| A Double Resonance Approach to Submillimeter/Terahertz Remote Sensing at Atmospheric Pressure |
FEB 2009 |
12 pages |
| Authors:
Frank C. De Lucia; Douglas T. Petkie; Henry O. Everitt; OHIO STATE UNIV COLUMBUS DEPT OF PHYSICS
|
 | The remote sensing of gases in complex mixtures at atmospheric pressure is a challenging problem and much attention has been paid to it. The most fundamental difference between this application and highly successful astrophysical and upper atmospheric remote sensing is the line width associated with atmospheric pressure broadening, 5 GHz in all spectral regions. In this paper, we discuss quantitatively a new approach that would use a short pulse infrared ... |
|
| Computational Modeling of Light Induced Transformations in Organic Molecule |
31-Aug-2008 |
34 pages |
| Authors:
Boris Gelmont; Raphael Moon; VIRGINIA UNIV CHARLOTTESVILLE OFFICE OF SPONSORED PROGRAMS
|
| The goal of this research is to investigate theoretically and experimentally the feasibility of a new Multi-State Spectral Sensing (MS3) concept where bio-signature information can be collected from multiple metastable conformations for enhanced sensing in the THz region. Several geometric isomeric molecular systems have been investigated including 2-butenes, retinals, and stilbenes, in order to (1) study THz spectra of different molecular conformation; (2) illustrate a basic procedure through which optical ... |
|
| 1.56 Terahertz 2-Frames per Second Standoff Imaging |
JAN 2008 |
12 pages |
| Authors:
Thomas M. Goyette; Jason C. Dickinson; Kurt J. Linden; William R. Neal; Cecil S. Joseph; William J. Gorveatt; Jerry Waldman; Robert Giles; William E. Nixon; MASSACHUSETTS UNIV LOWELL SUBMILLIMETER-WAVE TECH LAB
|
| A Terahertz imaging system intended to demonstrate identification of objects concealed under clothing was designed, assembled, and tested. The system design was based on a 2.5 m standoff distance, with a capability of visualizing a 0.5 m by 0.5 m scene at an image rate of 2 frames per second. The system optical design consisted of a 1.56 THz laser beam, which was raster swept by a dual torsion mirror ... |
|
| The Lightcraft Technology Demonstration Program. Part 1 |
NOV 2007 |
304 pages |
| Authors:
Jr Mead Franklin B.; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| Part I - The Lightcraft Technology Demonstration Program (LTD) is a report on the development of laser propulsion at the Air Force Research Laboratory (AFRL) between 1996 and 1999. The LTD Program was originally planned in five phases. Phase I, Lightcraft Concept Demonstration, was to demonstrate the feasibility of the basic concept. This phase ended in December 1998. Phase II, Lightcraft Vertical Launches to Extreme Altitudes, was a five-year effort ... |
|
| Feasibility Study of the Plasma Mirror Concept for High Power Lasers |
SEP 2006 |
22 pages |
| Authors:
Dieter Schuoecker; VIENNA UNIV OF TECHNOLOGY (AUSTRIA)
|
| This report results from a contract tasking Vienna University of Technology as follows: 1) Theoretical Assessment: The reflectivity of a plasma at least at the radiation of a carbon dioxide laser depends strongly on the number of free electrons per unit volume. The latter electron density is known from the literature for the case of a metal vapor plasma in deep penetration laser welding or drilling for the case of ... |
|
| Laser Sources for Standoff Chem-Bio Detection |
DEC 2004 |
3 pages |
| Authors:
Cynthia R. Swim; EDGEWOOD CHEMICAL BIOLOGICAL CENTER ABERDEEN PROVING GROUND MD
|
| The US Army Edgewood Chemical Biological Center is the leader in development of military laser-based systems for chemical and biological defense in collaboration with all Services, other Government laboratories academia and industry. Chemical and biological (CB) laser sensing principles. unique capabilities. state-of-the-art sensors. and emerging technologies will be discussed. Expected advancements in laser sources for CB detection offer significant improvements to the operational capability of the Future Combat System (FCS) ... |
