| Ultraviolet Resonance Raman Enhancements in the Detection of Explosives |
01-Jun-2009 |
100 pages |
| Authors:
Short; Billy J Jr; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
 | Raman-based spectroscopy is potentially militarily useful for standoff detection of high explosives. Normal (nonresonance) and resonance Raman spectroscopies are both light scattering techniques that use a laser to measure the vibrational spectrum of a sample. In resonance Raman, the laser is tuned to match the wavelength of a strong electronic absorbance in the molecule of interest, whereas, in normal Raman the laser is not tuned to any strong electronic absorbance ... |
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| Quantitative UV Absorbance Spectra of Chemical Agents and Simulants |
MAR 2008 |
41 pages |
| Authors:
J. M. Lochner; Aaron M. Hyre; STEVEN D. CHRISTESEN; Kristina R. Gonser; EDGEWOOD CHEMICAL BIOLOGICAL CENTER ABERDEEN PROVING GROUND MD RESEARCH AND TECHNOLOGY DIR
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| The quantitative UV absorption spectra of selected chemical agents and simulants have been measured for wavelengths in the near UV from 200 to 400 nm. Although these data are of interest in their own right, they are also necessary for predicting the sensitivity of UV Raman based detection systems. Of particular interest are the absorption values at 248.25 nm and 262 nm as these correspond to excitation wavelengths used by ... |
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| Quantitative UV Absorbance Spectra of Chemical Agents and Simulants |
MAR 2008 |
42 pages |
| Authors:
J. M. Lochner; Aaron M. Hyre; STEVEN D. CHRISTESEN; Kristina R. Gonser; EDGEWOOD CHEMICAL BIOLOGICAL CENTER ABERDEEN PROVING GROUND MD RESEARCH AND TECHNOLOGY DIR
|
| The quantitative UV absorption spectra of selected chemical agents and simulants have been measured for wavelengths in the near UV from 200 to 400 nm. Although these data are of interest in their own right, they are also necessary for predicting the sensitivity of UV Raman based detection systems. Of particular interest are the absorption values at 248.25 nm and 262 nm as these correspond to excitation wavelengths used by ... |
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| Bio-Inspired Organic/Inorganic Hybrid Electronic and Photonic Materials and Structures |
31 DEC 2007 |
10 pages |
| Authors:
Alex K-Y. Jen; Mehmet Sarikaya; David Ginger; WASHINGTON UNIV SEATTLE DEPT OF MATERIALS SCIENCE AND ENGINEERING
|
| The goal of this project was to use DNA and protein as templates to assemble nanoparticles and functional molecules for photonic and electronic applications such as plasmon-enhanced fluorescence and surface-enhanced Raman scattering (SERS) (Fig. 1). Towards this goal, we have utilized both genetic and materials engineering tools. We have followed the molecular biomimetic approach in the assembly of nanoparticles. We have developed protocols using involving biological attachment of nanoparticles and ... |
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| Quantum Computing and Control by Optical Manipulation of Molecular Coherences: Towards Scalability |
14 SEP 2007 |
12 pages |
| Authors:
V. A. Apkarian; CALIFORNIA UNIV IRVINE DEPT OF CHEMISTRY
|
| Principles of quantum computing using molecular vibronic states and time-frequency resolved coherent anti-stokes Raman scattering (TFRCARS) were demonstrated through, and the execution of standard algorithms were elaborated along with measures of fidelity. These proof-of-principle implementations are on ensembles of molecules in the gas phase, unlikely to be a realistic architecture in practical implementations. We have therefore focused on solid-state implementations of the same, where now the understanding and control of ... |
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| Inactivation of Viruses by Coherent Excitations with a Low Power Visible Femtosecond Laser |
05 JUN 2007 |
6 pages |
| Authors:
K. T. Tsen; Shaw-Wei D. Tsen; Chih-Long Chang; Chien-Fu Hung; T.-C. Wu; Juliann G. Kiang; ARIZONA STATE UNIV TEMPE DEPT OF PHYSICS
|
| Background: Resonant microwave absorption has been proposed in the literature to excite the vibrational states of microorganisms in an attempt to destroy them. But it is extremely difficult to transfer microwave excitation energy to the vibrational energy of microorganisms due to severe absorption of water in this spectral range. We demonstrate for the first time that, by using a visible femtosecond laser, it is effective to inactivate viruses such as ... |
