelength 632.8 nm. The results of therapy have been based on the patient's interviews and examinations of patients as well as on the Laitinen pain questionnaire. The results prove analgesic effects in usage of low- power laser radiation therapy can be obtained.

  15. Laser Diode Cooling For High Average Power Applications

    NASA Astrophysics Data System (ADS)

    Mundinger, David C.; Beach, Raymond J.; Benett, William J.; Solarz, Richard W.; Sperry, Verry

    1989-06-01

    Many applications for semiconductor lasers that require high average power are limited by the inability to remove the waste heat generated by the diode lasers. In order to reduce the cost and complexity of these applications a heat sink package has been developed which is based on water cooled silicon microstructures. Thermal resistivities of less than 0.025°C/01/cm2) have been measured which should be adequate for up to CW operation of diode laser arrays. This concept can easily be scaled to large areas and is ideal for high average power solid state laser pumping. Several packages which illustrate the essential features of this design have been fabricated and tested. The theory of operation will be briefly covered, and several conceptual designs will be described. Also the fabrication and assembly procedures and measured levels of performance will be discussed.

  16. Laser beacon adaptive optics for power beaming applications

    NASA Astrophysics Data System (ADS)

    Fugate, Robert Q.

    1994-05-01

    This paper discusses the laser beam control system requirements for power beaming applications. Power beaming applications include electric and thermal engine propulsion for orbit transfer, station changing, and recharging batteries. Beam control includes satellite acquisition, high accuracy tracking, higher order atmospheric compensation using adaptive optics, and precision point-ahead. Beam control may also include local laser beam clean-up with a low order adaptive optics system. This paper also presents results of tracking and higher-order correction experiments on astronomical objects. The results were obtained with a laser beacon adaptive optics system at Phillips Laboratory's Starfire Optical Range near Albuquerque, NM. At a wavelength of 0.85 micrometers , we have achieved Strehl ratios of approximately 0.50 using laser beacons and approximately 0.65 using natural stars for exposures longer than one minute on objects of approximately 8th magnitude. The resulting point spread function has a full width half maximum (FWHM) of 0.13 arcsec.

  17. 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.

  18. INTERACTION OF LASER RADIATION WITH MATTER. LASER PLASMA: Ion acceleration by ultrahigh-power ultrashort laser pulses

    NASA Astrophysics Data System (ADS)

    Brantov, A. V.; Bychenkov, V. Yu; Rozmus, V.

    2007-09-01

    Two- and three-dimensional numerical simulations of fast-ion generation under ultrashort high-power laser pulse irradiation of stratified targets of different density and thickness are performed by the 'particle-in-cell' technique. The intent of these simulations was to determine the optimal target for maximising the ion energy for a given energy of the laser pulse. The simulations were carried out for the presently highest laser radiation intensities.

  19. High brilliance and high efficiency: optimized high power diode laser bars

    NASA Astrophysics Data System (ADS)

    Hülsewede, R.; Schulze, H.; Sebastian, J.; Schröder, D.; Meusel, J.; Hennig, P.

    2008-02-01

    The strong increasing laser market has ongoing demands to reduce the costs of diode laser pumped systems. For that reason JENOPTIK Diode Lab GmbH (JDL) optimized the bar brilliance (small vertical far field divergence) and bar efficiency (higher optical power operation) with respect to the pump applications. High efficiency reduces the costs for mounting and cooling and high brilliance increases the coupling efficiency. Both are carefully adjusted in the 9xx nm - high power diode laser bars for pump applications in disc- and fiber lasers. Based on low loss waveguide structures high brilliance bars with 19° fast axis beam divergence (FWHM) with 58 % maximum efficiency and 27° fast axis beam divergence (FWHM) with 62 % maximum efficiency are developed. Mounted on conductive cooled heat sinks high power operation with lifetime > 20.000 hours at 120 W output power level (50 % filling factor bars) and 80W (20 % filling factor bars) is demonstrated. 808nm bars used as pump sources for Nd:YAG solid state lasers are still dominating in the market. With respect to the demands on high reliability at high power operation current results of a 100 W high power life time test are showing more than 9000 hour operation time for passively cooled packaged high efficiency 50 % filling factor bars. Measurement of the COMD-level after this hard pulse life time test demonstrates very high power levels with no significant droop in COMD-power level. This confirms the high facet stability of JDL's facet technology. New high power diode laser bars with wavelength of 825 nm and 885 nm are still under development and first results are presented.

  20. Efficiencies of photovoltaic cell receivers for laser power transmission under the lunar environment

    SciTech Connect

    Yugami, H.; Naito, H.; Itagaki, H.

    1998-07-01

    Major space activities in the next century will substantially increase the demand for power. The system of powering a very diverse set of remote missions will be an important infrastructure in space. Especially, the nighttime power supply to a space base placed on the Moon is a central problem in the development and utilization of the Moon, because the period of the nighttime on the Moon corresponds to 15 Earth-days. Photovoltaic cells could potentially be used as power receivers for several lasers at visible and near infrared regions. Several paper studies on the solar-cell response to laser illumination are available. However, the efficiency and response of cells would be quite different if these were used on the nighttime Moon surface since the temperature of lunar environment drops very low during the nighttime (about {minus}170 C). A feasibility of a laser energy transmission concept for a first stage lunar mission on 2005--2015 has been studied by NASDA. The lunar energy system consists of a small battery and a receiver (solar cell panel) on the lunar surface and a laser power transmission satellite on the moon orbit. In order to study the plausible lunar laser energy transmission system based on the state of the art of lasers and PV cell technologies, the authors report the cell efficiencies illuminated with several kinds of CW and pulsed lasers under the temperature range from {minus}190 C to 60 C. Solar cells of c-Si, GaAs for space use, CuInSe{sub 2} and infrared enhanced c-Si photodiode have been tested by changing the laser power from 3mW/cm{sup 2} to 1000mW/cm{sup 2}. The authors observed that the temperature dependence of the efficiency for YAG fundamental laser light is quite different from that for LD and Ar ion laser. In the latter cases, the efficiency increases with decreasing temperature. This is the general feature for the efficiency of conventional solar cells. In contrast with those, the PV cell efficiency under YAG fundamental light

  1. High-power passive-cooled diode laser device

    NASA Astrophysics Data System (ADS)

