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Ultrabright Laser-based MeV-class Light Source

Description: We report first light from a novel, new source of 10-ps 0.776-MeV gamma-ray pulses known as T-REX (Thomson-Radiated Extreme X-rays). The MeV-class radiation produced by TREX is unique in the world with respect to its brightness, spectral purity, tunability, pulse duration and laser-like beam character. With T-REX, one can use photons to efficiently probe and excite the isotope-dependent resonant structure of atomic nucleus. This ability will be enabling to an entirely new class of isotope-specific, high resolution imaging and detection capabilities.
Date: April 2, 2008
Creator: Albert, F; Anderson, G; Anderson, S; Bayramian, A; Berry, B; Betts, S et al.
Partner: UNT Libraries Government Documents Department

A Laser Technology Test Facility for Laser Inertial Fusion Energy (LIFE)

Description: A LIFE laser driver needs to be designed and operated which meets the rigorous requirements of the NIF laser system while operating at high average power, and operate for a lifetime of >30 years. Ignition on NIF will serve to demonstrate laser driver functionality, operation of the Mercury laser system at LLNL demonstrates the ability of a diode-pumped solid-state laser to run at high average power, but the operational lifetime >30 yrs remains to be proven. A Laser Technology test Facility (LTF) has been designed to specifically address this issue. The LTF is a 100-Hz diode-pumped solid-state laser system intended for accelerated testing of the diodes, gain media, optics, frequency converters and final optics, providing system statistics for billion shot class tests. These statistics will be utilized for material and technology development as well as economic and reliability models for LIFE laser drivers.
Date: October 6, 2009
Creator: Bayramian, A J; Campbell, R W; Ebbers, C A; Freitas, B L; Latkowski, J; Molander, W A et al.
Partner: UNT Libraries Government Documents Department

FY96-98 Summary Report Mercury: Next Generation Laser for High Energy Density Physics SI-014

Description: The scope of the Mercury Laser project encompasses the research, development, and engineering required to build a new generation of diode-pumped solid-state lasers for Inertial Confinement Fusion (ICF). The Mercury Laser will be the first integrated demonstration of laser diodes, crystals, and gas cooling within a scalable laser architecture. This report is intended to summarize the progress accomplished during the first three years of the project. Due to the technological challenges associated with production of 900 nm diode-bars, heatsinks, and high optical-quality Yb:S-FAP crystals, the initial focus of the project was primarily centered on the R&D in these three areas. During the third year of the project, the R&D continued in parallel with the development of computer codes, partial activation of the laser, component testing, and code validation where appropriate.
Date: May 25, 2000
Creator: Bayramian, A.; Beach, R.; Bibeau, C.; Chanteloup, J.-C.; Ebbers, C.; Emanuel, M. et al.
Partner: UNT Libraries Government Documents Department

The Mercury Project: A High Average Power, Gas-Cooled Laser For Inertial Fusion Energy Development

Description: Hundred-joule, kilowatt-class lasers based on diode-pumped solid-state technologies, are being developed worldwide for laser-plasma interactions and as prototypes for fusion energy drivers. The goal of the Mercury Laser Project is to develop key technologies within an architectural framework that demonstrates basic building blocks for scaling to larger multi-kilojoule systems for inertial fusion energy (IFE) applications. Mercury has requirements that include: scalability to IFE beamlines, 10 Hz repetition rate, high efficiency, and 10{sup 9} shot reliability. The Mercury laser has operated continuously for several hours at 55 J and 10 Hz with fourteen 4 x 6 cm{sup 2} ytterbium doped strontium fluoroapatite (Yb:S-FAP) amplifier slabs pumped by eight 100 kW diode arrays. The 1047 nm fundamental wavelength was converted to 523 nm at 160 W average power with 73% conversion efficiency using yttrium calcium oxy-borate (YCOB).
Date: November 3, 2006
Creator: Bayramian, A; Armstrong, P; Ault, E; Beach, R; Bibeau, C; Caird, J et al.
Partner: UNT Libraries Government Documents Department

Diode-pumped solid-state lasers: next generation drivers for inertial fusion energy and high energy density plasma physics

Description: We are in the process of developing and building a laser system as the first in a series of a new generation of diode-pumped solid-state Inertial Confinement Fusion (ICF) lasers at LLNL (see Fig. 1 below). This laser system named �Mercury� will be the first integrated demonstration of a scalable laser architecture compatible with advanced high energy density (HED) physics applications. Primary performance goals include 10% efficiencies at 10 Hz and a 1- 10 ns pulse with lo energies of 100 J and with 2(omega)J/3(omega) frequency conversion.
Date: August 3, 1998
Creator: Beach, R. J.; Bibeau, C.; Ebbers, C. A.; Emanuel, M. A.; Honea, E. C.; Krupke, W. F. et al.
Partner: UNT Libraries Government Documents Department

