| Power Enhancement of a Rubidium Vapor Laser With a Master Oscillator Power Amplifier (Postprint) |
15-Sep-2009 |
6 pages |
| Authors:
David A Hostutler; Wade L Klennert; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
 | A master oscillator power amplifier (MOPA) with variable amplifier gain lengths was built to demonstrate power enhancement of an alkali vapor laser. A small signal gain of 0.91 / cm for two different gain lengths was observed. For a 2 cm long amplifier gain length an amplification of 7.9 dB was observed. |
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| The Aggregate Behavior of Branch Points I - The Creation and Evolution of Branch Points (Postprint) |
19-Jun-2009 |
18 pages |
| Authors:
Darryl J Sanchez; Denis W Oesch; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| It has long been known that branch points cause degradation in adaptive optic performance. Here, we begin a study on the aggregate nature of branch points, specifically beginning the process to relate branch points measured in the pupil to the upstream turbulence that created them. As such, we study not only the wave as measured in the telescope's pupil, but also the wave in the intervening region between the turbulence ... |
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| Experimental Analysis of Perspective Elongation Effects Using a Laser Guide Star in an Adaptive-Optics System (POSTPRINT) |
01 Jun 2009 |
14 pages |
| Authors:
Kevin P Vitayaudom; Darryl J Sanchez; Denis W Oesch; Patrick R Kelly; Carolyn M Tewksbury-Christle; Julie C Smith; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| The use of a laser guidestar (LGS) for the purpose of a beacon in an adaptive-optics (AO) system is prone to perspective elongation effects on the spots of a Shack-Hartmann wavefront sensor. The elongated spots can vary in size over the subapertures and affect the gradient sensitivity of the sensor. The Air Force Research Laboratory (AFRL) has developed a LGS model that outputs gradient gains which represent the effects of ... |
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| A New Sodium Guidestar Adaptive Optics System for the Starfire Optical Range 3.5 m Telescope (Postprint) |
18-May-2009 |
6 pages |
| Authors:
ROBERT JOHNSON; Dennis Montera; Timothy Schneeberger; James Spinhirne; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| A new adaptive optics is being installed on the Starfire 3.5 m telescope. Its uses the existing 50 watt pump to create a sodium guidestar. Transmission to the wavefront sensor is improved from 0.16 to 0.75. |
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| An Investigation of a Gas Laser Pressure Recovery System Diffuser |
19-Dec-2008 |
10 pages |
| Authors:
Carrie A Noren; Theodore Ortiz; Michael Wilkinson; Wade Klennert; Timothy J Madden; Richard W Chan; H W Behrens; Robert Walter; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| A diffuser, with the purpose of efficiently recovering pressure from a gas laser system, was designed and studied. A diffuser, as part of a pressure recovery system, is used in a gas laser system to transition the laser cavity's low pressure to the ambient pressure outside the device. The diffuser studied here is made up of a constant-area supersonic section and a diverging subsonic section. The diffuser is studied experimentally ... |
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| A Comparison of Multi-Frame Blind Deconvolution and Speckle Imaging Energy Spectrum Signal-to-Noise Ratios (Preprint) |
11-Sep-2008 |
14 pages |
| Authors:
Charles L Matson; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| An analytical signal-to-noise ratio (SNR) expression is derived for unbiased estimates of energy spectra obtained using multi-frame blind deconvolution (MFBD) algorithms. Because an analytical variance expression cannot, in general, be derived, Cramer-Rao lower bounds are used in place of the variances. As a result, the SNR expression provides upper bounds to the achievable SNRs that are independent of the MFBD algorithm implementation. The SNR expression is evaluated for the scenario ... |
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| Measuring Tilt and Focus for Sodium Beacon Adaptive Optics on the Starfile 3.5 Meter Telescope -- Conference Proceedings (Preprint) |
01-Sep-2008 |
10 pages |
| Authors:
ROBERT JOHNSON; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| Adaptive optics systems can measure high-order aberrations using an artificial laser beacon without the need for a relatively bright object near the object being imaged. Unfortunately, tilt and focus measurements are difficult to obtain from a laser beacon. One solution is to use light from the object being imaged to measure tilt and focus. Through analysis, I estimate the performance of using a Shack-Hartmann wavefront sensor with 2 by 2 ... |
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| Quantitative Mixing Measurements of a Supersonic Injection COIL Nozzle with Trip Jets |
13-Jun-2008 |
170 pages |
| Authors:
Carrie A Noren; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| A supersonic nozzle with supersonic iodine injection was designed and studied with Planar Laser-Induced Fluorescence (PLIF). The nozzle simulates Chemical Oxygen Iodine Laser (COIL) flow conditions with non-reacting, cold flows. A laser sheet near 565 nm excited the iodine, and the fluorescence was imaged with an intensified and gated CCD camera. Streamwise and semi-spanwise (oblique-view) images were taken, where the presence of injected flow was highlighted. With these images, the ... |
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| A Fast and Optimal Multi-Frame Blind Deconvolution Algorithm for High-Resolution Ground-Based Imaging of Space Objects--Journal Article (Preprint) |
01-Apr-2008 |
47 pages |
| Authors:
Stuart Jefferies; Charles L Matson; Kathy Borelli; Beckner; Charles C Jr; E K Hege; Michael Lloyd-Hart; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| We report on a multi-frame blind deconvolution algorithm that we have developed for imaging through the atmosphere. The algorithm has been parallelized to a significant degree for execution on high-peformance computer, with an emphasis on distributed-memory systems so that it can be hosted on commodity clusters. As a result, image restorations can be obtained in seconds to minutes. We have compared the quality of its output to the associated Crammer-Rao ... |
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| Energy Losses in Simulated Relativistic Michigan A6 Magnetron with Shaped Cathode |
Apr-2008 |
2 pages |
| Authors:
Peter Mardahl; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| Recently there has been much research interest in improving magnetron performance by employing various priming techniques, such as shaped cathodes and nonuniform magnetic fields. These priming techniques have been successfully applied to reduce magnetron noise and improve mode-locking and efficiency. Inserting a shaped cathode into the simulated Michigan magnetron yields a maximum efficiency (the radiofrequency (RF) output power for a cycle divided by the current times voltage input for that ... |
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| Development of Numerical Simulation Methods for Analysis of Laser Guided Arc Discharge |
29-Feb-2008 |
46 pages |
| Authors:
William Page; William Zimmerman; Brian Fisk; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| Modeling of the Use of USP laser pre-ionization as a guide path for a high voltage discharge in air was addressed. The physical processes involved are complex and span many orders of magnitude in the temporal and spatial resolution that must be considered. A two dimensional simulation model was produced that treats the problem in different time regimes with suitable approximations. The theoretical models and numerical models developed are described ... |
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| An Algorithm-Independent Analysis of the Quality of Images Produced Using Multi-Frame Blind Deconvolution Algorithms--Conference Proceedings (Postprint) |
01-Sep-2007 |
10 pages |
| Authors:
Charles Matson; Alim Haji; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| Multi-frame blind deconvolution (MFBD) algorithms can be used to generate a deblurred image of an object from a sequence of short-exposure and atmospherically-blurred images of the object by jointly estimating the common object and all the blurring functions. In this paper we present fundamental limits (Cramer-Rao lower bounds) to the quality of restored images generated with MFBD algorithms. We show that image restorations are less noisy when using a Zemike-based ... |
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| Stimulated Brillouin Scattering (SBS) Suppression Techniques |
31 JUL 2007 |
28 pages |
| Authors:
Michael W. Zmuda; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| In an effort to increase SBS threshold for future high power fiber amplifier applications, several mitigation techniques have been evaluated and modeled. Among these techniques include novel modulation schemes, core material modifications, and utilization of the core thermal differential during amplification. The most promising techniques were combined to provide an estimated increase in SBS threshold by over a decade. |
