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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. Techniques for increasing output power from mode-locked semiconductor lasers

    SciTech Connect

    Mar, A.; Vawter, G.A.

    1996-02-01

    Mode-locked semiconductor lasers have drawn considerable attention as compact, reliable, and relatively inexpensive sources of short optical pulses. Advances in the design of such lasers have resulted in vast improvements in pulsewidth and noise performance, at a very wide range of repetition rates. An attractive application for these lasers would be to serve as alternatives for large benchtop laser systems such as dye lasers and solid-state lasers. However, mode-locked semiconductor lasers have not yet approached the performance of such systems in terms of output power. Different techniques for overcoming the problem of low output power from mode-locked semiconductor lasers will be discussed. Flared and arrayed lasers have been used successfully to increase the pulse saturation energy limit by increasing the gain cross section. Further improvements have been achieved by use of the MOPA configuration, which utilizes a flared semiconductor amplifier s amplify pulses to energies of 120 pJ and peak powers of nearly 30W.

  3. 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.

  4. 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.

  5. 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.

  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 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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 ...

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. High Power Short Wavelength Laser Development

    DTIC Science & Technology

    1977-11-01

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

  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. 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.

  5. 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.

  6. 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.

  7. High-Power Amplifier Free Electron Lasers

    DTIC Science & Technology

    2006-06-01

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

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  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. 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.

  15. 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.

  16. 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)

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Scaling brilliance of high power laser diodes

    NASA Astrophysics Data System (ADS)

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

    2010-02-01

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

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. Development of high coherence high power 193nm laser

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  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. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  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. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  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. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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).

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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)

  19. 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.

  20. 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.

  1. 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.

  2. Automated Power Control for Mobile Laser Speckle Imaging System

    PubMed Central

    Bae, Hyeoungho; Huang, Yu-Chih; Yang, Owen; Chou, Pai H.; Choi, Bernard

    2010-01-01

    Recently, Laser Speckle Imaging (LSI) has been applied to measure blood perfusion in human skin. Attractive features of LSI are its temporal resolution and relatively simple instrumentation. The progressive reduction in the cost and size of camera technology now enables development of mobile LSI instrumentation. To reduce the size of LSI to a mobile platform, we are faced with new challenges in terms of reducing power consumption and heat without sacrificing detection accuracy. To address these challenges, we propose pulsed laser operation using a new automated power control (APC) circuit. By synchronizing the pulses to the laser diode driver with the camera shutter, the camera detects a similar raw speckle image as before while consuming only a small fraction of the power. Furthermore, the reduced power consumption in turn keeps the temperature of the case low, increasing the stability of the system. We validated our solution using simulations in Pspice, and we evaluated the operation of the circuit using a prototype APC board and a commercial camera. PMID:21052486

  3. Atmospheric Propagation and Combining of High-Power Lasers

    DTIC Science & Technology

    2015-09-08

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

  4. 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.

  5. 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].

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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).

  15. 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.

  16. 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.

  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. 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.

  19. 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.

  20. 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.

  1. Limitation of the output power of cw electric-discharge CO{sub 2} lasers

    SciTech Connect

    Nevdakh, Vladimir V

    1999-04-30

    The output power of a sealed-off tunable cw CO{sub 2} laser was optimised. The dependences of the small-signal gain for the 10P(20) line and of the output powers for different transmittances of the cavity on the discharge current were determined. The distributed loss coefficient and the saturation parameter were measured. The saturation parameter increased continuously with increase in the discharge current, leading to a mismatch between the output power and gain maxima. It was established that the principal factor limiting the output power of cw electric-discharge CO{sub 2} lasers is not an increase in the temperature of the active medium but the dissociation of CO{sub 2} molecules. When the latter is minimised in order to achieve the maximum laser power, low gas temperatures are not required. (lasers)

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. 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)

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. 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.

  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. 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.

  6. 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.

  7. 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.

  8. 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

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

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

  10. 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.

  11. 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.

  12. 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.

  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. 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.

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

    NASA Astrophysics Data System (ADS)

    Lu, Baida; Bin, Zhang

    1996-11-01

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

  16. 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 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}}.

  18. 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.

  19. 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)

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  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 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  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. 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.

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

    DTIC Science & Technology

    2009-03-30

    thulium upper laser level through cross-relaxation [5, 6]. Phosphate glass is also an attractive host for high-power single-frequency 2-µm Tm3+- doped...12, (8), p. 512 (1976) [4] D. G. Lancaster, A. Sabella, A. Hemming, S. Bennetts, S.D. Jackson, “Power-scalable thulium and holmium fibre lasers...efficient high-power thulium -doped germanate glass fiber laser,” Optics Letters, 32, (6), p. 638 (2007) [6] S. Jackson, “Power scaling method for 2-μm

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  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. 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.

  10. 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.

  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 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

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

    PubMed

    Lehmann, G; Spatschek, K H

    2016-06-03

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

  14. High power 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.

  15. 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.

  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. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Illuminating the Hazards of Powerful Laser Products

    MedlinePlus

    ... the laser and the potential to pose serious danger if used improperly. The labeling for Classes II– ... to Keep Kids Safe More in Consumer Updates Animal & Veterinary Children's Health Cosmetics Dietary Supplements Drugs Food ...

  4. 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}.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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)

  11. 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.

  12. 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].

  13. 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.

  14. 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

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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%.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Characterization of mechanical shock waves in aluminum 6061-T6 using a high power laser pulse

    NASA Astrophysics Data System (ADS)

    Gonzalez Romero, J. R.; García-Torales, G.; Gómez Rosas, G.; Ocaña, J. L.; Flores, Jorge L.

    2016-09-01

    Strengthening techniques allows enhance metal physical properties. Laser shock peening (LSP) technique consist in a surface treatment which a high power laser pulse induces a compressive residual stress field through mechanical shock waves, increasing hardness, corrosion resistance, fatigue resistance. In comparison with the shot peening technique, LSP is a method that allows precision controlling the laser incidence on the surface under treatment increasing the surface quality in the surface under treatment. In this work, mechanical shock waves are induced in aluminum and measure using two different experimental approaches. First, using a PVDZ sensors and secondly, strain gauges are used. Experimental results are presented.

  20. 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. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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)

  9. 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.

  10. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2007-02-01

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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. VACUUM WINDOW DESIGN FOR HIGH-POWER LASERS.

    SciTech Connect

    SHAFTAN, T.

    2005-04-21

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

  19. 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.

  20. 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.

  1. 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.``

  2. 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

  3. 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.

  4. 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

  5. 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.

  6. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2010-04-01

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

  8. 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.

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

    PubMed

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

    2013-09-01

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

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Cascaded combiners for a high power CW fiber laser

    NASA Astrophysics Data System (ADS)

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

    2016-02-01

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

  15. Ultrahigh-power semiconductor lasers and their applications

    NASA Astrophysics Data System (ADS)

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

    1998-08-01

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

  16. 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

  17. 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

  18. Auxetic piezoelectric energy harvesters for increased electric power output

    NASA Astrophysics Data System (ADS)

    Li, Qiang; Kuang, Yang; Zhu, Meiling

    2017-01-01

    This letter presents a piezoelectric bimorph with auxetic (negative Poisson's ratio) behaviors for increased power output in vibration energy harvesting. The piezoelectric bimorph comprises a 2D auxetic substrate sandwiched between two piezoelectric layers. The auxetic substrate is capable of introducing auxetic behaviors and thus increasing the transverse stress in the piezoelectric layers when the bimorph is subjected to a longitudinal stretching load. As a result, both 31- and 32-modes are simultaneously exploited to generate electric power, leading to an increased power output. The increasing power output principle was theoretically analyzed and verified by finite element (FE) modelling. The FE modelling results showed that the auxetic substrate can increase the transverse stress of a bimorph by 16.7 times. The average power generated by the auxetic bimorph is 2.76 times of that generated by a conventional bimorph.

  19. High-power thulium-doped fiber laser in an all-fiber configuration

    NASA Astrophysics Data System (ADS)

    Baravets, Yauhen; Todorov, Filip; Honzatko, Pavel

    2016-12-01

    High-power Tm-doped fiber lasers are greatly suitable for various applications, such as material processing, medicine, environmental monitoring and topography. In this work we present an all-fiber narrowband CW laser in near fundamental mode operation based on a Tm-doped double-clad active fiber pumped by 793 nm laser diodes with a central wavelength stabilized at 2039 nm by a fiber Bragg grating. The achieved output power is 60 W with a slope efficiency of 46%. The measured beam quality factor is less than 1.4. Further increasing of the output power is possible using various power scaling techniques, for example, coherent combination of several Tm-doped fiber lasers. The developed fiber laser could be employed for welding, cutting and marking of thermoplastics in industry, minimally invasive surgery in medicine or sensors in lidar systems. Future improvements of thulium fiber lasers are possible due to the extremely wide gain-bandwidth of the active medium and the rapid growth of 2-μm fiber components production.

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. High-power laser source evaluation

    SciTech Connect

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

    1998-07-01

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

  6. High-Power 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Effects of low-power laser irradiation on cell locomotion in protozoa.

    PubMed

    Koutna, Marketa; Janisch, Roman; Unucka, Marek; Svobodnik, Adam; Mornstein, Vojtech

    2004-01-01

    Low-power lasers are commonly used in human medicine for treatment of various pathological conditions, but mechanisms of their healing effects are still poorly understood. The results of this study provide information related to these effects at the cellular level. Two different protozoan species, Euglena gracilis and Tetrahymena thermophila, were used to study changes in locomotion behavior in response to low-power lasers. The cells were irradiated at 830 and 650 nm generated by a semiconductor laser (99 J/cm2, 360 mW) and a laser pointer (0.75 J/cm2, 5 mW), respectively, and their locomotion was recorded by a TV camera and analyzed using computer software. Exposure to laser light, regardless of the wavelength, resulted in increased cell velocity in both species (P <0.001). Exposure to 650 nm produced an equal increase in median cell velocity in both E. gracilis (19.0%) and T. thermophila (18.2%), and some increase persisted in the postirradiation 30 s period. Irradiation by the 830 nm laser resulted in a markedly higher response in Tetrahymena (29.4%) than in Euglena (15.2%), and the two median values remained increased after irradiation was discontinued. Different reactions found in the species studied and some mechanisms underlying the response of cells to radiation are discussed.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. High-power 1550 nm tapered DBR lasers fabricated using soft UV-nano-imprint lithography

    NASA Astrophysics Data System (ADS)

    Viheriälä, Jukka; Aho, Antti T.; Mäkelä, Jaakko; Salmi, Joel; Virtanen, Heikki; Leinonen, Tomi; Dumitrescu, Mihail; Guina, Mircea

    2016-03-01

    Paper reports the DBR-RWG surface grating design, the fabrication process, and the output characteristics of tapered DBR laser diodes for the applications, like for example LIDAR and range finding, that require eye-safe high-power single-mode coherent light sources. The fabricated regrowth-free DBR AlGaInAs/InP lasers exhibited a CW output power as high as 560 mW in single-mode operation at room temperature. At maximum output power the SMSR was 38 dB, proving the excellent behavior of the surface gratings. The tapered section enabled scaling the maximum CW power at room temperature from 125 mW to 560 mW, by increasing its length from 0.5 mm to 4.0 mm. The paper discusses the limitations and performance variation associated to the power scaling by using the tapered section length as a scaling parameter.

  2. 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

  3. Novel Radiation Sources Based on Ultra-High-Power Lasers: New Capabilities for Radiology and Radiotherapy

    NASA Astrophysics Data System (ADS)

    Umstadter, Donald

    2008-03-01

    As the maximum power level of compact lasers steadily increases, new opportunities are enabled for their use in bio-medicine and medicine. For instance, the Diocles laser at the University of Nebraska, Lincoln, now produces a peak power of 150-terawatts (1.5x10^14 W) from a table-top-size system. When light at this power level is focused, it can accelerate electrons, and produce quasi-monoenergetic beams of x-rays, similar to those produced by much larger synchrotron light sources. Such MeV-energy beams create new opportunities in biomedicine, radiology and radiography. Examples to be discussed include structural analysis of bio-molecules, diffraction-enhanced imaging for computed tomography, and radio-sensitization-enhanced radiotherapy. This talk will describe the current status of laser-based x-ray technology, as well as the potential advantages and prospects for their use in medicine.