|
| Measured Infrared Absorption and Extinction Cross Sections for a Variety of Chemically and Biologically Derived Aerosol Simulants |
JUN 2004 |
22 pages |
| Authors:
Kristan P. Gurton; Rachid Dahmani; David Ligon; Burt Bronk; ARMY RESEARCH LAB ADELPHI MD
|
| In an effort to establish a more reliable set of optical cross sections for a variety of chemical and biological aerosol simulants, we have developed a flow-through photo-acoustic system capable of measuring the absolute, mass-normalized, extinction and absorption cross sections. By employing a flow-through design, we avoid issues associated with closed aerosol photo-acoustic systems and improve sensitivity. Although the results shown here were conducted over the tunable carbon dioxide laser ... |
|
| Measurement and Control of the Properties of Gases Produced by Ablation of Delrin (Polyformaldehyde) with a CO2 Laser |
19 FEB 2003 |
5 pages |
| Authors:
Franklin Mead; Bill Larsen; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE WEST
|
| The primary objective of this research is to enable control of the properties of gases that are produced by ablation of solid Delrin with a pulsed C02 laser. Target gas properties are: (1) a specific energy content greater than 100 MJ/Kg, (2) a specific impulse range from 200 to 800 seconds, and (3) an overall conversion efficiency of laser energy to jet kinetic energy of at least 50%. |
|
| Modeling of Metal Laser Cutting Processes in Supersonic Jet in Inert Gas |
JUL 2002 |
|
| Authors:
O. B. Kovalev; A. M. Orishich; V. M. Fomin; V. B. Shulyatev; RUSSIAN ACADEMY OF SCIENCES NOVOSIBIRSK INST OF THEORETICAL AND APPLIED MECHANICS
|
 | Up-to-date CO2 lasers are widely used in laser treatment of materials (drilling, welting, cutting). Technical achievements of laser methods both in Russia and abroad are limited and have been applied only for some types of ferrous metals until now (iron, steel, stainless steel, electrical steel). A number of works, cannot describe satisfactory the processes of gas-laser metal cutting, and this fact implies consideration of a great number of complex and ... |
|
| Comparative Lightcraft Impulse Measurements |
13 MAR 2002 |
13 pages |
| Authors:
F. B. Mead Jr.; C. W. Larson; W. M. Kalliomaa; W. O. Schall; H. A. Eckel; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE WEST
|
| The impulse coupling coefficients of two radically different laser propulsion thruster concepts (lightcrafts), each 10 cm in diameter, have been measured under equal conditions using two different pendulum test stands. One test stand and one lightcraft of toroidal shape were provided by the U.S. Air Force Research Laboratory. The other test stand and a bell shaped (i.e. a paraboloid) lightcraft were those of the German Aerospace Center (DLR). All experiments ... |
|
| Solid Freeform Fabrication from Gas Precursors Using Laser Processing |
31 JAN 2002 |
18 pages |
| Authors:
Harris L. Marcus; CONNECTICUT UNIV STORRS INST OF MATERIALS SCIENCE
|
| The objective of the research was to establish the technical approaches required to use localized laser induced chemical vapor deposition as an approach for solid freeform fabrication (SFF). The Three processing approaches to be developed are Selective Area Laser Deposition (SALD), Selective Area Laser Deposition Vapor Infiltration (SALDVI), and Selective Area Laser Deposition Joining (SALD-Joining) of ceramics. |
|
| Ultrafast Vibrational Spectrometer for Engineered Nanometric Energetic Materials |
03 JAN 2002 |
3 pages |
| Authors:
Dana D. Dlott; ILLINOIS UNIV AT URBANA FREDRICK SEITZ MATERIALS RESEARCH LAB
|
