| Nonlinear Optical Properties and Subpicosecond Dynamics of Excitons and Electron-Hole Plasmas in Multiple Quantum Well Structures |
DEC 87 |
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| Authors:
T. F. Boggess; A. L. Smirl; R. A. MacFarlene; J. F. Lam; ARMY LAB COMMAND WATERTOWN MA MATERIAL TECHNOLOGY LAB
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 | This report describes progress in measuring and modeling the nonlinear optical properties of and picosecond carrier dynamics in bulk ternary alloys and multiple quantum wells (MQWs). Studies of the bulk alloy Al(x)Ga(1-x) As have been produced the first experimental isolation of the electron exchange energy in a dense electron-hole plasma, and the observation of enhanced band-gap renormalization as a consequence of alloy disorder, stimulated emission from the indirect gap for ... |
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| Nonlinear Optical Properties and Subpicosecond Dynamics of Excitons and Electron-Hole Plasmas in Multiple Quantum Well Structures |
16 MAR 87 |
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| Authors:
A. L. Smirl; R. A. McFarlane; J. F. Lam; HUGHES RESEARCH LABS MALIBU CA
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| Time resolved photoluminescence measurements are reported for MBE- grown Aluminum, Gallium, Arsenide samples having alloy compositions which result in both direct gap and indirect gap materials. Quantitative results have been obtained for bandgap renormalization induced at high carrier densities and the results compared with a theoretical model. Detailed studies are reported of a marginally indirect sample displaying stimulated emission from both direct and indirect bandgaps. Keywords: Photoluminescence, Transient Absorption, Nonlinear ... |
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| Experimental and Theoretical Studies of Laser Cooling and Emittance Control of Neutral Beams |
31 JAN 87 |
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| Authors:
J. F. Lam; R. A. McFarlane; A. J. Palmer; D. G. Steel; R. S. Turley; HUGHES RESEARCH LABS MALIBU CA
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| Experimental and theoretical studies are made of issues relevant to laser cooling and emittance control of neutral beams. Experimental accomplishments include development of a technique for state specific velocity selection in atomic beams, observation of the Optical Kapitza Dirac Effect, construction of sodium and atomic hydrogen beam facilities, and initial development of a tunable, transform limited, Vacuum Ultraviolet source. Theoretical accomplishments include development of a theory of pi pulse cooling, ... |
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| Nonlinear Optical Properties and Subpicosecond Dynamics of Excitons and Electron-Hole Plasmas in Multiple Quantum Well Structures |
26 JAN 87 |
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| Authors:
A. L. Smirl; R. A. McFarlane; J. F. Lam; HUGHES RESEARCH LABS MALIBU CA
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| Time resolved photoluminescence measurements are reported for Molecular Beam Epitaxially-grown AlxGa(1-x) As samples having alloy compositions which result in both direct gap and indirect gap materials. Quantitative results have been obtained for bandgap renormalization inducted at high carrier densities and the results compared with a theoretical model. Ultrafast spectroscopy measurements on an MBE grown x=0.52 sample following optical excitation well above the bandgap show presistent bleaching of the direct absorption, ... |
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| Nonlinear Optical Properties and Subpicosecond Dynamics of Excitons and Electron-Hole Plasmas in Multiple Quantum Well Structures |
21 AUG 86 |
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| Authors:
A. L. Smirl; R. A. McFarlane; J. F. Lam; HUGHES RESEARCH LABS MALIBU CA
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| Progress is reported in measuring the nonlinear optical properties and picosecond dynamics of carriers in multiple quantum wells and other bulk and Molecular Beam Epitaxially grown structures. Discussions of our progress are divided into six parts; (1) fabrication and characterization, (2) picosecond time-resolved transient absorption, (3) picosecond time-resolved photoluminescence, (4) theory of dressed excitons, (5) picosecond photorefractive effects, and (6) picosecond and femtosecond laser development. |
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| Experimental and Theoretical Studies of Laser Cooling and Emittance Control of Neutral Beams |
OCT 1984 |
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| Authors:
R. A. McFarlane; D. G. Steel; R. S. Turley; J. F. Lam; A. J. Palmer; HUGHES RESEARCH LABS MALIBU CA