  4. 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.

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

    SciTech Connect

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

    1999-10-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

  7. Influence of powerful laser irradiation on electromagneto-optical dependences of yttrium iron garnets

    SciTech Connect

    Koronovskyy, V. E.

    2009-09-15

    Electromagneto-optical properties of yttrium iron garnets have been investigated in a longitudinal geometry by using optical polarimetry method. It is revealed that irradiation of yttrium iron garnet films by powerful laser impulse leads to essential increase in the electromagneto-optical effect value, which can be due to the elimination of the local mechanical strain or nonuniform pressure in them.

  8. High peak power diode stacks for high energy lasers

    NASA Astrophysics Data System (ADS)

    Negoita, Viorel C.; Vethake, Thilo; Jiang, John; Roff, Robert; Shih, Ming; Duck, Richard; Bauer, Marc; Mite, Roberto; Boucke, Konstantin; Treusch, Georg

    2015-02-01

    High energy solid state lasers are being developed for fusion experiments and other research applications where high energy per pulse is required but the repetition rate is rather low, around 10Hz. We report our results on high peak power diode laser stacks used as optical pumps for these lasers. The stacks are based on 10 mm bars with 4 mm cavity length and 55% fill factor, with peak power exceeding 500 W per bar. These bars are stacked and mounted on a cooler which provides backside cooling and electrical insulation. Currently we mount 25 bars per cooler for a nominal peak power of 12.5 kW, but in principle the mounting scheme can be scaled to a different number of devices depending on the application. Pretesting of these bars before soldering on the cooler enables us to select devices with similar wavelength and thus we maintain tight control of the spectral width (FWHM less than 6 nm). Fine adjustments of the centroid wavelength can be done by means of temperature of the cooling fluid or bias current. The available wavelength range spans from 880 nm to 1000 nm, and the wavelength of the entire assembly of stacks can be controlled to within 0.5 nm of the target value, which makes these stacks suitable for pumping a variety of gain media. The devices are fast axis collimated, with over 95% power being collimated in 6 mrad (full angle). The slow axis divergence is 9° (full angle) for 95% power content.

  9. Phosphate glass useful in high power lasers

    DOEpatents

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

    1990-01-01

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

  10. Meteorological effects on laser propagation for power transmission

    NASA Technical Reports Server (NTRS)

    Beverly, R. E., III

    1982-01-01

    An examination of possible laser operating parameters for power transmission to earth from solar power satellites is presented, with particular attention paid to assuring optimal delivery at midlatitudes. The degradation of beam efficiency due to molecular scattering, molecular absorption, aerosol scattering, and aerosol absorption during beam propagation through the atmosphere can be alleviated by judicious choice of wavelength windows, elevating the receptor sites, using a vertical propagation path, or by hole boring, i.e., vaporizing the aerosol particles in the beam path. Analyses are given for the beam propagation through fog, haze, clouds, and snow using various transitions. Only weapons-quality lasers are seen as being capable of boring through clouds and aerosols, employing a CW beam with superimposed pulses at high power densities. It is concluded that further short wavelength transmission experiments be performed to demonstrate transmission feasibility with the CW/pulsed mode of beam propagation.

  11. Fiber coupling design of high power cm-bar laser diodes based on Zemax

    NASA Astrophysics Data System (ADS)

    Wang, Kai-ming; Qu, Yi; Zhu, Hong-bo; Li, Hui; Zhang, Jian-jia

    2015-10-01

    In order to further increase the fiber-coupled module output power, eight cm-bar 808 nm laser diodes, 50 w output each, fiber coupling module has been designed by using ZEMAX optical design software through space and polarization beam combination method. The core diameter of output fiber is 400 μm with a numerical aperture of 0.22. Finally the fiber output power is 350.2 W, with a coupling efficiency of 87.6%.

  12. Thermoelectronic laser energy conversion for power transmission in space

    NASA Technical Reports Server (NTRS)

    Britt, E. J.; Yuen, C.

    1977-01-01

    Long distance transmission of power in space by means of laser beams is an attractive concept because of the very narrow beam divergence. Such a system requires efficient means to both generate the laser beam and to convert the light energy in the beam into useful electric output at the receiver. A plasma-type device known as a Thermo-Electronic Laser Energy Converter (TELEC) has been studied as a method of converting a 10.6 micron CO2 laser beam into electric power. In the TELEC process, electromagnetic radiation is absorbed directly in the plasma electrons producing a high electron temperature. The energetic electrons diffuse out of the plasma striking two electrodes with different areas. Since more electrons are collected by the larger electrode there is a net transport of current, and an EMF is generated in the external circuit. The smaller electrode functions as an electron emitter to provide continuity of the current. Waste heat is rejected from the large electrode. A design for a TELEC system with an input 1 MW laser beam was developed as part of the study. The calculated performance of the system showed an overall efficiency of about 42%.

  13. Laser power beaming system analyses. Final report

    SciTech Connect

    Zeiders, G.W. Jr.

    1993-08-01

    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.

  14. Plasma-based amplification and manipulation of high-power laser pulses

    NASA Astrophysics Data System (ADS)

    Lehmann, Goetz

    2016-10-01

    In the last decade the increasing availability of Tera- and Petawatt class lasers with ps to fs pulse duration has intensified the interest in the relativistic interaction between laser radiation and matter. Today laser intensities up to 1022 W/cm2 can be achieved. Most high intensity lasers today rely on amplification schemes that can only hardly be scaled to higher power levels due to material damage thresholds. An alternative approach that allows circumventing these issues is the use of plasma as an amplification medium. Langmuir or ion waves may be used as optical components, scattering the energy from a long pump pulse into a short seed pulse. Damage thresholds of solid-state materials are not only limiting the generation of high power laser light, but also its subsequent manipulation. Again, plasma can provide an alternative approach to light manipulation. We recently proposed the concept of transient plasma photonic crystals, which aims at transferring and extending the concept of photonic crystals to the realm of plasma physics in the range of optical frequencies. In my presentation I will discuss Brillouin type plasma-based laser amplifiers and show that the ion plasma waves, driven by the two laser pulses, eventually form photonic crystals. The properties and possible future applications of these plasma photonic crystals as efficient Bragg type mirrors or polarizers will be discussed.

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

    NASA Astrophysics Data System (ADS)

    Schuoecker, Dieter

    1986-01-01

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

  16. Increased epidermal laser fluence through simultaneous ultrasonic microporation

    NASA Astrophysics Data System (ADS)

    Whiteside, Paul J. D.; Chininis, Jeff A.; Schellenberg, Mason W.; Qian, Chenxi; Hunt, Heather K.

    2016-03-01

    Lasers have demonstrated widespread applicability in clinical dermatology as minimally invasive instruments that achieve photogenerated responses within tissue. However, before reaching its target, the incident light must first transmit through the surface layer of tissue, which is interspersed with chromophores (e.g. melanin) that preferentially absorb the light and may also generate negative tissue responses. These optical absorbers decrease the efficacy of the procedures. In order to ensure that the target receives a clinically relevant dose, most procedures simply increase the incident energy; however, this tends to exacerbate the negative complications of melanin absorption. Here, we present an alternative solution aimed at increasing epidermal energy uence while mitigating excess absorption by unintended targets. Our technique involves the combination of a waveguide-based contact transmission modality with simultaneous high-frequency ultrasonic pulsation, which alters the optical properties of the tissue through the agglomeration of dissolved gasses into micro-bubbles within the tissue. Doing so effectively creates optically transparent pathways for the light to transmit unobstructed through the tissue, resulting in an increase in forward scattering and a decrease in absorption. To demonstrate this, Q-switched nanosecond-pulsed laser light at 532nm was delivered into pig skin samples using custom glass waveguides clad in titanium and silver. Light transmission through the tissue was measured with a photodiode and integrating sphere for tissue with and without continuous ultrasonic pulsation at 510 kHz. The combination of these techniques has the potential to improve the efficiency of laser procedures while mitigating negative tissue effects caused by undesirable absorption.

  17. Hole-boring through clouds for laser power beaming

    SciTech Connect

    Lipinski, R.J.; Walter, R.F.

    1994-12-31

    Power beaming to satellites with a ground-based laser can be limited by clouds. Hole-boring through the clouds with a laser has been proposed as a way to overcome this obstacle. This paper reviews the past work on laser hole-boring and concludes that hole-boring for direct beaming to satellites is likely to require 10--100 MW. However, it may be possible to use an airborne relay mirror at 10--25 km altitude for some applications in order to extend the range of the laser (e.g., for beaming to satellites near the horizon). In these cases, use of the relay mirror also would allow a narrow beam between the laser and the relay, as well as the possibility of reducing the crosswind if the plane matched speed with the cloud temporarily. Under these conditions, the power requirement to bore a hole through most cirrus and cirrostratus clouds might be only 500-kW if the hole is less than 1 m in diameter and if the crosswind speed is less than 10 m/s. Overcoming cirrus and cirrostratus clouds would reduce the downtime due to weather by a factor of 2. However, 500 kW is a large laser, and it may be more effective instead to establish a second power beaming site in a separate weather zone. An assessment of optimum wavelengths for hole boring also was made, and the best options were found to be 3.0--3.4 {mu}m and above 10 {mu}m.

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

    SciTech Connect

    Gronberg, J; Stuart, B; Seryi, A

    2010-05-17

    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. We look at the behavior of a simple four mirror cavity as shown in Fig. 1. As a unit input pulse is applied to the coupling mirror a pulse begins to build up in the interior of the cavity. If the drive pulses and the interior pulse arrive at the coupling mirror in phase the interior pulse will build up to a larger value. The achievable enhancement is a strong function of the reflectivity of the cavities. The best performance if attained when the reflectivities of the input coupler is matched to the internal reflectivities of the cavity. In Fig. 2 we show the build up of the internal pulse after a certain number of drive pulses, assuming the input coupler has a reflectivity of 0.996 and the interior mirrors have 0.998 reflectivity. With these parameters the cavity will reach an enhancement factor of 450. Reducing the coupler reflectivity gives a faster cavity loading rate but with a reduced enhancement of the internal pulse. The enhancement as a function of coupler reflectivity and total internal cavity reflectivity is shown in Fig. 3. The best enhancement is achieved when the coupling mirror is matched to the reflectivity of the cavity. A coupler reflectivity just below the internal cavity reflectivity minimizes the required laser power.

  19. High-power diode lasers for optical communications applications

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Kodama, Ryosuke

    2013-10-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1983-01-01

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

  2. Increasing Electronic Nose Recognition Ability by Laser Irradiation

    NASA Astrophysics Data System (ADS)

    Alejandra, Massacane; Juan, Vorobioff; Karina, Pierpauli; Norberto, Boggio; Silvia, Reich; Carlos, Rinaldi; Alfredo, Boselli; Alberto, Lamagna; Laura, Azcárate M.; Jorge, Codnia; Francisco, Manzano

    2009-05-01

    We present a method to increase the capability of an electronic nose to discriminate between a priori similar odours. We analyze the case of olive oil because it is well known that the characteristics of its aroma impair in many cases the discrimination between different kinds of olive oils especially when they are from similar geographic regions. In the present work we study how to improve the electronic nose performance for the above mentioned discrimination by the use of two IR laser wavelengths for vaporization.

  3. Compact high-brightness and high-power diode laser source for materials processing

    NASA Astrophysics Data System (ADS)

    Treusch, Hans-Georg; Harrison, Jim; Morris, Robert; Powers, Jeff J.; Brown, Dennis; Martin, Joey

    2000-03-01

    A compact, reliable semiconductor laser source for materials processing, medical and pumping applications is described. This industrial laser source relies on a combination of technologies that have matured in recent years. In particular, effective means of stacking and imaging monolithic semiconductor laser arrays (a.k.a., bars), together with advances in the design and manufacture of the bars, have enabled the production of robust sources at market-competitive costs. Semiconductor lasers are presently the only lasers known that combine an efficiency of about 50% with compact size and high reliability. Currently the maximum demonstrated output power of a 10-mm-wide semiconductor laser bar exceeds the 260 W level when assembled on an actively cooled heat sink. (The rated power is in the range of 50 to 100 W.) Power levels in the kW range can be reached by stacking such devices. The requirements on the stacking technique and the optic assembly to achieve high brightness are discussed. Optics for beam collimation in fast and slow axis are compared. An example for an optical setup to use in materials processing will be shown. Spot sizes as low as 0.4 mm X 1.2 mm at a numerical aperture of 0.3 and output power of 1 kW are demonstrated. This results in a power density of more than 200 kW/cm2. A setup for further increase in brightness by wavelength and polarization coupling will be outlined. For incoherent coupling of multiple beams into a single core optical fiber, a sophisticated beam-shaping device is needed to homogenize the beam quality of stacked semiconductor lasers.