Mercury and Beyond: Diode-Pumped Solid-State Lasers for Inertial Fusion Energy

Description: We have begun building the ''Mercury'' laser system as the first in a series of new generation diode-pumped solid-state lasers for inertial fusion research. Mercury will integrate three key technologies: diodes, crystals, and gas cooling, within a unique laser architecture that is scalable to kilojoule and megajoule energy levels for fusion energy applications. The primary near-term performance goals include 10% electrical efficiencies at 10 Hz and 1005 with a 2-10 ns pulse length at 1.047 {micro}m wavelength. When completed, Mercury will allow rep-rated target experiments with multiple chambers for high energy density physics research.
Date: December 1, 1999
Creator: Bibeau, C.; Bayramian, A.; Beach, R.J.; Chanteloup, J.C.; Ebbers, C.A.; Emanuel, M.A. et al.
Partner: UNT Libraries Government Documents Department

Performance of a diode-end-pumped Yb:YAG laser

Description: Using an end-pumped technology developed at LLNL we have demonstrated a Yb:YAG laser capable of delivering up to 434 W of CW power and 280 W of Q-switched power. In addition, we have frequency doubled the output to 515 nm using a dual crystal scheme to produce 76 W at 10 kHz in a 30 ns pulse length.
Date: May 5, 1997
Creator: Bibeau, C.; Beach, R.; Ebbers, C. & Emanuel, M.
Partner: UNT Libraries Government Documents Department

CW and Q-switched performance of a diode end-pumped Yb:YAG laser. Revision 1

Description: Using an end-pumped technology developed at LLNL we have demonstrated a Yb:YAG laser capable of delivering up to 434 W of CW power and 226 W of Q-switched power. In addition, we have frequency doubled the output to 515 nm using a dual crystal scheme to produce 76 W at 10 kHz in a 30 ns pulse length.
Date: February 19, 1997
Creator: Bibeau, C.; Beach, R.; Ebbers, C.; Emanuel, M. & Skidmore, J.
Partner: UNT Libraries Government Documents Department

Mercury and Beyond: Diode-Pumped Solid-State Lasers for Inertial Fusion Energy

Description: We have begun building the ''Mercury'' laser system as the first in a series of new generation diode-pumped solid-state lasers for inertial fusion research. Mercury will integrate three key technologies: diodes, crystals, and gas cooling, within a unique laser architecture that is scalable to kilojoule energy levels for fusion energy applications. The primary performance goals include 10% electrical efficiencies at 10 Hz and 100 J with a 2-10 ns pulse length at 1.047 pm wavelength. When completed, Mercury will allow rep-rated target experiments with multiple target chambers for high energy density physics research.
Date: October 19, 1999
Creator: Bibeau, C.; Beach, R.J.; Bayramian, A.; Chanteloup, J.C.; Ebbers, C.A.; Emanuel, M.A. et al.
Partner: UNT Libraries Government Documents Department

The Mercury Laser System: An Average power, gas-cooled, Yb:S-FAP based system with frequency conversion and wavefront correction

Description: We report on the operation of the Mercury laser with fourteen 4 x 6 cm{sup 2} Yb:S-FAP amplifier slabs pumped by eight 100 kW peak power diode arrays. The system was continuously run at 55 J and 10 Hz for several hours, (2 x 10{sup 5} cumulative shots) with over 80% of the energy in a 6 times diffraction limited spot at 1.047 um. Improved optical quality was achieved in Yb:S-FAP amplifiers with magneto-rheological finishing, a deterministic polishing method. In addition, average power frequency conversion employing YCOB was demonstrated at 50% conversion efficiency or 22.6 J at 10 Hz.
Date: August 31, 2005
Creator: Bibeau, C; Bayramian, A; Armstrong, P; Ault, E; Beach, R; Benapfl, M et al.
Partner: UNT Libraries Government Documents Department

FY2005 Progress Summary and FY2006 Program Plan Statement of Work and Deliverables for Development of High Average Power Diode-Pumped Solid State Lasers, and Complementary Technologies, for Applications in Energy and Defense

