Measurements of phonons generated by optical excitation of GaAs, using a superlattice phonon spectrometer

Previously we have demonstrated that a weakly coupled AlAs/GaAs superlattice (SL) works as a tuneable phonon spectrometer. In this paper we describe measurements made using the SL spectrometer of the phonons generated by relaxation of optically excited carriers in bulk GaAs. We find that, sub-THz acoustic phonons (≈420 GHz) are generated by direct optical excitation of bulk GaAs. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)