  4. Phosphate glass useful in high power lasers

    DOEpatents

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

    1990-05-29

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

  5. Optical monitoring of high power direct diode laser cladding

    NASA Astrophysics Data System (ADS)

    Liu, Shuang; Farahmand, Parisa; Kovacevic, Radovan

    2014-12-01

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

  6. Powerful laser pulse absorption in partly homogenized foam plasma

    NASA Astrophysics Data System (ADS)

    Cipriani, M.; Gus'kov, S. Yu.; De Angelis, R.; Andreoli, P.; Consoli, F.; Cristofari, G.; Di Giorgio, G.; Ingenito, F.; Rupasov, A. A.

    2016-03-01

    The internal volume structure of a porous medium of light elements determines unique features of the absorption mechanism of laser radiation; the characteristics of relaxation and transport processes in the produced plasma are affected as well. Porous materials with an average density larger than the critical density have a central role in enhancing the pressure produced during the ablation by the laser pulse; this pressure can exceed the one produced by target direct irradiation. The problem of the absorption of powerful laser radiation in a porous material is examined both analytically and numerically. The behavior of the medium during the process of pore filling in the heated region is described by a model of viscous homogenization. An expression describing the time and space dependence of the absorption coefficient of laser radiation is therefore obtained from the model. A numerical investigation of the absorption of a nanosecond laser pulse is performed within the present model. In the context of numerical calculations, porous media with an average density larger than the critical density of the laser-produced plasma are considered. Preliminary results about the inclusion of the developed absorption model into an hydrodynamic code are presented.

  7. Energy coupling and plume dynamics during high power laser heating of metals

    SciTech Connect

    Jeong, S. |

    1997-05-01

    High power laser heating of metals was studied utilizing experimental and numerical methods with an emphasis on the laser energy coupling with a target and on the dynamics of the laser generated vapor flow. Rigorous theoretical modeling of the heating, melting, and evaporation of metals due to laser radiation with a power density below the plasma shielding threshold was carried out. Experimentally, the probe beam deflection technique was utilized to measure the propagation of a laser induced shock wave. The effects of a cylindrical cavity in a metal surface on the laser energy coupling with a solid were investigated utilizing photothermal deflection measurements. A numerical calculation of target temperature and photothermal deflection was performed to compare with the measured results. Reflection of the heating laser beam inside the cavity was found to increase the photothermal deflection amplitude significantly and to enhance the overall energy coupling between a heating laser beam and a solid. Next, unsteady vaporization of metals due to nanosecond pulsed laser heating with an ambient gas at finite pressure was analyzed with a one dimensional thermal evaporation model for target heating and one dimensional compressible flow equations for inviscid fluid for the vapor flow. Lastly, the propagation of a shock wave during excimer laser heating of aluminum was measured with the probe beam deflection technique. The transit time of the shock wave was measured at the elevation of the probe beam above the target surface; these results were compared with the predicted behavior using ideal blast wave theory. The propagation of a gaseous material plume was also observed from the deflection of the probe beam at later times.

  8. Transmission media appropriate laser-microwave solar power satellite system

    NASA Astrophysics Data System (ADS)

    Schäfer, C. A.; Gray, D.

    2012-10-01

    As a solution to the most critical problems with Solar power Satellite (SPS) development, a system is proposed which uses laser power transmission in space to a receiver high in the atmosphere that relays the power to Earth by either cable or microwave power transmission. It has been shown in the past that such hybrid systems have the advantages of a reduction in the mass of equipment required in geostationary orbit and avoidance of radio frequency interference with other satellites and terrestrial communications systems. The advantage over a purely laser power beam SPS is that atmospheric absorption is avoided and outages due to clouds and precipitation will not occur, allowing for deployment in the equatorial zone and guaranteeing year round operation. This proposal is supported by brief literature surveys and theoretical calculations to estimate crucial parameters in this paper. In relation to this concept, we build on a recently proposed method to collect solar energy by a tethered balloon at high altitude because it enables a low-cost start for bringing the first Watt of power to Earth giving some quick return on investment, which is desperately missing in the traditional SPS concept. To tackle the significant problem of GW-class SPSs of high launch cost per kg mass brought to space, this paper introduces a concept which aims to achieve a superior power over mass ratio compared to traditional satellite designs by the use of thin-film solar cells combined with optical fibres for power delivery. To minimise the aperture sizes and cost of the transmitting and receiving components of the satellite and high altitude receiver, closed-loop laser beam pointing and target tracking is crucial for pointing a laser beam onto a target area that is of similar size to the beam's diameter. A recently developed technique based on optical phase conjugation is introduced and its applicability for maintaining power transmission between the satellite and high altitude receiver is

  9. Increasing Protein Charge State When Using Laser Electrospray Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Karki, Santosh; Flanigan, Paul M.; Perez, Johnny J.; Archer, Jieutonne J.; Levis, Robert J.

    2015-05-01

    Femtosecond (fs) laser vaporization is used to transfer cytochrome c, myoglobin, lysozyme, and ubiquitin from the condensed phase into an electrospray (ES) plume consisting of a mixture of a supercharging reagent, m-nitrobenzyl alcohol ( m-NBA), and trifluoroacetic acid (TFA), acetic acid (AA), or formic acid (FA). Interaction of acid-sensitive proteins like cytochrome c and myoglobin with the highly charged ES droplets resulted in a shift to higher charge states in comparison with acid-stable proteins like lysozyme and ubiquitin. Laser electrospray mass spectrometry (LEMS) measurements showed an increase in both the average charge states (Zavg) and the charge state with maximum intensity (Zmode) for acid-sensitive proteins compared with conventional electrospray ionization mass spectrometry (ESI-MS) under equivalent solvent conditions. A marked increase in ion abundance of higher charge states was observed for LEMS in comparison with conventional electrospray for cytochrome c (ranging from 19+ to 21+ versus 13+ to 16+) and myoglobin (ranging from 19+ to 26+ versus 18+ to 21+) using an ES solution containing m-NBA and TFA. LEMS measurements as a function of electrospray flow rate yielded increasing charge states with decreasing flow rates for cytochrome c and myoglobin.

  10. Threshold pump power of a solar-pumped dye laser

    NASA Technical Reports Server (NTRS)

    Lee, Ja H.; Kim, Kyung C.; Kim, Kyong H.

    1988-01-01

    Threshold solar power for dye laser pumping has been determined by measuring the gain of a rhodamine 6G dye laser amplifier at various solar-simulated irradiances on an amplifier cell. The measured threshold was 20,000 solar constants (2.7 kW/sq cm) for the dye volume of 2 x 5 x 40 cu mm and the optimum dye concentration of 0.001 M. The threshold is about one-third of that achievable with a high-intensity solar concentrator.

  11. APPLICATION OF LASERS AND LASER-OPTICAL METHODS IN LIFE SCIENCES Low power cw-laser signatures on human skin

    NASA Astrophysics Data System (ADS)

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

    2011-01-01

    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 ~12 mm2, and the multispectral visualisation method with the use of a multispectral imaging camera for visualising long-term autofluorescence changes in a skin area of ~4 cm2. 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.

  12. Kilowatt class high-power CW Yb:YAG cryogenic laser

    NASA Astrophysics Data System (ADS)

    Brown, D. C.; Singley, J. M.; Yager, E.; Kowalewski, K.; Guelzow, J.; Kuper, J. W.

    2008-04-01

    We discuss progress towards a kilowatt class CW Yb:YAG cryogenic 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. Results are presented for a high power Yb:YAG oscillator that has produced over 550 W of output power with good slope and optical-optical efficiencies while maintaining single transverse mode output. We also describe a new oscillator-amplifier cryogenic Yb:YAG system nearing completion, that will build on the work presented here and result in CW power output of > 1 kW while maintaining near-diffraction-limited beam quality. The oscillator described here 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 100 W fiber-coupled 940 nm pump diodes. The laser system 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 an oscillator-amplifier 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. We will present experimental results including output power, threshold power, and slope and optical-optical efficiencies.

  13. Catastrophic optical degradation of the output facet of high-power single-transverse-mode diode lasers. 1. Physical model

    SciTech Connect

    Miftakhutdinov, D R; Bogatov, Alexandr P; Drakin, A E

    2010-09-10

    The physical model of catastrophic optical degradation (COD) of the output facet of high-power single- transverse-mode diode lasers is developed. The model excels other models both in completeness of the physical analysis of the processes leading to COD and in allowance for design feature of lasers used to increase the COD threshold - protective coating of the output facet and current limitations near it. (lasers)

  14. Transmission characteristics of high-power 589-nm laser beam in photonic crystal fiber

    NASA Astrophysics Data System (ADS)

    Ito, Meguru; Hayano, Yutaka; Saito, Norihito; Akagawa, Kazuyuki; Kato, Mayumi; Saito, Yoshihiko; Takazawa, Akira; Takami, Hideki; Iye, Masanori; Wada, Satoshi; Colley, Stephen A.; Dinkins, Matthew C.; Eldred, Michael; Golota, Taras I.; Guyon, Olivier; Hattori, Masayuki; Oya, Shin; Watanabe, Makoto

    2006-06-01

    We are developing Laser Guide Star Adaptive Optics (LGSAO) system for Subaru Telescope at Hawaii, Mauna Kea. We achieved an all-solid-state 589.159 nm laser in sum-frequency generation. Output power at 589.159 nm reached 4W in quasi-continuous-wave operation. To relay the laser beam from laser location to laser launching telescope, we used an optical fiber because the optical fiber relay is more flexible and easier than mirror train. However, nonlinear scattering effect, especially stimulated Raman scattering (SRS) and stimulated Brillouin scattering (SBS), will happen when the inputted laser power increases, i.e., intensity at the fiber core exceed each threshold. In order to raise the threshold levels of each nonlinear scattering, we adopt photonic crystal fiber (PCF). Because the PCF can be made larger core than usual step index fiber (SIF), one can reduce the intensity in the core. We inputted the high power laser into the PCF whose mode field diameter (MFD) is 14 μm and the SIF whose MFD is 5 μm, and measured the transmission characteristics of them. In the case of the SIF, the SRS was happen when we inputted 2 W. On the other hand, the SRS and the SBS were not induced in the PCF even for an input power of 4 W. We also investigated polarization of the laser beam transmitting through the PCF. Because of the fact that the backscattering efficiency of exciting the sodium layer with a narrowband laser is dependent on the polarization state of the incident beam, we tried to control the polarization of the laser beam transmitted the PCF. We constructed the system which can control the polarization of input laser and measure the output polarization. The PCF showed to be able to assume as a double refraction optical device, and we found that the output polarization is controllable by injecting beam with appropriate polarization through the PCF. However, the Laser Guide Star made by the beam passed through the PCF had same brightness as the state of the polarization.

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

    DOEpatents

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

    2015-05-12

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

  16. Staging Laser Plasma Accelerators for Increased Beam Energy

    SciTech Connect

    Panasenko, D.; Shu, A. J.; Schroeder, C. B.; Gonsalves, A. J.; Nakamura, K.; Matlis, N. H.; Cormier-Michel, E.; Plateau, G.; Lin, C.; Toth, C.; Geddes, C. G. R.; Esarey, E.; Leemans, W. P.

    2009-01-22

    Staging laser plasma accelerators is an efficient way of mitigating laser pump depletion in laser driven accelerators and necessary for reaching high energies with compact laser systems. The concept of staging includes coupling of additional laser energy and transporting the electron beam from one accelerating module to another. Due to laser damage threshold constraints, in-coupling laser energy with conventional optics requires distances between the accelerating modules of the order of 10 m, resulting in decreased average accelerating gradient and complicated e-beam transport. In this paper we use basic scaling laws to show that the total length of future laser plasma accelerators will be determined by staging technology. We also propose using a liquid jet plasma mirror for in-coupling the laser beam and show that it has the potential to reduce distance between stages to the cm-scale.

