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Development of short pulse laser pumped x-ray lasers

Description: X-ray lasers have been extensively studied around the world since the first laboratory demonstration on the Novette laser at LLNL in 1984. The characteristic properties of short wavelength, high monochromaticity, collimation and coherence make x-ray lasers useful for various applications. These include demonstrations of biological imaging within the water window, interferometry of laser plasmas and radiography of laser-heated surfaces. One of the critical issues has been the high power pump req… more
Date: February 22, 2000
Creator: Dunn, J; Osterheld, A L; Hunter, J R & Shlyaptsev, V N
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Strong field atomic physics in the mid-infrared

Description: We examine strong field atomic physics in a wavelength region (3-4 microns) where very little work has previously been done. The soft photon energy allows the exploration of one-electron atoms with low binding energies (alkali metals). We find that photoionization spectra differ from rare gas studies at shorter wavelengths due to more complex ion core potentials. Harmonic generation is studied, and we find that harmonic bandwidths are consistent with theory and the possibility of compression to… more
Date: March 15, 2000
Creator: Sheehy, B.; Martin, J. D. D.; Clatterbuck, T. O.; Kim, D. W.; DiMauro, L. F.; Agostini, P. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Long wavelength GaN blue laser (400-490nm) development

Description: Room temperature (RT) pulsed operation of blue nitride based multi-quantum well (MQW) laser diodes grown on c-plane sapphire substrates was achieved. Atmospheric pressure MOCVD was used to grow the active region of the device which consisted of a 10 pair In{sub 0.21}Ga{sub 0.79}N (2.5nm)/In{sub 0.07}Ga{sub 0.93}N (5nm) InGaN MQW. The threshold current density was reduced by a factor of 2 from 10 kA/cm{sup 2} for laser diodes grown on sapphire substrates to 4.8 kA/cm{sub 2} for laser diodes grow… more
Date: October 26, 2000
Creator: DenBaars, S. P.; Abare, A.; Sink, K.; Kozodoy, P.; Hansen, M.; Bowers, J. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

New Mid-IR Lasers Based on Rare-Earth-Doped Sulfide and Chloride Materials

Description: Applications in remote-sensing and military countermeasures have driven a need for compact, solid-state mid-IR lasers. Due to multi-phonon quenching, non-traditional hosts are needed to extend current solid-state, room-temperature lasing capabilities beyond {approx} 4 {micro}m. Traditional oxide and fluoride hosts have effective phonon energies in the neighborhood of 1000 cm{sup -1} and 500 cm{sup -1}, respectively. These phonons can effectively quench radiation above 2 and 4 {micro}m, respecti… more
Date: September 1, 2000
Creator: Nostrand, M
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Ultrasonic Imaging and Theoretical Prediction of Orthotropic Plate Stiffness in all Planar Directions

Description: Exact and approximate theoretical analysis of the wavelengths of plate wave mode propagation in all planar directions for the dispersive antisymmetric Lamb wave mode are compared with measurements from a laser ultrasonic imaging approach that records the out of plane ultrasonic motion over a large area in a single frame without scanning. Good agreement is demonstrated, based on independent determination of the elastic constants, for two different types of paper.
Date: July 1, 2000
Creator: Telschow, Kenneth Louis; Deason, Vance Albert; Mukdadi, O. & Datta, S. K.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Development of Novel, Simple, Multianalyte Sensors for Remote Environmental Analysis

Description: We will develop simple, inexpensive new chemical sensing materials which can be used as visual color test strips to sensitively and selectively report on the concentration and identity of environmental pollutants such as cations of Pb, U, Pu, Sr, Hg, Cs, Co as well as other species. We will develop inexpensive chemical test strips which can be immersed in water to determine these analytes in the field. We will also develop arrays of these chemical sensing materials which will be attached to fib… more
Date: June 1, 2000
Creator: Asher, Sanford A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Detection and Characterization of Chemicals Present in Tank Waste

Description: The principal goal of this three-year project is to develop and demonstrate novel multiparameter micro-electro-mechanical system (MEMS) sensors that are robust and can be used to simultaneously detect the presence of target chemicals in a mixture, radiation emitted from radioactive materials, and the heat generated by the absorption of photons of specific wavelength by the target chemicals. A major emphasis of this program is to study and develop effective methods of modifying MEMS surfaces wit… more
Date: June 1, 2000
Creator: Datskos, Panos G. & Sepaniak, Michael J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Extreme Ultraviolet Lithography - Reflective Mask Technology

Description: EUVL mask blanks consist of a distributed Bragg reflector made of 6.7nm-pitch bi-layers of MO and Si deposited upon a precision Si or glass substrate. The layer deposition process has been optimized for low defects, by application of a vendor-supplied but highly modified ion-beam sputter deposition system. This system is fully automated using SMIF technology to obtain the lowest possible environmental- and handling-added defect levels. Originally designed to coat 150mm substrates, it was upgrad… more
Date: May 9, 2000
Creator: Walton, C. C.; Kearney, P. A.; Mirkarimi, P. B.; Bowers, J. M.; Cerjan, C.; Warrick, A. L. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Uncharted Frontiers in the Spectroscopy of Highly Charged Ions