    Bonati, Guido F.; Hennig, Petra; Rollig, Ullrich; Lorenzen, Dirk

    2003-06-01

    In order to achieve a thermally stable diode laser system based on high power diode laser bars, actively cooled heatsinks in form of micro channel heat sinks (MCHS) are used to face the power loss density of 106 W/m2 while requiring a minimum device volume. At identical junction temperature, passively cooled diode lasers are usually lower in power and the device volume is much higher due to the heat flux spreading design of passive heatsinks. However, as a matter of principle, the cooling with MCHS sinks requires a sealing between the heat sink itself and the system around. This sealing is usually achieved by o-rings, what can never avoid the transfer of vapor from the cooling system into the vicinity of the diode laser. Extreme requirements on availability, which lead to corresponding lifetime requirements, like in telecom applications, already require passively cooled diode lasers without any water in the inner system boundaries. For applications not requiring the extreme compact design volume of actively cooled diode lasers but requiring extreme lifetime or a minimum outlay on the periphery, we started looking into passively cooled diode laser stacks. To achieve a minimized temperature rise in the junction, we already developed a new copper-based heat sink, spreading the power loss in an optimized manner. Based on this heatsink, we started developing a heat exchanger with a low thermal resistance while keeping the water out of the inner system boundaries. The thermal resistance is low enough to run up to 12 passively cooled diode lasers on a low ambient temperature with a minimum of periphery requirements.

  2. 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.

  3. Enhanced fiber coupled laser power and brightness for defense applications through tailored diode and thermal design

    NASA Astrophysics Data System (ADS)

    Patterson, Steve; Koenning, Tobias; Köhler, Bernd; Ahlert, Sandra; Bayer, Andreas; Kissel, Heiko; Müntz, Holger; Noeske, Axel; Rotter, Karsten; Segref, Armin; Stoiber, Michael; Unger, Andreas; Wolf, Paul; Biesenbach, Jens

    2012-06-01

    Advances in both diode laser design and packaging technology, particularly thermal management, are needed to enhance the brightness of fiber coupled diode lasers while maintaining the small size and light weight required for defense applications. The principles of design for high efficiency fiber coupling are briefly covered. Examples are provided of fielded and demonstrated 100 and 200 micron diameter fiber coupled packages ranging in output from a few hundred to kW-class units in fibers, to include sub-kg/kW capabilities. The demand for high-power and high-brightness fiber coupled diode laser devices is mainly driven by applications for solid-state and fiber laser pumping. The ongoing power scaling of fiber lasers requires scalable fiber-coupled diode laser devices with increased power and brightness. A modular diode laser concept combining high power, high brightness, wavelength stabilization and low weight, which is considerable concern in the SWaP trades needed to field defense systems, has been developed. In particular the defense technology requires robust but lightweight high-power diode laser sources in combination with high brightness. The heart of the concept is a specially tailored diode laser bar, with the epitaxial and lateral structures 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. This paper presents 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 800W coupled into a 400 μm NA 0.22 fiber. In addition we present a lightweight laser unit with an output

  4. 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.

  5. Low power cw-laser signatures on human skin

    SciTech Connect

    Lihachev, A; Lesinsh, J; Jakovels, D; Spigulis, J

    2011-01-24

    Impact of cw laser radiation on autofluorescence features of human skin is studied. Two methods of autofluorescence detection are applied: the spectral method with the use of a fibreoptic probe and spectrometer for determining the autofluorescence recovery kinetics at a fixed skin area of {approx}12 mm{sup 2}, and the multispectral visualisation method with the use of a multispectral imaging camera for visualising long-term autofluorescence changes in a skin area of {approx}4 cm{sup 2}. The autofluorescence recovery kinetics after preliminary laser irradiation is determined. Skin autofluorescence images with visible long-term changes - 'signatures' of low power laser treatment are acquired. (application of lasers and laser-optical methods in life sciences)

  6. 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.

  7. 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.

  8. Performance characteristics and output power stability of a multichannel fibre laser

    NASA Astrophysics Data System (ADS)

    Kuzmenkov, A. I.; Lukinykh, S. N.; Nanii, O. E.; Odintsov, A. I.; Smirnov, A. P.; Fedoseev, A. I.; Treshchikov, V. N.

    2016-09-01

    The effect of the density and number of spectral channels on the output power stability in a multichannel cw laser has been studied theoretically and experimentally. In our calculations, we used a model in which the interaction between channels due to gain medium saturation was determined by channel frequency spacingdependent cross-saturation coefficients. The key features of lasing have been analysed and illustrated by the examples of three-, fiveand nine-channel lasers. It has been shown that, at a given excess of the pump power over threshold, the channel powers can be equalised by introducing additional losses into the highest power channels. At a sufficiently high channel density, raising the pump power then leads to termination of lasing in the even channels. As the number of channels increases, the laser system retains its stability, but the time needed for the transition to a steady state increases sharply. In our experiments, we used an erbium-doped fibre laser whose design ensured independent control over the powers of up to 40 spectral channels anchored on the telecommunication frequency grid. Our experimental data are in qualitative agreement with the calculation results. In particular, a long-term relative instability less than 3 dB was only observed at a number of channels less than seven and channel frequency spacings above 400 GHz. Instability was shown to increase with an increase in the number and density of channels.

  9. 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.

  10. 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.

  11. Indium phosphide solar cells for laser power beaming applications

    NASA Technical Reports Server (NTRS)

    Jain, Raj K.; Landis, Geoffrey A.

    1992-01-01

    Lasers can be used to transmit power to photovoltaic cells. Solar cell efficiencies are enhanced significantly under monochromatic light, and therefore a laser beam of proper wavelength could be a very effective source of illumination for a solar array operating at very high efficiencies. This work reviews the modeling studies made on indium phosphide solar cells for such an application. These cells are known to be very radiation resistant and have a potential for high efficiency. Effects of cell series resistance, laser intensity, and temperature on cell performance have been discussed.

  12. Indium phosphide solar cells for laser power beaming applications

    NASA Technical Reports Server (NTRS)

    Jain, Raj K.; Landis, Geoffrey A.