| The proposer requested funding for laser equipment that would be used to study engineered nanometric energetic materials consisting of nanometer metal particles, passivation layers and oxidizing binders. The laser equipment is set up for vibrational sum-frequency generation spectroscopy, which looks at the vibrational transitions of molecules at interfaces between metal particles, their passivation layer and the surrounding oxidizer, in real time while the material is being combusted by a carbon ... |
|
| The Mechanism and Dynamics of Explosive Combustion in Aerosol Fuels |
NOV 2001 |
5 pages |
| Authors:
Roger Miller; Tomas Baer; NORTH CAROLINA UNIV AT CHAPEL HILL DEPTOF CHEMISTRY
|
| Our initial experiments explored the mechanism of vaporization/ ionization in liquid and nitrobenzene aerosols using CO2 laser evaporation and 193 run excimer laser ionization. Those experiments were critical in characterizing the capabilities of our apparatus and in laying the framework for the behavior of non-reactive species in our two-laser design. The use of multi- photon ionization schemes with the excimer laser resulted in highly fragmented mass spectra, making the identification ... |
|
| HI-CLASS on AEOS: A Large Aperture Laser Radar for Space Surveillance/ Situational Awareness Investigations |
04 APR 2001 |
|
| Authors:
Kirstie Ayers; J. Gonglewski; S. Czyzak; D. Werling; M. Groden; MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB
|
| Agenda: HI-CLASS Program; Support to Mission Needs; HI-CLASS System Design; 0.6 m Laser Beam Director (LBD); 3.67 m Advanced Electro-Optical System (AEOS); Recent Results; Current Program Activities; Summary. |
|
| A 1.56 THz Spot Scanning Radar Range for Fully Polarimetric W-Band Scale Model Measurements |
OCT 2000 |
7 pages |
| Authors:
Guy B. DeMartinis; Thomas M. Goyette; Michael J. Coulombe; Jerry Waldman; William Nixon; MASSACHUSETTS UNIV LOWELL SUBMILLIMETER-WAVE TECH LAB
|
| A radar transceiver operating at 1.56 THz was recently developed to obtain coherent, fully polarimetric W-band (98 GHz) Radar Cross Section (RCS) images of 1:16 scale-model targets. The associated optical system operates by scanning a small focused beam of swept frequency radiation across a scale-model target to resolve individual scattering centers and to obtain the scaled RCS values for the centers. Output from a tunable microwave source (10-17 GHz) is ... |
|
| A Broadband Low Noise Heterodyne Receiver at 2.5 THz |
29 SEP 2000 |
4 pages |
| Authors:
K. Huber; H. Brand; L. P. Schmidt; ERLANGEN-NUERNBERG UNIV (GERMANY) LEHRSTUHL FUR HOCHFREQUENZTECHNIQ
|
| A 2.5 THz low noise heterodyne receiver with an IF bandwidth of about 7 GHz operating at room temperature is presented. Its main component is an open structure Schottky diode mixer with a substrate-ess Schottky diode designed and fabricated at the IHFT Darmstadt. The weak IF-signals are amplified by a noise-matched IF-amplifier in a frequency range from 6 to 13 GHz, covering the emission lines of several important molecules involved ... |
|
| Corneal Damage from Infrared Radiation |
MAR 2000 |
46 pages |
| Authors:
Russell L. McCally; C. B. Bargeron; JOHNS HOPKINS UNIV LAUREL MD
|
| This report summarizes research on corneal damage from exposures to multiple pulses of CO(2) laser radiation at 10.6 (micrometer) and Tm: YAG laser radiation at 2.02 (micrometer). Retinal damage from sources with rectangular irradiance distributions was also modeled. Thresholds for CO(2) exposures were determined for sequences of up to 1024 pulses (80 ns duration) at frequencies of 10 and 16 Hz. Thresholds for Tm: YAG exposures were determined sequences of ... |
|
| Model Validation for High-Power Laser Ignition of JA2 Propellant |
SEP 1999 |
33 pages |
| Authors:
A. Cohen; R. A. Beyer; K. McNesby; A. J. Kotlar; A. Whren; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| A study of JA2 ignition using high-power (3 kW) pulsed Nd: glass lasers at low loading densities was undertaken to help construct models for predicting initial pressurization in bombs at high loading densities. Comparisons were made with results of experiments using a low-power (0.1 kW) continuous wave (cw) CO2 laser. Differences in wavelength dependence of optical properties and time dependence of the laser pulse were considered. Measured infrared (IR) emission ... |