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| A Broadband High Spectral Brightness Fiber Based Two-Photon Source |
19 MAR 2007 |
8 pages |
| Authors:
Jingyun Fan; Alan L. Migdall; NATIONAL INST OF STANDARDS AND TECHNOLOGY GAITHERSBURG MD
|
| After characterizing the Raman scattering in a fused silica polarization-maintaining microstructure optical fiber, we built a fiber-based two-photon light source of high spectral brightness, broad spectral range, and very low noise background at room temperature. The resulting bright low-noise two-photon light can be used for a number of quantum information applications. |
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| Direct Diode Pumped Raman Fiber Amplifier Based on a Multimode Graded Index Fiber |
MAR 2007 |
62 pages |
| Authors:
C. J. Baird; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT/DEPT OF ENGINEERING PHYSICS
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| The direct pumping of a Raman fiber amplifier (RFA) was attempted using an array of four 25W, fiber pigtailed diodes at 936nm, combined via a 7 channel fiber beam combiner. The initial attempt was conducted using a 1.8 km, 100 micron core, GRIN fiber with an NA of .29 and attenuation 3.6 dB/km at 936nm. While amplification was not achieved, over 200mW of conversion was shown, with 10.4W of pump ... |
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| Alternate Approaches to Laser Guided Discharges |
19 APR 2006 |
25 pages |
| Authors:
J. Davis; R. E. Terry; G. M. Petrov; A. L. Velikovich; NAVAL RESEARCH LAB WASHINGTON DC
|
| We propose a novel use of laser induced breakdown channels to establish a transmission line through air, which terminates at a distant load object. |
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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
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| 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 ... |
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| Aerodynamic Loss and Mixing Over a Cavity Flame Holder Located Downstream of Pylon-Aided Fuel Injection |
MAR 2006 |
170 pages |
| Authors:
Lane C. Haubelt; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
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| Cavity-based fuel injection and flame holding found in hydrocarbon-fueled scramjet applications are of interest. The Air Force Research Lab (AFRL) and the Air Force Institute of Technology (AFIT) at Wright-Patterson Air Force Base in Ohio are investigating the enhancement of fuel-air mixing with small pylons that project into the supersonic flow upstream of a flame holder cavity. This follows previous qualitative (Mie scattering and NO-PLIF visualizations) results which suggested that ... |
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| Active Laser and Raman Materials for 1.3-5 Micron Spectral Range |
MAR 2006 |
183 pages |
| Authors:
Tasoltan Basiev; GENERAL PHYSICS INST MOSCOW (RUSSIA) LASER MATERIALS AND TECHNOLOGY RESEARCH CENTER
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| This report results from a contract tasking General Physics Institute of the Russian Academy of Sciences as follows: The spectral range of 4 - 5 microns is one of the most interesting atmospheric optical transmission windows. High peak power laser sources operating in this region are of special importance for various lidar applications. Solid state lasers with their compactness, high efficiency, and reliability in rugged conditions are quite promising for ... |
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| Smart Gold Nanobowls (Nano-Crescent Moon) with Sub-10 nm Circular Edge for Local Electromagnetic Field Enhancement Effect, Spatial, and NIR Temporal/Thermal Modulations for Molecular and Cellular Dynamic Imaging |
31 JAN 2006 |
28 pages |
| Authors:
Luke P. Lee; CALIFORNIA UNIV BERKELEY
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| Cell signaling involves the production and activation of many intracellular biomolecules. The dynamic detection of the biomolecular reactions is essential to understand the undefined signaling pathway. Current fluorescence based methods have difficulty detecting the dynamic reactions of biomolecules such as nucleolytic, proteolytic, and phosphorylation. In contrast, label-free Raman scattering spectroscopy can detect subtle biochemical changes without fluorescent molecules. First, we have created gold-based nanocrescent Surface Enhanced Raman Scattering (SERS) probes ... |
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| A Novel Spectroscopic Methodology for the Investigation of Individual Bacillus Spores |
01 OCT 2005 |
8 pages |
| Authors:
Troy A. Alexander; Paul Pellegrino; James B. Gillespie; ARMY RESEARCH LAB ADELPHI MD
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| A methodology has been developed for the investigation of bacterial spores. Specifically, this method has been used to probe the spore coat composition of two different Bacillus stearothermophilus variants. This unique detection scheme is based on the NIR Surface-Enhanced-Raman-Scattering (SERS) from single optically trapped, bacterial spores. The light from a 787-nm laser diode was used to trap/manipulate as well as simultaneously excite the SERS of an individual bacterial spore. Comparison ... |
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| Applications of Laser Diagnostics |
MAR 2005 |
708 pages |
| Authors:
Larry P. Goss; INNOVATIVE SCIENTIFIC SOLUTIONS INC DAYTON OH
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| This report describes the results of experimental and numerical investigations on gas-turbine combustion and fuel processes. The purpose of this program is the advancement of the state-of-the-art in laser diagnostics, modeling and simulations, propulsion sciences, advanced propulsion concepts, current and next-generation gas-turbine-engine components, and high-impact revolutionary technologies for airbreathing propulsion systems. The objectives of this research program include: Development, evaluation, and utilization of state-of-the-art-laser diagnostic techniques and analytical simulations and ... |
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| A Potential Remote-Sensing Technique for Thermospheric Temperature with Ground-Based Resonant Atomic Oxygen Raman Lidar |
2005 |
10 pages |
| Authors:
Ramesh D. Sharma; Phan D. Dao; AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE VEHICLES DIRECTORATE
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| We propose a remote-sensing technique to measure temperature in the lower thermosphere with a resonant Raman lidar. A ground-based pulsed laser operating at 630.0304 (636.3776) nm excites [exp-3] P [sub-2] ([exp-3] P [sub-1]) multiplet level of the ground electronic state of atomic oxygen in the atmosphere to the electronically excited [exp-1] D [sub-2] state and the back-scattered photons at 636.3776 (630.0304) nm, while the atom transitions to [exp-3] P [sub-1] ... |
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| Studies of Electromagnetically Induced Transparency and Its Relation to Nonlinear Optics |
DEC 2004 |
20 pages |
| Authors:
S. E. Harris; LELAND STANFORD JUNIOR UNIV STANFORD CA
|
| This report summarizes our work on the use of electromagnetically induced transparency to make new types of optical devices. Key accomplishments during this program period include the generation of the first single-cycle optical pulse and the development of a radiation source with four octaves of bandwidth. In a second area of work we have demonstrated nonlinear optical processes at the lowest photon flux ever used. |
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| Development of High Spectral Resolution Technique for Registration Quasielastic Light Scattering Spectra Including Rayleigh and Brillouin Scattering as a Diagnostic Tool in Materials Characterization |
22 SEP 2004 |
24 pages |
| Authors:
Bakhysh H. Bairamov; RUSSIAN ACADEMY OF SCIENCES SAINT PETERSBURG IOFFE PHYSICAL- TECHNICAL INST
|
| This report results from a contract tasking Ioffe Physico-Technical Institute as follows: As detailed in an on-line proposal the contractor will: 1) develop and build an optical device, fitted to a Fabry-Perot interferometer, to perform high-resolution quasieleastic light scattering spectroscopy; 2) develop related techniques for registering quasieleastic laser light scattering spectra; 3) measure temperature-dependent (77-300 degrees Kelvin) electrical conductivity to characterize metal/polymer/metal systems; 4) perform high-resolution Raman scattering mapping of ... |
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| Injection of Fluids into Supercritical Environments |
02 SEP 2004 |
46 pages |
| Authors:
M. Oschwald; J. J. Smith; R. Branam; J. Hussong; A. Schik; GERMAN AEROSPACE CENTER LAMPOLDSHAUSEN (GERMANY)
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| This paper summarizes and compares the results of systematic research programs at two independent laboratories regarding the injection of cryogenic liquids at subcritical and supercritical pressures, with application to liquid rocket engines. Both single jets and coaxial jets have been studied. Cold flow studies provided valuable information without introducing the complexities of combustion. Initial studies utilized a single jet of cryogenic nitrogen injected into a quiescent room temperature nitrogen environment ... |