    1992-01-01

    Lasers can be used to transmit power to photovoltaic cells. Solar cell efficiencies are enhanced significantly under monochromatic light, and therefore a laser beam of proper wavelength could be a very effective source of illumination for a solar array operating at very high efficiencies. This work reviews the modeling studies made on indium phosphide solar cells for such an application. These cells are known to be very radiation resistant and have a potential for high efficiency. Effects of cell series resistance, laser intensity, and temperature on cell performance have been discussed.

  13. Modeling of dynamic effects of a low power laser beam

    NASA Technical Reports Server (NTRS)

    Lawrence, George N.; Scholl, Marija S.; Khatib, AL

    1988-01-01

    Methods of modeling some of the dynamic effects involved in laser beam propagation through the atmosphere are addressed with emphasis on the development of simple but accurate models which are readily implemented in a physical optics code. A space relay system with a ground based laser facility is considered as an example. The modeling of such characteristic phenomena as laser output distribution, flat and curved mirrors, diffraction propagation, atmospheric effects (aberration and wind shear), adaptive mirrors, jitter, and time integration of power on target, is discussed.

  14. 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.``

  15. 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.

  16. 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

  17. 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.

  18. Effects of laser power density on static and dynamic mechanical properties of dissimilar stainless steel welded joints

    NASA Astrophysics Data System (ADS)

    Wei, Yan-Peng; Li, Mao-Hui; Yu, Gang; Wu, Xian-Qian; Huang, Chen-Guang; Duan, Zhu-Ping

    2012-10-01

    The mechanical properties of laser welded joints under impact loadings such as explosion and car crash etc. are critical for the engineering designs. The hardness, static and dynamic mechanical properties of AISI304 and AISI316 L dissimilar stainless steel welded joints by CO2 laser were experimentally studied. The dynamic strain-stress curves at the strain rate around 103 s-1 were obtained by the split Hopkinson tensile bar (SHTB). The static mechanical properties of the welded joints have little changes with the laser power density and all fracture occurs at 316 L side. However, the strain rate sensitivity has a strong dependence on laser power density. The value of strain rate factor decreases with the increase of laser power density. The welded joint which may be applied for the impact loading can be obtained by reducing the laser power density in the case of welding quality assurance.

  19. 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.

  20. 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

  1. Power scaling of ultrafast laser inscribed waveguide lasers in chromium and iron doped zinc selenide.

    PubMed

    McDaniel, Sean A; Lancaster, Adam; Evans, Jonathan W; Kar, Ajoy K; Cook, Gary

    2016-02-22

    We report demonstration of Watt level waveguide lasers fabricated using Ultrafast Laser Inscription (ULI). The waveguides were fabricated in bulk chromium and iron doped zinc selenide crystals with a chirped pulse Yb fiber laser. The depressed cladding structure in Fe:ZnSe produced output powers of 1 W with a threshold of 50 mW and a slope efficiency of 58%, while a similar structure produced 5.1 W of output in Cr:ZnSe with a laser threshold of 350 mW and a slope efficiency of 41%. These results represent the current state-of-the-art for ULI waveguides in zinc based chalcogenides.

  2. Comparison Between NIST and AF Laser Energy Standards Using High Power Lasers.

    PubMed

    Li, Xiaoyu; Scott Retired, Thomas; Cromer, Chris; Cooper, David; Comisford, Steven

    2007-01-01

    We report the results of a high-energy laser calorimeter comparison conducted by the National Institute of Standards and Technology (NIST), Boulder, Colorado and the U.S. Air Force Primary Standards laboratory (AFPSL), Heath, Ohio. A laser power meter, used as a transfer standard, was calibrated at each laboratory, sequentially, and the measurement results were compared. These measurements were performed at a nominal power of 800 W and a wavelength of 10.6 μm using CO2 lasers. Excellent measurement agreement (1.02 %) was demonstrated, which was well within each of the expanded uncertainties from the two laboratories involved in this comparison.

  3. Combinatorial pulse position modulation for power-efficient free-space laser communications

    NASA Technical Reports Server (NTRS)

    Budinger, James M.; Vanderaar, M.; Wagner, P.; Bibyk, Steven

    1993-01-01

    A new modulation technique called combinatorial pulse position modulation (CPPM) is presented as a power-efficient alternative to quaternary pulse position modulation (QPPM) for direct-detection, free-space laser communications. The special case of 16C4PPM is compared to QPPM in terms of data throughput and bit error rate (BER) performance for similar laser power and pulse duty cycle requirements. The increased throughput from CPPM enables the use of forward error corrective (FEC) encoding for a net decrease in the amount of laser power required for a given data throughput compared to uncoded QPPM. A specific, practical case of coded CPPM is shown to reduce the amount of power required to transmit and receive a given data sequence by at least 4.7 dB. Hardware techniques for maximum likelihood detection and symbol timing recovery are presented.

  4. 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.

  5. 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.

  6. 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.

  7. Fission-activated laser as primary power for CW laser propulsion

    NASA Astrophysics Data System (ADS)

    Monroe, David K.

    1994-05-01

    Recent advances in the development of reactor-pumped lasers (RPLs) have stimulated renewed interest in the concept of laser-powered propulsion. This paper surveys a number of laser propulsion concepts and identifies the one that is most promising from the standpoint of practicality. It is proposed that a ground-based FALCON (fission-activated laser concept) RPL can provide primary power for this launch vehicle design. The laser-vehicle system could launch small payloads into low-earth orbit (LEO) with high repetition rates and at low costs per kilogram. For the favored design, thruster efficiencies are currently estimated to be about 50%, with 80% being seen as a potentially reliable goal after further design refinements. Laser launch system simulations indicate that, with a buy-in laser power of 10 MW, it will be possible to obtain specific impulses in the range of 600 to 800 seconds and payload-to-power ratios of 1 to 3 kg/MW.

  8. 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.