  17. Study of laser output power stabilization for a deuterium cyanide laser interferometer on the Experimental Advanced Superconducting Tokamak

    NASA Astrophysics Data System (ADS)

    Shi, N.; Gao, X.; Jie, Y. X.; Wang, E. H.

    2011-02-01

    A control system which can improve stabilization of laser power in long-term operation automatically is designed for a deuterium cyanide (DCN) far-infrared laser interferometer on the Experimental Advanced Superconducting Tokamak. It stabilizes the output power of the laser by a closed-loop control system aided by a programmable logic controller. The system has been applied to the DCN laser and it has been proven that it is effective in stabilizing the laser near the highest scope of the output power.

  18. Development of high-brightness high-power fiber laser pump sources

    NASA Astrophysics Data System (ADS)

    Priest, J. A.; Faircloth, Brian O.; Swint, Reuel B.; Coleman, James J.; Forbes, David V.; Zediker, Mark S.

    2004-06-01

    High power fiber lasers have strong potential for use in both commercial and military applications. Improved wall plug efficiency over Nd:YAG and CO2 lasers combined with up to a 10-fold improvement in beam quality, make fiber lasers extremely attractive for industrial applications such as welding and cutting. In military applications, fiber lasers offer a simplified logistic train, a deep magazine limited only by electric power, and a compact footprint, allowing theater defense and self-protection of combat platforms with speed of light engagement and flexible response. Commercial viability of these systems, however, is limited by the availability of compact, cost effective, and reliable diode laser pump sources in the multi-kilowatt regime. The relatively low brightness of diode laser sources has complicated the task of building high power pumps at a reasonable cost. In response to this need, Nuvonyx, Inc. in conjunction with the University of Illinois at Urbana-Champaign, has been developing a new technology for producing high power, single lateral mode devices which do not suffer form the instabilities mentioned above. The waveguide consists of a narrow section, approximately 2 μm wide, which flares to approximately 12 μm wide at the output facet. The flaring of the waveguide increases the gain volume and reduces the optical power density at the facet allowing for higher output power capability. The index guide is defined using an epitaxial process which allows the confinement of the mode to be reduced as the width of the guide expands. Thus, the mode is confined in a single mode waveguide throughout the cavity maintaining stability of the mode to the emitting facet. In November 2002, Nuvonyx, Inc. was awarded a contract with the Air Force Research Lab, Kirtland AFB, Albuquerque, NM, to transition these devices to production quality for use in high-power fiber laser pumps. Partnered with Alfalight, Inc. and the University of Illinois, we have begun initial

  19. POWER RECYCLING OF BURST-MODE LASER PULSES FOR LASER PARTICLE INTERACTIONS

    SciTech Connect

    Liu, Yun

    2016-01-01

    A number of laser-particle interaction experiments such as the laser assisted hydrogen ion beam stripping or X-/ -ray generations via inverse-Compton scattering involve light sources operating in a burst mode to match the tem-poral structure of the particle beam. To mitigate the laser power challenge, it is important to make the interaction inside an optical cavity to recycle the laser power. In many cases, conventional cavity locking techniques will not work since the burst normally has a very small duty factor and low repetition rate and it is impossible to gen-erate an effective control signal. This work reports on the development of a doubly-resonant optical cavity scheme and its locking techniques that enables a simultaneous resonance of two laser beams with different spectra and/or temporal structures. We demonstrate that such a cavity can be used to recycle burst-mode ultra-violet laser pulses with arbitrary burst lengths and repetition rates.

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

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

  2. Increased power density from a spiral wound microbial fuel cell.

    PubMed

    Jia, Boyang; Hu, Dawei; Xie, Beizhen; Dong, Kun; Liu, Hong

    2013-03-15

    Using Microbial fuel cell (MFC) to convert organic and inorganic matter into electricity is of great interest for powering portable devices, which is now still limited by the output of MFC. In this study, a spiral wound MFC (SWMFC) with relatively large volume normalized surface area of separator (4.2 cm(2)/ml) was fabricated to enhance power generation. Compared with double-membrane MFC (DMMFC) and conventional double chamber MFC (DCMFC), the power density of SWMFC increased by 42% and 99% resulted from its lower internal resistance. Besides larger separator area, the better performance of SWMFC benefited from its structure sandwiching the cathodes between two separators. This point was proved again by a comparison of another DCMFC and a triple chamber MFC (TCMFC) as well as a simulation using finite element method. Moreover, the feature of SWMFC was more convenient and compact to scale up. Therefore, SWMFC provides a promising configuration for high power output as a portable power source.

  3. Low-power laser efficacy in peripheral nerve lesion treatment

    NASA Astrophysics Data System (ADS)

    Antipa, Ciprian; Nacu, Mihaela; Bruckner, Ion I.; Bunila, Daniela; Vlaiculescu, Mihaela; Pascu, Mihail-Lucian; Ionescu, Elena

    1998-07-01

    In order to establish the low energy laser (LEL) effects on nervous tissue regeneration in clinical practice, we evaluated in double blind, placebo controlled study, the efficacy of LEL in the functional recovery of 46 patients with distal forearm post- traumatic nerve lesion, after surgical suture. The patients were divided into two groups: A-26 patients were treated with LEL; B- 20 patients, as control, were treated with placebo lasers and classical medical and physical therapy. Lasers used were: HeNe, 632.5 nm wavelength, 2 mW power, and GaAlAs diode laser, 880 nm wavelength, pulsed emission with an output power about 3 mW. Before, during and after the treatment, electromyography (EMG) and electroneurography (ENG) were done in order to measure objectively the efficacy of the treatment. We obtained good results after 4 - 5 months at 80.7% patients from group A and about the same results at 70% patients from group B, but after at least 8 months. The good results were noticed concerning the improvement of EMG and ENG registrations and on the involution of pain, inflammations, movements and force of the fingers. Finally we can say that the favorable results were obtained in at least half the time with LEL treatment faster than with classical therapy.

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

    PubMed

    Vorontsov, Mikhail A; Weyrauch, Thomas

    2016-12-10

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

  5. Laser beacon adaptive optics for power beaming applications

    SciTech Connect

    Fugate, R.Q.

    1994-12-31

    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 {mu}m, the author has 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}8{sup th} magnitude. The resulting point spread function has a full width half maximum (FWHM) of 0.13 arcsec.

  6. Edge-facet pumped, multi-aperture, thin-disk laser geometry for very high average power output scaling

    DOEpatents

    Zapata, Luis E.

    2004-12-21

    The average power output of a laser is scaled, to first order, by increasing the transverse dimension of the gain medium while increasing the thickness of an index matched light guide proportionately. Strategic facets cut at the edges of the laminated gain medium provide a method by which the pump light introduced through edges of the composite structure is trapped and passes through the gain medium repeatedly. Spontaneous emission escapes the laser volume via these facets. A multi-faceted disk geometry with grooves cut into the thickness of the gain medium is optimized to passively reject spontaneous emission generated within the laser material, which would otherwise be trapped and amplified within the high index composite disk. Such geometry allows the useful size of the laser aperture to be increased, enabling the average laser output power to be scaled.

  7. Optical Frequency Optimization of a High Intensity Laser Power Beaming System Utilizing VMJ Photovoltaic Cells

    NASA Technical Reports Server (NTRS)

    Raible, Daniel E.; Dinca, Dragos; Nayfeh, Taysir H.

    2012-01-01

    An effective form of wireless power transmission (WPT) has been developed to enable extended mission durations, increased coverage and added capabilities for both space and terrestrial applications that may benefit from optically delivered electrical energy. The high intensity laser power beaming (HILPB) system enables long range optical 'refueling" of electric platforms such as micro unmanned aerial vehicles (MUAV), airships, robotic exploration missions and spacecraft platforms. To further advance the HILPB technology, the focus of this investigation is to determine the optimal laser wavelength to be used with the HILPB receiver, which utilizes vertical multi-junction (VMJ) photovoltaic cells. Frequency optimization of the laser system is necessary in order to maximize the conversion efficiency at continuous high intensities, and thus increase the delivered power density of the HILPB system. Initial spectral characterizations of the device performed at the NASA Glenn Research Center (GRC) indicate the approximate range of peak optical-to-electrical conversion efficiencies, but these data sets represent transient conditions under lower levels of illumination. Extending these results to high levels of steady state illumination, with attention given to the compatibility of available commercial off-the-shelf semiconductor laser sources and atmospheric transmission constraints is the primary focus of this paper. Experimental hardware results utilizing high power continuous wave (CW) semiconductor lasers at four different operational frequencies near the indicated band gap of the photovoltaic VMJ cells are presented and discussed. In addition, the highest receiver power density achieved to date is demonstrated using a single photovoltaic VMJ cell, which provided an exceptionally high electrical output of 13.6 W/sq cm at an optical-to-electrical conversion efficiency of 24 percent. These results are very promising and scalable, as a potential 1.0 sq m HILPB receiver of

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

    PubMed

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

    2006-08-01

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

  9. High-power laser arrays for optical computing

    NASA Astrophysics Data System (ADS)

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

    1991-12-01

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

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

    PubMed

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

    2009-08-17

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

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

    SciTech Connect

    Campbell, J.H.

    1996-05-14

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

  12. Low Power Consumption Lasers for Next Generation Miniature Optical Spectrometers for Major Constituent and Trace Gas Analysis

    NASA Technical Reports Server (NTRS)

    Forouhar, Siamak; Soibel, Alexander; Frez, Clifford; Qiu, Yueming; Chen, J.; Hosoda, T.; Kipshidze, G.; Shterengas, L.; Tsvid, G.; Belenky, G.; Franz, Kale J.; Gmachl, Claire; Scherer, Benjamin

    2010-01-01

    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. The minimum instrument size requires lasers with emission wavelength coinciding with the absorption of the fundamental frequency of the target gases which are mostly in the 3.0-5.0 micrometers 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 micrometers and quantum cascade (QC) lasers in the 4.0-5.0 micrometers range. These lasers will enable the development of miniature, low-power laser spectrometers for environmental monitoring of the spacecraft.

  13. Assessment of the limits to peak power of 1100nm broad area single emitter diode lasers under short pulse conditions

    NASA Astrophysics Data System (ADS)

    Wang, X.; Crump, P.; Pietrzak, A.; Schultz, C.; Klehr, A.; Hoffmann, T.; Liero, A.; Ginolas, A.; Einfeldt, S.; Bugge, F.; Erbert, G.; Tränkle, G.

    2009-02-01

    High power diode lasers are the root source of optical energy in all high performance laser systems. As their performance advances, diode lasers are increasingly taking the place of other sources. Short pulse, sub-microsecond-class, high power lasers are important for many applications but historically, diode lasers have not been able to reach high enough peak pulse powers with adequate reliability, limited by physical effects such as facet failure. By combining robust facet passivation with thick super large optical cavity waveguides, greatly increased optical output power can be achieved. We present here the results of a study using commercial high current short pulse sources (>200A, <500ns) to assess the performance and endurance limits of high power broad area devices. We find that our lasers can be driven with a peak power density of over 110MWcm-2 without failure for more than 3×107 pulses. For example, on testing to 240A, single emitter 200μm stripe 1100nm broad area devices reach 124W (46μJ) without failure, and 60μm stripes reach 88W. In practice, high injection effects such as carrier accumulation in waveguide typically limit peak power. We review these remaining limitations, and discuss how they can be overcome.

