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Horizontal Path Laser Communications Employing MEMS Adaptive Optics Correction

Description: Horizontal path laser communications are beginning to provide attractive alternatives for high-speed optical communications, In particular, companies are beginning to sell fiberless alternatives for intranet and sporting event video. These applications are primarily aimed at short distance applications (on the order of 1 km pathlength). There exists a potential need to extend this pathlength to distances much greater than a 1km. For cases of long distance optical propagation, atmospheric turbul… more
Date: September 5, 2001
Creator: Thompson, C. A.; Wilks, S. C.; Brase, J. M.; Young, R. A.; Johnson, G. W. & Ruggiero, A. J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Intracavity adaptive correction of a 10 kW, solid-state, heat-capacity laser.

Description: The Solid-State, Heat-Capacity Laser (SSHCL), under development at Lawrence Livermore National Laboratory is a large aperture (100 cm{sup 2}), confocal, unstable resonator requiring near-diffraction-limited beam quality. There are two primary sources of the aberrations in the system: residual, static aberrations from the fabrication of the optical components and predictable, time-dependent, thermally-induced index gradients within the gain medium. A deformable mirror placed within the cavity is… more
Date: January 12, 2004
Creator: LaFortune, K N; Hurd, R L; Johansson, E M; Dane, C B; Fochs, S N & Brase, J M
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Partner: UNT Libraries Government Documents Department
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X-ray imaging: Status and trends

Description: There is a veritable renaissance occurring in x-ray imaging. X-ray imaging by radiography has been a highly developed technology in medicine and industry for many years. However, high resolution imaging has not generally been practical because sources have been relatively dim and diffuse, optical elements have been nonexistent for most applications, and detectors have been slow and of low resolution. Materials analysis needs have therefore gone unmet. Rapid progress is now taking place because … more
Date: August 1, 1987
Creator: Ryon, R. W.; Martz, H. E.; Hernandez, J. M.; Haskins, J. J.; Day, R. A.; Brase, J. M. et al.
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Partner: UNT Libraries Government Documents Department
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Direct imaging of extra-solar planets

Description: Direct imaging of extra-solar planets may be possible with the new generation of large ground-based telescopes equipped with state- of- the-art adaptive optics (AO) systems to compensate for the blurring effect of the Earth`s atmosphere. The first of these systems is scheduled to begin operation in 1998 on the 10 in Keck II telescope. In this paper, general formulas for high-contrast imaging with AO systems are presented and used to calculate the sensitivity of the Keck AO system. The results o… more
Date: March 1, 1997
Creator: Olivier, S. S.; Max, V. E.; Brase, J. M.; Caffano, C. J.; Gavel, D. T. & Macintosh, B. A.
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Partner: UNT Libraries Government Documents Department
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Joint UK/US Radar Program progress reports for period December 1--31, 1994

Description: Topics discussed in this report are current accomplishments in many functions to include: airborne RAR/SAR, radar data processor, ground based SAR signal processing workstation, static airborne radar, multi-aperture space-time array radar, radar field experiments, data analysis and detection theory, management, radar data analysis, modeling and analysis, current meter array, UCSB wave tank, stratified flow facility, Russian Institute of Applied Physics, and budget status.
Date: January 23, 1995
Creator: Twogood, R. E.; Brase, J. M.; Mantrom, D. D.; Rino, C.; Chambers, D. H.; Robey, H. F. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Joint UK/US Radar Program progress reports for period January 1--31, 1995

Description: Our current objectives are to modify the Hughes x-band radar for airborne implementation, to upgrade it to polarimetry, high-power, and add SLAR mode, and then to deploy in UK/US field experiments as needed. We are on schedule and within budget on bringing the airborne (Hughes A-3) system for future SAR and eventually, SLAR imaging at low grazing angles. Hughes and LLNL continued work on system integration, radar hardware, and associated control hardware and software. The belly radome design mo… more
Date: February 15, 1995
Creator: Twogood, R. E.; Brase, J. M.; Robey, H. F.; Mantrom, D. D.; Rino, C.; Chambers, D. H. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Preliminary results of the LLNL airborne experimental test-bed SAR system