  9. Process optimization in high-average-power ultrashort pulse laser microfabrication: how laser process parameters influence efficiency, throughput and quality

    NASA Astrophysics Data System (ADS)

    Schille, Joerg; Schneider, Lutz; Loeschner, Udo

    2015-09-01

    In this paper, laser processing of technical grade stainless steel and copper using high-average-power ultrashort pulse lasers is studied in order to gain deeper insight into material removal for microfabrication. A high-pulse repetition frequency picosecond and femtosecond laser is used in conjunction with high-performance galvanometer scanners and an in-house developed two-axis polygon scanner system. By varying the processing parameters such as wavelength, pulse length, fluence and repetition rate, cavities of standardized geometry are fabricated and analyzed. From the depths of the cavities produced, the ablation rate and removal efficiency are estimated. In addition, the quality of the cavities is evaluated by means of scanning electron microscope micrographs or rather surface roughness measurements. From the results obtained, the influence of the machining parameters on material removal and machining quality is discussed. In addition, it is shown that both material removal rate and quality increase by using femtosecond compared to picosecond laser pulses. On stainless steel, a maximum throughput of 6.81 mm3/min is achieved with 32 W femtosecond laser powers; if using 187 W picosecond laser powers, the maximum is 15.04 mm3/min, respectively. On copper, the maximum throughputs are 6.1 mm3/min and 21.4 mm3/min, obtained with 32 W femtosecond and 187 W picosecond laser powers. The findings indicate that ultrashort pulses in the mid-fluence regime yield most efficient material removal. In conclusion, from the results of this analysis, a range of optimum processing parameters are derived feasible to enhance machining efficiency, throughput and quality in high-rate micromachining. The work carried out here clearly opens the way to significant industrial applications.

  10. Temperature Model of a New High-powered SrBr{sub 2} Laser

    SciTech Connect

    Iliev, I. P.; Gocheva-Ilieva, S. G.; Temelkov, K. A.; Vuchkov, N. K.; Sabotinov, N. V.

    2010-11-25

    The radial temperature in the cross-section of a strontium copper bromide vapor laser is studied on the basis of a previously constructed mathematical model. The model has been expanded so as to allow for changes to the structural elements of the tube, in order to develop a new laser with an increased power output. The limits of the maximum allowed operating temperature of the gas have been established. The numerical results of the simulations have been presented.

  11. Novel Approach to Increase the Energy-related Process Efficiency and Performance of Laser Brazing

    NASA Astrophysics Data System (ADS)

    Mittelstädt, C.; Seefeld, T.; Radel, T.; Vollertsen, F.

    Although laser brazing is well established, the energy-related efficiency of this joining method is quite low. That is because of low absorptivity of solid-state laser radiation, especially when copper base braze metals are used. Conventionally the laser beam is set close to the vertical axis and the filler wire is delivered under a flat angle. Therefore, the most of the utilized laser power is reflected and thus left unexploited. To address this situation an alternative processing concept for laser brazing, where the laser beam is leading the filler wire, has been investigated intending to make use of reflected shares of the laser radiation. Process monitoring shows, that the reflection of the laser beam can be used purposefully to preheat the substrate which is supporting the wetting and furthermore increasing the efficiency of the process. Experiments address a standard application from the automotive industry joining zinc coated steels using CuSi3Mn1 filler wire. Feasibility of the alternative processing concept is demonstrated, showing that higher processing speeds can be attained, reducing the required energy per unit length while maintaining joint properties.

  12. 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.

  13. Advances in tunable powerful lasers: The advanced free-electron laser

    SciTech Connect

    Singer, S.; Sheffield, R.

    1993-12-31

    In the past several decades, remarkable progress in laser science and technology has made it possible to obtain laser light from the ultra-violet to the far infra-red from a variety of laser types, and at power levels from milliwatts to kilowatts (and, some day, megawatts). However, the availability of tunable lasers at ``high`` power (above a few tens of watts) is more limited. Figure 1, an assessment of the availability of tunable lasers, shows the covered range to be about 400 to 2000 nanometers. A variety of dye lasers cover the visible and near infra red, each one of which is tunable over approximately a 10% range. In the same region, the TI:saphire laser is adjustable over a 20 to 25% range. And finally, optical parametric oscillators can cover the range from about 400 nanometers out to about 2000 nm (even farther at reduced energy output). The typical output energy per pulse may vary from a few to one hundred millijoules, and since repetition rates of 10 to 100 Hertz are generally attainable, average output powers of tens of watts are possible. In recent years, a new approach to powerful tunable lasers -- the Free-Electron Laser (FEL) -- has emerged. In this paper we will discuss advances in FEL technology which not only enable tunability at high average power over a very broad range of wavelengths, but also make this device more usable. At present, that range is about one micron to the far infra red; with extensions of existing technology, it should be extendable to the vacuum ultra violet region.

  14. 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.

  15. A new proposal of high repetitive Nd:YAG laser power supply adopted the sequential charge and discharge circuit.

    NASA Astrophysics Data System (ADS)

    Hong, Jung-Hwan; Park, Koo-Ryul; Kim, Byung-Gyun; Kim, Whi-Young; Lee, Dong-Hoon; Kim, Hee-Je; Kang, Uk

    1999-12-01

    The pulsed Nd:YAG laser is the most commonly used type of solid-state laser in many fields. In material processing, the power density control of a laser beam has been considered to be significant, which depends on the flashlamp current pulse width and pulse repetition rate. In this study, we have proposed a new method of sequential charge and discharge circuit (SCADC) to control the laser power density. The power supply of SCADC is composed of low frequency capacitors instead of very expensive high frequency capacitors. We could find the stability of laser output as well as the flashlamp current up to the pulse repetition rate of 150 pps. As increasing a repetition rate from 30 to 150 pps by the step of 30 pps, it is known that the laser outputs increased by 10 W.

  16. 124. TV MESSAGE FROM WHITE HOUSE AUTHORIZING LWBR POWER INCREASE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    124. TV MESSAGE FROM WHITE HOUSE AUTHORIZING LWBR POWER INCREASE TO 100%, DECEMBER 2, 1977 - Shippingport Atomic Power Station, On Ohio River, 25 miles Northwest of Pittsburgh, Shippingport, Beaver County, PA

  17. 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.

  18. 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.

  19. 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.