  14. Computational design of an experimental laser-powered thruster

    NASA Technical Reports Server (NTRS)

    Jeng, San-Mou; Litchford, Ronald; Keefer, Dennis

    1988-01-01

    An extensive numerical experiment, using the developed computer code, was conducted to design an optimized laser-sustained hydrogen plasma thruster. The plasma was sustained using a 30 kW CO2 laser beam operated at 10.6 micrometers focused inside the thruster. The adopted physical model considers two-dimensional compressible Navier-Stokes equations coupled with the laser power absorption process, geometric ray tracing for the laser beam, and the thermodynamically equilibrium (LTE) assumption for the plasma thermophysical and optical properties. A pressure based Navier-Stokes solver using body-fitted coordinate was used to calculate the laser-supported rocket flow which consists of both recirculating and transonic flow regions. The computer code was used to study the behavior of laser-sustained plasmas within a pipe over a wide range of forced convection and optical arrangements before it was applied to the thruster design, and these theoretical calculations agree well with existing experimental results. Several different throat size thrusters operated at 150 and 300 kPa chamber pressure were evaluated in the numerical experiment. It is found that the thruster performance (vacuum specific impulse) is highly dependent on the operating conditions, and that an adequately designed laser-supported thruster can have a specific impulse around 1500 sec. The heat loading on the wall of the calculated thrusters were also estimated, and it is comparable to heat loading on the conventional chemical rocket. It was also found that the specific impulse of the calculated thrusters can be reduced by 200 secs due to the finite chemical reaction rate.

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

    PubMed

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

    2014-12-01

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

  16. High average power magnetic modulator for metal vapor lasers

    DOEpatents

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

    1994-01-01

    A three-stage magnetic modulator utilizing magnetic pulse compression designed to provide a 60 kV pulse to a copper vapor laser at a 4.5 kHz repetition rate is disclosed. This modulator operates at 34 kW input power. The circuit includes a step up auto transformer and utilizes a rod and plate stack construction technique to achieve a high packing factor.

  17. Influence of energy-transfer-upconversion on threshold pump power in quasi-three-level solid-state lasers.

    PubMed

    Kim, J W; Mackenzie, J I; Clarkson, W A

    2009-07-06

    A simple analytical expression for threshold pump power in an end-pumped quasi-three-level solid-state laser, which takes into account the influence of energy-transfer-upconversion (ETU), is derived. This expression indicates that threshold pump power can be increased dramatically by ETU, especially in low gain lasers and lasers with pronounced three-level character due to the need for high excitation densities in the upper manifold to reach threshold. The analysis has been applied to an Er:YAG laser operating at 1645 nm in-band pumped by an Er,Yb fiber laser at 1532 nm. Predicted values for threshold pump power as a function of erbium doping concentration are in very good agreement with measured values. The results indicate that very low erbium doping levels (approximately 0.25 at.% or less) are required to avoid degradation in performance due to ETU even under continuous-wave lasing conditions in Er:YAG.

  18. Possible power source found for fiber optic lasers

    SciTech Connect

    Krupa, Tyler J.

    2000-05-01

    Scientists at the US Department of Energy's Sandia National Laboratory are researching ways to use a new semiconductor alloy, indium gallium arsenide nitride (InGaAsN), as as photovoltaic power source for lasers in fiber optics and space communication satellites. The efficiency of electricity-generating solar cells utilizing InGaAsN is predicted to be 40%-nearly twice the efficiency rate of a standard silicon solar cell. The use of InGaAsN in solar cells is a potential power source for satellites and other space systems. (AIP) (c)

  19. High power semiconductor laser source for space applications

    NASA Astrophysics Data System (ADS)

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

    1986-07-01

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

  20. Low Power Consumption Laser for Next Generation 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 mu m 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 mu m and quantum cascade (QC) lasers in the 4.0-5.0 mu m range. These lasers will enable the development of miniature, low-power laser spectrometers for environmental monitoring of the spacecraft

  1. Laser driven nuclear science and applications: The need of high efficiency, high power and high repetition rate Laser beams

    NASA Astrophysics Data System (ADS)

    Gales, S.

    2015-10-01

    Extreme Light Infrastructure (ELI) is a pan European research initiative selected on the European Strategy Forum on Research Infrastructures Roadmap that aims to close the gap between the existing laboratory-based laser driven research and international facility-grade research centre. The ELI-NP facility, one of the three ELI pillars under construction, placed in Romania and to be operational in 2018, has as core elements a couple of new generation 10 PW laser systems and a narrow bandwidth Compton backscattering gamma source with photon energies up to 19 MeV. ELI-NP will address nuclear photonics, nuclear astrophysics and quantum electrodynamics involving extreme photon fields. Prospective applications of high power laser in nuclear astrophysics, accelerator physics, in particular towards future Accelerator Driven System, as well as in nuclear photonics, for detection and characterization of nuclear material, and for nuclear medicine, will be discussed. Key issues in these research areas will be at reach with significant increase of the repetition rates and of the efficiency at the plug of the high power laser systems as proposed by the ICAN collaboration.

  2. A microscopic analysis of the effects of root surface scaling with different power parameters of Er,Cr:YSGG laser.

    PubMed

    de Oliveira, Guilherme José Pimentel Lopes; Cominotte, Mariana Aline; Beraldo, Tamara Pádua Pereira; Sampaio, José Eduardo Cezar; Marcantonio, Rosemary Adriana Chiérici

    2015-06-01

    The aim of this study was to evaluate the effects of different power parameters of an Erbium, Cromium: Yttrium, Scandium, Gallium, Garnet laser (Er,Cr:YSGG laser) on the morphology, attachment of blood components (ABC), roughness, and wear on irradiated root surfaces. Sixty-five incisive bovine teeth were used in this study, 35 of which were used for the analysis of root surface morphology and ABC. The remaining 30 teeth were used for roughness and root wear analysis. The samples were randomly allocated into seven groups: G1: Er,Cr:YSGG laser, 0.5 W; G2: Er,Cr:YSGG laser, 1.0 W; G3: Er,Cr:YSGG laser, 1.5 W; G4: Er,Cr:YSGG laser, 2.0 W; G5: Er,Cr:YSGG laser, 2.5 W; G6: Er,Cr:YSGG laser, 3.0 W; G7: scaling and root planning (SRP) with manual curettes. The root surfaces irradiated by Er,Cr:YSGG at 1.0 W and scaling with manual curettes presented the highest degrees of ABC. The samples irradiated by the Er,Cr:YSGG laser were rougher than the samples treated by the manual curette, and increasing the laser power parameters caused more root wear and greater roughness on the root surface. The Er,Cr:YSGG laser is safe to use for periodontal treatment, but it is not appropriate to use irradiation greater than 1.0 W for this purpose.

  3. Continuous-wave wavelength conversion for high-power applications using an external cavity diamond Raman laser.

    PubMed

    Kitzler, Ondrej; McKay, Aaron; Mildren, Richard P

    2012-07-15

    We demonstrate continuous-wave (cw) operation of a diamond Raman laser at 1240 nm in an external cavity configuration. The output power increased linearly with pump power with a 49.7% slope efficiency and reached 10.1 W at the maximum available pump power of 31 W. The combination of resonator design with diamond provides a novel approach to power-scalable cw wavelength and beam conversion.

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

    DTIC Science & Technology

    2012-06-08

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

  5. High-power high-brightness semiconductor lasers

    NASA Astrophysics Data System (ADS)

    Botez, D.

    2005-01-01

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

  6. Power scaling of high-efficiency 1.5 μm cascaded Raman fiber lasers.

    PubMed

    Supradeepa, V R; Nicholson, Jeffrey W

    2013-07-15

    High-power fiber lasers operating at the 1.5 μm wavelength region have attractive features, such as eye safety and atmospheric transparency, and cascaded Raman fiber lasers offer a convenient method to obtain high-power sources at these wavelengths. A limitation to power scaling, however, has been the lower conversion efficiency of these lasers. We recently introduced a high-efficiency architecture for high-power cascaded Raman fiber lasers applicable for 1.5 μm fiber lasers. Here we demonstrate further power scaling using this new architecture. Using numerical simulations, we identify the ideal operating conditions for the new architecture. We demonstrate a high-efficiency 1480 nm cascaded Raman fiber laser with an output power of 301 W, comparable to record power levels achieved with rare-earth-doped fiber lasers in the 1.5 μm wavelength region.

  7. Thermo-optic nonlinearity of the laser dye LDS 867 under low power CW laser excitation

    NASA Astrophysics Data System (ADS)

    Mary, K. A. Ann; Mary, E. J. Sonia; Vidyadharan, Viji; Philip, Reji; Unnikrishnan, N. V.

    2015-02-01

    Thermally induced optical nonlinearity of the laser dye LDS 867 is studied in ethanol solution using the self phase modulation and closed aperture z-scan techniques, employing a continuous wave low power He-Ne laser beam for excitation. The nonlinear optical (NLO) coefficients are obtained by analyzing the z-scan curve on the basis of the thermal lens model. The dye exhibits a negative thermal nonlinearity which can be inferred from the occurrence of a pre-focal peak followed by a post-focal valley in the z-scan. The large nonlinear refractive index (n2) measured at the excitation wavelength of 633nm reveals that the material is NLO active even at low excitation powers of less than 1 mW. Results indicate that LDS 867 is a promising material for optical power limiting applications.

  8. Advances in high-power 9XXnm laser diodes for pumping fiber lasers

    NASA Astrophysics Data System (ADS)

    Skidmore, Jay; Peters, Matthew; Rossin, Victor; Guo, James; Xiao, Yan; Cheng, Jane; Shieh, Allen; Srinivasan, Raman; Singh, Jaspreet; Wei, Cailin; Duesterberg, Richard; Morehead, James J.; Zucker, Erik

    2016-03-01

    A multi-mode 9XXnm-wavelength laser diode was developed to optimize the divergence angle and reliable ex-facet power. Lasers diodes were assembled into a multi-emitter pump package that is fiber coupled via spatial and polarization multiplexing. The pump package has a 135μm diameter output fiber that leverages the same optical train and mechanical design qualified previously. Up to ~ 270W CW power at 22A is achieved at a case temperature ~ 30ºC. Power conversion efficiency is 60% (peak) that drops to 53% at 22A with little thermal roll over. Greater than 90% of the light is collected at < 0.12NA at 16A drive current that produces 3.0W/(mm-mr)2 radiance from the output fiber.

  9. Quantifying the increasing sensitivity of power systems to climate variability

    NASA Astrophysics Data System (ADS)

    Bloomfield, H. C.; Brayshaw, D. J.; Shaffrey, L. C.; Coker, P. J.; Thornton, H. E.

    2016-12-01

    Large quantities of weather-dependent renewable energy generation are expected in power systems under climate change mitigation policies, yet little attention has been given to the impact of long term climate variability. By combining state-of-the-art multi-decadal meteorological records with a parsimonious representation of a power system, this study characterises the impact of year-to-year climate variability on multiple aspects of the power system of Great Britain (including coal, gas and nuclear generation), demonstrating why multi-decadal approaches are necessary. All aspects of the example system are impacted by inter-annual climate variability, with the impacts being most pronounced for baseload generation. The impacts of inter-annual climate variability increase in a 2025 wind-power scenario, with a 4-fold increase in the inter-annual range of operating hours for baseload such as nuclear. The impacts on peak load and peaking-plant are comparably small. Less than 10 years of power supply and demand data are shown to be insufficient for providing robust power system planning guidance. This suggests renewable integration studies—widely used in policy, investment and system design—should adopt a more robust approach to climate characterisation.

  10. High-power directly diode-pumped femtosecond Yb:KGW lasers with optimized parameters

    NASA Astrophysics Data System (ADS)

    Kim, G. H.; Yang, J.; Kulik, A. V.; Sall, E. G.; Chizhov, S. A.; Yashin, V. E.; Kang, U.

    2014-02-01

    We report a diode-pumped Yb:KGW laser that is capable of operating as a Q-switched oscillator or as a regenerative amplifier with average power of more than 20 W. The laser is based on a dual-crystal configuration where the pump thermal load is distributed over relatively long two crystals. It permits a sufficiently large number of passes with low passive losses and maximizes the energy extraction efficiency. The amplification bandwidth was extended by spectral combining of two Yb:KGW crystals with spectrally shifted gain maxima, that allows to mitigate spectral gain narrowing and provides pulse length down to 200 fs after compression in a stretcher-compressor module. The output power saturated with increasing pump power and output beam quality was defined by aberration of thermal lenses. Optimization of laser cavity allows us to compensate thermal lens partially and provide output beams with quality M2<1.2. Efficient frequency doubling and tripling of high-power femtosecond Yb:KGW laser is demonstrated in a nonlinear BBO crystal. Second or third harmonic generation with respective conversion efficiency of 55% or 24% was achieved in a single-pass configuration.