|
| Sapphire Statistical Characterization and Risk Reduction (SSCARR) program for Windows and Domes |
18 AUG 1999 |
17 pages |
| Authors:
Donald McClure; Robert Cayse; ARMY SPACE AND MISSILE DEFENSE COMMAND HUNTSVILLE AL
|
| This paper contains the slide used in a presentation on 18 August 1999, concerning the IRIS Speciality Group Meeting on Materials and Detectors, Lexington, MA. |
|
| Atom Imaging |
23 JUL 1999 |
10 pages |
| Authors:
J. E. Thomas; DUKE UNIV DURHAM NC DEPT OF PHYSICS
|
| Three major results of this program are described: (1) Raman-induced resonance imaging is used to measure the distribution of atoms in a magneto- optical trap; (2) Nonoptical sources of heating in atom traps are explored theoretically. including laser-noise induced heating in optical traps and quantum-diffractive background gas collision-induced heating in shallow magnetic or optical traps; (3) An ultrastable CO2 laser trap is demonstrated that achieves ... |
|
| Wildcat Chemical Sensor |
FEB 1999 |
|
| Authors:
D. B. Cohn; L. F. Klaras; J. A. Fox; C. R. Swim; RAYTHEON SYSTEMS CO EL SEGUNDO CA
|
| The WILDCAT sensor is being developed to provide laser-based, standoff detection of chemical and biological agent vapor and aerosol clouds. This includes range-resolved DISC for identification and mapping and long range DIAL for concentration-path length determination. The sensor is composed of two subsections, including a telescope/gimbal assembly and a beam diagnostics section. The 60 cm dia telescope is mounted to a yoke gimbal which can point over a hemisphere and ... |
|
| Surface Contamination Mapping |
FEB 1999 |
9 pages |
| Authors:
Cynthia Swim; Fancis D'Amico; EDGEWOOD CHEMICAL BIOLOGICAL CENTER ABERDEEN PROVING GROUND MD
|
| A new application of laser standoff detection is being investigated, namely, the prediction and mapping of surface contamination. The hardware and software of an existing CO2 lidar was modified to allow improved scanning and real-time processing and display. The lidar was then used to demonstrate the capability of mapping surface contamination to a 1 g/m2 level by detecting aerosol and rain fallout from an airburst during field tests. |
|
| The Mechanism and Dynamics of Explosive Combustion in Aerosol Fuels |
1999 |
|
| Authors:
Roger E. Miller; Tomas Baer; NORTH CAROLINA UNIV AT CHAPEL HILL DEPTOF CHEMISTRY
|
| This project investigates the explosive combustion of aerosol fuels using a single particle mass spectrometer. Initiating explosive reactions of small samples (^10 (exp -12) grams) in vacuum allows the intermediate products of the reaction to escape into a collisionless region where we detect them using laser spectroscopy. Recent results from our laboratory explore the mechanism of amine sensitization in nitromethane. We initiate the decomposition of ... |
|
| Imaging Pyrometry of Laser-Heated Sapphire |
1999 |
9 pages |
| Authors:
David H. Terry; Michael E. Thomas; Milton J. Linevsky; Daniel T. Prendergast; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| A long-wave infrared camera was used in an imaging pyrometric mode to determine the spatially resolved outer surface temperature of sapphire samples heated with a carbon dioxide (CO2) laser. Tests were conducted by APL at the Laser Hardened Materials Evaluation Laboratory, Wright-Patterson Air Force Base, Ohio. Sapphire disks were assessed first to demonstrate the CO2 laser heating technique and the capabilities of the infrared pyrometry system. Additional testing was conducted ... |
|
| Digital Data Acquisition for Laser Radar for Vibration Analysis |
JUN 1998 |
56 pages |
| Authors:
Felix G. Montes; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF PHYSICS
|