  20. High power lasers for gamma source

    NASA Astrophysics Data System (ADS)

    Durand, Magali; Sangla, Damien; Trophème, Benoit; Sevillano, Pierre; Casanova, Alexis; Caillon, Laurianne; Courjaud, Antoine

    2017-02-01

    A high intensity Gamma source is required for Nuclear Spectroscopy, it will be delivered by the interaction between accelerated electron and intense laser beams. Those two interactions lasers are based on a multi-stage amplification scheme that ended with a second harmonics generation to deliver 200 mJ, 3.5 ps pulses at 515 nm and 100 Hz. A t-Pulse oscillator with slow and fast feedback loop implemented inside the oscillator cavity allows the possibility of synchronization to an optical reference. A temporal jitter of 120 fs rms is achieved, integrated from 10 Hz to 10 MHz. Then a regenerative amplifier, based on Yb:YAG technology, pumped by fiber-coupled QCW laser diodes, delivers pulses up to 30 mJ. The 1 nm bandwidth was compressed to 1.5 ps with a good spatial quality: M2 of 1.1. This amplifier is integrated in a compact sealed housing (750x500x150 cm), which allows a pulse-pulse stability of 0.1% rms, and a long-term stability of 1,9% over 100 hours (with +/-1°C environment). The main amplification stage uses a cryocooled Yb:YAG crystal in an active mirror configuration. The crystal is cooled at 130 K via a compact and low-vibration cryocooler, avoiding any additional phase noise contribution, 340 mJ in a six pass scheme was achieved, with 0.9 of Strehl ratio. The trade off to the gain of a cryogenic amplifier is the bandwidth reduction, however the 1030 nm pulse was compressed to 3.5 ps.

  1. 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

  2. Laser Drilling - Drilling with the Power of Light

    SciTech Connect

    Iraj A. Salehi; Brian C. Gahan; Samih Batarseh

    2007-02-28

    Gas Technology Institute (GTI) has been the leading investigator in the field of high power laser applications research for well construction and completion applications. Since 1997, GTI (then as Gas Research Institute- GRI) has investigated several military and industrial laser systems and their ability to cut and drill into reservoir type rocks. In this report, GTI continues its investigation with a 5.34 kW ytterbium-doped multi-clad high power fiber laser (HPFL). When compared to its competitors; the HPFL represents a technology that is more cost effective to operate, capable of remote operations, and requires considerably less maintenance and repair. Work performed under this contract included design and implementation of laboratory experiments to investigate the effects of high power laser energy on a variety of rock types. All previous laser/rock interaction tests were performed on samples in the lab at atmospheric pressure. To determine the effect of downhole pressure conditions, a sophisticated tri-axial cell was designed and tested. For the first time, Berea sandstone, limestone and clad core samples were lased under various combinations of confining, axial and pore pressures. Composite core samples consisted of steel cemented to rock in an effort to represent material penetrated in a cased hole. The results of this experiment will assist in the development of a downhole laser perforation or side tracking prototype tool. To determine how this promising laser would perform under high pressure in-situ conditions, GTI performed a number of experiments with results directly comparable to previous data. Experiments were designed to investigate the effect of laser input parameters on representative reservoir rock types of sandstone and limestone. The focus of the experiments was on laser/rock interaction under confining pressure as would be the case for all drilling and completion operations. As such, the results would be applicable to drilling, perforation, and

  3. Temperature dependence of optically dumped far-infrared (FIR) laser output power

    NASA Technical Reports Server (NTRS)

    Lawandy, N. M.

    1978-01-01

    The temperature dependence of the small signal gain and saturation power are derived using temperature-dependent rates in a four-level model. An expression is developed for the output power of a far-infrared oscillator as a function of temperature for both fixed pressure and fixed density. The results are valid in the regime of homogeneous broadening of the rotational transition and Doppler broadening of the pump transition. It is shown that, for most lasers, both the small signal gain and the saturation power decrease with increasing temperature. These effects have the overall result of increasing output power with decreasing temperatures.

  4. Acousto-optical imaging using a powerful long pulse laser

    NASA Astrophysics Data System (ADS)

    Rousseau, Guy; Blouin, Alain; Monchalin, Jean-Pierre

    2008-06-01

    Acousto-optical imaging is an emerging biodiagnostic technique which provides an optical spectroscopic signature and a spatial localization of an optically absorbing target embedded in a strongly scattering medium. The transverse resolution of the technique is determined by the lateral extent of ultrasound beam focal zone while the axial resolution is obtained by using short ultrasound pulses. Although very promising for medical diagnostic, the practical application of this technique is presently limited by its poor sensitivity. Moreover, any method to enhance the signal-to-noise ratio must obviously satisfy the in vivo safety limits regarding the acceptable power level of both the ultrasonic pressure wave and the laser beam. In this paper, we propose to improve the sensitivity by using a pulsed single-frequency laser source to raise the optical peak power applied to the scattering medium and to collect more ultrasonically tagged photons. Such a laser source also allows illuminating the tissues mainly during the transit time of the ultrasonic wave to maintain the average optical power below the maximum permissible exposure. In our experiment, a single-frequency Nd:YAG laser emitting 500-μs pulses with a peak power superior to 100 W was used. Photons were tagged in few-cm thick optical phantoms with tone bursts generated by an ultrasonic transducer. Tagged photons were detected with a GaAs photorefractive interferometer characterized by a large optical etendue to process simultaneously a large number of speckle grains. When pumped by high intensity laser pulses, such an interferometer also provides the fast response time essential to obtain an apparatus insensitive to the speckle decorrelation due to mechanical vibrations or tissues movements. The use of a powerful long pulse laser appears promising to enhance the signal level in ultrasound modulated optical imaging. When combined with a photorefractive interferometer of large optical etendue, such a source could

  5. 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.

  6. 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.

  7. 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

  8. Optimization of microchannel cooler of high power diode laser array package

    NASA Astrophysics Data System (ADS)

    Wu, Dihai; Zhang, Pu; Nie, Zhiqiang; Liang, Xuejie; Wang, Jingwei; Liu, Xingsheng

    2017-02-01

    High power diode laser arrays have found increasing applications in the field of pumping solid-state lasers and fiber lasers. Due to the thermal crosstalk across diode laser arrays and non-uniformity of local flow rate within microchannel cooler, junction temperature distribution becomes inhomogeneous, consequently leading to spectrum broadening and large beam divergence of diode laser pumping sources. In this work, an analytical method and numerical heat transfer based on finite volume method were employed to optimize the inner structure of microchannel cooler so as to obtain low thermal resistance and uniform junction temperature distribution for the diode laser arrays. Three-dimensional numerical models were developed to study the fluid flow and heat transfer of copper stacked microchannel coolers with different dimensions and arrangements of inner channels and fins. More uniform junction temperature distribution of diode laser array package could be achieved by self-heating compensation with specific coolant covering width. These results could provide significant guidance for the design of microchannel coolers of high power diode laser arrays for better performance.

