Observation of coherent zone-folded acoustic phonons generated by Raman scattering in a superlattice
Author(s) -
P. Hawker,
A. J. Kent,
L. J. Challis,
A. Bartels,
T. Dekorsy,
H. Kurz,
K. Köhler
Publication year - 2000
Publication title -
applied physics letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 442
eISSN - 1077-3118
pISSN - 0003-6951
DOI - 10.1063/1.1324981
Subject(s) - superlattice , phonon , excitation , excited state , raman scattering , wavelength , laser , scattering , condensed matter physics , physics , optics , materials science , raman spectroscopy , atomic physics , quantum mechanics
We have used pulse time-of-flight techniques to examine the phonon emission from an optically excited GaAs/AlAs superlattice structure. For laser excitation wavelengths shorter than 767 nm (the energy of E1HH1 transition), we detect a significant longitudinal acoustic phonon component directed in a narrow beam normal to the structure. Under identical excitation conditions, generation of coherent longitudinal acoustic phonons has previously been observed in this structure. We suggest that the excitation wavelength and angular characteristics of the longitudinal acoustic emission is consistent with those of propagating modes produced as coherent phonons "leak" from, the superlattice structure
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