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Feasibility Of High Power Diode Laser Array Surrogate To Support Development Of Predictive Laser Lethality Model
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Book Synopsis Feasibility of High-Power Diode Laser Array Surrogate to Support Development of Predictive Laser Lethality Model by :
Download or read book Feasibility of High-Power Diode Laser Array Surrogate to Support Development of Predictive Laser Lethality Model written by and published by . This book was released on 2011 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: Predictive modeling and simulation of high power laser-target interactions is sufficiently undeveloped that full-scale, field testing is required to assess lethality of military directed-energy (DE) systems. The cost and complexity of such testing programs severely limit the ability to vary and optimize parameters of the interaction. Thus development of advanced simulation tools, validated by experiments under well-controlled and diagnosed laboratory conditions that are able to provide detailed physics insight into the laser-target interaction and reduce requirements for full-scale testing will accelerate development of DE weapon systems. The ultimate goal is a comprehensive end-to-end simulation capability, from targeting and firing the laser system through laser-target interaction and dispersal of target debris; a 'Stockpile Science' - like capability for DE weapon systems. To support development of advanced modeling and simulation tools requires laboratory experiments to generate laser-target interaction data. Until now, to make relevant measurements required construction and operation of very high power and complex lasers, which are themselves costly and often unique devices, operating in dedicated facilities that don't permit experiments on targets containing energetic materials. High power diode laser arrays, pioneered by LLNL, provide a way to circumvent this limitation, as such arrays capable of delivering irradiances characteristic of De weapon requires are self-contained, compact, light weight and thus easily transportable to facilities, such as the High Explosives Applications Facility (HEAF) at Lawrence Livermore National Laboratory (LLNL) where testing with energetic materials can be performed. The purpose of this study was to establish the feasibility of using such arrays to support future development of advanced laser lethality and vulnerability simulation codes through providing data for materials characterization and laser-material interaction models and to validate the accuracy of code predictions. This project was a Feasibility Study under the LLNL Laboratory Directed Research and Development (LDRD) Program.
Book Synopsis Epitaxial Design Optimizations for Increased Efficiency in GaAs-Based High Power Diode Lasers by : Thorben Kaul
Download or read book Epitaxial Design Optimizations for Increased Efficiency in GaAs-Based High Power Diode Lasers written by Thorben Kaul and published by Cuvillier Verlag. This book was released on 2021-04-09 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work presents progress in the root-cause analysis of power saturation mechanisms in continuous wave (CW) driven GaAs-based high-power broad area diode lasers operated at 935 nm. Target is to increase efficiency at high optical CW powers by epitaxial design. The novel extreme triple asymmetric (ETAS) design was developed and patented within this work to equip diode lasers that use an extremely thin p-waveguide with a high modal gain. An iterative variation of diode lasers employing ETAS designs was used to experimentally clarify the impact of modal gain on the temperature dependence of internal differential quantum efficiency (IDQE) and optical loss. High modal gain leads to increased free carrier absorption from the active region. However, less power saturation is observed, which must then be attributed to an improved temperature sensitivity of the IDQE. The effect of longitudinal spatial hole burning (LSHB) leads to above average non-linear carrier loss at the back facet of the device. At high CW currents the junction temperature rises. Therefore, not only the asymmetry of the carrier profile increases but also the average carrier density in order to compensate for the decreased material gain and increased threshold gain. This carrier non-pinning effect above threshold is found in this work to enhance the impact of LSHB already at low currents, leading to rapid degradation of IDQE with temperature. This finding puts LSHB into a new context for CW-driven devices as it emphasizes the importance of low carrier densities at threshold. The carrier density was effectively reduced by applying the novel ETAS design. This enabled diode lasers to be realized that show minimized degradation of IDQE with temperature and therefore improved performance in CW operation.