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| Mid-Infrared Optically Pumped, Unstable Resonator Lasers (Postprint) |
19 JUN 2007 |
5 pages |
| Authors:
A. P. Ongstad; R. Kaspi; G. C. Dente; M. L. Tilton; J. Chavez; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| The authors describe high-brightness, broad area midinfrared semiconductor lasers. These devices were fabricated in the authors laboratory using a commercial solid-source molecular beam epitaxial system. The laser structures incorporated 14 type-II quantum wells embedded in thick waveguide/ absorber regions composed of In0.2Ga0.8As0.18Sb0.82. The optically pumped devices achieved higher brightness operation as unstable resonators. Each unstable resonator was realized by polishing a diverging cylindrical mirror at one of the facets. For ... |
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| Mid-Infrared Optically Pumped, Unstable Resonator Lasers (Preprint) |
31 MAY 2007 |
13 pages |
| Authors:
A. P. Ongstad; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| The authors describe high-brightness, broad area midinfrared semiconductor lasers. These devices were fabricated in the authors laboratory using a commercial solid-source molecular beam epitaxial system. The laser structures incorporated 14 type-II quantum wells embedded in thick waveguide/ absorber regions composed of In0.2 Ga0.8 As0.18 Sb0.82. The optically pumped devices achieved higher brightness operation as unstable resonators. Each unstable resonator was realized by polishing a diverging cylindrical mirror at one of ... |
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| High-Efficiency Diode-Pumped Rubidium Laser: Experimental Results (Preprint) |
29 JAN 2007 |
8 pages |
| Authors:
Ty A. Perschbacher; David A. Hostutler; Thomas M. Shay; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| A diode-pumped rubidium laser with an optical slope efficiency of 69% has been constructed. This study utilized a narrow-line diode laser pump source for the experiments. The trade space study included optimization of various parameters such as lasing cell composition, temperature, and output coupler reflectivities. The results of the experimental study are given. |
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| Noise Reduction in Support-Constrained Multi-Frame Blind-Deconvolution Restorations as a Function of the Number of Data Frames and the Support Constraint Sizes (Preprint) |
06 DEC 2006 |
6 pages |
| Authors:
Charles Matson; Alim Haji; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| Multi-frame blind deconvolution (MFBD) algorithms seek to estimate jointly an object being imaged along with all the system point spread functions (PSFs) present in the measured data frames. It is well known that the quality of an object restoration improves as the number of data frames included in the restoration process is increased and as the sizes of the support constraints used in the algorithm decrease in size (while still ... |
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| PLIF Visualization and Quantitative Mixing Measurements of a Supersonic Injection Nozzle |
16 OCT 2006 |
9 pages |
| Authors:
Carrie A. Noren; C. R. Truman; Peter V. Vorobieff; Timothy J. Madden; Gordon D. Hager; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| Planar Laser-Induced Fluorescence (PLIF) was used to visualize the flow of a supersonic nozzle with a single supersonic injector. The nozzle simulates Chemical Oxygen Iodine Laser (COIL) flow conditions with non-reacting, cold flows, where the injected flow is seeded with iodine. A laser sheet near 565nm excites the iodine, and the florescence is imaged with a gated, CCD camera. Streamwise and semi-spanwise (oblique-view) images were taken, where the presence of ... |
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| PLIF Flow Visualization of a Supersonic Coil Nozzle (Postprint) |
16 OCT 2006 |
9 pages |
| Authors:
Carrie A. Noren; Gretchen Gothschopf; Ty Perschbacher; Timothy J. Madden; Gordon D. Hager; C. R. Truman; Peter V. Vorobieff; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| This paper describes Planar Laser-Induced Fluorescence (PLIF) flow visualization of a supersonic nozzle with supersonic injection. The nozzle simulates Chemical Oxygen Iodine Laser (COIL) flow conditions with non-reacting, cold flows, where the injected flow was seeded with iodine. A laser sheet near 565nm excited the iodine, and the fluorescence was imaged with a gated, CCD camera. Spanwise and steamwise images were taken, where the relative concentration of the injected to ... |