  11. Highly reliable high-power AlGaAs/GaAs 808 nm diode laser bars

    NASA Astrophysics Data System (ADS)

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

    2007-02-01

    There are strong demands at the market to increase power and reliability for 808 nm diode laser bars. Responding to this JENOPTIK Diode Lab GmbH developed high performance 808 nm diode laser bars in the AlGaAs/GaAs material system with special emphasis to high power operation and long term stability. Optimization of the epitaxy structure and improvements in the diode laser bar design results in very high slope efficiency of >1.2 W/A, low threshold current and small beam divergence in slow axis direction. Including low serial resistance the overall wall plug efficiency is up to 65% for our 20%, 30% and 50% filling factor 10 mm diode laser bars. With the JENOPTIK Diode Lab cleaving and coating technique the maximum output power is 205 W in CW operation and 377 W in QCW operation (200 μs, 2% duty cycle) for bars with 50% filling factor. These bars mounted on micro channel cooled package are showing a very high reliability of >15.000 h. Mounted on conductive cooled package high power operation at 100 W is demonstrated for more than 5000h.

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

    PubMed

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

    2013-10-21

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

  13. Improving the efficiency of high-power diode lasers using diamond heat sinks

    SciTech Connect

    Parashchuk, Valentin V; Baranov, V V; Telesh, E V; Mien, Vu Doan; Luc, Vu Van; Truong, Pham Van; Belyaeva, A K

    2010-06-23

    Using multifunctional ion beam and magnetron sputtering systems, we have developed chemical and vacuum techniques for producing metallic coatings firmly adherent to various surfaces, with application to copper and diamond heat sinks for diode lasers. Conditions have been optimised for mounting diode lasers and bars using the proposed metallisation processes, and significant improvements in the output parameters of the devices have been achieved. The power output of cw laser diodes on diamond heat sinks increases by up to a factor of 2, the linear (working) portion of their power-current characteristic becomes markedly broader, and their slope efficiency increases by a factor of 1.5 - 2 relative to that of lasers on copper heat spreaders. The use of diamond heat sinks extends the drive current range of pulsed diode bars by a factor of 2 - 3 and enables them to operate at more than one order of magnitude longer pump pulse durations (up to milliseconds) when the pulse repetition rate is at least 10 Hz. (lasers)

  14. Electrostatic-accelerator free-electron lasers for power beaming

    SciTech Connect

    Pinhasi, Y.; Yakover, I.M.; Gover, A.

    1995-12-31

    Novel concepts of electrostatic-accelerator free-electron lasers (EA-FELs) for energy transfer through the atmosphere are presented. The high average power attained from an EA-FEL makes it an efficient source of mm-wave for power beaming from a ground stations. General aspects of operating the FEL as a high power oscillator (like acceleration voltage, e-beam. current, gain and efficiency) are studied and design considerations are described. The study takes into account requirements of power beaming application such as characteristic dips in the atmospheric absorption spectrum, sizes of transmitting and receiving antennas and meteorological conditions. We present a conceptual design of a moderate voltage (.5-3 MeV) high current (1-10 Amp) EA-FEL operating at mm-wavelength bands, where the atmospheric attenuation allows efficient power beaming to space. The FEL parameters were calculated, employing analytical and numerical models. The performance parameters of the FEL (power, energy conversion efficiency average power) will be discussed in connection to the proposed application.

  15. Manufacturing Technology Development of Advanced Components for High Power Solid State Lasers

    DTIC Science & Technology

    2010-07-19

    Thulium lasers with a low quantum defect (-9%). However, since the Holmium laser is a quasi-three level system, the laser emission suffers re...reported in Thulium pumped Holmium lasers. We have also measured the laser output power as function of the repetition rate for fixed pump power of 21 W and...Lett. 21, 728-730 (1996). [5] X. Mu, H. Meissner, H.-C. Lee, ’ Thulium fiber laser 4-pass end-pumped high efficiency 2.09-um Ho.YAG Laser," Proc. CLEO

  16. Control of lateral divergence in high-power, broad-area photonic crystal lasers

    NASA Astrophysics Data System (ADS)

    Rong, Jiamin; Xing, Enbo; Wang, Lijie; Shu, Shili; Tian, Sicong; Tong, Cunzhu; Wang, Lijun

    2016-07-01

    One-dimensional photonic bandgap crystal (PBC) lasers have demonstrated ultra-low vertical divergence and record brightness; however, their future development is limited by their lateral beam quality. In this paper, a fishbone microstructure is proposed to control the lateral modes in broad-area PBC lasers. The findings reveal that the introduction of the microstructure improves the full width at half maximum of the lateral far field by 22.2% and increases the output power to a small extent. The detailed measurements show that the lateral beam parameter product decreases by 15.9%.

  17. High-power and highly efficient Tm3+-doped silica fiber lasers pumped with diode lasers operating at 1150 nm.

    PubMed

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

    2007-10-01

    An output power of 1.74 W at 2.03 microm was generated at a slope efficiency of 51% when a double-clad Tm(3+)-doped silica fiber laser was pumped with high-power 1150 nm diode lasers. Pump excited state absorption from the upper laser level populates higher energy levels allowing cross relaxation to repopulate the upper laser level at a quantum efficiency greater than unity and to limit losses relating to additional pump excited state absorption. The output power was scaled to 4.77 W when both ends of the fiber were pumped.

  18. Discharge formation in a XеCl laser pumped by high specific power

    NASA Astrophysics Data System (ADS)

    Panchenko, Yu. N.; Losev, V. F.

    2013-02-01

    Stable glow of the discharge of various types in the gas mixture of a XeCl laser is investigated for specific pumping power in the range 1.2-4.6 MW/cm3 and pulse duration of 40 ns. It is demonstrated that formation of partially homogeneous plasma with many intensive cathode spots on the electrode allows the maximum energy and duration of the lasing pulse to be obtained with laser efficiency of 2.4%. It is revealed that for the specific pumping powers up to 1.5 MW/cm3, a very homogeneous volume discharge with a small number of lowintensive cathode spots is formed in the discharge gap. With further increase in the specific pumping power exceeding 4.5 MW/cm3, current microinhomogeneities are formed in the volume discharge of this type leading to lasing breakdown.

  19. Pulsed laser excitation power dependence of photoluminescence peak energies in bulk ZnO

    NASA Astrophysics Data System (ADS)

    Dang, Giang T.; Kanbe, Hiroshi; Kawaharamura, Toshiyuki; Taniwaki, Masafumi

    2011-10-01

    Photoluminescence (PL) spectra of hydrothermal bulk ZnO were measured in the temperature range from 5 to 298 K. The sample was excited by means of the 266-nm line of an Nd3+: YAG Q-switched pulsed laser with numerous average excitation powers in the range from 0.33 to 7.50 mW. At constant temperatures, the most intense PL peak red-shifts with average excitation power, whereas positions of other near-band-edge peaks remain unchanged. It was experimentally proven that the red-shift is not due to local heating at the excited spot. Rather, it is due to relaxation of photoexcited carriers to lower energy transitions as the most intense transition is saturated by high excitation photon density. Furthermore, the temperature dependence of energy of the most intense PL peak was fitted with the Varshni equation. The Varshni coefficients α and β decrease with increasing pulsed laser excitation power.

  20. A high-power free electron laser using a short rayleigh length

    SciTech Connect

    William Colson; Alan Todd; George Neil

    2004-09-01

    Free electron lasers have always had the potential for high average power, since the laser medium cannot be damaged and is transparent to all wavelengths while the exhaust heat is removed at the speed of light. At MW power levels, the resonator mirrors of the oscillator are vulnerable to damage because of the small beam size in the undulator. We present a description of an FEL that uses a resonator with a short Rayleigh length in order to increase the mode area at the mirrors and reduce the intensity. The corresponding undulator must also be short. The whole FEL system is designed to be compact and efficient, producing about 1 MW of power at 1 mu-m infrared wavelength using an electron beam of about 140 MeV with about 0.6A of recirculating average current.

  1. High peak-power kilohertz laser system employing single-stage multi-pass amplification

    DOEpatents

    Shan, Bing; Wang, Chun; Chang, Zenghu

    2006-05-23

    The present invention describes a technique for achieving high peak power output in a laser employing single-stage, multi-pass amplification. High gain is achieved by employing a very small "seed" beam diameter in gain medium, and maintaining the small beam diameter for multiple high-gain pre-amplification passes through a pumped gain medium, then leading the beam out of the amplifier cavity, changing the beam diameter and sending it back to the amplifier cavity for additional, high-power amplification passes through the gain medium. In these power amplification passes, the beam diameter in gain medium is increased and carefully matched to the pump laser's beam diameter for high efficiency extraction of energy from the pumped gain medium. A method of "grooming" the beam by means of a far-field spatial filter in the process of changing the beam size within the single-stage amplifier is also described.

  2. CO2 laser-driven Stirling engine. [space power applications

    NASA Technical Reports Server (NTRS)

    Lee, G.; Perry, R. L.; Carney, B.

    1978-01-01

    A 100-W Beale free-piston Stirling engine was powered remotely by a CO2 laser for long periods of time. The engine ran on both continuous-wave and pulse laser input. The working fluid was helium doped with small quantities of sulfur hexafluoride, SF6. The CO2 radiation was absorbed by the vibrational modes of the sulfur hexafluoride, which in turn transferred the energy to the helium to drive the engine. Electrical energy was obtained from a linear alternator attached to the piston of the engine. Engine pressures, volumes, and temperatures were measured to determine engine performance. It was found that the pulse radiation mode was more efficient than the continuous-wave mode. An analysis of the engine heat consumption indicated that heat losses around the cylinder and the window used to transmit the beam into the engine accounted for nearly half the energy input. The overall efficiency, that is, electrical output to laser input, was approximately 0.75%. However, this experiment was not designed for high efficiency but only to demonstrate the concept of a laser-driven engine. Based on this experiment, the engine could be modified to achieve efficiencies of perhaps 25-30%.

  3. High-power arrays of quantum cascade laser master-oscillator power-amplifiers.

    PubMed

    Rauter, Patrick; Menzel, Stefan; Goyal, Anish K; Wang, Christine A; Sanchez, Antonio; Turner, George; Capasso, Federico

    2013-02-25

    We report on multi-wavelength arrays of master-oscillator power-amplifier quantum cascade lasers operating at wavelengths between 9.2 and 9.8 μm. All elements of the high-performance array feature longitudinal (spectral) as well as transverse single-mode emission at peak powers between 2.7 and 10 W at room temperature. The performance of two arrays that are based on different seed-section designs is thoroughly studied and compared. High output power and excellent beam quality render the arrays highly suitable for stand-off spectroscopy applications.

  4. Low-powered laser therapy associated with oral implantology

    NASA Astrophysics Data System (ADS)

    Lizarelli, Rosane F. Z.; Ciconelli, Karen P. C.; Braga, Carlos A.; Berro, Renato J.

    1999-05-01

    The objective of this present work to evaluate in the level of pain and tumor the effect of the low-power density laser irradiation of GaAlAs 790 nm in implanted patients during the postoperative period. Forty five clinic situations were selected and divided in three different groups: Group I, control, without laser application, but with analgesic and anti-inflammatory medication; Group II, patients were irradiated on the day of the surgery, after the same concluded, and on the two subsequent days; and Group III, patients were irradiated on the day of the surgery, on the day of the surgery, before and after the end of the same, and in the two subsequent days after. All the applications were accomplished using the same energy parameters and by the same operator. The measures, with relationship to the pain and the tumor, they were accomplished in the immediate postoperative, in the postoperative (24 hours and also 72 hours after) always by the same examiner. The statistical analysis sustained the clinic observations. In our study, the low power density laser of GaAlAs 790 nm suggested the same clinical results when pain and tumor formation were controlled by analgesic and anti- inflammatory medication.