Book Synopsis Tailoring the Emission of Stripe-array Diode Lasers with External Cavities to Enable Nonlinear Frequency Conversion by : Andreas Jechow
Download or read book Tailoring the Emission of Stripe-array Diode Lasers with External Cavities to Enable Nonlinear Frequency Conversion written by Andreas Jechow and published by Universitätsverlag Potsdam. This book was released on 2009 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: A huge number of applications require coherent radiation in the visible spectral range. Since diode lasers are very compact and efficient light sources, there exists a great interest to cover these applications with diode laser emission. Despite modern band gap engineering not all wavelengths can be accessed with diode laser radiation. Especially in the visible spectral range between 480 nm and 630 nm no emission from diode lasers is available, yet. Nonlinear frequency conversion of near-infrared radiation is a common way to generate coherent emission in the visible spectral range. However, radiation with extraordinary spatial temporal and spectral quality is required to pump frequency conversion. Broad area (BA) diode lasers are reliable high power light sources in the near-infrared spectral range. They belong to the most efficient coherent light sources with electro-optical efficiencies of more than 70%. Standard BA lasers are not suitable as pump lasers for frequency conversion because of their poor beam quality and spectral properties. For this purpose, tapered lasers and diode lasers with Bragg gratings are utilized. However, these new diode laser structures demand for additional manufacturing and assembling steps that makes their processing challenging and expensive. An alternative to BA diode lasers is the stripe-array architecture. The emitting area of a stripe-array diode laser is comparable to a BA device and the manufacturing of these arrays requires only one additional process step. Such a stripe-array consists of several narrow striped emitters realized with close proximity. Due to the overlap of the fields of neighboring emitters or the presence of leaky waves, a strong coupling between the emitters exists. As a consequence, the emission of such an array is characterized by a so called supermode. However, for the free running stripe-array mode competition between several supermodes occurs because of the lack of wavelength stabilization. This leads to power fluctuations, spectral instabilities and poor beam quality. Thus, it was necessary to study the emission properties of those stripe-arrays to find new concepts to realize an external synchronization of the emitters. The aim was to achieve stable longitudinal and transversal single mode operation with high output powers giving a brightness sufficient for efficient nonlinear frequency conversion. For this purpose a comprehensive analysis of the stripe-array devices was done here. The physical effects that are the origin of the emission characteristics were investigated theoretically and experimentally. In this context numerical models could be verified and extended. A good agreement between simulation and experiment was observed. One way to stabilize a specific supermode of an array is to operate it in an external cavity. Based on mathematical simulations and experimental work, it was possible to design novel external cavities to select a specific supermode and stabilize all emitters of the array at the same wavelength. This resulted in stable emission with 1 W output power, a narrow bandwidth in the range of 2 MHz and a very good beam quality with M²<1.5. This is a new level of brightness and brilliance compared to other BA and stripe-array diode laser systems. The emission from this external cavity diode laser (ECDL) satisfied the requirements for nonlinear frequency conversion. Furthermore, a huge improvement to existing concepts was made. In the next step newly available periodically poled crystals were used for second harmonic generation (SHG) in single pass setups. With the stripe-array ECDL as pump source, more than 140 mW of coherent radiation at 488 nm could be generated with a very high opto-optical conversion efficiency. The generated blue light had very good transversal and longitudinal properties and could be used to generate biphotons by parametric down-conversion. This was feasible because of the improvement made with the infrared stripe-array diode lasers due to the development of new physical concepts.
Book Synopsis Development of High Power Diode Laser Systems by : Bodo Ehlers
Download or read book Development of High Power Diode Laser Systems written by Bodo Ehlers and published by . This book was released on 2005 with total page 111 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis High-Power CW Diode-Laser-Array-Pumped Solid-State Lasers and Efficient Non-Linear-Optical Frequency Conversion by :
Download or read book High-Power CW Diode-Laser-Array-Pumped Solid-State Lasers and Efficient Non-Linear-Optical Frequency Conversion written by and published by . This book was released on 1997 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt: The goals of this program were: development of high-power, cw diode-laser-array-pumped, Nd:YAG lasers, and efficient nonlinear frequency conversion of their output. Two minislab laser heads constructed as a single high power dual-head oscillator (96W, multi-mode) were operated separately to support Q-switched and cw nonlinear frequency conversion studies and single-frequency injection-locking studies and the start of cw amplifier research. A cw singly resonant optical parametric oscillator (SRO) utilizing bulk periodically poled LiNbO3 (PPLN) for tunable mid-IR radiation using the Q-switched laser as the pump was developed, and SHG output at 532 nm was increased from 800 mW average power (15 KHz rep rate) to 1300 mW average power (8.4 KHz rep rate). Coherent laser radar with high-power, high-coherence sources was pursued through a highly-coherent master oscillator cw power amplifier approach. We operated one laser head as a (1OW TEM00) oscillator and the second laser head as a triple-pass amplifier achieving 26 W TEM00 output. More extensive experiments on cw diode-laser pumped laser amplifiers for high-power, high-coherence sources were carried out to test the ability of theoretical modeling to predict amplifier output power.