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| Stability and Transient Effects in Ultraviolet Filaments |
SEP 2004 |
135 pages |
| Authors:
Thomas A. Niday; ARIZONA UNIV TUCSON OPTICAL SCIENCES CENTER
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| Short, high intensity laser pulses induce nonlinear optical effects in the atmosphere that have the potential to make them propagate for long distances. Applications for long distance propagation of short pulses include active spectral remote sensing and laser lightning control. Much of the work in this field has been done with infrared pulses; however, it has been proposed that ultraviolet pulses have the advantage that longer pulse lengths can be ... |
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| Formation of Porous Silicon Carbide and its Suitability as a Chemical and Temperature Detector |
19 AUG 2004 |
151 pages |
| Authors:
Tilghman L. Rittenhouse; ILLINOIS UNIV AT URBANA DEPT OF CHEMISTRY
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| The need to sense chemical mixtures in a variety of hostile environments (such as high temperature caustic gases) continues to grow. However, silicon electrical devices are limited to relatively low temperatures (< 250 deg C). For this reason, wide bandgap materials such as silicon carbide have received increased attention. Current SiC sensors such as Schottky diodes composed of catalytic metals show deficiencies such as unacceptable drift in the signal. Alternative ... |
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| Adiabatic Three-Wave Symmetric Volume Hologram |
10 AUG 2004 |
3 pages |
| Authors:
C. C. Tsai; L. B. Glebov; v. i. smirnov; B. Ya. Zeldovich; UNIVERSITY OF CENTRAL FLORIDA ORLANDO SCHOOL OF OPTICS/CREOL
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| A transmission hologram with two synmmetrically oriented volume gratings is considered in the regime of difraction of wave A into wave B via intermediate weakly excited wave C Adiabatic regime of highly efficient diffraction has the advantage of very low sensitivity to the strength of the gratings. |
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| Study of Optoelectronics Properties of Anisotropic Semiconductor Compounds with Ordered Stochiometric Vacancy |
AUG 2004 |
57 pages |
| Authors:
Iouri Roud; SCIENTIFIC ENGINEERING CENTER FOR MICROELECTRONICS AT IOFFE INST ST PETERSBURG (RUSSIA)
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| This report results from a contract tasking loffe Institute as follows: The main aim of the project is to carry out basic research on optoelectronic properties of CdGeAs2 and (Zn,Cd,Hg)(Ga,Al,ln)2(S,Se,Te)4 materials and to supply samples of these materials to the US AFRL/ML. This research include measurements of X-ray diffraction as well as spectra of polarized first- and second-order Raman scattering by lattice vibrations photoconductivity. and photoluminescence measurements in a temperature ... |
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| Quantum Computing and Information Transfer by Optical Manipulation of Molecular Coherences |
2004 |
6 pages |
| Authors:
V. A. Apkarian; CALIFORNIA UNIV IRVINE DEPT OF CHEMISTRY
|
| While formally quantum computation has become a rather well defined theoretical science, physical demonstrations are few, limited to several qubits, and to several steps in processing. At present, there is not a recognized, scalable physical method of implementation that meets the promise of true computation. We have proposed nonlinear spectroscopic methods of coherence manipulation, and in particular, Time-Frequency Resolved Coherent Anti-Stokes Raman Scattering (TFRCARS) in the molecular re-vibronic Hilbert space ... |
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| Realizations of Electromagnetic Pulsed-Beam Wavelets and Applications of Physics-Based Radar Analysis and Sensing |
31 DEC 2003 |
5 pages |
| Authors:
Gerald Kaiser; VIRGINIA CENTER FOR SIGNALS AND WAVES GLEN ALLEN
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| A solid and rigorous understanding of electromagnetic pulsed beam wavelet (PBW) sources has been established, though more work is needed to compute realizable current sources (eliminating magnetic charges). New results on using branch cuts to form spheroidal antennas are promising, as they determine the necessary boundary conditions to make the sources nonsingular. The recent computation of the 4D Fourier transform of PBW opens the way toward efficient numerical computations with ... |