| Laser radar for vibration analysis represents a military application to develop a target identification system in the future. The problem addressed is how to analyze the vibrations of a target illuminated by the laser radar to achieve a positive identification. This thesis develops a computer-based data acquisition and analysis system for improving the laser radar capability. Specifically, a review is made of the CO2 laser ... |
|
| Flight Experiments and Evolutionary Development of a Laser Propelled, Trans-Atmospheric Vehicle |
26 FEB 1998 |
5 pages |
| Authors:
Franklin B. Mead Jr.; Leik N. Myrabo; Donald G. Messitt; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE WEST
|
| In a series of spectacular experiments conducted at the High Energy Laser Systems Test Facility (HELSTF), White Sands Missile Range (WSMR), NM, using 13- to 15-cm diameter, 40- to 60-g vehicles designed to fly on the 10 kW PLVTS pulsed carbon dioxide laser (1kJ pulses for 30 us duration at 10 Hz), Prof. Leik Myrabo of Rensselaer Polytechnic Institute (RPI) and Dr. Franklin Mead of the Air Force Research Laboratory's ... |
|
| Sapphire Statistical Strength from Laser Thermal Fracture for Seeker Window Performance Assessment |
1998 |
8 pages |
| Authors:
D. H. Platus; O. Esquivel; J. D. Barrie; P. D. Chaffee; AEROSPACE CORP EL SEGUNDO CA
|
| As part of the BMDO-funded Sapphire Statistical Characterization and Risk Reduction (SSCARR) program, thin circular disks of seeker window-grade sapphire are thermally fractured using a CO2 laser. The resulting test data will be used to benchmark window failure models being developed under SSCARR that will utilize mechanical bend-bar data obtained for sapphire with the same processing and pedigree. A significant advantage of thermal stress testing over ... |
|
| Sixth International Workshop on Laser Physics (LPHYS 97) Volume 8, No. 1 |
1998 |
379 pages |
| Authors:
Alexander M. Prokhorov; RUSSIAN ACADEMY OF SCIENCES MOSCOW INST OF GENERAL PHYSICS
|
| The Final Proceedings for International Workshop on Laser Physics, 4 August 1997 - 8 August 1997. The Topics covered include: (1) New laser sources, (2) measurement and diagnostics, (3) lasers in R&D, (4) communications and informatics, and (5) lasers in medicine. |
|
| Infrared Protector Countermeasure System |
30 DEC 1997 |
|
| Authors:
Delbert B. Meeker; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| A countermeasure system adapted for use on board an aircraft for confusing an incoming missile as to the location and heading of the aircraft. The countermeasure system generates for each side of the aircraft at least two infrared energy images which are projected onto the aircraft's fuselage and then swept across the aircraft's fuselage to confuse the incoming missile's infrared seeker. Each infrared energy image is generated by at least ... |
|
| Development of Polymer Gel Sensors and Devices Controlled by Infrared Light and Ultrasonic Waves |
24 AUG 97 |
5 pages |
| Authors:
Zhibing Hu; NORTH TEXAS STATE UNIV DENTON DEPT OF PHYSICS
|
| This research aims to develop sensors and devices based on polymer gels. Under the support of the ARO grants (Technical monitor: Dr. Douglas Kiserow, Grant No. DAAH04-93-G-0215), we have made significant progress toward understanding, synthesis and application of gel systems. The major inventions are: (1) Synthesis and application of modulated polymer gels, (2) Bending of N- isopropylacrylamide gel under influence of infrared light, (3) CO2 laser controlled transmission of visible ... |
|
| Single Mode Twenty Atmosphere CO2 Laser |
05 JUN 1997 |
30 pages |
| Authors:
Jerald R. Izatt; ALABAMA UNIV UNIVERSITY
|
| A high power, UV preionised, twenty-atmosphere CO2 laser has been designed and constructed Its primary line narrowing and tuning configuration comprises a two-grating/retromirror assembly in which both gratings are worked near grazing incidence and double passed. It is used in a three-mirror resonator cavity. In preliminary tests the new laser has produced 130 nsec, 200 mJ pulses with a linewidth less than 200 MHz, which can be tuned continuously in ... |