  9. 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.

  10. Human teeth exposed to argon laser irradiation: determination of power-time-temperature working conditions.

    PubMed

    Kurachi, C; Eduardo, C P; Magalhães, D V; Bagnato, V S

    1999-12-01

    This study was conducted to establish the operating parameters of the argon laser without thermal damage to the pulp tissue for clinical applications. Previous studies have mainly compared the temperature modifications of the pulp chamber in a very limited situation, where a complete view of the thermal history cannot be obtained nor even extrapolated to new applications. We used samples of molar and premolar tooth where a class V cavity was prepared and illuminated with an argon laser at different power levels, fixing the exposition area for all cases. Situations including open cavity and teeth restoration were analyzed. High-precision thermistors were placed in four different positions, one of which was inside the pulp chamber. The temperature evolution was monitored continuously by an interfaced computer during all laser exposure. Special attention was paid to the intrapulpal temperature variation because it is considered the most vulnerable thermal region. The temperature time evolution allowed the determination of the operating conditions (power-time-temperature variation) in which the use of the argon laser causes no pulpal damage. As a function of temperature variation, we divided the whole parameter space (power-time-temperature) into zones and the optimum zone of operation was determined. We created a diagram called power-time-temperature (PTT) where zones of temperature increased under laser irradiation allow the verification of which condition is safe for clinical laser application. The results have a broad use when this type of analysis is applicable.

  11. Lithium neodymium tetraphosphate lasers pumped via close-coupling to high-power laser diode arrays

    SciTech Connect

    Dixon, G.J.; Lingvay, L.S.; Jarman, R.H.

    1989-05-01

    The authors report what they believe to be the first demonstration of a LiNdP/sub 4/O/sub 12/ solid-state laser in which the active medium was close-coupled to the pump diode. With a pump power of approximately 250 mW, a TEM/sub 00/, multilongitudinal mode output power of 73 mW has been obtained from an external mirror device operating simultaneously on the two lines at 1047 and 1055 nm. Devices operating at 1317 nm have also been studied and a close-coupled, monolithic laser with an output power in excess of 28 mW has been demonstrated.

  12. LDRD final report on high power broadly tunable Mid-IR quantum cascade lasers for improved chemical species detection.

    SciTech Connect

    Wanke, Michael Clement; Hudgens, James J.; Fuller, Charles T.; Samora, Sally; Klem, John Frederick; Young, Erik W.

    2006-01-01

    The goal of our project was to examine a novel quantum cascade laser design that should inherently increase the output power of the laser while simultaneously providing a broad tuning range. Such a laser source enables multiple chemical species identification with a single laser and/or very broad frequency coverage with a small number of different lasers, thus reducing the size and cost of laser based chemical detection systems. In our design concept, the discrete states in quantum cascade lasers are replaced by minibands made of multiple closely spaced electron levels. To facilitate the arduous task of designing miniband-to-miniband quantum cascade lasers, we developed a program that works in conjunction with our existing modeling software to completely automate the design process. Laser designs were grown, characterized, and iterated. The details of the automated design program and the measurement results are summarized in this report.

  13. 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.

  14. 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.

  15. Recent brightness improvements of 976 nm high power laser bars

    NASA Astrophysics Data System (ADS)

    Bachmann, Alexander; Lauer, Christian; Furitsch, Michael; König, Harald; Müller, Martin; Strauß, Uwe

    2017-02-01

    Pump modules for fiber lasers and fiber-coupled direct diode laser systems require laser diodes with a high beam quality. While in fast axis direction diode lasers exhibit a nearly diffraction limited output beam, the maximum usable output power is usually limited by the slow axis divergence blooming at high power levels. Measures to improve the lateral beam quality are subject of extensive research. Among the many influencing factors are the chip temperature, thermal crosstalk between emitters, thermal lensing, lateral waveguiding and lateral mode structure. We present results on the improvements of the lateral beam divergence and brightness of gain-guided mini-bars for emission at 976 nm. For efficient fiber coupling into a 200 μm fiber with NA 0.22, the upper limit of the lateral beam parameter product is 15.5 mm mrad. Within the last years, the power level at this beam quality has been improved from 44 W to 52 W for the chips in production, enabling more cost efficient pump modules and laser systems. Our work towards further improvements of the beam quality focuses on advanced chip designs featuring reduced thermal lensing and mode shaping. Recent R&D results will be presented, showing a further improvement of the beam quality by 15%. Also, results of a chip design with an improved lateral emitter design for highest brightness levels will be shown, yielding in a record high brightness saturation of 4.8 W/mm mrad.

  16. 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.

  17. Power optimization of random distributed feedback fiber lasers.

    PubMed

    Vatnik, Ilya D; Churkin, Dmitry V; Babin, Sergey A

    2012-12-17

    We present a comprehensive study of power output characteristics of random distributed feedback Raman fiber lasers. The calculated optimal slope efficiency of the backward wave generation in the one-arm configuration is shown to be as high as ~90% for 1 W threshold. Nevertheless, in real applications a presence of a small reflection at fiber ends can appreciably deteriorate the power performance. The developed numerical model well describes the experimental data.

  18. Fission-activated laser as primary power for CW laser propulsion

    SciTech Connect

    Monroe, D.K.

    1993-12-31

    Recent advances in the development of reactor-pumped lasers (RPL`s) have stimulated renewed interest in the concept of laser-powered propulsion. This paper surveys a number of laser propulsion concepts and identifies the one that is most promising from the standpoint of practicality. It is proposed that a ground-based FALCON (Fission-Activated Laser CONcept) RPL can provide primary for this launch vehicle design. The laser-vehicle system could launch small payloads into low-earth orbit (LEO) with high repetition rates and at low costs per kilogram. For the favored design, thruster efficiencies are currently estimated to be about 50%, with 80% being seen as a potentially realizable goal after further design refinements. Laser launch system simulations indicate that with a buy-in laser power of 10 MW, it will be possible to obtain specific impulses in the range of 600 to 800 seconds and payload-to-power ratios of 1 to 3 kg/MW.

  19. 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.

  20. 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.