Description: The development of novel techniques is critical for maintaining a state-of-the-art core competency in atomic physics and readiness for evolving programmatic needs. We have carried out a three-year effort to develop novel spectroscopic instrumentation that added new dimensions to our capabilities for measuring energy levels, radiative transition probabilities, and electron-ion excitation processes. The new capabilities created were in areas that heretofore had been inaccessible to scientific scr… more
Date: January 8, 2000
Creator: Beiersdorfer, P.; Brown, G.; Crespo, J.; Kim, S. H.; Neill, P.; Utter, S. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Laboratory Data for X-Ray Astronomy

Description: Laboratory facilities have made great strides in producing large sets of reliable data for X-ray astronomy, which include ionization and recombination cross sections needed for charge balance calculations as well as the atomic data needed for interpreting X-ray line formation. We discuss data from the new generation sources and pay special attention to the LLNL electron beam ion trap experiment, which is unique in it's ability to provide direct laboratory access to spectral data under precisely… more
Date: March 2, 2000
Creator: Beiersdorfer, P.; Brown, G.V.; Chen, H.; Gu, M.F.; Kahn, S.M.; Lepson, J.K. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Laser Research and Development Studies for Laser Guide Star Systems

Description: In this paper we consider two CW solid state laser approaches to a 589 nm LGS system. Both are based on the technique of sum-frequency generation, but differ in the cavity architecture. Both technologies are very promising and are worth of further consideration. This preliminary proposal is intended to encompass both designs. A down select shall be performed early in the project execution to focus on the most promising option. The two design options consist of: (1) A dual-frequency resonator wi… more
Date: February 23, 2000
Creator: Pennington, D.; Beach, R.; Ebbers, C.; Erbert, G.; Nguyen, H.; Page, R. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

MICROANALYSIS OF MATERIALS USING SYNCHROTRON RADIATION.

Description: High intensity synchrotron radiation produces photons with wavelengths that extend from the infrared to hard x rays with energies of hundreds of keV with uniquely high photon intensities that can be used to determine the composition and properties of materials using a variety of techniques. Most of these techniques represent extensions of earlier work performed with ordinary tube-type x-ray sources. The properties of the synchrotron source such as the continuous range of energy, high degree of … more
Date: December 2000
Creator: Jones, K. W. & Feng, H.
Item Type: Refine your search to only Book
Partner: UNT Libraries Government Documents Department
open access

Technologies for Advanced Induction Accelerators

Description: To harness fusion energy is one of today's greatest technological challenges, and one well worth pursuing. Success in the development of fusion power would result in a virtually inexhaustible source of energy. The fusion reaction, the process that powers the sun and the stars, can be duplicated on Earth. However, to date these fusion processes have been the products of large-scale experimental efforts. They have yet to achieve fusion in a manner that is cost effective and efficient enough to be… more
Date: April 20, 2000
Creator: Hernandez, M. A.; Kamin, G.; Hanks, R.; Sharp, W.; Duncan, G.; Sangster, C. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Fluorescence lifetime measurements of boronate derivatives to determine glucose concentration

Description: A novel investigation into the fluorescence lifetimes of molecules, both established and newly designed, was performed. These molecules are the basis of a continuous, minimally invasive, glucose sensor based on fluorescence lifetime measurements. This sensor, if coupled with an automated insulin delivery device, would effectively create an artificial pancreas allowing for the constant monitoring and control of glucose levels in a person with diabetes. The proposed sensor includes a fluorescent … more
Date: June 1, 2000
Creator: Gable, J H
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Comparison of AMOS computer code wakefield real part impedances with analytic results

Description: We have performed eleven AMOS (Azimuthal Mode Simulator)[1] code runs with a simple, right circular cylindrical accelerating cavity inserted into a circular, cylindrical, lossless beam pipe to calculate the real part of the n = 1(dipole) transverse wakefield impedance of this structure. We have compared this wakefield impedance in units of ohms/m(Wm) over the frequency range of 0-1 GHz to analytic predictions from Equation (2.3.8) of Briggs et al[2]. The results from Equation (2.3.8) were conve… more
Date: November 30, 2000
Creator: Mayhall, D J & Nelson, S D
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Room temperature continuous-wave operation of GaInNAs long wavelength VCSELs

Description: Vertical cavity surface-emitting lasers (VCSELs) are becoming increasingly important for short-haul optical fiber transmission systems. Given the commercial success of GaAs-based 850nm VCSELs, dramatic enhancements in transmission bandwidth and distance can be achieved in conventional single- and multi-mode fiber by extending the emission wavelength to the 1300nm-1550nm range. GaInNAs is a promising active layer material grown on GaAs that can achieve 1300nm emission [l], and electrically pulse… more
Date: June 22, 2000
Creator: Larson, M C; Coldren, C W; Spruytte, S G; Peterson, H E & Harris, J S
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Saturated Plasma X-Ray Laser at 19 nm