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| GaN/AlGaN Strain-Balanced Heterostructures for Near-IR Quantum Well Photodetectors |
03 DEC 2003 |
22 pages |
| Authors:
Paul Harrison; LEEDS UNIV (UNITED KINGDOM) DEPT OF ELECTRICAL AND ELECTRONIC ENGINEERING
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| This report results from a contract tasking University of Leeds as follows: The contractor will design, fabricate, and analyze Quantum Well Infrared Photodetectors (QWIP) that detect in the 2-6 micron region. The QWIPs performance will be compared to standard MerCad Telluride (HgCdTe) photodector devices working in the same wavelength region. |
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| Metallic Nanoprobes for Enhanced Raman and Fluorescence Spectroscopy |
18 NOV 2003 |
24 pages |
| Authors:
Mitchell R. Zakin; PHYSICAL SCIENCES INC ANDOVER MA
|
| Metallic Nanoprobe Fabrication: Current approaches include deposition of metal island films on substrates and salt-induced aggregation of metallic colloids; good enhancement is observed but reproducibility is a serious issue; variability in nanoprobe fabrication is responsible for assay variability. Our approach is to synthesize metallic nanosphere structures with controlled interparticle spacing to exploit significant field enhancement between particles; start with simplest structure nanosphere dimer; dimers permit fully solution-based assay. |
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| Understanding Injection Into High Pressure Supercritical Environments |
09 OCT 2003 |
37 pages |
| Authors:
B. Chehroudi; D. Talley; W. Mayer; R. Branam; J. J. Smith; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| This paper summarizes the results of systematic research programs at both the DLR and the AFRL which began nearly ten years ago. The research is aimed at improving the understanding of atomization, mixing, and combustion processes associated with coaxially injected liquid propellant rocket engines. Cold flow studies are imperative for investigations without the complexities introduced with combustion. Initial studies utilized liquid nitrogen (LN2) without a co-flow stream into a chamber ... |
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| Novel Experimental, Theoretical, and Calculational Approaches to Understanding the Detonation of Explosives |
14 JUN 2003 |
10 pages |
| Authors:
Craig J. Eckhardt; NEBRASKA UNIV LINCOLN
|
| Report of results of research on the initial stage of detonation is made. Experimental results involve location of a heretofore undetected intramolecular mode in RDX and confirmation of prior findings on the Raman scattering of HMX. Preliminary Brillouin scattering studies have permitted experimental determination of approximate values of all components of the HMX crystals' stiffness tensor. The results of a mechanochemical theory are presented. The model account for the initial ... |
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| Advanced Laser Diagnostics of Compressible Flows |
FEB 2003 |
38 pages |
| Authors:
Kuang-Yu Hsu; Tarun Mathur; INNOVATIVE SCIENTIFIC SOLUTIONS INC DAYTON OH
|
| Advanced laser diagnostics have been developed to study the fundamentals of supersonic flows for scramjet applications. Filtered Rayleigh scattering and planar laser-induced fluorescence (PLIF) techniques were developed and applied for measuring temperature and species in reacting and nonreacting flows. Fundamental studies of a cavity flame-holder in reacting and nonreacting supersonic flows were conducted. Several cavity-configuration and fueling schemes were employed, and combustion performance was documented. Raman scattering was utilized to ... |
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| Fundamental Optical Criteria to Optimize Tunable Solid State Laser Crystals |
14 JAN 2003 |
10 pages |
| Authors:
R. R. Alfano; M. Y. Sharonov; S. Owen; W. B. Wang; CITY COLL NEW YORK
|
| Impurity ion-doped dielectric crystals have extensive applications in lasers, photodetectors, nonlinear crystals, displays, and scintillators. The performance of these devices is intrinsically correlated with their ability to transfer energy from the photoexcited impurity ion into the surrounding host. We have experimentally shown the importance of exact energy resonance between phonon and local modes in the decay pathway route of the nonradiative relaxation processes. Resonance Raman scattering and up-converted hot luminescence ... |
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| Preferred Orientation in Fibers of Hipco Single Wall Carbon Nanotubes from Diffuse X-Ray Scattering |