Description: The primary focus this year was to operate the system with two amplifiers populated with and pumped by eight high power diode arrays. The system was operated for extended run periods which enabled average power testing of components, diagnostics, and controls. These tests were highly successful, with a demonstrated energy level of over 55 joules for 4 cumulative hours at a repetition rate of 10 Hz (average power 0.55 kW). In addition, high average power second harmonic generation was demonstrated, achieving 227 W of 523.5 nm light (22.7 J, 10 Hz, 15 ns, 30 minutes) Plans to achieve higher energy levels and average powers are in progress. The dual amplifier system utilizes a 4-pass optical arrangement. The Yb:S-FAP slabs were mounted in aerodynamic aluminum vane structures to allow turbulent helium gas flow across the faces. Diagnostic packages that monitored beam performance were deployed during operation. The laser experiments involved injecting a seed beam from the front end into the system and making four passes through both amplifiers. Beam performance diagnostics monitored the beam on each pass to assess system parameters such as gain and nearfield intensity profiles. This year, an active mirror and wavefront sensor were procured and demonstrated in an off-line facility. The active mirror technology can correct for low order phase distortions at user specified operating conditions (such as repetition rates different than 10 Hz) and is a complementary technology to the static phase plates used in the system for higher order distortions. A picture of the laser system with amplifier No.2 (foreground) and amplifier No.1 (background) is shown in Fig. 1.0.1.1. The control system and diagnostics were recently enhanced for faster processing and allow remote operation of the system. The growth and fabrication of the Yb:S-FAP slabs constituted another major element of our program objectives. Our goal ...
Date: March 24, 2006
Creator: Ebbers, C
Partner: UNT Libraries Government Documents Department

The Mercury Laser System-A scaleable average-power laser for fusion and beyond

Description: Nestled in a valley between the whitecaps of the Pacific and the snowcapped crests of the Sierra Nevada, Lawrence Livermore National Laboratory (LLNL) is home to the nearly complete National Ignition Facility (NIF). The purpose of NIF is to create a miniature star-on demand. An enormous amount of laser light energy (1.8 MJ in a pulse that is 20 ns in duration) will be focused into a small gold cylinder approximately the size of a pencil eraser. Centered in the gold cylinder (or hohlraum) will be a nearly perfect sphere filled with a complex mixture of hydrogen gas isotopes that is similar to the atmosphere of our Sun. During experiments, the laser light will hit the inside of the gold cylinder, heating the metal until it emits X-rays (similar to how your electric stove coil emits visible red light when heated). The X-rays will be used to compress the hydrogen-like gas with such pressure that the gas atoms will combine or 'fuse' together, producing the next heavier element (helium) and releasing energy in the form of energetic particles. 2010 will mark the first credible attempt at this world-changing event: the achievement of fusion energy 'break-even' on Earth using NIF, the world's largest laser! NIF is anticipated to eventually perform this immense technological accomplishment once per week, with the capability of firing up to six shots per day - eliminating the need for continued underground testing of our nation's nuclear stockpile, in addition to opening up new realms of science. But what about the day after NIF achieves ignition? Although NIF will achieve fusion energy break-even and gain, the facility is not designed to harness the enormous potential of fusion for energy generation. A fusion power plant, as opposed to a world-class engineering research facility, would require that the laser deliver ...
Date: March 26, 2008
Creator: Ebbers, C A & Moses, E I
Partner: UNT Libraries Government Documents Department

The Mercury Laser Advances Laser Technology for Power Generation

Description: 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.
Date: January 21, 2009
Creator: Ebbers, C A; Caird, J & Moses, E
Partner: UNT Libraries Government Documents Department

Summary of known linear and nonlinear optical properties of LiInS{sub 2}

Description: LiInS{sub 2} is a potentially useful crystal for cascaded parametric frequency conversion in the mid-IR. It is nearly noncritically phasematched for 1.064 {mu}m pumped, degenerate 2.12 {mu}m generation and 2 micron pumped generation of 3--5 {mu}m light. The nonlinear optical coefficients are 2{times} larger than those of KTP or KTA, while the transparency extends from 0.5--8 {mu}m. LiInS{sub 2} crystals are currently available in volumes up to 5 mm{sup 3}. This memo provides a brief summary of the current literature concerning the growth and linear and nonlinear optical properties of LiInS{sub 2}.
Date: February 24, 1994
Creator: Ebbers, C.
Partner: UNT Libraries Government Documents Department