|
| Influence of High Cycle Thermal Loads on Thermal Fatigue Behavior of Thick Thermal Barrier Coatings |
MAY 97 |
51 pages |
| Authors:
Dongming Zhu; Robert A. Miller; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH LEWIS RESEARCH CEN TER
|
| Thick thermal barrier coating systems in a diesel engine experience severe thermal low cycle fatigue (LCF) and high cycle fatigue (HCF) during engine operation. In the present study, the mechanisms of fatigue crack initiation and propagation, as well as of coating failure, under thermal loads which simulate engine conditions, are investigated using a high power CO2 laser. In general, surface vertical cracks initiate early and grow continuously under LCF and ... |
|
| Conference Record of the 1996 Twenty-Second International Power Modulator Symposium, June 25-27, 1996, Boca Raton, Florida |
MAR 97 |
|
| Authors:
Mark Goldfarb; PALISADES INST FOR RESEARCH SERVICES INC ARLINGTON VA
|
| PARTIAL CONTENTS INCLUDE : (1) MODULATOR-RELATED TECHNOLOGY AND USER OVERVIEWS; (2) SOLID-STATE DEVICES; (3) COMMERCIAL APPLICATIONS; (4) RF SYSTEMS; (5) GAS SWITCHES AND INSULATION; (6) ADVANCES IN POWER MODULATORS; (7) ACCELERATOR SYSTEMS; AND (8) POWER CONDITIONING AND COMPONENTS. |
|
| Analysis of the EOSS+ Module for the Consolidated Automated Support System (CASS) |
MAR 1997 |
|
| Authors:
Daniel B. Levine; George S. Hopper; Bernard L. Retterer; Howard S. Savage; INSTITUTE FOR DEFENSE ANALYSES ALEXANDRIA VA
|
| This report documents research by the Institute for Defense Analyses on the cost and capabilities of the Electro Optic Subsystem (EOSS+), the electro-optical module that the Northrop Grumman company is developing for the Navy's Consolidated Automated Support System (CASS). The research, which was completed in the spring of 1996, was sponsored by the Director, Weapon Support Improvement Group, Office of the Assistant Secretary of Defense (Economic Security) and conducted for ... |
|
| Atmospheric Attenuation of Common Applied Lasers |
29 JAN 97 |
|
| Authors:
Song Zhengfang; NATIONAL AIR INTELLIGENCE CENTER WRIGHT-PATTERSON AFB OH
|
| A survey of the atmospheric attenuation properties of usually applied laser (GaAs, YAG, HF, DF, and CO2) is given. From an analysis of the results of absorption and scattering processes produced by the interaction of atmospheric medium and laser radiation, comprehensive comparisons of transmission property are performed. Lastly, the optimum applied environment of every laser is indicated. ANNOTATION: Atmospheric Attenuation of Common Applied Lasers, --Translation. |
|
| Modelocked-Laser Laser Radar Performance in the Detection of TMD and NMD Targets |
97 |
12 pages |
| Authors:
Douglas G. Youmans; Rodney Robertson; SCHAFER (W J) ASSOCIATES INC CHELMSFORD MA
|
| Ultra compact mode locked CO2 lasers and mode locked Nd:fiber lasers are being developed for Theater Missile Defense (TMD) and National Missile Defense (NMD) applications. These lasers produce a coherent train of narrow pulses which may be used in a coherent laser radar (ladar) to form an image of a possible target. The distance to the target is irrelevant as long as there is enough received energy. These images are ... |
|
| Corneal Damage from Infrared Radiation |
DEC 96 |
21 pages |
| Authors:
Russell L. McCally; JOHNS HOPKINS UNIV BALTIMORE MD
|
| This report summarizes our research during the past year on the interaction of short pulses of infrared radiation produced by a CO2-TEA laser with the cornea. The report discusses the re-establishment of our laboratory, revision and testing of our computer program for computing temperature histories, confirmation of earlier results for single-pulse damage thresholds, the determination of the damage threshold for a sequence of two 80 ns pulses at 5 Hz, ... |