  1. Power enhancement of a Rubidium vapor laser with a master oscillator power amplifier.

    PubMed

    Hostutler, David A; Klennert, Wade L

    2008-05-26

    A master oscillator power amplifier (MOPA) with variable amplifier gain lengths was built to demonstrate power enhancement of an alkali vapor laser. A small signal gain of 0.91 / cm for two different gain lengths was observed. For a 2 cm long amplifier gain length an amplification of 7.9 dB was observed.

  2. Characterizing the Effect of Laser Power on Laser Metal Deposited Titanium Alloy and Boron Carbide

    NASA Astrophysics Data System (ADS)

    Akinlabi, E. T.; Erinosho, M. F.

    2017-09-01

    Titanium alloy has gained acceptance in the aerospace, marine, chemical, and other related industries due to its excellent combination of mechanical and corrosion properties. In order to augment its properties, a hard ceramic, boron carbide has been laser cladded with it at varying laser powers between 0.8 and 2.4 kW. This paper presents the effect of laser power on the laser deposited Ti6Al4V-B4C composites through the evolving microstructures and microhardness. The microstructures of the composites exhibit the formation of α-Ti phase and β-Ti phase and were elongated towards the heat affected zone. These phases were terminated at the fusion zone and globular microstructures were found growing epitaxially just immediately after the fusion zone. Good bondings were formed in all the deposited composites. Sample A1 deposited at a laser power of 0.8 kW and scanning speed of 1 m/min exhibits the highest hardness of HV 432 ± 27, while sample A4 deposited at a laser power of 2.0 kW and scanning speed of 1 m/min displays the lowest hardness of HV 360 ± 18. From the hardness results obtained, ceramic B4C has improved the mechanical properties of the primary alloy.

  3. Development of high-power copper vapor laser system

    NASA Astrophysics Data System (ADS)

    Kimura, Hironobu; Aoki, Nobutada; Kobayashi, Noriyasu; Konagai, Chikara; Seki, Eiji; Abe, Motohisa; Mori, Hideo

    2000-01-01

    A high power copper vapor laser (CVL) system in master oscillator power amplifier configuration has been developed for laser isotope separation program in Japan. Maximum output power of 650 W has been successfully achieved with 9- cm diameter and 350 cm discharge length amplifier. Also MOPA output power of 2.4 kW has been demonstrated in small master oscillator with 4 cm bore and 4 stage power amplifier with 9 cm bore configuration. The authors developed a thermal calculation code to maintain an optimum copper vapor density throughout a large volume and a new thermal insulation structure design method has been proposed to combine two different heat insulators to make longitudinal temperature distribution of the laser tube as flat as possible. A CVL discharge circuit has been improved by applying an excellent magnetic switch which prove a approximately 90 kV-4000 A pulse to a CVL at 4.4 kHz repetition rate. This paper reports such CVL design methods together with the performance of the designed high power CVL system.

  4. 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.

  5. Micro-ablation with high power pulsed copper vapor lasers.

    PubMed

    Knowles, M

    2000-07-17

    Visible and UV lasers with nanosecond pulse durations, diffraction-limited beam quality and high pulse repetition rates have demonstrated micro-ablation in a wide variety of materials with sub-micron precision and sub-micron-sized heat-affected zones. The copper vapour laser (CVL) is one of the important industrial lasers for micro-ablation applications. Manufacturing applications for the CVL include orifice drilling in fuel injection components and inkjet printers, micro-milling of micromoulds, via hole drilling in printed circuit boards and silicon machining. Recent advances in higher power (100W visible, 5W UV), diffraction-limited, compact CVLs are opening new possibilities for manufacturing with this class of nanosecond laser.

  6. Laser-powered MHD generators for space application

    NASA Technical Reports Server (NTRS)

    Jalufka, N. W.

    1986-01-01

    Magnetohydrodynamic (MHD) energy conversion systems of the pulsed laser-supported detonation (LSD) wave, plasma MHD, and liquid-metal MHD (LMMHD) types are assessed for their potential as space-based laser-to-electrical power converters. These systems offer several advantages as energy converters relative to the present chemical, nuclear, and solar devices, including high conversion efficiency, simple design, high-temperature operation, high power density, and high reliability. Of these systems, the Brayton cycle liquid-metal MHD system appears to be the most attractive. The LMMHD technology base is well established for terrestrial applications, particularly with regard to the generator, mixer, and other system components. However, further research is required to extend this technology base to space applications and to establish the technology required to couple the laser energy into the system most efficiently. Continued research on each of the three system types is recommended.

  7. Microchannel heatsinks for high average power laser diode arrays

    SciTech Connect

    Beach, R.; Benett, B.; Freitas, B.; Ciarlo, D.; Sperry, V.; Comaskey, B.; Emanuel, M.; Solarz, R.; Mundinger, D.

    1992-01-01

    Detailed performance results and fabrication techniques for an efficient and low thermal impedance laser diode array heatsink are presented. High duty factor or even CW operation of fully filled laser diode arrays is enabled at high average power. Low thermal impedance is achieved using a liquid coolant and laminar flow through microchannels. The microchannels are fabricated in silicon using a photolithographic pattern definition procedure followed by anisotropic chemical etching. A modular rack-and-stack architecture is adopted for the heatsink design allowing arbitrarily large two-dimensional arrays to be fabricated and easily maintained. The excellent thermal control of the microchannel cooled heatsinks is ideally suited to pump array requirements for high average power crystalline lasers because of the stringent temperature demands that result from coupling the diode light to several nanometers wide absorption features characteristic of leasing ions in crystals.

  8. Microchannel cooled heatsinks for high average power laser diode arrays

    SciTech Connect

    Bennett, W.J.; Freitas, B.L.; Ciarlo, D.; Beach, R.; Sutton, S.; Emanuel, M.; Solarz, R.

    1993-01-15

    Detailed performance results for an efficient and low impedance laser diode array heatsink are presented. High duty factor and even cw operation of fully filled laser diode arrays at high stacking densities are enabled at high average power. Low thermal impedance is achieved using a liquid coolant and laminar flow through microchannels. The microchannels are fabricated in silicon using an anisotropic chemical etching process. A modular rack-and-stack architecture is adopted for heatsink design, allowing arbitrarily large two-dimensional arrays to be fabricated and easily maintained. The excellent thermal control of the microchannel heatsinks is ideally suited to pump army requirements for high average power crystalline laser because of the stringent temperature demands are required to efficiently couple diode light to several-nanometer-wide absorption features characteristic of lasing ions in crystals.

