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Picosecond Optical Nonlinearities and Stimulated Emission in Indirect Al x Ga 1− x As
Author(s) -
Kalt H.,
Smirl A. L.,
Boggess T. F.
Publication year - 1988
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221500285
Subject(s) - picosecond , band gap , electron , materials science , plasma , absorption (acoustics) , refractive index , spectroscopy , absorption edge , atomic physics , molecular physics , condensed matter physics , chemistry , optics , optoelectronics , physics , laser , quantum mechanics , composite material
The nonlinear optical properties of indirect‐gap Al x Ga 1− x As in the presence of a dense electron‐hole plasma are studied by picosecond luminescence and transient transmission spectroscopy. The fundamental X‐band gap is found to be renormalized by exchange and correlation effects within the plasma. Higher‐lying band gaps in the same sample are also renormalized but here the electron‐exchange contribution to the narrowing is negligible. Strong plasma‐induced nonlinearities like persistent bleaching of absorption, enhanced absorption, and large changes of the refractive index are observed at the direct absorption edge for lattice temperatures of 15 as well as 293 K. Stimulated emission from the indirect X‐band is made possible by alloy‐disorder induced band mixing.