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Lawrence Livermore Laser Fusion Program: a status report

Description: The Laser Fusion Program at the Lawrence Livermore Laboratory is presently emerging from a three-year period of intensive development of the tools required for significant DT implosion experiments of continuously increasing scale. These diverse tools include target design codes, sophisticated target fabrication techniques, radically new diagnostics instrumentation, high peak- power-high brightness laser technology, and fully integrated laser-target- diagnostic irradiation facilities. These tools have recently led to the successful production of neutrons from compressed DT-containing targets together with a wealth of correlating plasma physics data. The current status of major program activities at LLL will be reviewed and major future milestones will be projected. (auth)
Date: April 15, 1975
Creator: Krupke, W.F.
Partner: UNT Libraries Government Documents Department

Specific heat loading in Nd:glass lasers

Description: The specific thermal load parameter, chi, for xenon flashlamp-pumped Nd:glass gain media is written as a function of neodymium concentration, pump pulse duration, and energy extraction efficiency. The currently available data on radiative and nonradiative decay probabilities of several commercial Nd:glasses are used to calculate and graph specific thermal load parameter values. By factoring these results into performance scaling relationships for zig-zag and disk lasers, specific Nd:glasses can be selected for optimized laser performance.
Date: August 7, 1985
Creator: Krupke, W.F.
Partner: UNT Libraries Government Documents Department

Advanced crystalline laser materials

Description: To guide the laser materials research and development effort, we have analyzed the scaling laws for zig-zag and flow-cooled disk amplifiers, defined materials figures of merit, and developed laser performance applications maps. Within this technical framework, we have embarked on an effort to synthesize, characterize, select, and develop new materials useful for a variety of robust laser applications.
Date: January 1, 1984
Creator: Krupke, W.F.
Partner: UNT Libraries Government Documents Department

Insulator materials in high power lasers for inertial fusion: present and future

Description: A summary is given of the important characteristics of currently used insulator materials. Figures of merit for materials needed in future systems are identified. A methodology for identifying and evaluating new materials meeting the stringent performance requirements of future fusion laser systems is outlined.
Date: November 11, 1983
Creator: Krupke, W.F.
Partner: UNT Libraries Government Documents Department

Modern solid state laser materials

Description: This document contains visual aids used in an invited talk entitled Modern Solid State Laser Materials, presented at the Conference on Lasers and Electro-Optics (CLEO) held in Anaheim, California, on June 20, 1984. Interest at LLNL in solid state lasers focuses on evaluating the potential of solid state laser media for high average power applications, including inertial fusion power production. This talk identifies the relevant bulk material parameters characterizing average power capacity and uses chromium and neodymium co-doped gadolinium scandium gallium garnet (Nd:Cr:GSGG) as an example of a laser material with improved laser properties relative to Nd:YAG (plausible large-scale growth, more efficient spectral coupling to xenon flashlamp radiation, reduced stimulated emission cross section, adequate thermal shock and optical damage threshold parameters, etc.). Recently measured spectroscopic, kinetic, and thermo-mechanical properties of Nd:Cr:GSGG are given.
Date: June 20, 1984
Creator: Krupke, W.F.
Partner: UNT Libraries Government Documents Department

Solid state laser driver for an ICF reactor

Description: A conceptual design is presented of the main power amplifier of a multi-beamline, multi-megawatt solid state ICF reactor driver. Simultaneous achievement of useful beam quality and high average power is achieved by a proper choice of amplifier geometry. An amplifier beamline consists of a sequence of face-pumped rectangular slab gain elements, oriented at the Brewster angle relative to the beamline axis, and cooled on their large faces by helium gas that is flowing subsonically. The infrared amplifier output radiation is shifted to an appropriately short wavelength (<500 nm) using nonlinear crystals that are also gas cooled. We project an overall driver efficiency >10% (including all flow cooling input power) when the amplifiers are pumped by efficient high-power AlGaAs semiconductor laser diode arrays. 11 refs., 3 figs., 7 tabs.
Date: January 1, 1988
Creator: Krupke, W.F.
Partner: UNT Libraries Government Documents Department