|
| Atmospheric Effects on Optical Propagation |
04 OCT 96 |
59 pages |
| Authors:
Patrick McNicholl; PHOTOMETRICS INC WOBURN MA
|
| A program to perform coordinated research employing complementary electro-optical techniques to characterize optical and physical properties of the atmosphere are described in this report. Emphasis was on upgrading and operating the CO2 wind sensing lidar, upgrading and operating the Nd:YAG backscatter lidar, on working with the multichannel transmissometer, and on upgrading the MAPM system. |
|
| Study on the Propagation of High-Power Laser Beams in the Atmosphere |
20 SEP 96 |
15 pages |
| Authors:
Zhenhua Guo; Jianhui Gu; Desheng Xu; NATIONAL AIR INTELLIGENCE CENTER WRIGHT-PATTERSON AFB OH
|
| This article reports on studies of continuous wave high power CO2 laser beam atmospheric propogation near the surface. Laser powers are 3kW-5kW. Propagation distances are 77m-107m. Patterns of changes associated with laser reception spots, given rise to by beam distortion and atmospheric influences, were obtained. ANNOTATION: Study on the Propagation of High-Power Laser Beams in the Atmosphere. --Translation. |
|
| Laser Guide Stars and Near-Infrared Na2 Oscillation. (Selected Articles) |
06 DEC 95 |
46 pages |
| Authors:
NATIONAL AIR INTELLIGENCE CENTER WRIGHT-PATTERSON AFB OH
|
| Contents: Laser Guide Stars For Adaptive Optical System With Partial Correction; Military Mid- And Low-Powered CO2 Laser Technology; Coating Of Resonator Mirrors For New-Infrared Na2 Oscillation. ANNOTATION: Laser Guide Stars and Near-Infrared Na2 Oscillation. (Selected Articles)--Translation. |
|
| Steady-State Kinetics of Br(2P 1/2) yields CO2(101) Electronic-to- Vibrational Energy Transfer Laser System |
27 NOV 95 |
107 pages |
| Authors:
Stephen J. Karis; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
|
| Steady state photolysis experiments were conducted to gain information relevant to the construction of a continuous wave electronic to vibrational pumped infrared laser. An Ar+ laser =488 nm) was used to produce the electronically excited state Br(2P1/2) (B*) via photolysis of molecular bromine. Energy was then transferred to the near resonant vibrational state CO2(101) (CO2) via the collisional quenching of Br* by CO2. The dependence of the 2.71 micron Br0 ... |
|
| High Power Lasers - Science and Engineering |
29 JUL 95 |
662 pages |
| Authors:
Ram Kossowsky; Miroslav Jelinek; Robert F. Walter; KLUWER ACADEMIC PUBLISHERS NORWELL MA
|
|
| Influence of CO2 Continuous Laser Preprocessed Substrates on Optical Thin Film Damage Thresholds |
26 APR 95 |
17 pages |
| Authors:
Wu Zhouling; Gao Yang; Fan Zhengxiu; Wang Zhijiang; NATIONAL AIR INTELLIGENCE CENTER WRIGHT-PATTERSON AFB OH
|
| As far as experimental research into the influences of CO2 laser preprocessed substrates on optical thin film damage threshold values is concerned, it was discovered that, with regard to single layer films and antireflective coatings, radiation pretreatment causes threshold values to clearly go up. At their highest, they reach 5 times those not radiation treated. However, on high reflection films, radiation pretreatment has no great influence. Using repetition frequency pulse ... |
|
| Cryogenic BRDF Measurements at 10.6 micrometers and 0.63 micrometers on Contaminated Mirrors |
FEB 95 |
88 pages |
| Authors:
B. L. Seiber; R. J. Bryson; W. T. Bertrand; B. E. Wood; ARNOLD ENGINEERING DEVELOPMENT CENTER ARNOLD AFS TN
|
| Effects of contaminants on optical surface are concern for space- based systems. Many systems contain cryogenic optical systems that operate at temperatures where gases condense. This study presents experimental results of the effects of condensed gases and spacecraft contaminants on highly polished (superpolished) mirror surfaces cooled, under vacuum to temperatures near 16 K and 70 K. After condensing contaminants on the mirror, the change in the bidirectional reflectance distribution function ... |