Book Synopsis Design, simulation and analysis of laterally-longitudinally non-uniform edge-emitting GaAs-based diode lasers (Band 73) by : Jan-Philipp Koester
Download or read book Design, simulation and analysis of laterally-longitudinally non-uniform edge-emitting GaAs-based diode lasers (Band 73) written by Jan-Philipp Koester and published by Cuvillier Verlag. This book was released on 2023-09-19 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: Edge-emitting quantum-well diode lasers based on GaAs combine a high conversion efficiency, a wide range of emission wavelengths covering a span from 630 nm to 1180 nm, and the ability to achieve high output powers. The often used longitudinal-invariant Fabry-Pérot-type resonators are easy to design but often lead to functionality or performance limitations. In this work, the application of laterally-longitudinally non-uniform resonator configurations is explored as a way to reduce unwanted and performance-limiting effects. The investigations are carried out on existing and entirely newly developed laser designs using dedicated simulation tools. These include a sophisticated time-dependent laser simulator based on a traveling-wave model of the optical fields in the lateral-longitudinal plane and a Maxwell solver based on the eigenmode expansion method for the simulation of passive waveguides. Whenever possible, the simulation results are compared with experimental data. Based on this approach, three fundamentally different laser types are investigated: • Dual-wavelength lasers emitting two slightly detuned wavelengths around 784 nm out of a single aperture • Ridge-waveguide lasers with tapered waveguide and contact layouts that emit light of a wavelength of around 970 nm • Broad-area lasers with slightly tapered contact layouts emitting at 910 nm The results of this thesis underline the potential of lateral-longitudinal non-uniform laser designs to increase selected aspects of device performance, including beam quality, spectral stability, and output power.
Book Synopsis High-Power CW Diode-Laser-Array-Pumped Solid-State Lasers and Efficient Nonlinear Optical Frequency by :
Download or read book High-Power CW Diode-Laser-Array-Pumped Solid-State Lasers and Efficient Nonlinear Optical Frequency written by and published by . This book was released on 1994 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the interim period of this bridging contract, we have continued to work on the development of high-power cw diode-laser-array-pumped solid-state lasers. Towards that end, we have built lower power lasers in order to test individual components needed for the high-power laser, specifically we have built a 1 watt ring laser and a 5 watt slab laser. The 1 watt laser was used to study the injection locking process while assembling all the necessary electronics. We have demonstrated that it is possible to injection lock a diode- pumped laser using a single piezo-mounted mirror due to the lower intrinsic laser noise compared to an arc-lamp-pumped system. This allows us to optimize the injection locking servo loop and build a more stable locking system. The 5 watt laser was used as a test bed to find a practical way to mount the slab laser while minimizing the losses that occur at the total internal reflection (TIR) points in the slab. After trying many different means of protecting the TIR surfaces, we found that a new product from DuPont, Teflon AF 1600, has all the properties needed to provide a low loss protective coating. Using this material, the laser had a cavity loss of below 2%, which allowed for efficient operation of the laser in a side-pumped design. This laser produced 5 watts of output power with a slope efficiency near 20%.
Download or read book Diode Laser Arrays written by Dan Botez and published by . This book was released on 1994 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a thorough overview of the principles and uses of semiconductor diode laser arrays.