Advanced lasers for fusion applications

Description: Projections indicate that MJ/MW laser systems, operating with efficiencies in escess of 1 percent, are required to drive laser fusion power reactors. Moreover, a premium in pellet performance is anticipated as the wavelength of the driver laser system is decreased. Short wavelength laser systems based on atomic selenium (lambda = 0.49..mu..), terbium molcular vapors (0.55..mu..), thulium doped dielectric solids (0.46..mu..), and on pulse compressions of KrF excimer laser radiaton (0.27..mu..) have been proposed and studied for this purpose. The technological scalability and efficiency of each of these systems is examined in this paper. All of these systems are projected to meet minimum systems requirements. Amont them, the pulse-compressed KrF system is projected to have the highest potential efficiency (6%) and the widest range of systems design options.
Date: November 1, 1978
Creator: Krupke, W.F.
Partner: UNT Libraries Government Documents Department

Diode-pumped solid state lasers (DPSSLs) for Inertial Fusion Energy (IFE)

Description: The status of diode-pumped, transverse-gas-flow cooled, Yb-S-FAP slab lasers is reviewed. Recently acquired experimental performance data are combined with a cost/performance IFE driver design code to define a cost-effective development path for IFE DPSSL drivers. Specific design parameters are described for the Mercury 100J/10 Hz, 1 kW system (first in the development scenario).
Date: October 1, 1996
Creator: Krupke, W.F.
Partner: UNT Libraries Government Documents Department

Applications of high average power nonlinear optics

Description: Nonlinear optical frequency convertors (harmonic generators and optical parametric oscillators are reviewed with an emphasis on high average power performance and limitations. NLO materials issues and NLO device designs are discussed in reference to several emerging scientific, military and industrial commercial applications requiring {approx} 100 watt average power level in the visible and infrared spectral regions. Research efforts required to enable practical {approx} 100 watt class NLO based laser systems are identified.
Date: February 5, 1996
Creator: Velsko, S.P. & Krupke, W.F.
Partner: UNT Libraries Government Documents Department

Physics of laser fusion. Volume IV. The future development of high-power solid-state laser systems

Description: Solid state lasers, particularly neodymium glass systems, have undergone intensive development during the last decade. In this paper, we review solid state laser technology in the context of high-peak-power systems for inertial confinement fusion. Specifically addressed are five major factors: efficiency, wavelength flexibility, average power, system complexity, and cost; these factors today limit broader application of the technology. We conclude that each of these factors can be greatly improved within current fundamental physical limits. We further conclude that the systematic development of new solid state laser madia, both vitreous and crystalline, should ultimately permit the development of wavelength-flexible, very high average power systems with overall efficiencies in the range of 10 to 20%.
Date: November 1, 1982
Creator: Emmett, J.L.; Krupke, W.F. & Trenholme, J.B.
Partner: UNT Libraries Government Documents Department

Potential of high-average-power solid state lasers

Description: 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.
Date: September 25, 1984
Creator: Emmett, J.L.; Krupke, W.F. & Sooy, W.R.
Partner: UNT Libraries Government Documents Department

Laser program annual report, 1980

Description: Volume 3 is comprised of three sections, beginning with Section 8 on Advanced Lasers. Both theoretical and experimental research and development activities on advanced laser systems are presented here. Section 9 contains the results of studies in areas of energy and military applications, including those relating to electrical energy production by inertial confinement fusion systems. Finally, Section 10 presents results from selected activities in the Advanced Isotope Separation Program.
Date: June 1, 1981
Creator: Coleman, L.W.; Krupke, W.F. & Strack, J.R. (eds.)
Partner: UNT Libraries Government Documents Department

Laser program annual report, 1980

Description: Volume 1 provides a Program Overview, presenting highlights of the technical accomplishments of the elements of the Program, a summary of activities carried out under the Glass Laser Experiments Lead Laboratory Program, as well as discussions of Program resources and facilities. Section 2, also in the first volume, covers the work on solid state Nd:glass lasers, including systems operations, Nova and Novette system development, and supporting research and development activities.
Date: June 1, 1981
Creator: Coleman, L.W.; Krupke, W.F. & Strack, J.R. (eds.)
Partner: UNT Libraries Government Documents Department

