This volume of the LLE Review, covering the period April--June 1990, contains articles in two main sections, Progress in Laser Fusion and Advanced Technology Developments. The first article presents the theoretical interpretation of the glass-ablator cryogenic-implosion experiments recently conducted on OMEGA. It is followed by an article describing the analysis of neutron time-of-flight data taken during DT and DD experiments; and a discussion of the improvements to laser diagnostics that now provide for precise control of the OMEGA laser is given. This paper contains a report on the development of transparent conductive coatings for KDP crystals, and a discussion of the study of the transient-surface Debye-Waller effect in materials irradiated with an ultrafast laser.

This volume of the LLE Review, covering the period July--September 1990, contains articles in two main sections: the OMEGA Upgrade and Advanced Technology Developments. The first article in Section 1 describes the changes in the overall system design of the 60-beam OMEGA Upgrade since the release of the OMEGA Upgrade Preliminary Design Document in October 1989. It is followed by an article that presents results of an investigation into stimulated rotational Raman scattering as it relates to the propagation of high-fluence ultraviolet laser beams in the OMEGA Upgrade. The third article is a report on the energy-transport measurements made on the multisegmented amplifier (MSA), built as a prototype amplifier for the original OMEGA Upgrade system configuration. The final article in Section 1 describes the design of the 20-cm-clear-aperture, single-segmented amplifier (SSA), which will be the final amplifier in the current OMEGA Upgrade system configuration. Section 2 presents the results to date of an intensive in-house effort at LLE to develop the various optical coatings required for the OMEGA Upgrade.

This volume of the LLE Review, contains articles describing the results of imploding-target burnthrough experiments using smoothing by spectral dispersion (SSD), and a practical nonlocal model for electron transport in laser plasmas. The section on advanced technology includes a report on explosion fraction measurements of water-cooled xenon flashlamps, results on perfluorinated copolymer coatings for high-power laser applications, and a time-resolved study of surface disordering of Pb(110). A brief report reviewing the projects from the high school summer student program is also included. Finally, the activities of the National Laser Users Facility and the GDL and OMEGA laser facilities are summarized.

This volume of the LLE Review, covering the period October-December 1991, contains articles on the analysis of argon-filled target experiments, and a theoretical analysis of the impact of nonlocal heat transport in laser filamentation in plasmas. In the Advanced Technology section there is an article on mechanisms that affect thin-film conductivity, and a report on the gain characteristics of the 20-cm SSA prototype amplifier to be used in the OMEGA Upgrade. Finally, the activities of the National Laser Users Facility and the GDL and OMEGA laser facilities are summarized. Highlights of the research reported in this issue are: argon radiation from argon-filled, polymer-shell targets is used as a core-temperature diagnostic and density diagnostic of the surrounding region in a regime where the argon line radiation is strongly absorbed. A theoretical analysis of the impact of nonlocal heat transport on laser filamentation in plasmas is developed. The resulting model is compared with experimental observations and the implications for ICF are discussed. A study of thermal conductivity in thin films seeks to identify mechanisms that result in degradation of thin-film conductivity. Identifying these mechanisms can lead to changes in the thin-film manufacture that will improve their resistance to laser damage.

This volume of the LLE Review, covering the period January--March 1992, contains articles on the use of diffraction gratings in laser applications, and the fabrication of gratings for use in these applications. there are two articles on the use of lasers to explore fundamental physics issues and an article on the use of a solid-state diode array for x-ray imaging. Finally, the activities of the National Laser Users Facility and the GDL and OMEGA laser systems are summarized.

This volume of the LLE Review, covering the period April--June 1992, contains articles on laser-plasma interaction experiments in long-scale-length plasmas and on the theory of a new form of the stimulated Brillouin scattering instabilitity. The advanced technology section includes reports on the optical response of superconducting films, the development of high-reflectance transport mirrors for the OMEGA Upgrade, and a new high-brightness mono-mode laser oscillator. Finally, the activities of the National Laser Users Facility and the GDL and OMEGA laser systems are summarized.