Book Synopsis Improvement of the beam quality of high-power broad area semiconductor diode lasers by means of an external resonator by : Ahmad Ibrahim Bawamia
Download or read book Improvement of the beam quality of high-power broad area semiconductor diode lasers by means of an external resonator written by Ahmad Ibrahim Bawamia and published by Cuvillier Verlag. This book was released on 2012-04-03 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: The operation of high-power broad area laser diodes in an external resonator is studied with respect to the improvement of their lateral beam quality. A simple setup with a broad area laser diode as gain medium, two lenses and an external mirror is considered. The concept relies on the ability of the active region of the laser diode to act as a spatial filter for higher order modes oscillating inside the resonator. The geometries of the external cavity laser that favor fundamental mode operation in the lateral direction are inferred with the help of a theoretical model based on the ABCDmatrix treatment of Gaussian beams in a passive stable resonator. Thermal lensing that arises in the broad area laser diode is included in the model. The simulation results show that, for a given strength of the thermal lens arising inside the broad area laser diode, there exists one geometry of the external resonator that produces single mode operation as well as a high overlap between the optical mode and the gain medium of the laser diode. A novel experimental procedure that quantifies the thermal lens arising in the broad area laser diode to be used inside the external resonator is developed. The thermal lens coefficient is determined for different injection currents and pulse widths. The reliability of the method is validated by the comparison of the obtained results with values of the thermal lens coefficient derived from independent measurements and from the simulation of the temperature distribution inside the laser diode. Furthermore, the latter simulation at different pulse widths enables to explain the observed saturation of the thermal lens coefficient as injection current and pulse width are increased. The external cavity laser comprising a test broad area laser diode that emits at a wavelength in the region of 1.06μm, two lenses, and an external mirror is implemented. Additionally, an adjustable intra-cavity slit that serves as a supplementary spatial filter is inserted in the setup. The evolution of the output power and of the beam quality of the device as a function of the length of the resonator and of the width of the slit is studied at injection currents of 1A (close to laser threshold) and 5A (high power operation). It is observed that at both injection currents, the beam quality of the emission is significantly improved when the length of the resonator and the width of the slit are adjusted to their optimal values. In the case of the experiments at an injection current of 1A, the optimal conditions for the operation of the external resonator correspond to the theoretical predictions, but, at an injection current of 5A, they have to be determined experimentally since the behavior of the laser cannot be explained by the model of the passive resonator anymore. The criterion used to assess the performance of the external cavity laser, as compared to a similar free running laser, is the maximum output power weighted by the M2 value. In that respect, at an injection current of 1A, the M2 value is improved from 9.0 to 3.5, with an output power of 0.35W. At the injection current of 5A, the M2 value is improved from 18.7 to 5.6, with a corresponding output power of 2.5W. The latter result compares with the best values reported in the literature for the operation of broad area laser diodes in an external resonator.
Book Synopsis Development of High Power Lasers for Materials Interactions by : L. A. Hackel
Download or read book Development of High Power Lasers for Materials Interactions written by L. A. Hackel and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 radiation for radiography, particle beam generation and eventually for a new class of fusion experiments call fast ignition. We have also built a record setting 50 watts of average output from a picosecond class laser and are using this technology for materials processing such as fine hole drilling and safe cutting of munitions. The laser science and technology program has developed and deployed a laser guide star on the Lick telescope on Mt. Hamilton and most recently on the Keck telescope in Hawaii. Our current development work in this area is focused on developing a much more compact all solid state diode pumped laser fiber system. Finally in a program originally initiated by DARPA we have developed a phase conjugated Nd:glass laser system with record setting performance and successfully deployed it for Navy and Air Force satellite imaging applications and have more recently successfully transferred it to industry for use in an emerging technology called laser peening. This laser technology is capable of 25 J to 100 J per pulse, 10 ns to 1000 ns pulse duration, 5 Hz laser. The technology has been industrially deployed and is proving to be highly effective in generating high intensity shocks that induce compressive residual stress into metal components. The compressive stress retards fatigue and stress corrosion cracking and is proving to extend the lifetime of high value components by factors of ten. This processing adds lifetime, enhances safety and can improve performance of aircraft systems. Laser peening is now being evaluated to reduce the weight of aircraft and may play a major role in the future combat system and its air transport by enabling lighter craft, longer range and greater payload. The laser peening technology is also being moved forward in NRC license application as the means to eliminate stress corrosion cracking for Yucca Mountain nuclear waste disposal canisters as well as a broad range of other applications.
Book Synopsis Optimization of Broad-area GaAs Diode Lasers for High Powers and High Efficiencies in the Temperature Range 200-220 K by : Frevert Carlo
Download or read book Optimization of Broad-area GaAs Diode Lasers for High Powers and High Efficiencies in the Temperature Range 200-220 K written by Frevert Carlo and published by . This book was released on 2019-07-11 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work focuses on the development of AlGaAs-based diode laser (DL) bars optimized for reaching highest powers and efficiencies at low operation temperatures. Specifically, the quasi continuous wave (QCW) pumping of cryogenically cooled Yb: YAG solid-state lasers is targeted, setting requirements on the wavelength (940 nm), the pulse conditions (pulse length 1.2 ms) and frequency (10 Hz) as well as the lowest DL operating temperature THS 200 K, consistent with economic cooling. High fill-factor bars for QCW operation are to reach high optical performance with optical output powers of P 1.5 kW and power conversion efficiencies of ŋE 60% at these power levels. Understanding the efficiency-limiting factors and the behavior at lower temperatures is necessary to design these devices. Optimizations are performed iteratively in three stages. First, vertical epitaxial designs are studied theoretically, adjusted to the targeted operation temperatures and specific laser parameters are extracted. Secondly, resulting vertical designs are processed into low power single emitters and their electro-optical behavior at low currents is experimentally assessed over a wide range of temperatures. The obtained laser parameters characteristic to the vertical design are then used to extrapolate the laser's performance up to the high targeted currents. Finally, vertical designs promising to reach the targeted values for power and efficiency are processed into high power single emitters and bars which are measured up to the highest currents. Eventually, laser bars are fabricated reaching output powers of 2 kW and efficiencies of 61% at 1.5 kW at an operation temperature of 203 K.