Description: The Imaging and Detection Program (IDP) within Laser Programs at Lawrence Livermore National Laboratory (LLNL) in cooperation with the Hughes Aircraft Company has developed a versatile, high performance, airborne experimental test-bed (AETB) capability. The test-bed has been developed for a wide range of research and development experimental applications including radar and radiometry plus, with additional aircraft modifications, optical systems. The airborne test-bed capability has been develo… more
Date: January 16, 1996
Creator: Miller, M. G.; Mullenhoff, C. J.; Kiefer, R. D.; Brase, J. M.; Wieting, M. G.; Berry, G. L. et al.
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Partner: UNT Libraries Government Documents Department
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Experimental demonstration of high resolution three-dimensional x-ray holography

Description: Tomographic x-ray holography may make possible the imaging of biological objects at high resolution in three dimensions. We performed a demonstration experiment with soft x-rays to explore the feasibility of this technique. Coherent 3.2-nm undulator radiation was used to record Fourier transform holograms of a microfabricated test object from various illumination angles. The holograms were numerically reconstructed according to the principles of diffraction tomography, yielding images of the ob… more
Date: January 1, 1992
Creator: McNulty, I.; Trebes, J. E.; Brase, J. M.; Yorkey, T. J.; Levesque, R.; Szoke, H. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Experimental demonstration of high resolution three-dimensional x-ray holography

Description: Tomographic x-ray holography may make possible the imaging of biological objects at high resolution in three dimensions. We performed a demonstration experiment with soft x-rays to explore the feasibility of this technique. Coherent 3.2-nm undulator radiation was used to record Fourier transform holograms of a microfabricated test object from various illumination angles. The holograms were numerically reconstructed according to the principles of diffraction tomography, yielding images of the ob… more
Date: December 1, 1992
Creator: McNulty, I.; Trebes, J. E.; Brase, J. M.; Yorkey, T. J.; Levesque, R.; Szoke, H. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Modeling of Adaptive Optics-Based Free-Space Communications Systems

Description: We introduce a wave-optics based simulation code written for air-optic laser communications links, that includes a detailed model of an adaptive optics compensation system. We present the results obtained by this model, where the phase of a communications laser beam is corrected, after it propagates through a turbulent atmosphere. The phase of the received laser beam is measured using a Shack-Hartmann wavefront sensor, and the correction method utilizes a MEMS mirror. Strehl improvement and amo… more
Date: August 6, 2002
Creator: Wilks, S. C.; Morris, J. R.; Brase, J. M.; Olivier, S. S.; Henderson, J. R.; Thyompson, C. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Laser Damage Inspection Final Report

Description: Large, high-power laser systems are often designed as reimaging multipass cavities to maximize the extraction of energy from the amplifiers. These multipass cavities often have vacuum spatial filters that suppress the growth of beam instability via B-integral effects. These spatial filters also relay images of laser damage, often nearly superimposing these images in common planes. Also, the fluence damage threshold limits the minimum size of the optics. When used as vacuum barriers in the spati… more
Date: February 26, 2001
Creator: Salmon, J T; Brase, J M; Bliss, E S; Carrano, C J; Kegelmeyer, L M; Miller, M G et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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ASAP progress and expenditure report for the month of February 1--29, 1996

Description: This is the ASAP progress and expenditure report for the month of February, 1996. The individual projects` report includes the sponsoring organization, the project identification, the principal investigator, long term objectives, short term objectives, accomplishments this reporting period, identification of issues or concerns, project budget estimate for the fiscal year, and monthly actual and year to date expenditures. The research project concerns a joint US/UK program to develop a high-prio… more
Date: March 20, 1996
Creator: Twogood, R. E.; Brase, J. M.; Chambers, D. H.; Mantrom, D. M.; Miller, M. G.; Newman, M. J. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Technical challenges for the future of high energy lasers