This volume of the LLE Review, covering the period July--September 1992, contains articles on methods of balancing the beam power on the OMEGA Upgrade and on the damping of ion-sound waves in laser-produced plasmas. The advanced technology section includes reports on optical nonlinearities in high-temperature superconductors, a method of increasing gas retention time for laser-fusion targets, and a study of stimulated Raman scattering of laser beams in air. Highlights of the research reported in this issue are: An efficient method has been developed for balancing the power in the 60 beams of the OMEGA Upgrade. The method can achieve 2% power balance for both main and foot beams using only four system shots. A study of ion-sound-wave damping has substantially revised and expanded our knowledge of this effect. The damping of ion waves can have important consequences for laser-plasma interaction. The use of femtosecond laser pulses to study the properties of thin-film, high-temperature superconductors is discussed. A method for increasing the gas retention time of polymer-shell laser-fusion targets by overcoating them with a thin layer of aluminum is described. A code has been developed to study stimulated rotational Raman scattering in high-power laser beams propagating through air.

This volume of the LLE Review covers the three-month period October--December 1992. On 18 December, the OMEGA Laser Facility fired its last shot. It will be decommissioned during the next quarter to make room for the OMEGA Upgrade Laser Facility. This volume deals with two areas of interest for the OMEGA Upgrade, the development of advanced x-ray and neutron diagnostics and the development of long-pulse (>1-ns) laser sources. The first three articles discuss the development of time-dependent diagnostics. The development of an x-ray framing camera is described and measurements of the high-voltage pulse propagation in the camera are presented. Time-resolved and time-integrated neutron diagnostics for the OMEGA Upgrade are then discussed. Two schemes for the generation of >1-ns laser pulses are presented. Finally, the activities of the National Laser Users Facility and the GDL and OMEGA laser facilities are summarized.

This volume of the LLE Review covers the three-month period January--March 1993. The OMEGA laser facility was decommissioned during this quarter to make room for the OMEGA Upgrade laser facility. The decommissioning is described in this volume. Electron thermal transport in the corona and laser-irradiation uniformity are related issues for direct-drive laser fusion. Thermal transport can affect the laser-irradiation uniformity requirements. The status of Fokker-Planck modeling of electron transport at LLE is reviewed and is followed by a description of a new technique for achieving high laser uniformity using zero-correlation phase masks. The use of fast, optically triggered, superconducting opening switches can, in principle, reduce the peak electrical load requirements of systems like the OMEGA Upgrade. Recent research in this area is described. The last three articles discuss vacuum ultraviolet and x-ray emission from short-pulse, laser-matter interactions. The generation of a high spectral brightness, picosecond K{alpha} source is described. The subsequent articles describe the generation of high-order harmonics of a high-intensity laser system laser system in low- density, laser-atom interactions and the novel gas target used.

This volume of the LLE Review, covering the period April--June 1993, contains articles on spectral features from argon-filled target implosions on OMEGA, and on the theory of an implicit difference scheme for the Fokker-Planck equation. The advanced technology section includes reports on a novel polymer liquid-crystal wave plate and a new scheme for phase conversion of the OMEGA Upgrade beams that results in greater, smoother energy deposition on fusion targets. Finally, reports on the as-designed configuration of the OMEGA newly configured glass development laser system are summarized.

This volume of the LLE Review, covering the period July--September 1993, contains articles on self-focusing of broad-bandwidth laser light with angular dispersion, laser patterning of thin-film circuits, and construction of foam-shell fusion targets. Reports on the detailed designs of major subsystems of the OMEGA Upgrade and on the continuing activation of the upgraded Glass Development Laser system are summarized. Descriptions of research proposals for NLUF are also included in this issue. Highlights of the research reported in this issue are: Previous investigations of self-focusing behavior of broad-bandwidth laser light without angular dispersion showed only slight differences when compared to laser light with angular dispersion. A new, numerical investigation of self-focusing with applied angular dispersion shows the development of transverse amplitude modulation, which can act to enhance or impede instantaneous self-focusing. Averaging over one period of phase modulation with imposed bandwidth shows consistent smoothing of the beam, nearly replicating the original spatial profile, including smoothing of induced perturbations due to laser-system imperfections. A continuous-wave argon-ion laser beam is focused onto a Y-Ba-Cu-O thin-film circuit. The laser beam selectively heats the epitaxy, which enriches oxygen in irradiated regions alongside depleted regions. Oxygen enrichment results in the formation of superconducting regions, while oxygen …

During this quarter, the visible fruits of long design labors on the OMEGA Upgrade began to appear. The target mirror structure was put in place, along with the target chamber itself. The laser bay structures were also installed, and the bay is now being prepared to receive optomechanical, control, and laser assemblies. Further details are in the OMEGA Upgrade Status Report in this issue. Theory and analysis of previous experiments continued during this reporting period. Articles contained herein describe an improved theory of the ablative Rayleigh-Taylor instability; a novel proposal for characterizing plasma-density profiles by using grid image refractometry; a much-improved treatment of the damping of ion sound waves in a mixture of light and heavy ions; and, finally, a new interpretation of measurements of 3/2-harmonic radiation emitted from the long-scale-length plasmas created in earlier OMEGA experiments.