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| Analytical Study of Sub Terahertz Radiation from Ultrashort Laser Pulse Propagation Streamers |
05 OCT 2006 |
18 pages |
| Authors:
William Page; Laverne Schlie; William Zimmerman; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| A numerical calculation based on Maxwell's equations was made to examine the details of this process. The numerical calculation proceeded from Maxwell's Curl equations and included the treatment of the of the polarization current by means of a non-linear oscillator model. The oscillator is linear for small displacements but becomes non-linear for large fields where the Kerr Effect is important. The oscillator equations of motion determine a non-linear polarization current ... |
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| Parallelization of a Blind Deconvolution Algorithm (Postprint) |
01 SEP 2006 |
10 pages |
| Authors:
Charles L. Matson; Kathy J. Borelli; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| Often it is of interest to deblur imagery in order to obtain higher-resolution images. Deblurring requires knowledge of the blurring function - information that is often not available separately from the blurred imagery. Blind deconvolution algorithms overcome this problem by jointly estimating both the high-resolution image and the blurring function from the blurred imagery. Because blind deconvolution algorithms are iterative in nature, they can take minutes to days to deblur ... |
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| Cramer-Rao Lower Bound for Support-Constrained and Pixel-Based Multi-Frame Blind Deconvolution (Postprint) |
01 SEP 2006 |
12 pages |
| Authors:
Charles Matson; Aiim Haji; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| Multi-frame blind deconvolution (MFBD) algorithms can be used to reconstruct a single high-resolution image of an object from one or more measurement frames of that are blurred and noisy realizations of that object. The blind nature of MFBD algorithms permits the reconstruction process to proceed without having separate measurements of knowledge of the blurring functions in each of the measurement frames. This is accomplished by estimating the object common to ... |
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| Closed-Loop Control Techniques for an Adaptive-Optical System with an Interferometric Wavefront Sensor (Postprint) |
01 SEP 2006 |
11 pages |
| Authors:
Laura M. Klein; Troy A. Rhoadarmer; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| The self-referencing interferometer (SRI) wavefront sensor (WRS) is being developed for applications requiring laser propagation in strong scintillation. Because it directly measures the optical field of the wavefront, the SRI WFS is less effected by scintillation than conventional WFSs. This feature also means the phrase determined from the WRS measurements is limited to the range-pie to pie, due to the use of the arctangent function. If a segmented wavefront corrector ... |
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| Biased Cramer-Rao Lower Bound Calculations for Inequality-Constrained Estimators (Preprint) |
01 SEP 2006 |
12 pages |
| Authors:
Charles Matson; Alim Haji; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| Unbiased Cramer-Rao lower bound (CRB) theory can be used to calculate lower bounds to the variances of unbiased estimates of a set of parameters given only the probability density function of a random vector conditioned on the true parameter values. However, when the estimated parameter values are required to satisfy inequality constraints such as positivity, the resulting estimator is typically biased. To calculate CRBs for biased estimates of the parameter ... |
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| Intensity Redistribution for Multiconjugate Adaptive Optics (postprint) |
10 AUG 2006 |
11 pages |
| Authors:
Troy Rhoadarmer; Jr. Beckner Charles C.; Laura M. Klein; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| Multi-Conjugate Adaptive-Optical (MCAO) systems have been proposed as a means of compensating both intensity and phase aberrations in a beam propagating through strong-scintillation environments. Progress made on implementing a MCAO system at the Starfire Optical Range (SOR), Air Force Research Laboratory, Kirtland AFB, is discussed. As a preliminary step toward controlling a two Deformable Mirror (DM) system, the first-stage intensity redistribution experiment (FIRE) examines one aspect of an MCAO system-control ... |