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| Experimental and theoretical progress has been made in the areas of experimental observation of the Optical Stern-Gerlach Effect (OSGE), resonant two-photon ionization of neutral hydrogen, and a theoretical study of pi-pulse cooling. In the OSGE studies, we have improved our spatial resolution, the spatial beam profile monitor, magnetic substate selection, the size of the interaction region, the signal-to-noise ration, and our computer codes for acquiring and analyzing the data. In ... |
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| Nonlinear Optical Studies of Rydberg Atoms Using Degenerate Four-Wave Mixing |
AUG 1984 |
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| Authors:
J. F. Lam; R. A. McFarlane; D. G. Steel; HUGHES RESEARCH LABS MALIBU CA
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| The spectral behavior of the third order nonlinear optical response of atomic sodium was studied. As a result, new kinds of frequency domain spectroscopy techniques were developed: nearly degenerate four-wave mixing, polarization nearly degenerate four-wave mixing, frequency domain three-state spectroscopy, and nonlinear Hanle effect in degenerate four-wave mixing. These techniques have provided new information on several areas of collision physics including: dephasing collisions (spectral broadening and frequency shift), velocity changing ... |
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| Phased Locked Array Laser Systems. |
21 MAY 1984 |
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| Authors:
J. F. Lam; DEPARTMENT OF THE NAVY WASHINGTON DC
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| A phase locked array laser system encloses a set of laser oscillators by a sawtooth mirror or corner cube reflector on one side and a partially reflecting sawtooth mirror on the other side. The system is fully enclosed by having two mirrors or corner cube reflectors at the top and bottom ends of the partially reflecting sawtooth mirror to coherently couple each laser oscillator to the others. (Author) |
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| Locking of Diode Gain Modules Using Optical Conjugation Techniques |
MAR 1984 |
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| Authors:
J. F. Lam; D. A. Rockwell; HUGHES RESEARCH LABS MALIBU CA OPTICAL PHYSICS DEPT
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| This report reviews results of a study program to investigate technical issues relating to the coupling of multiple diode lasers using a phase conjugate resonator. We present calculations showing the effects on the far- field intensity distribution of either systematic or random phase differences between adjacent gain elements; these results dramatically illustrate the beneficial impact of exact phase locking. The use of phase conjugation to phase- lock the individual emitters ... |
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| Phase Conjugate Optical Resonator |
NOV 1983 |
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| Authors:
R. A. McFarlane; R. C. Lind; G. J. Dunning; R. K. Jain; J. F. Lam; HUGHES RESEARCH LABS MALIBU CA
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| This is the Final report on a program to study the properties of phase conjugate optical resonators. Laser oscillation was achieved using both atomic sodium and photorefractive BaTi03 in four-wave mixing geometry as a phase conjugate resonator. Spectral and transverse mode characteristics were measured. A self-pumped phase conjugate mirror was also used in an oscillator and a computer code developed to model power output and transverse mode profile. Aberration correction ... |
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| Collisionally Induced Narrowing of the Longitudinal Relaxation Linewidth in Nearly Degenerate Four-Wave Mixing |
19 JUL 1982 |
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| Authors:
J. F. Lam; D. G. Steel; R. A. McFarlane; HUGHES RESEARCH LABS MALIBU CA
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| High-Resolution Spectroscopy and Collision Studies of High-Lying Atomic States Using Four-Wave Mixing |
09 FEB 1982 |
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| Authors:
D. G. Steel; J. F. Lam; R. A. McFarlane; HUGHES RESEARCH LABS MALIBU CA
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| Correction of Phase Distortion by Nonlinear Optical Techniques |
MAY 1981 |
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| Authors:
R. C. Lind; W. B. Brown; R. K. Jain; J. F. Lam; R. A. McFarlane; HUGHES RESEARCH LABS MALIBU CA
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| This is the final report on a program designed to explore a recently recognized property of certain nonlinear optical interactions of generating conjugate wavefronts that can be used to correct optical distortions in laser systems. These distortions include optical train aberrations, laser medium distortions, and atmospheric propagation aberrations. The program was divided into three basic areas that bridge the gap between a preliminary exploration of the applicable nonlinear processes and ... |
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Reports by Author