This volume of the LLE Review, covering the period Jan - Mar 1994, contains articles on backlighting diagnostics; the effect of electron collisions on ion-acoustic waves and heat flow; using PIC code simulations for analysis of ultrashort laser pulses interacting with solid targets; creating a new instrument for characterizing thick cryogenic layers; and a description of a large-aperture ring amplifier for laser-fusion drivers. Three of these articles - backlighting diagnostics; characterizing thick cryogenic layers; and large-aperture ring amplifier - are directly related to the OMEGA Upgrade, now under construction. Separate abstracts have been prepared for articles from this report.

This volume contains articles on efficient generation of second-harmonic radiation from short-pulse lasers; calculation of the stabilization cutoff wave numbers for the Rayleigh-Taylor instability; a high-frequency silicon optical modulator; the angular dependence of stimulated Brillouin scattering; and femtosecond dynamics of ladder polymers. Three of these articles--second-harmonic generation, Rayleigh-Taylor cutoff wave numbers, and angular dependence of Brillouin scattering--are directly related to the OMEGA Upgrade, currently under construction. A summary of the status of the OMEGA Upgrade laser facility and the NLUF News for FY94 are included in this volume.

This volume of the LLE review, covering the period of October--December 1994, contains articles on a diagnostic method employing krypton spectroscopy for measurement of temperature and shell-fuel mixing in high-temperature implosions; the first direct assessment of the ion-acoustic decay instability in a large-scale length, hot plasma; measurements of polarization mode dispersion and group-velocity walkaway in birefringent media using a frequency domain interferometer; an evaluation of the magnetic flux dynamics occurring in an optically triggered, thin-film superconducting switch; the effect of slurry fluid chemistry on particle size distribution during aqueous polishing of optical glass; and the influence of thermal and mechanical processing history in the preparation of well-ordered liquid crystal elastomer systems.

This volume of the LLE review, covering the period of January-March 1995, contains articles on the evaluation of the mechanism for laser damage in OMEGA UV multilayer coatings using a combination of conventional laser-damage characterization methods and atomic force microscopy; a dual-amplitude, fiber-coupled waveguide integrated-optic modulation device for generating temporally shaped optical pulses in OMEGA-, a proposal for modifying the indirect-drive irradiation geometry of the National Ignition Facility (NIF) to provide the additional flexibility for performing direct-drive experiments; direct measurements of terminal-level lifetime in several different Nd:YLF laser media; an overview of the materials science issues, basic mechanisms, and potential device applications for light-emitting porous silicon; and a study of the time-dependent reflection and surface temperatures for laser-irradiated dental hard tissue at two CO{sub 2} laser wavelengths.

This volume of the LLE Review, covering the period of April--June 1995, includes a description of the initial performance results of the upgraded OMEGA laser system. A series of acceptance tests were completed, demonstrating that all 60 beams can irradiate targets with more energy and better beam balance than was required by the Department of Energy`s acceptance criteria. Other articles in this volume include a description of a novel energy measurement system used to diagnose all 60 OMEGA beams; a theoretical calculation of the cutoff wave number of the ablative Rayleigh-Taylor instability, applicable to both direct and indirect drive; a description of a new algorithm used for designing distributed phase plates that will produce super-Gaussian focal-plane irradiance profiles: a study of the photoresponse of high-{Tc} YBCO thin films; and a description of magnetorheological finishing, a new process for optics polishing.

This volume of the LLE Review, covering the period July--September 1995, includes a description of the first target experiments performed on the upgraded OMEGA laser system. These experiments, carried out to active and test several diagnostics systems, have demonstrated successful functioning of the overall experimental system and have produced high neutron yields and high core temperatures. Other articles in this volume describe the diagnosis of core conditions using krypton line spectroscopy, a mix model for LILAC that can be applied to study the deceleration instability at the pusher-core interface, a simulated-annealing algorithm for improved phase-plate design, a simple method for characterizing the thickness and uniformity of transparent laser-fusion targets, and femtosecond pump-probe experiments on semiconducting YBCO.