Description: Saturated operation of a tabletop laser plasma X-ray laser at 19 nm is demonstrated with output energy of 2.5 {micro}J. The narrow beam divergence, high repetition rate, wavelength scalability, short pulse duration, high monochromaticity and high brightness make it a potential tool for X-ray laser applications, including seeding a future X-ray free electron laser.
Date: November 30, 2000
Creator: Li, Y.; Dunn, J.; Nilsen, J.; Osterheld, A.; Barbee, T. W., Jr. & Shlyaptsev, V. N.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Metal Processing with Ultra-Short Laser Pulses

Description: Femtosecond laser ablation has been shown to produce well-defined cuts and holes in metals with minimal heat effect to the remaining material. Ultrashort laser pulse processing shows promise as an important technique for materials processing. We will discuss the physical effects associated with processing based experimental and modeling results. Intense ultra-short laser pulse (USLP) generates high pressures and temperatures in a subsurface layer during the pulse, which can strongly modify the … more
Date: May 1, 2000
Creator: Banks, P S; Feit, M D; Komashko, A M; Perry, M D; Rubenchik, A M & Stuart, B C
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

New imaging technique gets under the skin...deep

Description: Using a combination of simple optical techniques, plain old white light, and image processing, two Lawrence Livermore researchers and a colleague from the City College of New York (CCNY) have developed a technique for imaging tissue structures--tendons, veins, tumors--deep beneath the skin. The ultimate goal of this research is to dramatically improve the ability to perform minimally invasive cancer detection. ''With a technique called spectral polarization difference imaging [SPDI], we use dif… more
Date: November 1, 2000
Creator: Radousky, H & Demos, S
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Testing of the IMRA Wattlite Laser

Description: Long term testing of the IMRA Wattlite oscillator began this month. The oscillator was operated for over 250 hours while monitoring the output power, the center wavelength and the pointing stability. Due to safety requirements, data was only collected during normal working hours. At night, the external shutter was closed so no data was collected, however, the laser continued to operate. In this mode of operation, approximately 80 hours of data was taken during the 250 hours of operation. The la… more
Date: June 21, 2000
Creator: Biswal, S & Erbert, G
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Mask Blank Defect Detection

Description: Mask blanks are the substrates that hold the master patterns for integrated circuits. Integrated circuits are semiconductor devices, such as microprocessors (mPs), dynamic random access memory (DRAMs), and application specific integrated circuits (ASICs) that are central to the computer, communication, and electronics industries. These devices are fabricated using a set of master patterns that are sequentially imaged onto light-sensitive coated silicon wafers and processed to form thin layers o… more
Date: February 4, 2000
Creator: Johnson, M A & Sommargren, G E
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Progress with the lick adaptive optics system

Description: Progress and results of observations with the Lick Observatory Laser Guide Star Adaptive Optics System are presented. This system is optimized for diffraction-limited imaging in the near infrared, 1-2 micron wavelength bands. We describe our development efforts in a number of component areas including, a redesign of the optical bench layout, the commissioning of a new infrared science camera, and improvements to the software and user interface. There is also an ongoing effort to characterize th… more
Date: March 1, 2000
Creator: Gavel, D T; Olivier, S S; Bauman, B; Max, C E & Macintosh, B
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Ablation Front Rayleigh Taylor Dispersion Curve in Indirect Drive

Description: The Rayleigh-Taylor (RT) instability, which occurs when a lower-density fluid accelerates a higher-density layer, is common in nature. At an ablation front a sharp reduction in the growth rate of the instability at short wave-lengths can occur, in marked contrast to the classical case where growth rates are highest at the shortest wavelengths. Theoretical and numerical investigations of the ablative RT instability are numerous and differ considerably on the level of stabilization expected. We p… more
Date: November 17, 2000
Creator: Budil, K. S.; Lasinski, B.; Edwards, M. J.; Wan, A. S.; Remington, B. A.; Weber, S. V. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

A Fundamental Study of Laser-Induced Breakdown Spectroscopy Using Fiber Optics for Remote Measurements of Trace Metals

Description: Develop a fiber-optic imaging probe for microanalysis of solid samples. Design a time-resolved plasma imaging system to measure the development of the LIBS signal. Setup a laboratory system capable of timing two lasers independently, for optimizing and characterizing dual-pulse LIBS. Compare the development of laser-induced plasmas generated with a single laser pulse to the development of laser induced plasmas generated with a pre-ablation spark prior to sample ablation. Examine the effect of s… more
Date: June 1, 2000
Creator: Goode, Scott R. & Angel, S. Michael
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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