  5. A preliminary study of pulse-laser powered orbital launcher

    NASA Astrophysics Data System (ADS)

    Katsurayama, Hiroshi; Komurasaki, Kimiya; Arakawa, Yoshihiro

    2009-10-01

    An air-breathing pulse-laser powered orbital launcher has been proposed as an alternative to conventional chemical launch systems. The aim of the present study is to assess its feasibility through the estimation of its achievable payload mass per unit beam power and launch cost. A transfer trajectory from the ground to a geosynchronous Earth orbit (GEO) is proposed, and the launch trajectory to its geosynchronous transfer orbit (GTO) is computed using the realistic performance modeled in the pulsejet, ramjet, and rocket flight modes of the launcher. Results show that the launcher can transfer 0.084 kg of payload per 1 MW beam power to a geosynchronous earth orbit. The cost becomes a quarter of existing systems if one can divide a single launch into 24,000 multiple launches.

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

    DOEpatents

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

    2017-02-07

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

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

    NASA Astrophysics Data System (ADS)

    Chin, Aland K.; Bertaska, Rick K.

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

  8. High power 2 {mu}m diode-pumped Tm:YAG laser

    SciTech Connect

    Beach, R.J.; Sutton, S.B.; Honea, E.C.; Skidmore, J.A.; Emanuel, M.A.

    1996-01-01

    Using a scaleable diode end-pumping technology developed at LLNL, we have demonstrated a compact Tm:YAG laser capable of generating more than 50 W of cw 2 {mu}m laser output power. The design and operational characteristics of this laser, which was built originally for use in assessing laser surgical techniques, are discussed.

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

    DOEpatents

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

    2016-01-26

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

  10. High Power Laser Cutting of Fiber Reinforced Thermoplastic Polymers with cw- and Pulsed Lasers

    NASA Astrophysics Data System (ADS)

    Schneider, F.; Wolf, N.; Petring, D.

    Glass fiber and carbon fiber reinforced polymers with thermoplastic matrix enable high volume production with short cycle times. Cutting and trimming operations in these production chains require the use of high average laser power for an efficient cutting speed, but employment of high laser power runs the risk to induce a wide heat affected zone (HAZ). This paper deals with investigations with cw and ns-pulsed CO2-laser radiation in the kilowatt range in single-pass and multiple-pass processes. Using multi-pass processing at high processing speeds of 100 m/min and above a reduced heat affected zone in the range of 100 μm to 200 μm could be achieved by the ns-pulsed radiation. With cw radiation at the same average power of 1 kW however, the HAZ was 300-400 μm. Also employing ns-pulses in the kW-range average power leads to heat accumulation in the material. Small HAZ were obtained with sufficient break times between subsequent passes.

  11. Formation of secondary messengers by blood-formed elements in low-power laser irradiation

    NASA Astrophysics Data System (ADS)

    Brill, Gregory E.; Proshina, Olga V.; Zhigalina, Valentina N.; Filimonovskaya, Lyudmila S.; Romanova, Tatyana P.; Petrisheva, Svetlana G.; Zolotarjova, Tamara M.

    1995-05-01

    Irradiation of heparinized rat blood by He-Ne laser light ((lambda) - 632.8 nm, power density - 5 mW/cm2) during 15 or 30 min was performed in vitro experiments. The complex of biochemical parameters of erythrocytes, plasma and cytochemical parameters of polymorphonuclear leucocytes was studied. Laser irradiation was stated to cause different metabolic changes in red blood cells and neutrophils depending on the dose. In both doses of irradiation glucose-6-phosphate dehydrogenase activity lowers in erythrocytes, succinate dehydrogenase activity and lysosomal cationic proteins content increase in neutrophils. Stimulation of oxygen active forms production in cellular membranes of blood formed elements results in plasma malonic dialdehyde level increase and in the change of the balance between primary and secondary lipid peroxidation products. Cooperative interaction between different blood cells in the process of realization of system response to laser exposure is supposed to exist.

  12. Laser processes and analytics for high power 3D battery materials

    NASA Astrophysics Data System (ADS)

    Pfleging, W.; Zheng, Y.; Mangang, M.; Bruns, M.; Smyrek, P.

    2016-03-01

    Laser processes for cutting, modification and structuring of energy storage materials such as electrodes, separator materials and current collectors have a great potential in order to minimize the fabrication costs and to increase the performance and operational lifetime of high power lithium-ion-batteries applicable for stand-alone electric energy storage devices and electric vehicles. Laser direct patterning of battery materials enable a rather new technical approach in order to adjust 3D surface architectures and porosity of composite electrode materials such as LiCoO2, LiMn2O4, LiFePO4, Li(NiMnCo)O2, and Silicon. The architecture design, the increase of active surface area, and the porosity of electrodes or separator layers can be controlled by laser processes and it was shown that a huge impact on electrolyte wetting, lithium-ion diffusion kinetics, cell life-time and cycling stability can be achieved. In general, the ultrafast laser processing can be used for precise surface texturing of battery materials. Nevertheless, regarding cost-efficient production also nanosecond laser material processing can be successfully applied for selected types of energy storage materials. A new concept for an advanced battery manufacturing including laser materials processing is presented. For developing an optimized 3D architecture for high power composite thick film electrodes electrochemical analytics and post mortem analytics using laser-induced breakdown spectroscopy were performed. Based on mapping of lithium in composite electrodes, an analytical approach for studying chemical degradation in structured and unstructured lithium-ion batteries will be presented.

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

    NASA Technical Reports Server (NTRS)

    Chan, Kinpui

    1988-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

  15. Cladded single crystal fibers for high power fiber lasers

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

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

  16. Extremely high-power CO2 laser beam correction.

    PubMed

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

    2015-05-10

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

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

    DOEpatents

    Gruen, Dieter M.

    2000-01-01

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

  18. Method and system for modulation of gain suppression in high average power laser systems

    DOEpatents

    Bayramian, Andrew James [Manteca, CA

    2012-07-31

    A high average power laser system with modulated gain suppression includes an input aperture associated with a first laser beam extraction path and an output aperture associated with the first laser beam extraction path. The system also includes a pinhole creation laser having an optical output directed along a pinhole creation path and an absorbing material positioned along both the first laser beam extraction path and the pinhole creation path. The system further includes a mechanism operable to translate the absorbing material in a direction crossing the first laser beam extraction laser path and a controller operable to modulate the second laser beam.

  19. Advantages offered by high average power picosecond lasers

    NASA Astrophysics Data System (ADS)

    Moorhouse, C.

    2011-03-01

    As electronic devices shrink in size to reduce material costs, device size and weight, thinner material thicknesses are also utilized. Feature sizes are also decreasing, which is pushing manufacturers towards single step laser direct write process as an attractive alternative to conventional, multiple step photolithography processes by eliminating process steps and the cost of chemicals. The fragile nature of these thin materials makes them difficult to machine either mechanically or with conventional nanosecond pulsewidth, Diode Pumped Solids State (DPSS) lasers. Picosecond laser pulses can cut materials with reduced damage regions and selectively remove thin films due to the reduced thermal effects of the shorter pulsewidth. Also, the high repetition rate allows high speed processing for industrial applications. Selective removal of thin films for OLED patterning, silicon solar cells and flat panel displays is discussed, as well as laser cutting of transparent materials with low melting point such as Polyethylene Terephthalate (PET). For many of these thin film applications, where low pulse energy and high repetition rate are required, throughput can be increased by the use of a novel technique to using multiple beams from a single laser source is outlined.

  20. f Number Increase of a High-Intensity Green Laser Beam in a Plasma

    NASA Astrophysics Data System (ADS)

    Cobble, J. A.; Johnson, R. P.; Mason, R. J.

    1997-11-01

    Earlier(J. A. Cobble, R. P. Johnson, R. J. Mason, Phys. Plasmas 6, 3006 (1997).), we studied the increase in f number of a high-intensity, 1054-nm laser beam passing through a low density, preformed plasma, i. e., an exploding foil. We have extended this work to 527-nm light. Again we find an increase in the f number of the probe beam. Near field imaging of the transmitted green beam shows a factor of four reduction in beam divergence at 8 percent of the critical density. The change is less for lower densities, and the beam compression corresponds to the critical power dropping below the laser power (0.6 TW) as the density increases. The density is estimated from the spectra of stimulated Raman back scatter and from modeling of the target plasma with LASNEX. A CCD camera and a spectrometer with a 200-nm bandwidth were used to record the backscattered spectra. *Work performed under the auspices of the U. S. Department of Energy.

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

    SciTech Connect

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

    1997-06-01

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

  2. High power master oscillator power amplifier (MOPA) AlGaAs laser for intersatellite communications

    NASA Technical Reports Server (NTRS)

    Cornwell, Donald M., Jr.

    1992-01-01

    A master oscillator power amplifier (MOPA) configuration has been developed using an anti-reflection-coated AlGaAs semiconductor broad area laser in a reflective amplifier mode. For CW injection, the MOPA produced 340 mW of diffraction-limited power. The semiconductor MOPA configuration also produced peak diffraction-limited powers of 360 mW and 320 mW for quaternary pulse position Q-PPM modulation rates of 50 Mbps and 325 Mbps, respectively, for a peak injected power of 100 mW. Angular beamsteering during modulation was minimized by collimating the injected beam. The diffraction-limited peak power was limited by the frequency chirp of the master oscillator and also by the coupling losses of the injected beam.

  3. Advantages of China Lake for laser power beaming

    NASA Astrophysics Data System (ADS)

    Bennett, Harold E.

    1995-04-01

    The site for the proposed National Advanced Optic Mission Initiative (NAOMI) facility will be in the mountains near China Lake, California. This location has 260 clear days per year (more than any other feasible site in the U.S.). In 1993 there were 5 completely overcast days all year. The area near the proposed site is unpopulated. The solar insolation in this general area is the greatest of any area in the United States. The NAOMI system will be installed at an altitude of 5600 feet. Astronomical seeing there is excellent. Even at a less favored site than that planned for NAOMI the average Fried seeing coefficient ro is 12 cm in the visible region and 20 cm values of ro (comparable to the best observatories) are commonly observed. The area is centrally located in and entirely surrounded by one of the largest restricted airspace/military operating airspace complexes in the United States, 12% of the entire airspace in California. Electrical power is available from either the nearly Coso Geothermal plant, second largest in the United States, or from the even closer cogeneration plant at Trona, California. Cooling water can be obtained from the nearby area or from the lake itself. Although a dry playa, the lake has a high brackish groundwater level. Most of the commercial satellites over the U.S. could be reached by a laser/telescope system located on government land at the Naval Air Weapons Station (NAWS) military reservation at China Lake. This telescope/laser system will be a prototype for five other systems planned for around the world. The complex will provide laser power beaming to all satellites and put the United States into the position of world leader in satellite technology and power beaming to space.

  4. Laser damage of dichroic coatings in a high average power laser vacuum resonator

    SciTech Connect

    Arnold, P A; Berzins, L V; Chow, R; Erbert, G V

    1999-07-28

    In our application, dichroics in a high average power, near-infrared, laser system have short operating lifetimes. These dichroics were used as the resonator fold mirrors and permitted the transmission of the pumping argon (Ar) ion laser light. Representative samples of two different dichroic optics were taken off-line and the transmission performance monitored in various scenarios. Irradiating these optics under resonator vacuum conditions, ({le}1 mT, 11.7 kW/cm{sup 2}, Ar laser running all wavelengths) resulted in a degradation of transmission with time. Irradiating these optics in a rarefied oxygen atmosphere (1 to 10 T of oxygen, 11.7 kW/cm{sup 2}, Ar laser running all wavelengths) the transmission remained steady over a period of days. The transmission loss observed in the optic tested in vacuum was somewhat reversible if the optic was subsequently irradiated in a rarefied oxygen atmosphere. This reversibility was only possible if the transmission degradation was not too severe. Further tests demonstrated that an atmosphere of 10 T of air also prevented the transmission degradation. In addition, tests were performed to demonstrate that the optic damage was not caused by the ultra-violet component in the Ar ion laser. Mechanisms that may account for this behavior are proposed.