  9. Recent Accomplishments in Laser-Photovoltaic Wireless Power Transmission

    NASA Technical Reports Server (NTRS)

    Fikes, John C.; Henley, Mark W.; Mankins, John C.; Howell, Joe T.; Fork, Richard L.; Cole, Spencer T.; Skinner, Mark

    2003-01-01

    Wireless power transmission can be accomplished over long distances using laser power sources and photovoltaic receivers. Recent research at AMOS has improved our understanding of the use of this technology for practical applications. Research by NASA, Boeing, the University of Alabama-Huntsville, the University of Colorado, Harvey Mudd College, and the Naval Postgraduate School has tested various commercial lasers and photovoltaic receiver configurations. Lasers used in testing have included gaseous argon and krypton, solid-state diodes, and fiber optic sources, at wavelengths ranging from the visible to the near infra-red. A variety of Silicon and Gallium Arsenide photovoltaic have been tested with these sources. Safe operating procedures have been established, and initial tests have been conducted in the open air at AMOS facilities. This research is progressing toward longer distance ground demonstrations of the technology and practical near-term space demonstrations.

  10. 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.

  11. Materials processing with a high power diode laser

    SciTech Connect

    Li, L.; Lawrence, J.; Spencer, J.T.

    1996-12-31

    This paper reports on work exploring the feasibility of a range of materials processing applications using a Diomed 60W diode laser delivered through a 600{mu}m diameter optical fibre to a 3 axis CNC workstation. The applications studied include: marking/engraving natural stones (marble and granite), marking ceramic tiles, sealing tile grouts, cutting and marking glass, marking/engraving wood, stripping paint and lacquer, and welding metallic wires. The study shows that even at the present limited power level of diode lasers, many materials processing applications can be accomplished with satisfactory results. Through the study an initial understanding of interaction of high power diode laser (HPDL) beam with various materials has been gained. Also, within the paper basic beam characteristics, and current R&D activities in HPDL technology and materials processing applications are reviewed.

  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 efficiency solar cells for laser power beaming applications

    NASA Technical Reports Server (NTRS)

    Jain, Raj K.; Landis, G. A.

    1995-01-01

    Understanding solar cell response to pulsed laser outputs is important for the evaluation of power beaming applications. The time response of high efficiency GaAs and silicon solar cells to a 25 nS monochromatic pulse input is described. The PC-1D computer code is used to analyze the cell current during and after the pulse for various conditions.

  14. 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.

  15. Bright High Average Power Table-top Soft X-Ray Lasers

    SciTech Connect

    Rocca, Jorge; Reagan, Brendon; Wernsing, Keith; Luther, Brad; Curtis, Alden; Nichols,, Anthony; Wang, Yong; Alessi, David; Martz, Dale; Yin, Liang; Wang, Shoujun; Berrill, Mark A; Furch, Federico; Woolston, Mark; Patel, Dinesh; Marconi, Mario; Menoni, Carmen

    2012-01-01

    We have demonstrated the generation of bright soft x-ray laser pulses with record-high average power from compact plasma amplifiers excited by ultrafast solid state lasers. These lasers have numerous applications in nanoscience and nanotechnology.

  16. Power and death: Mortality salience increases power seeking while feeling powerful reduces death anxiety.

    PubMed

    Belmi, Peter; Pfeffer, Jeffrey

    2016-05-01

    According to Terror Management Theory, people respond to reminders of mortality by seeking psychological security and bolstering their self-esteem. Because previous research suggests that having power can provide individuals a sense of security and self-worth, we hypothesize that mortality salience leads to an increased motivation to acquire power, especially among men. Study 1 found that men (but not women) who wrote about their death reported more interest in acquiring power. Study 2A and Study 2B demonstrated that when primed with reminders of death, men (but not women) reported behaving more dominantly during the subsequent week, while both men and women reported behaving more prosocially during that week. Thus, mortality salience prompts people to respond in ways that help them manage their death anxiety but in ways consistent with normative gender expectations. Furthermore, Studies 3-5 showed that feeling powerful reduces anxiety when mortality is salient. Specifically, we found that when primed to feel more powerful, both men and women experienced less mortality anxiety. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  17. System-wide emissions implications of increased wind power penetration.

    PubMed

    Valentino, Lauren; Valenzuela, Viviana; Botterud, Audun; Zhou, Zhi; Conzelmann, Guenter

    2012-04-03

    This paper discusses the environmental effects of incorporating wind energy into the electric power system. We present a detailed emissions analysis based on comprehensive modeling of power system operations with unit commitment and economic dispatch for different wind penetration levels. First, by minimizing cost, the unit commitment model decides which thermal power plants will be utilized based on a wind power forecast, and then, the economic dispatch model dictates the level of production for each unit as a function of the realized wind power generation. Finally, knowing the power production from each power plant, the emissions are calculated. The emissions model incorporates the effects of both cycling and start-ups of thermal power plants in analyzing emissions from an electric power system with increasing levels of wind power. Our results for the power system in the state of Illinois show significant emissions effects from increased cycling and particularly start-ups of thermal power plants. However, we conclude that as the wind power penetration increases, pollutant emissions decrease overall due to the replacement of fossil fuels.

  18. System-wide emissions implications of increased wind power penetration.

    SciTech Connect

    Valentino, L.; Valenzuela, V.; Botterud, A.; Zhou, Z.; Conzelmann, G.

    2012-01-01

    This paper discusses the environmental effects of incorporating wind energy into the electric power system. We present a detailed emissions analysis based on comprehensive modeling of power system operations with unit commitment and economic dispatch for different wind penetration levels. First, by minimizing cost, the unit commitment model decides which thermal power plants will be utilized based on a wind power forecast, and then, the economic dispatch model dictates the level of production for each unit as a function of the realized wind power generation. Finally, knowing the power production from each power plant, the emissions are calculated. The emissions model incorporates the effects of both cycling and start-ups of thermal power plants in analyzing emissions from an electric power system with increasing levels of wind power. Our results for the power system in the state of Illinois show significant emissions effects from increased cycling and particularly start-ups of thermal power plants. However, we conclude that as the wind power penetration increases, pollutant emissions decrease overall due to the replacement of fossil fuels.

  19. 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

  20. 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.