A high average power electro-optic switch using KTP

Description: High damage threshold, high thermal conductivity, and small thermo-optic coefficients make KTiOPO{sub 4} (KTP) an attractive material for use in a high average power Q-switch. However, electro-chromic damage and refractive index homogeneity have prevented the utilization of KTP in such a device in the past. This work shows that electro-chromic damage is effectively suppressed using capacitive coupling, and a KTP crystal can be Q-switched for 1.5 {times} 10{sup 9} shots without any detectable electro-chromic damage. In addition, KTP with the high uniformity and large aperture size needed for a KTP electro-optic Q-switch can be obtained from flux crystals grown at constant temperature. A thermally compensated, dual crystal KTP Q-switch, which successfully produced 50 mJ pulses with a pulse width of 8 ns (FWHM), has been constructed. In addition, in off-line testing the Q-switch showed less than 7% depolarization at an average power loading of 3.2 kW/cm{sup 2}.
Date: April 1, 1994
Creator: Ebbers, C. A.; Cook, W. M. & Velsko, S. P.
Partner: UNT Libraries Government Documents Department

Optical and thermo-optical characterization of KTP and its isomorphs for 1.06 {micro}m pumped OPO`s

Description: The need to protect personnel from inadvertent eye trauma from fielded laser sources dictates that the highest externally accessible fluences produced by these systems be kept below the maximum permissible exposure (MPE) for intra-beam viewing. The large MPE value for a typical Q-switched (10 ns pulsewidth) source is 1 J/cm{sup 2} for wavelengths in the range of 1.5--1.8 microns, while the MPE for a similar pulsewidth Nd:YAG source is 5 {micro}J/cm{sup 2}. This 5 order of magnitude difference in the MPE is one reason for the trend towards shifting the output of near infrared sources used for remote sensing or ranging to the eyesafe wavelength region, even at the expense of overall system efficiency. There are 5 nonlinear optical crystals available with apertures of at least 10 x 10 mm{sup 2} which are also highly transparent in the 1.5 micron region; LiNbO{sub 3}, KNbO{sub 3}, KTP, KTA, and RTA. All 5 crystals are capable of 1,555 nm generation in an orientation with a favorable nonlinear optical coupling. However, KTP, KTA, or RTA are preferred materials, given that the generated signal of the OPO should remain at a fixed wavelength, insensitive to angular or thermal variations. The authors have characterized the phasematching angle, linewidth, thermal conductivity, and d{lambda}/dT for KTP, KTA, and RTA optical parametric oscillators.
Date: February 17, 1996
Creator: Ebbers, C.A. & Velsko, S.P.
Partner: UNT Libraries Government Documents Department

Short-pulse Laser Capability on the Mercury Laser System

Description: Applications using high energy ''petawatt-class'' laser drivers operating at repetition rates beyond 0.01 Hz are only now being envisioned. The Mercury laser system is designed to operate at 100 J/pulse at 10 Hz. We investigate the potential of configuring the Mercury laser to produce a rep-rated, ''petawatt-class'' source. The Mercury laser is a prototype of a high energy, high repetition rate source (100 J, 10 Hz). The design of the Mercury laser is based on the ability to scale in energy through scaling in aperture. Mercury is one of several 100 J, high repetition rate (10 Hz) lasers sources currently under development (HALNA, LUCIA, POLARIS). We examine the possibility of using Mercury as a pump source for a high irradiance ''petawatt-class'' source: either as a pump laser for an average power Ti:Sapphire laser, or as a pump laser for OPCPA based on YCa{sub 4}O(BO{sub 3}){sub 3} (YCOB), ideally producing a source approaching 30 J /30 fs /10 Hz--a high repetition rate petawatt. A comparison of the two systems with nominal configurations and efficiencies is shown in Table 1.
Date: June 22, 2006
Creator: Ebbers, C; Armstrong, P; Bayramian, A; Barty, C J; Bibeau, C; Britten, J et al.
Partner: UNT Libraries Government Documents Department

Laser System for Livermore's Mono Energetic Gamma-Ray Source

Description: A Mono-energetic Gamma-ray (MEGa-ray) source, based on Compton scattering of a high-intensity laser beam off a highly relativistic electron beam, requires highly specialized laser systems. To minimize the bandwidth of the {gamma}-ray beam, the scattering laser must have minimal bandwidth, but also match the electron beam depth of focus in length. This requires a {approx}1 J, 10 ps, fourier-transform-limited laser system. Also required is a high-brightness electron beam, best provided by a photoinjector. This electron source requires a second laser system with stringent requirements on the beam including flat transverse and longitudinal profiles and fast rise times. Furthermore, these systems must be synchronized to each other with ps-scale accuracy. Using a novel hyper-dispersion compressor configuration and advanced fiber amplifiers and diode-pumped Nd:YAG amplifiers, we have designed laser systems that meet these challenges for the X-band photoinjector and Compton-scattering source being built at Lawrence Livermore National Laboratory.
Date: March 14, 2011
Creator: Gibson, D; Albert, F; Bayramian, A; Marsh, R; Messerly, M; Ebbers, C et al.
Partner: UNT Libraries Government Documents Department