2003 |
6 pages |
| Authors:
W. Zhou; K. I. Winey; J. E. Fischer; PENNSYLVANIA UNIV PHILADELPHIA DEPT OFMATERIALS SCIENCE AND ENGINEERING
|
| Neat Fibers of HiPco single wall carbon nanotubes extruded from strong acid suspensions exhibit preferred orientation along fiber axes. We characterize the extrusion-induced alignment using x-ray fiber diagrams and polarized Raman scattering, using a model which allows for some fraction of the sample to remain completely unaligned. We show that both x-ray and Raman data are required for a complete texture analysis of SWNT fibers. |
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| Measurement of Chemical Oxygen-Iodine Laser Singlet Oxygen Generator Parameter Using Raman Spectroscopy |
17 JUL 2002 |
6 pages |
| Authors:
Weili Zhao; Fengting Sang; Liping Duo; Fang Chen; Yuelong Zhang; ACADEMIA SINICA DALIAN (CHINA) DALIAN INST OF CHEMICAL PHYSICS
|
| Using a doubled Nd:YAG laser as a spontaneous vibrational Raman scattering source, and a single intensified CCD array at the exit of an imaging monochromator, the Raman scattering system is used to directly measure the concentrations of the O2(alpha sup 1 delta) and the O2(X sup 3 Sigma)) in the chemical oxygen-iodine laser singlet oxygen generator in real time. We present the results from the tests that conducted on a ... |
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| Method Cars for Measurement of High Pressure Burning Temperature |
JUL 2002 |
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| Authors:
B. F. Boyarshinov; S. Yu. Fedorov; RUSSIAN ACADEMY OF SCIENCES NOVOSIBIRSKINST OF THERMOPHYSICS
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 | The aim of this paper is the development of a two-frequency CARS method for burning temperature measurement of stochiometric mixture of ammonium dinitramid with poly-caproamide. This model fuel contains nitrogen in exhaust. Time of burning of a one sample is 0.5 s at the pressure of 4.0 MPa in measuring volume. |
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| Unconventional Laser Guide Stars and Wavefront Correction of Blue Starlight |
28 MAY 2002 |
10 pages |
| Authors:
Robert W. Hellwarth; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES DEPT OF ELECTRICAL ENGINEERING
|
| In this project we established by theory and experiment (1) that a 1/ 4 Joule, 20 ns, ultraviolet laser pulse could create (near 20 km altitude) a return signal to the transmitting telescope that would appear, for 20 ns, to have a brightness temperature of millions of degrees, and thus serve as a guide star for high-order corrections of blue starlight, (2) that a much lower energy (approx. one hundred ... |
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| Broadly Tunable, High Average Power, Narrow Bandwidth Laser System for Characterization of High Energy Density Materials |
24 FEB 2002 |
15 pages |
| Authors:
G. Scoles; K. K. Lehmann; PRINCETON UNIV NJ DEPT OF CHEMISTRY
|
| Under support from this DURIP grant, a unique high resolution kHz repetition rate Ti: Sapphire laser has been purchased. Considerable custom modifications were done to produce a stable, broadly tunable light source that cover the near IR through deep UV. A Nd:YAG laser was also rebuilt as a cavity dumped, injection seeded, Q-switched laser. The two lasers are being used for stimulated Raman Scattering experiments on pH2 clusters in the ... |
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| Barrier to Aggregation for Light-Atom Dopants of Solid Hydrogen |
20 FEB 2002 |
27 pages |
| Authors:
G. Scoles; K. K. Lehmann; PRINCETON UNIV NJ DEPT OF CHEMISTRY
|
| In this report the development of the use of spectroscopy in highly quantum clusters made of H2 or He to study the possibility to increase the energy contents of solid H2 by seeding in it, in a stable way, relatively high (^ 5%) of light metal atoms or complexes. Experimental results on the solvation (or lack of it) of metal atoms (Mg and Al) with both spherical (Mg) and not- ... |
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| Studies of the Time Dependent Reactant Temperatures and Concentrations in RF Nitride Deposition Plasmas Using CARS |
29 SEP 2001 |
128 pages |
| Authors:
Rene Rodriguez; IDAHO STATE UNIV POCATELLO
|
| A radiofrequency pulsed plasma enhanced chemical vapor deposition reactor for silicon nitride production was designed, tested, and used to investigate the relationship of the reactor conditions to the depletion of and temperature of gas phase reactants in the rf plasma and to the properties of the deposited silicon nitride thin films and nano-particles. Correlations were found to exist between the depletion of silane and the uniformity of the thin films ... |