Book Synopsis High-Power Diode Laser Arrays for Large Scientific Lasers and Inertial Fusion by :
Download or read book High-Power Diode Laser Arrays for Large Scientific Lasers and Inertial Fusion written by and published by . This book was released on 2014 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :Mark S. Zediker Publisher :SPIE-International Society for Optical Engineering ISBN 13 :9780819484550 Total Pages :330 pages Book Rating :4.4/5 (845 download)
Book Synopsis High-power Diode Laser Technology and Applications IX by : Mark S. Zediker
Download or read book High-power Diode Laser Technology and Applications IX written by Mark S. Zediker and published by SPIE-International Society for Optical Engineering. This book was released on 2011 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt: Includes Proceedings Vol. 7821
Book Synopsis Development of a High Power Stablized Diode Laser System by : Matthias Fuchs
Download or read book Development of a High Power Stablized Diode Laser System written by Matthias Fuchs and published by . This book was released on 2006 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis High Power Diode Pumped Solid State Laser Development at Lawrence Livermore National Laboratory by :
Download or read book High Power Diode Pumped Solid State Laser Development at Lawrence Livermore National Laboratory written by and published by . This book was released on 1994 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors recent developments in high powered diode pumped solid state lasers at Lawrence Livermore National Laboratory. Over the past year the authors have made continued improvements to semiconductor pump array technology which includes the development of higher average power and lower cost pump modules. They report the performance of high power AlGaAs, InGaAs, and AlGaInP arrays. They also report on improvement to the integrated micro-optics designs in conjunction with lensing duct technology which gives rise to very high performance end pumping designs for solid state lasers which have major advantages which they detail. Substantial progress on beam quality improvements to near the diffraction limit at very high power have also been made and will be reported. They also will discuss recent experiments on high power non-linear materials for q-switches, harmonic converters, and parametric oscillators. Advances in diode pumped devices at LLNL which include tunable Cr:LiSrAlF6, mid-IR Er:YAG, holmium based lasers and other developments will also be outlined. Concepts for delivering up to 30 kilowatts of average power from a DPSSL oscillator will be described.
Book Synopsis High-power Diode Laser Technology and Applications VII by : Mark S. Zediker
Download or read book High-power Diode Laser Technology and Applications VII written by Mark S. Zediker and published by Society of Photo Optical. This book was released on 2009 with total page 508 pages. Available in PDF, EPUB and Kindle. Book excerpt: Includes Proceedings Vol. 7821
Book Synopsis High-Power CW Diode-Laser-Array-Pumped Solid-State Lasers and Efficient Nonlinear Optical Frequency Conversion by :
Download or read book High-Power CW Diode-Laser-Array-Pumped Solid-State Lasers and Efficient Nonlinear Optical Frequency Conversion written by and published by . This book was released on 1993 with total page 53 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the past three years we have made substantial progress toward the goal of a fiber coupled, diode laser pumped 1OOW cw Nd:YAG minislab laser. We have diode pumped a 1W ring cavity laser and have operated it in a single frequency. We have diode pumped a testbed minislab Nd:YAG laser using fiber coupled diode laser bars and generated 5W of cw, TEMoo mode output power. We have designed and are implementing a 5OW cw minislab Nd:YAG laser to be pumped by 25 diode laser bars coupled through optical fibers. We plan, in the second phase of this program, to achieve the 1OOW cw output power level in a minislab Nd:YAG laser approach proposed as the goal of this research program In addition, we have demonstrated single frequency control of a high power Nd:YAG laser oscillator by injection locking; have frequency stabilized Nd:YAG oscillators by locking to high finesse Fabry Perot resonators; have absolutely stabilized Nd:YAG to one part in 10 to the -13th power by locking to iodine; have frequency converted Nd:YAG by second harmonic generation to 11.2W of cw TEMoo mode green output; have demonstrated the first cw 2 microns OPO in lithium niobate; and have demonstrated the first cw singly resonant OPO with 2W of output in a single frequency in KTP.