New solid state lasers from the ultraviolet to the mid-infrared

Description: The authors discuss three new laser materials that offer improved access to the ultraviolet, near infrared and mid-infrared spectral regions. In order for each of these materials to have been identified, a particular hurdle needed to be overcome with respect to the fundamental laser physics impacting the material. In the case of the 280-320nm Ce:LiSAF laser, the main issue is the need to reduce the loss associated with excited state absorption, while for 1047nm Yb:S-FAP it is the ground state absorption at the laser wavelength that must be minimized. Cr:ZnSe has been down-selected from a number of potential candidates which could lase in the 2200-3000nm region, in order to mitigate the detrimental impact of nonradiative decay. In all three cases the authors discuss how appropriate consideration of fundamental concerns has led to the identification and understanding of the new laser system.
Date: August 15, 1995
Creator: Payne, S.A.; Krupke, W.F. & Beach, R.J.
Partner: UNT Libraries Government Documents Department

Yb:FAP and related materials, laser gain medium comprising same, and laser systems using same

Description: An ytterbium doped laser material remarkably superior to all others, including Yb:YAG, comprises ytterbium doped apatite (Yb:Ca{sub 5}(PO{sub 4}){sub 3}F) or Yb:FAP, or ytterbium doped crystals structurally related to FAP. The new laser material is used in laser systems pumped by diode pump sources having an output near 0.905 microns or 0.98 microns, such as InGaAs and AlInGaAs, or other narrowband pump sources near 0.905 microns or 0.98 microns. The laser systems are operated in either the conventional or ground state depletion mode.
Date: December 31, 1991
Creator: Krupke, W.F.; Payne, S.A.; Chase, L.L. & Smith, L.K.
Partner: UNT Libraries Government Documents Department

Can solid-state laser technology serve usefully beyond fusion ignition facilities?

Description: We have explored the major technical and conceptual issues relating to the suitability of a diode-pumped solid state laser as a driver for an inertial fusion energy power plant. While solid state lasers have long served as the workhorse of inertial confinement fusion physics studies, the deployment of a driver possessing adequate efficiency, reliability, and repetition rate for inertial fusion energy requires the implementation of several technical innovations discussed in this article.
Date: July 28, 1995
Creator: Payne, S.A.; Powell, H.T. & Krupke, W.F.
Partner: UNT Libraries Government Documents Department

Diode-pumped solid state laser for inertial fusion energy

Description: The authors evaluate the prospect for development of a diode-pumped solid-state-laser driver in an inertial fusion energy power plant. Using a computer code, they predict that their 1 GWe design will offer electricity at 8.6 cents/kW {center_dot} hr with the laser operating at 8.6% efficiency and the recycled power level at 31%. The results of their initial subscale experimental testbed of a diode-pumped solid state laser are encouraging, demonstrating good efficiencies and robustness.
Date: November 1, 1994
Creator: Payne, S.A.; Krupke, W.F. & Orth, C.D.
Partner: UNT Libraries Government Documents Department

Room-temperature laser action at 4.3--4.4 {micro}m in CaGa{sub 2}S{sub 4}:Dy{sup 3+}

Description: The authors report room-temperature mid-IR laser operation in a new low-phonon-frequency, non-hygroscopic host crystal CaGa{sub 2}S{sub 4} (calcium thiogallate). Laser action at 4.31 {micro}m on the {sup 6}H{sub 11/2} {r_arrow}{sup 6}H{sub 13/2} transition of trivalent dysprosium was achieved with a slope efficiency of 1.6%.
Date: April 22, 1999
Creator: Nostrand, M; Page, R H; Payne, S A; Krupke, W F & Schunemann
Partner: UNT Libraries Government Documents Department

Trends in packaging of high power semiconductor laser bars

Description: Several different approaches to packaging high power diode laser bars for pumping solid state lasers or for direct diode laser applications are examined. The benefit and utility of each package is 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.
Date: July 1, 1997
Creator: Solarz, R.W.; Emanuel, M.A.; Skidmore, J.A.; Freitas, B.L. & Krupke, W.F.
Partner: UNT Libraries Government Documents Department