|
| A High Precision Reflectometer for Submillimeter Wavelengths |
FEB 1995 |
30 pages |
| Authors:
A. J. Gatesman; R. H. Giles; Jerry Waldman; MASSACHUSETTS UNIV LOWELL SUBMILLIMETER-WAVE TECH LAB
|
| A high-precision reflectometer was designed and built to measure directly the specular reflectance of materials in the submillimeter (SM) region of the spectrum. Problems that typically limit measurement precision, such as sample positioning, lack of an absolute reflection standard, and instabilities in the SM laser system, were investigated. Critical in this effort was the optical characterization of a high purity silicon wafer such that an etalon fabricated from this material ... |
|
| Propagation and Transformation Properties of Axicon Optical Systems for Laser Beams |
15 DEC 94 |
16 pages |
| Authors:
Bangwei Cai; Baida Lu; NATIONAL AIR INTELLIGENCE CENTER WRIGHT-PATTERSON AFB OH
|
| Axicon optical systems can transform a gaussian beam into a diffraction-free Bessel beam. In addition mutual, transformation between solid beam and annular beam can also be realized. The paper details theoretical analyses and experimental studies on the axicon and its composite optical system; both results are in agreement. Axicon optical systems are shown to have wide applications in laser techniques. (AN) ANNOTATION: Propagation and Transformation Properties of Axicon Optical Systems ... |
|
| Marine Boundary Layer Refractive Effects in the Infrared |
OCT 94 |
81 pages |
| Authors:
R. Feinberg; H. V. Hitney; H. G. Hughes; NAVAL COMMAND CONTROL AND OCEAN SURVEILLANCE CENTER RDT AND E DIV SAN DIEGO CA
|
| An experiment was conducted to determine whether ducting phenomena (gradients in refractivity) occur close to the ocean surface at infrared wavelengths. A CO2 laser beam (10.6 microns) was transmitted and received over an 8.5 km path in San Diego Bay. For the cases investigated (sea warmer than the air), the results of the study indicate that for air temperature gradients less than 1 C/meter, the distance to the infrared horizon ... |
|
| Thermal Dissociation of Halogen Azides |
SEP 94 |
160 pages |
| Authors:
D. J. Benard; ROCKWELL INTERNATIONAL THOUSAND OAKS CA SCIENCE CENTER
|
| Both FN3 and ClN3 were dissociated in the presence of a variety of donor molecules, either by pulsed CO2 laser excitation (using SF6 as a sensitizer) or by thermal excitation in a chemically driven shock tube. The donors were selected to support energy transfer from the metastable NF(a) and NCl(a) products of the azide dissociation reactions, and optical diagnostics were employed to study energy transfer rates, optical gain and lasing ... |
|
| Thermal Effects in End-Heated Laser Rods: A Time-Dependent Model and Diagnostic |
MAY 94 |
|
| Authors:
Dana C. Kopf; PHILLIPS LAB KIRTLAND AFB NM
|
| Unwanted heat generated in optically-pumped solid-state lasers causes thermal gradients, strain, and thermal expansion which in turn results in a nonuniform optical path difference (OPD) increase across the gain media. This ultimately results in poor beam quality. An interferometric based diagnostic for experimentally determining the time-dependent OPD change in an optically heated media was developed. This device is demonstrated by heating a glass (BK7) window with a CO sub 2 ... |
|
| Growth of Sapphire Fibers with a CO Laser |
30 APR 94 |
15 pages |
| Authors:
N. Djeu; UNIVERSITY OF SOUTH FLORIDA TAMPA DEPT OF PHYSICS
|
| The objective of this program was to explore ways to increase the growth rate of optical quality sapphire fibers produced by the Laser Heated Pedestal Growth (LHPG) technique. Prior to this program, the maximum rate at which this could be accomplished was 3-4 mm/min. When the latter rate was exceeded, the transmission of the fiber rapidly deteriorated. The cause of the degradation was thought to be the increasing disturbance by ... |
|
Reports by Keyword(s)
CARBON DIOXIDE LASERS