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| Amplification With Chalcogenide Glass Fiber |
12 JUL 2001 |
21 pages |
| Authors:
Leslie B. Shaw; DEPARTMENT OF THE NAVY WASHINGTON DC
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| This invention pertains to an optical device and method for using a chalcogenide glass waveguide to amplify a pump light beam by means of stimulated Raman scattering and obtaining a depleted pump light beam and an amplified beam at a wavelength higher than the wavelength of the depleted pump light beam. |
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| Optoelectronics Devices Based on Novel Semiconductor Structures |
JUL 2001 |
16 pages |
| Authors:
Yujie J. Ding; ARKANSAS UNIV FAYETTEVILLE DEPT OF PHYSICS
|
| We have observed quasi-phase-matched second-harmonic generation in the reflection geometry from GaAs/AIAs multilayers. By using GaAs/AIGaAs multilayers as a cavity, we have also achieved cavity-enhanced nonphase-matched second-harmonic generation from GaAs/AIAs multilayers. The linewidth for the first-order reflection-second-harmonic generation is limited only by-wave-vector mismatch. In addition, we have demonstrated two-order-of-magnitude enhancement on the conversion efficiency by using the cavity. Second, we have investigated effects of two-photon absorption on optical parametric oscillation. ... |
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| Advanced Stimulated Scattering Measurements in Supercritical Fluids |
19 JUN 2001 |
4 pages |
| Authors:
Gregory W. Faris; SRI INTERNATIONAL MENLO PARK CA
|
| We are using stimulated scattering (stimulated Rayleigh, Brillouin, and Raman scattering) to study supercritical fluids. New diagnostics are needed in the supercritical regime because low pressure diagnostics do not work well. From our measurements we can determine thermal, compressional, and compositional properties of supercritical fuels in situ. These techniques should improve our knowledge of fluid properties in the supercritical state. |
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| Raman Shifting High Power Near Infrared Laser Radiation |
10 JUN 2001 |
20 pages |
| Authors:
Wolfgang Rudolph; Jack McIver; NEW MEXICO UNIV ALBUQUERQUE
|
| Raman scattering for efficient wavelength conversion of mid infrared radiation was investigated theoretically and experimentally. Conversion efficiencies as high as 70% were observed with stimulated Raman scattering in H2. Several conversion schemes were analyzed theoretically and their applicability for the conversion of iodine lasers was investigated. The most efficient configuration uses a synchronously pumped Raman laser. For this technique, the single pulse of the iodine laser must be converted into ... |
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| Resonant Exciton-Phonon Spectra in ZnCdSe/ZnSe Single QW: Raman Scattering and Hot Luminescence; Extended and Localized Excitons |
JUN 2001 |
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| Authors:
V. V. Travniko; V. H. Kaibyshev; M. Rabe; F. Henneberger; RUSSIAN ACADEMY OF SCIENCES SAINT PETERSBURG IOFFE PHYSICAL-TECHNICAL INST
|
| The presented paper investigated in detail the structure and intensity of resonant exciton-phonon (REP) spectra in ZnCdSe/ZnSe QW structures as functions of tunable laser energy at 8 K. We have found that in REP spectra two types of lines are presented simultaneously. The most intensive REP component correspond to Raman scattering through extended exciton states. Other less intensive REP components correspond to hot luminescence of localized excitons. Analysis of phonon ... |
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| Silicon Nanoclusters Embedded in SiO2 Studies by Raman Scattering |
JUN 2001 |
|
| Authors:
F. J. Espinoza-Beltran; L. I. Diaz-Flores; J. Morales-Hernandez; J. M. Yanez-Limon; F. Rodriguez-Melgarejo; CENTRO DE INVESTIGACION YE DE ESTUDIOS AVANDOS DEL PIN QUERETARO (MEXICO) FACULTY OF ENGINEERING
|
| Low concentration of nanometric sized particles produced by a ball milling procedure were introduced into SiO(2) matrix by the sol-gel method. SiO(2) sol-gel formulations with high water-TEOS ratios were prepared. Samples with high silanol concentration was obtained for high temperatures as was proven by FTIR spectroscopy measurements. Raman scattering measurements showed evidence of a photo-oxidation effect of Si nanoparticles embedded into a SiO(2) matrix. Si particle sizes measured by Raman ... |
