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Observation of coherent zone-folded acoustic phonons generated by raman scattering in a superlattice

Beobachtung von kohärenten zonengefalteten akustischen Phononenerzeugt mittels Ramanstreuung in einem Übergitter
: Hawker, P.; Kent, A.; Challis, L.; Bartels, A.; Dekorsy, T.; Kurz, H.; Köhler, K.


Applied Physics Letters 77 (2000), No.20, pp.3209-3211
ISSN: 0003-6951
ISSN: 1077-3118
Journal Article
Fraunhofer IAF ()
III-V semiconductor; III-V Halbleiter; superlattice; Übergitter; optical measurement; optische Messung

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.