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| Appropriate Measures and Consistent Standard for High Energy Laser Beam Quality (Postprint) |
01 AUG 2006 |
|
| Authors:
T. S. Ross; William P. Latham; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
 | Along with power output of the laser system, laser optical quality or beam quality provides a suitable measure of performance. Power and beam quality are standards for the comparison of laser systems with each other and against mission requirements. An understanding of the meaning of beam quality is necessary to completely define laser performance capability. The current state of our community includes a multitude of different and not well understood ... |
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| Measuring the Yield of Singlet Oxygen in a Chemical Oxygen Iodine Laser (Postprint) |
01 AUG 2006 |
11 pages |
| Authors:
Kevin B. Hewett; John E. McCord; Manish Gupta; Thomas Owano; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| A critical parameter for understanding the performance of Chemical Oxygen Iodine Lasers is the yield of singlet oxygen produced by the generator. Off-Axis Integrated Cavity Output Spectroscopy (Off-Axis ICOS) has been utilized to measure the absolute density of both ground-state and singlet oxygen in the cavity of a COIL laser. |
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| Switching Requirements for Stacked Blumleins Commutated by Individual Switches |
May-2006 |
5 pages |
| Authors:
Matthew T Domonkos; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| Stacked Blumlein lines with solid dielectric potentially offer a compact pulsed power system for a variety of applications by combining the energy storage, voltage scaling, and pulse forming functions into a single device. By stacking the lines physically, not simply electrically, the line is made more compact because adjacent lines share electrodes. This design does not lend itself to the use of a single switch to commutate the stacked line, ... |
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| Reset Behavior of High Duty Cycle Pulse Transformers |
May-2006 |
5 pages |
| Authors:
J P O'Loughlin; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| Magnetic core pulse transformers operating in a repetitive mode must maintain the core flux density within the saturation bounds of the magnetic material to provide satisfactory performance. The instantaneous flux is established by the time integration of the induced winding voltage. Alternatively, the flux is also determined by the net instantaneous magneto-motive force acting on the core in relation to the core dimensions and material hysteresis characteristics. Core material is ... |
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| An Analysis of Mechanisms Underlying Flow Unsteadiness in Chemical Oxygen-Iodine Laser Mixing Systems |
12 MAR 2006 |
15 pages |
| Authors:
Timothy J. Madden; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| 3-dimensional Navier-Stokes simulations of chemical oxygen-iodine laser (COIL) hardware are performed to elucidate the unsteady fluid dynamic aspects of these flowfields. Reacting (COIL) and non-reacting flow simulations are performed on varying resolution grids to explore the unsteadiness and comparisons to experimental data are made. |
|
| Backward Amplification and Beam Cleanup of a Raman Fiber Laser Oscillator using a Multi-Mode Graded Index Fiber Amplifier |
MAR 2006 |
67 pages |
| Authors:
Jesse D. Morgan; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| This thesis tested a continuos wave (CW) fiber-based Raman amplifier implemented in a backward pumped geometry. To create a seed for the amplifier, a CW Nd:YAG (Neodymium:yttrium-aluminum-garnet) laser operating at 1.064micrometer was used to pump a 50micrometer multimode graded index fiber using fiber Bragg gratings to create a Raman Fiber Laser (RFL) Oscillator with a Stokes beam at 1.116micrometer. The Stokes beam was then used to seed two lengths, 5.3km ... |
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| Passive Multiple Beam Combination in Optical Fibers via Stimulated Brillouin Scattering |
MAR 2006 |
63 pages |
| Authors:
Kirk C. Brown; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| The goal of this research was to demonstrate the feasibility of passively combining multiple laser beams using Stimulated Brillouin Scattering (SBS) in a long multimode optical fiber. This method of combination employed a "Gatling gun" fiber array that allowed several collimated beams to be focused by a lens into an optical fiber. The ability to combine four single-mode off-axis input beams using a fiber array and a long multimode optical ... |
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| Development of a Multiple Beam Combiner Using Stimulated Raman Scattering in Multimode Fiber |
MAR 2006 |
81 pages |
| Authors:
Brian M. Flusche; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| Beam combination was demonstrated by splitting the beam from a Q-switched Nd:YAG (Neodymium:yttrium-aluminum-garnet) laser and pumping a multiple input, single output fiber squid. Beam cleanup of the resulting output beam using stimulated Raman scattering was then demonstrated in both 100 micrometer fiber and 200 micrometer fiber. Energy conversion efficiency into the Stokes beam was measured as a function of input energy and found to be limited by the attenuation characteristics ... |
|
| AFRL/Directed Energy, Generic Overview of AFRL/DE |
14 NOV 2005 |
32 pages |
| Authors:
Jan Bush; Gene Bednarz; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| Overview PowerPoint presentation of the Air Force Research Laboratory, Directed Energy Directorate, located at Kirtland AFB, NM, 8 September 2005 update. |
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| Performance Comparison of Optically Pumped Type-II Mid-Infrared Lasers (Briefing Charts) |
25 OCT 2005 |
14 pages |
| Authors:
AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
|
| Unstable Resonator Semiconductor Lasers |
25 OCT 2005 |
19 pages |
| Authors:
AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
|
| Performance Comparison of Optically Pumped Type-II Mid-Infrared Lasers |
25 OCT 2005 |
10 pages |
| Authors:
A. P. Ongstad; R. Kaspi; M. L. Tilton; J. R. Chavez; G. C. Dente; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| We report a comparative study on the performance of three optically pumped, type-II quantum well lasers with differing quantum well (QW) confinement. One of the active regions emphasized hole confinement, another emphasized electron confinement, while the third incorporated both electron and hole confinements. In all cases the wells were inserted in a thick In(sub x)Ga(sub 1-x)As(sub y)Sb(1-y) waveguide/absorber region. The lasing wavelengths at 84 K were 2.26, 3.44, and 2.37 ... |
|
| Membrane Adaptive Optics |
01 AUG 2005 |
10 pages |
| Authors:
Dan Marker; James Wilkes; Eric Riggiero; Dab Inman; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| An innovative adaptive optic is discussed that provides a range of capabilities unavailable with either existing, or newly reported, research devices. It is believed that this device will be inexpensive and uncomplicated to construct and operate, with a large correction range that should dramatically relax the static and dynamic structural tolerances of a telescope. As the areal density of a telescope primary is reduced, the optimal optical figure and the ... |
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| Performance Measurements of a Self-Referencing Interferometer Wavefront Sensor with Optical Amplification (Preprint) |
29 JUL 2005 |
10 pages |
| Authors:
Laura Klein; Troy A. Rhoadarmer; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| The Self-referencing Interferometer Wavefront Sensor (SRI WFS) has been shown to outperform conventional wavefront sensors in strong scintillation environments. Recently, the Starfire Optical Range has developed a prototype SRI to evaluate its performance. This paper discusses the purposes of optically amplifying the reference beam. Specifically, it addresses regions of operation where gain improves signal-to-noise ratio (SNR) values, and thus the SRI WFS performance. Conditions are also addresses when Amplified Spontaneous ... |
|
| Evaluation of Phase-Shifting Techniques for a Self-Referencing Interferometer Wavefront Sensor (Postprint) |
29 JUL 2005 |
14 pages |
| Authors:
Melissa S. Corley; Troy A. Rhoadarmer; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| The Air Force Research Laboratory is developing a Self-Referencing Interferometer (SRI) wavefront sensor (WFS) for applications requiring laser propagation in strong scintillation. This paper compares several phase-shifting techniques that can be used to capture interference patterns and examines their effects on SRI WFS performance. These techniques included temporal, spatial, spatial-temporal phase shifting. Temporal phase shifting allows for straightforward setup, alignment, and calibration, though its performance is degraded by changes in ... |