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| A Model to Interpret the Raman Spectra of Disordered, Amorphous and Nanostructured Carbons |
APR 2001 |
12 pages |
| Authors:
Andrea C. Ferrari; CAMBRIDGE UNIV (UNITED KINGDOM) DEPT OF ENGINEERING
|
| Raman spectroscopy is a very popular, non-destructive tool for the structural characterization of carbons. Raman scattering from carbons is always a resonant process, in which those configurations whose band gaps match the excitation energy are preferentially excited. The Raman spectra of carbons do not follow the vibration density of states, but consist of three basic features, the G and D peaks around 1600 and 1350 cm(exp-1) and an extra T ... |
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| Growth of Single Crystals and Fabrication of GaN and AlN Wafers |
MAR 2001 |
18 pages |
| Authors:
Z. Sitar; R. F. Davis; NORTH CAROLINA STATE UNIV AT RALEIGH
|
| GaN and AlN single crystals were grown from the vapor phase by evaporation of gallium or aluminum metals under an ammonia or nitrogen flow in a high temperature reactor. A growth rate of 500 micrometer/hr in the c direction was achieved for GaN while the growth rates for AlN were as high as a few millimeters per hour. The crystal size reached 3 mm for GaN and up to 15 ... |
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| Biological Detection System Technologies Technology and Industrial Base Study. A Primer on Biological Detection Technologies |
FEB 2001 |
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| Authors:
TRW SYSTEMS AND INFORMATION TECHNOLOGY GROUP RESTON VA
|
| As the most recent conflicts have shown, the threat of a biological attack is real and the ability to detect exposure to biological warfare agents early is of paramount importance to the safety of U.S. and Canadian military personnel. In light of these concerns both defense departments have increased efforts to develop and field biological agent detection systems to help protect their military forces and fixed assets. The study addresses ... |
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| Determining of the Material Parameters of Zn(x)Cd(y)Hg(1-x-y)Te by the Magnetophonon Spectroscopy |
2001 |
5 pages |
| Authors:
J. Cebulski; J. Polit; E. M. Sheregii; PEDAGOGICAL UNIV REJTANA (POLAND) INSTOF PHYSICS
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| The phonon and electron subsystems were studied in quaternary solid solutions of Zn(x)Cd(y)Hg(1-x-y)Te (ZMCT) by means of Raman scattering and Magnetophonon Resonance. The Raman spectra of several compositions confirm the three-mode behaviour of phonon spectra. The cluster mode has also been observed. Four kinds of LO-phonons (of HgTe-like, CdTe-like and ZnTe-like sublatticies and ZnTe-clusters) participate in the electron-phonon interaction. Four types of one-phonon Magnetophonon Resonances and two types of Magnetophonon ... |
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| Optical Sensing, Imaging and Manipulation for Biological and Biomedical Applications Held in Taipei, Taiwan on 26-27 July 2000. Proceedings |
29 JUL 2000 |
342 pages |
| Authors:
Robert R. Alfano; Ping-Pei Ho; Arthur E. Chiou; INDUSTRIAL TECHNOLOGY RESEARCH INST TAIPEI (TAIWAN)
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| This conference on Optical Sensing, Imaging and Manipulation for Biological and Biomedical Applications was part of the International Optoelectronics Symposium Held in Taipei, Taiwan on 26-28 July 200 in conjunction with Photonics Taiwan 2000 (See http://www.spie.org/web/meetings/ programs/pt00/pt00 home.html.). This conference brings together the state-of-the an biomedical photonics technologies from three continents for future product advancement. The main goal of photonics is aiming high-speed and high-volume communication and computation. Telemedicine and ... |
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| DURIP99 Neodymium-YAG Laser System for Combustion Scalar Flux Measurements |
19 JUL 2000 |
9 pages |
| Authors:
Robert W. Pitz; VANDERBILT UNIV NASHVILLE TN DIV OF SPONSORED RESEARCH
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| The Mechanical Engineering Department at Vanderbilt University obtained a high pulse energy Nd-YAG laser, together with a dye laser and frequency doubling/mixing system. This laser system provides the light sources necessary for nonintrusive, unseeded velocimetry of low temperature air flows, with applications to base flows and high speed flows around projectiles. The laser system also provides high pulse energy light for visible Raman scattering ... |
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Reports by Keyword(s)
RAMAN SCATTERING
