Theory of nonlinear optical absorption associated with free carriers in semiconductors

Journal Article · Sun Oct 31 23:00:00 EST 1982 · IEEE J. Quant. Electron.; (United States)

DOI:https://doi.org/10.1109/JQE.1982.1071469· OSTI ID:5863286

James, R B ^[1]; Smith, D L

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1. Oak Ridge National Lab., TN

Calculations are presented of the intensity dependence of the free-carrier absorption in semiconductors by high-intensity light with a wavelength near 10 ..mu..m. The paper is divided into two sections. The first section examines the nonlinear absorptive and dispersive proprties associated with free-hole transitions in semiconductors, and the second section presents calculations of the nonlinear absorption associated with free-electron intraband transitions in germanium. The dominant free-hole absorption of CO/sub 2/ laser light for most p-type semiconductors with a diamond or zinc-blende crystal structure is direct intervalence-band transitions where a hole in the heavy- (or light-) hole band absorbs a photon and makes a direct transition to another band within the valence band structure. The absorption coefficient due to this mechanism is found to decrease with increasing intensity in a manner closely approximated by an inhomogeneously broadened two-level model. Detailed results are presented for the saturation behavior of germanium as a function of temperature, wavelength, and doping density. Calculated values for the intensity dependence of the index of refraction and low-frequency conductivity are presented. Calculated values of the saturation intensity are also given for most of the other Groups IV and III-V semiconductors. In several n-type semiconductors, the dominant absorption of 10 ..mu..m light is free-electron intraband transitions where an electron absorbs a photon and is excited to a state in the same band. The interaction of the electron distribution with the high-intensity light increases the average energy of the electrons and leads to an increase in the free-carrier cross section.

• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 5863286
• Journal Information: IEEE J. Quant. Electron.; (United States), Journal Name: IEEE J. Quant. Electron.; (United States) Vol. QE-18:11; ISSN IEJQA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
ABSORPTIVITY
ALUMINIUM ARSENIDES
ALUMINIUM COMPOUNDS
ANTIMONY COMPOUNDS
ARSENIC COMPOUNDS
ARSENIDES
CARBON DIOXIDE LASERS
COUPLING
DATA
DIELECTRIC PROPERTIES
DISPERSIONS
DOPED MATERIALS
ELECTRICAL PROPERTIES
ELECTRONIC STRUCTURE
ELECTRONS
ELEMENTARY PARTICLES
ELEMENTS
EXPERIMENTAL DATA
FERMIONS
GALLIUM ANTIMONIDES
GALLIUM ARSENIDES
GALLIUM COMPOUNDS
GAS LASERS
GERMANIUM
INDIUM ARSENIDES
INDIUM COMPOUNDS
INFORMATION
INTERMEDIATE COUPLING
IONIZATION
L-S COUPLING
LASERS
LEPTONS
MATERIALS
METALS
MODE LOCKING
N-TYPE CONDUCTORS
NONLINEAR PROBLEMS
NUMERICAL DATA
OPTICAL PROPERTIES
P-TYPE CONDUCTORS
PHYSICAL PROPERTIES
PNICTIDES
REFRACTIVITY
SATURATION
SEMICONDUCTOR MATERIALS
THEORETICAL DATA