|
| Performance Measurements of a Self-Referencing Interferometer Wavefront Sensor with Optical Amplification--Briefing Charts (Preprint) |
29 JUL 2005 |
18 pages |
| Authors:
Laura Klein; Troy A. Rhoadarmer; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| The Self-referencing Interferometer Wavefront Sensor (SRI WFS) has been shown to outperform conventional wavefront sensors in strong scintillation environments. Recently, the Starfire Optical Range has developed a prototype SRI to evaluate its performance. This paper discusses the purposes of optically amplifying the reference beam. Specifically, it addresses regions of operation where gain improves signal-to-noise ratio (SNR) values, and thus the SRI WFS performance. Conditions are also addresses when Amplified Spontaneous ... |
|
| Primary and Secondary Superresolution by Data Inversion (preprint) |
06 JUN 2005 |
20 pages |
| Authors:
Charles L. Matson; David W. Tyler; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| Superresolution by data inversion is the extrapolation of measured Fourier data to regions outside the measurement bandwidth using postprocessing techniques. Here we characterize superresolution by data inversion for objects with finite support using the twin concepts of primary and secondary superresolution, where primary superresolution is the essentially unbiased portion of the superresolution data and secondary superresolution is the remainder. We show that this partition of superresolution into primary and secondary ... |
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| Primary and Secondary Superresolution by Data Inversion (Postprint) |
06 JUN 2005 |
16 pages |
| Authors:
Charles Matson; David W. Tyler; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| Super resolution by data inversion is the extrapolation of measured Fourier data to regions outside the measurement bandwidth using post processing techniques. Here we characterize super resolution by data inversion for objects with finite support using the twin concepts of primary and secondary super resolution, where primary super resolution is the essentially unbiased portion of the super resolution data and secondary super resolution is the remainder. We show that this ... |
|
| Laser Beam Control in Strong Turbulence (preprint) |
06 AUG 2004 |
5 pages |
| Authors:
Don Washburn; Dan Herrick; Troy Rhoadarmer; Mohammed Jamshidi; Charles Finley; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| The overall purpose of this task is to investigate control and diagnostic techniques that apply to laser propagation systems. The current emphasis is in two major areas: first to investigate full wave conjugation methods for optimal uplink efficiency from a laser source to a relay mirror; second, to investigate automatic diagnostic techniques that apply to complex systems Air Force systems. |
|
| Development of the Self-Referencing Interferometer Wavefront Sensor (Postprint) |
30 JUL 2004 |
17 pages |
| Authors:
Troy A. Rhoadarmer; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| The self-referencing Interferometer (SRI), is an innovative wavefront sensor (WFS) developed specifically for applications requiring laser propagation in strong scintillation. The performance of conventional gradient sensors, like a Shack-Hartmann WFS or lateral shearing interferometer are severely limited in these environments due to the presence of branch points in the wavefront phase. Unlike these sensors, the SRI WFS directly measures the wavefront field so that its performance is not affected by ... |
|
| Refractivity Turbulence Observation Using a New Balloon-Ring Platform (Preprint) |
12 MAR 2002 |
9 pages |
| Authors:
Frank D. Eaton; Patrick R. Kelly; Demos T. Kyrazis; Sheldon S. Stokes; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| This paper presents new methodology to address critical refractivity turbulence issues for laser propagation using a new measurement system-a portable "balloon-ring" platform with multiple fine wire sensors at several separations. All "raw" data is transmitted to ground station-allowing spectra to be calculated. The new platform is discussed and preliminary examples of observations, including artifacts, are shown and discussed. This new platform provides capabilities during the daytime as well as nighttime ... |
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Reports by Corporate Author