This volume of the LLE Review, covering the period October-December 1995, contains a description of the generation and characterization of continuous, deep-surface-relief phase plates that are more efficient and versatile than previous designs. The LLE program plan has scheduled a number of enhancements to OMEGA`s performance and uniformity, the first of which is the implementation of these new distributed phase plates. Other articles in this volume include the discussion of an x-ray diagnostic method to measure shell-fuel mixing, the theoretical analysis of ablation-front stability, a description of a major subsystem in the OMEGA control system software, a study of the population inversions in intensely pumped Nd:YLF, and a description of a new ultrafast laser system and its uses.

This volume of the LLE Review, covering the period January-March 1996, contains three articles related to spherical implosions and their diagnosis, one article that provides an analysis of laser-plasma interactions, and three articles on advanced technologies developed at LLE.

This volume contains articles detailing several nonlinear processes associated with lasers and their use, as well as an article describing the computer control systems necessary to maintain and operate a large laser system such as the 60-beam OMEGA laser. The specific topics discussed in this issue include stimulated scattering in laser plasmas, power exchange between interacting laser beams, charged particles interacting with a laser pulse, thermal equilibration of optically excited states, an overview of the laser control system software in OMEGA, and a technique for cancellation of the nonlinear phase accumulation in short-pulse lasers.

This volume of the LLE Review, covering the period of July-September 1996, includes a description of an important experiment carried out on OMEGA by researchers from LANL, LLNL, and LLE to demonstrate the feasibility of using OMEGA for indirect drive. Additional topics include tetrahedral hohlraums, the speckle properties of phase- converted laser beams, design criteria for SSD phase modulators, and the design of slab amplifiers. Highlights of the research presented in this issue are (1) Results from the proof-of-principle indirect- drive experiments in which up to 40 OMEGA beams were used to irradiate cylindrical hohlraums. Nova results were reproduced, and new capabilities not available on other lasers were demonstrated. (2) A discussion of tetrahedral hohlraums (spherical hohlraums with four laser entrance holes) as a means of achieving better capsule irradiation uniformity. Tetrahedral hohlraums also allow the use of all 60 OMEGA beams and may provide an alternate route to ignition on the NIF. (3) An analysis of the residual target irradiation nonuniformity due to the fine laser speckle remaining on the beam after being phase converted by the DPP`s. A model shows how a uniformly ablating plasma atmosphere reduces the speckle contribution to the effective time-averaged irradiation nonuniformity. (4) A …

This volume of the LLE Review, covering the period October-December 1996, includes a review of 2-D SSD as implemented on the OMEGA laser system. A summary of the detailed mathematical formalism is shown, and the predicted level of uniformity achievable on OMEGA is given. The first experimental results on uniformity using narrow-band 2-D SSD are compared to theoretical calculations. Excellent agreement between experiment and theory is found, which gives confidence that broadband 2-D SSD with polarization wedges should achieve an rms nonuniformity in the 1%-2% level necessary for cryogenic implosion experiments.

This volume of the LLE Review includes an article on the status of the optics on the OMEGA laser system after the first 18 months of operation. A vigorous program to monitor the performance of the optics has been followed since the inception of the OMEGA laser. The article presents results from these observations and defines the various types of possible damage. Many of the optics have not damaged, such as the frequency-conversion crystals, polarizers, calorimeters, and liquid crystal optics. The most significant damage has been sustained by the fused-silica spatial filter lenses. There has been no evidence of any propagation of damage downstream of damage optics. Other highlights of research presented here are: The development of a single-beam, ponderomotive optical trap for energetic free electrons. A description of the new diode-pumped Nd:YLF master oscillator for the OMEGA laser. Simulations of heat transfer from localized absorbing defects to the host coating material in HfO{sub 2}/SiO{sub 2} 351-nm high reflectors. An experimental study of target performance and mixing in titanium-doped target implosions on OMEGA. A theoretical calculation of the dephasing time of an electron accelerated by a laser pulse. Separate abstracts have been indexed into the energy database from articles in …