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Title: Spectroscopy of GaAs quantum wells

Abstract

A new type of optical dipole transition in GaAs quantum wells has been observed. The dipole occurs between two envelope states of the conduction band electron wavefunction, and is called a quantum well envelope state transition (QWEST). The QWEST is observed by infrared absorption in three different samples with quantum well thicknesses 65, 82, and 92 A and resonant energies of 152, 121, and 108 MeV, respectively. The oscillator strength is found to have values of over 12, in good agreement with prediction. The linewidths are seen as narrow as 10 MeV at room temperature and 7 MeV at low temperature, thus proving a narrow line resonance can indeed occur between transitions of free electrons. Techniques for the proper growth of these quantum well samples to enable observation of the QWEST have also been found using (AlGa)As compounds. This QWEST is considered to be an ideal material for an all optical digital computer. The QWEST can be made frequency matched to the inexpensive Carbon Dioxide laser with an infrared wavelength of 10 microns. The nonlinearity and fast relaxation time of the QWEST indicate a logic element with a subpicosecond switch time can be built in the near future, with amore » power level which will eventually be limited only by the noise from a lack of quanta to above approximately 10 microwatts. 64 refs., 35 figs., 6 tabs.« less

Authors:
Publication Date:
Research Org.:
Lawrence Livermore National Lab., CA (USA)
OSTI Identifier:
5970233
Report Number(s):
UCRL-53681
ON: DE86009612
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Technical Report
Resource Relation:
Other Information: Portions of this document are illegible in microfiche products. Original copy available until stock is exhausted. Thesis
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 36 MATERIALS SCIENCE; GALLIUM ARSENIDES; POTENTIALS; QUANTUM MECHANICS; ABSORPTION SPECTRA; ENERGY GAP; EXPERIMENTAL DATA; INFRARED RADIATION; NONLINEAR PROBLEMS; OPTICAL COMPUTERS; OSCILLATOR STRENGTHS; ARSENIC COMPOUNDS; ARSENIDES; COMPUTERS; DATA; ELECTROMAGNETIC RADIATION; GALLIUM COMPOUNDS; INFORMATION; MECHANICS; NUMERICAL DATA; PNICTIDES; RADIATIONS; SPECTRA; 656000* - Condensed Matter Physics; 360603 - Materials- Properties

Citation Formats

West, L.C. Spectroscopy of GaAs quantum wells. United States: N. p., 1985. Web. doi:10.2172/5970233.
West, L.C. Spectroscopy of GaAs quantum wells. United States. doi:10.2172/5970233.
West, L.C. Mon . "Spectroscopy of GaAs quantum wells". United States. doi:10.2172/5970233. https://www.osti.gov/servlets/purl/5970233.
@article{osti_5970233,
title = {Spectroscopy of GaAs quantum wells},
author = {West, L.C.},
abstractNote = {A new type of optical dipole transition in GaAs quantum wells has been observed. The dipole occurs between two envelope states of the conduction band electron wavefunction, and is called a quantum well envelope state transition (QWEST). The QWEST is observed by infrared absorption in three different samples with quantum well thicknesses 65, 82, and 92 A and resonant energies of 152, 121, and 108 MeV, respectively. The oscillator strength is found to have values of over 12, in good agreement with prediction. The linewidths are seen as narrow as 10 MeV at room temperature and 7 MeV at low temperature, thus proving a narrow line resonance can indeed occur between transitions of free electrons. Techniques for the proper growth of these quantum well samples to enable observation of the QWEST have also been found using (AlGa)As compounds. This QWEST is considered to be an ideal material for an all optical digital computer. The QWEST can be made frequency matched to the inexpensive Carbon Dioxide laser with an infrared wavelength of 10 microns. The nonlinearity and fast relaxation time of the QWEST indicate a logic element with a subpicosecond switch time can be built in the near future, with a power level which will eventually be limited only by the noise from a lack of quanta to above approximately 10 microwatts. 64 refs., 35 figs., 6 tabs.},
doi = {10.2172/5970233},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jul 01 00:00:00 EDT 1985},
month = {Mon Jul 01 00:00:00 EDT 1985}
}

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