Description: The Solid-State, Heat-Capacity Laser (SSHCL) program at Lawrence Livermore National Laboratory is a multi-generation laser development effort scalable to the megawatt power levels with current performance approaching 100 kilowatts. This program is one of many designed to harness the power of lasers for use as directed energy weapons. There are many hurdles common to all of these programs that must be overcome to make the technology viable. There will be a in-depth discussion of the general issu… more
Date: January 10, 2007
Creator: LaFortune, K. N.; Hurd, R. L.; Fochs, S. N.; Rotter, M. D.; Pax, P. H.; Combs, R. L. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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High-resolution wavefront control using liquid crystal spatial light modulators

Description: Liquid crystal spatial light modulator technology appropriate for high-resolution wavefront control has recently become commercially available. Some of these devices have several hundred thousand controllable degrees of freedom, more than two orders of magnitude greater than the largest conventional deformable mirror. We will present results of experiments to characterize the optical properties of these devices and to utilize them to correct aberrations in an optical system. We will also presen… more
Date: July 20, 1999
Creator: Bauman, B. J.; Brase, J. M.; Brown, C. G.; Cooke, J. B.; Kartz, M. W.; Olivier, S. S. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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First significant image improvement from a sodium-layer laser guide star adaptive optics system at Lick Observatory

Description: Atmospheric turbulence severely limits the resolution of ground-based telescopes. Adaptive optics can correct for the aberrations caused by the atmosphere, but requires a bright wavefront reference source in close angular proximity to the object being imaged. Since natural reference stars of the necessary brightness are relatively rare, methods of generating artificial reference beacons have been under active investigation for more than a decade. In this paper, we report the first significant i… more
Date: July 14, 1997
Creator: Olivier, S. S.; Max, C. E.; Friedman, H. W.; An, J.; Avicola, K.; Beeman, B. V. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Advanced Wavefront Control Techniques

Description: Programs at LLNL that involve large laser systems--ranging from the National Ignition Facility to new tactical laser weapons--depend on the maintenance of laser beam quality through precise control of the optical wavefront. This can be accomplished using adaptive optics, which compensate for time-varying aberrations that are often caused by heating in a high-power laser system. Over the past two decades, LLNL has developed a broad capability in adaptive optics technology for both laser beam con… more
Date: February 21, 2001
Creator: Olivier, S. S.; Brase, J. M.; Avicola, K.; Thompson, C. A.; Kartz, M. W.; Winters, S. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Initial Performance of the Keck AO Wavefront Controller System

Description: The wavefront controller for the Keck Observatory AO system consists of two separate real-time control loops: a tip-tilt control loop to remove tilt from the incoming wavefront, and a deformable mirror control loop to remove higher-order aberrations. In this paper, we describe these control loops and analyze their performance using diagnostic data acquired during the integration and testing of the AO system on the telescope. Disturbance rejection curves for the controllers are calculated from t… more
Date: March 1, 2001
Creator: Johansson, E. M.; Acton, D. S.; An, J. R.; Avicola, K.; Beeman, B. V.; Brase, J. M. et al.
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Partner: UNT Libraries Government Documents Department
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Improved performance of the laser guide star adaptive optics system at Lick Observatory

Description: Results of experiments with the laser guide star adaptive optics system on the 3-meter Shane telescope at Lick Observatory have demonstrated a factor of 4 performance improvement over previous results. Stellar images recorded at a wavelength of 2 {micro}m were corrected to over 40% of the theoretical diffraction-limited peak intensity. For the previous two years, this sodium-layer laser guide star system has corrected stellar images at this wavelength to {approx}10% of the theoretical peak inte… more
Date: July 20, 1999
Creator: An, J. R.; Avicola, K.; Bauman, B. J.; Brase, J. M.; Campbell, E. W.; Carrano, C. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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