  5. Dichroic mirror for high power Nd:YAG laser

    SciTech Connect

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

    1996-12-31

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

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

    DTIC Science & Technology

    1975-03-01

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

  7. High-resolution wavefront control of high-power laser systems

    SciTech Connect

    Brase, J; Brown, C; Carrano, C; Kartz, M; Olivier, S; Pennington, D; Silva, D

    1999-07-08

    Nearly every new large-scale laser system application at LLNL has requirements for beam control which exceed the current level of available technology. For applications such as inertial confinement fusion, laser isotope separation, laser machining, and laser the ability to transport significant power to a target while maintaining good beam quality is critical. There are many ways that laser wavefront quality can be degraded. Thermal effects due to the interaction of high-power laser or pump light with the internal optical components or with the ambient gas are common causes of wavefront degradation. For many years, adaptive optics based on thing deformable glass mirrors with piezoelectric or electrostrictive actuators have be used to remove the low-order wavefront errors from high-power laser systems. These adaptive optics systems have successfully improved laser beam quality, but have also generally revealed additional high-spatial-frequency errors, both because the low-order errors have been reduced and because deformable mirrors have often introduced some high-spatial-frequency components due to manufacturing errors. Many current and emerging laser applications fall into the high-resolution category where there is an increased need for the correction of high spatial frequency aberrations which requires correctors with thousands of degrees of freedom. The largest Deformable Mirrors currently available have less than one thousand degrees of freedom at a cost of approximately $1M. A deformable mirror capable of meeting these high spatial resolution requirements would be cost prohibitive. Therefore a new approach using a different wavefront control technology is needed. One new wavefront control approach is the use of liquid-crystal (LC) spatial light modulator (SLM) technology for the controlling the phase of linearly polarized light. Current LC SLM technology provides high-spatial-resolution wavefront control, with hundreds of thousands of degrees of freedom, more

  8. Impact of Line Width and Power of Laser on Radio over Fiber System

    NASA Astrophysics Data System (ADS)

    Sharma, Sakshi; Bhatia, Kamaljeet Singh; Kaur, Harsimrat

    2015-03-01

    In order to increase the capacity of the existing optical communication networks advanced modulation schemes are utilized. Keeping this in view, an radio-over-fiber subcarrier multiplexing (SCM) employing ASK modulation technique is proposed. Response of the system is analysed by varying the linewidth and the power of the CW Laser and the optimum value is concluded for the same so as to achieve reliable communication.

  9. High power and short pulse RF-excited CO II laser MOPA system for LLP EUV light source

    NASA Astrophysics Data System (ADS)

    Ariga, Tatsuya; Hoshino, Hideo; Miura, Taisuke; Endo, Akira

    2006-02-01

    Laser produced plasma EUV source is the candidate for high quality, 115 W EUV light source for the next generation lithography. Cost effective laser driver is the key requirement for the realization of the concept as a viable scheme. A CO II laser driven LPP system with a Xenon droplet target is therefore a promising light source alternative for EUV. We are developing a high power and high repetition rate CO II laser system to achieve 10 W intermediate focus EUV power. High conversion efficiency (CE) from the laser energy to EUV in-band energy is the primarily important issue for the concept to be realized. Numerical simulation analysis of a Xenon plasma target shows that a short laser pulse less than 15 ns is necessary to obtain a high CE by a CO II laser. This paper describes on the development of a CO II laser system with a short pulse length less than 15 ns, a nominal average power of a few kW, and a repetition rate of 100 kHz, based on RF-excited, axial flow CO II laser amplifiers. Output power of 1 kW has been achieved with a pulse length 15 ns at 100 kHz repletion rate in a small signal amplification condition with P(20) single line. The CO II laser system is reported on the conceptual design for a LPP EUV light source, and amplification performance in CW and short pulse using RF-excited axial flow lasers as amplifiers. Additional approach to increase the amplification efficiency is discussed.

  10. A study of pump power absorption efficiency of a diode side-pumped thin disk laser

    NASA Astrophysics Data System (ADS)

    Guo, Wei-rong; Feng, Chi; Li, Qiang; Yan, Le-lun; Jiang, Meng-hua

    2011-06-01

    A method computing the absorption efficiency with the difference between pump power entering the thin disk and pump power transmitted through the disk is introduced. Compared with directly computing the absorbed power, the method presented here needs much less computation to achieve the same accuracy, making it possible to compare much more absorption efficiency values at higher accuracy with a few parameters varied within certain ranges. Nonabsorption loss values were calculated with absorption coefficient, array distance and round disk radius varied within certain ranges. Results of calculation showed that the nonabsorption loss generally increases with increasing array distance, decreases with increasing round disk radius and decreases with increasing absorption coefficient. The method introduced by this paper presents a theoretical reference for the optimal design of thin disk lasers.

  11. Influence of laser power on atom probe tomographic analysis of boron distribution in silicon.

    PubMed

    Tu, Y; Takamizawa, H; Han, B; Shimizu, Y; Inoue, K; Toyama, T; Yano, F; Nishida, A; Nagai, Y

    2017-02-01

    The relationship between the laser power and the three-dimensional distribution of boron (B) in silicon (Si) measured by laser-assisted atom probe tomography (APT) is investigated. The ultraviolet laser employed in this study has a fixed wavelength of 355nm. The measured distributions are almost uniform and homogeneous when using low laser power, while clear B accumulation at the low-index pole of single-crystalline Si and segregation along the grain boundaries in polycrystalline Si are observed when using high laser power (100pJ). These effects are thought to be caused by the surface migration of atoms, which is promoted by high laser power. Therefore, for ensuring a high-fidelity APT measurement of the B distribution in Si, high laser power is not recommended.

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

    DTIC Science & Technology

    2014-10-31

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

  13. 16 W output power by high-efficient spectral beam combining of DBR-tapered diode lasers.

    PubMed

    Müller, André; Vijayakumar, Deepak; Jensen, Ole Bjarlin; Hasler, Karl-Heinz; Sumpf, Bernd; Erbert, Götz; Andersen, Peter E; Petersen, Paul Michael

    2011-01-17

    Up to 16 W output power has been obtained using spectral beam combining of two 1063 nm DBR-tapered diode lasers. Using a reflecting volume Bragg grating, a combining efficiency as high as 93.7% is achieved, resulting in a single beam with high spatial coherence. The result represents the highest output power achieved by spectral beam combining of two single element tapered diode lasers. Since spectral beam combining does not affect beam propagation parameters, M2-values of 1.8 (fast axis) and 3.3 (slow axis) match the M2-values of the laser with lowest spatial coherence. The principle of spectral beam combining used in our experiments can be expanded to combine more than two tapered diode lasers and hence it is expected that the output power may be increased even further in the future.

  14. Reversing pathologically increased EEG power by acoustic coordinated reset neuromodulation

    PubMed Central

    Adamchic, Ilya; Toth, Timea; Hauptmann, Christian; Tass, Peter Alexander

    2014-01-01

    Acoustic Coordinated Reset (CR) neuromodulation is a patterned stimulation with tones adjusted to the patient's dominant tinnitus frequency, which aims at desynchronizing pathological neuronal synchronization. In a recent proof-of-concept study, CR therapy, delivered 4–6 h/day more than 12 weeks, induced a significant clinical improvement along with a significant long-lasting decrease of pathological oscillatory power in the low frequency as well as γ band and an increase of the α power in a network of tinnitus-related brain areas. As yet, it remains unclear whether CR shifts the brain activity toward physiological levels or whether it induces clinically beneficial, but nonetheless abnormal electroencephalographic (EEG) patterns, for example excessively decreased δ and/or γ. Here, we compared the patients' spontaneous EEG data at baseline as well as after 12 weeks of CR therapy with the spontaneous EEG of healthy controls by means of Brain Electrical Source Analysis source montage and standardized low-resolution brain electromagnetic tomography techniques. The relationship between changes in EEG power and clinical scores was investigated using a partial least squares approach. In this way, we show that acoustic CR neuromodulation leads to a normalization of the oscillatory power in the tinnitus-related network of brain areas, most prominently in temporal regions. A positive association was found between the changes in tinnitus severity and the normalization of δ and γ power in the temporal, parietal, and cingulate cortical regions. Our findings demonstrate a widespread CR-induced normalization of EEG power, significantly associated with a reduction of tinnitus severity. PMID:23907785

  15. High-throughput machining using a high-average power ultrashort pulse laser and high-speed polygon scanner

    NASA Astrophysics Data System (ADS)

    Schille, Joerg; Schneider, Lutz; Streek, André; Kloetzer, Sascha; Loeschner, Udo

    2016-09-01

    High-throughput ultrashort pulse laser machining is investigated on various industrial grade metals (aluminum, copper, and stainless steel) and Al2O3 ceramic at unprecedented processing speeds. This is achieved by using a high-average power picosecond laser in conjunction with a unique, in-house developed polygon mirror-based biaxial scanning system. Therefore, different concepts of polygon scanners are engineered and tested to find the best architecture for high-speed and precision laser beam scanning. In order to identify the optimum conditions for efficient processing when using high-average laser powers, the depths of cavities made in the samples by varying the processing parameter settings are analyzed and, from the results obtained, the characteristic removal values are specified. For overlapping pulses of optimum fluence, the removal rate is as high as 27.8 mm3/min for aluminum, 21.4 mm3/min for copper, 15.3 mm3/min for stainless steel, and 129.1 mm3/min for Al2O3, when a laser beam of 187 W average laser powers irradiates. On stainless steel, it is demonstrated that the removal rate increases to 23.3 mm3/min when the laser beam is very fast moving. This is thanks to the low pulse overlap as achieved with 800 m/s beam deflection speed; thus, laser beam shielding can be avoided even when irradiating high-repetitive 20-MHz pulses.

  16. High average power diode pumped solid state laser

    NASA Astrophysics Data System (ADS)

    Gao, Yue; Wang, Yanjie; Chan, Amy; Dawson, Murray; Greene, Ben

    2017-03-01

    A new generation of high average power pulsed multi-joule solid state laser system has been developed at EOS Space Systems for various space related tracking applications. It is a completely diode pumped, fully automated multi-stage system consisting of a pulsed single longitudinal mode oscillator, three stages of pre-amplifiers, two stages of power amplifiers, completely sealed phase conjugate mirror or stimulated Brillouin scattering (SBS) cell and imaging relay optics with spatial filters in vacuum cells. It is capable of generating pulse energy up to 4.7 J, a beam quality M 2 ~ 3, pulse width between 10–20 ns, and a pulse repetition rate between 100–200 Hz. The system has been in service for more than two years with excellent performance and reliability.

  17. GaAs solar cells for laser power beaming

    NASA Technical Reports Server (NTRS)

    Olsen, Larry C.; Dunham, Glen; Huber, Daniel A.; Addis, F. William; Anheier, Norman; Coomes, E. P.

    1991-01-01

    Efforts to develop GaAs solar cells for coupling to laser beams in the wavelength range of 800 to 840 nm are described. This work was motivated primarily by interests in space-tp-space power beaming applications. In particular, the Battelle Pacific Northwest Laboratories is conducting studies of the utilization of power beaming for several future space missions. Modeling calculations of GaAs cell performance were carried out using PC-1D to determine an appropriate design for a p/n cell structure. Epitaxial wafers were grown by MOCVD and cells fabricated at WSU Tri-Cities. Under simulated conditions, an efficiency of 53 percent was achieved for a cell coupled to 806 nm light at 400 mW/sq cm.

  18. Annular resonators for high-power chemical lasers

    NASA Astrophysics Data System (ADS)

    Wade, Richard C.

    1993-08-01

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

  19. High power, high beam quality solid state lasers for materials processing applications

    SciTech Connect

    Hackel, L.A.; Dane, C.B.; Hermann, M.R.

    1994-08-01

    The Laser Science and Technology Department at Lawrence Livermore National Laboratory is developing solid state lasers with high average power and high beam quality. Specific systems include a laser to generate 10 to 14 {angstrom} x-rays for proximity print lithography, a 400 mJ, 500 Hz laser for 130 {angstrom} projection lithography and unique systems for speckle imaging, laser radars and medical treatments.

  20. Incoherent Combining of High-Power Fibers Lasers for Long-Range Directed Energy Applications

    DTIC Science & Technology

    2006-06-27

    Europe meeting IPG Photonics reported [2] CW powers of 2 kW at a wavelength of A = 1.075/.n from a ytterbium fiber laser . The fiber laser operated in a...propagation of the laser beams from the fiber array of Fig. 6 to the target. HELCAP is a 3 -dimensional, fully time-dependent, nonlinear atmospheric...configuration uses recently-developed, multi- kilowatt fiber lasers . These lasers , however, are not suitable for coherent beam combining because of their