Influence of the absorbed optical quanta energy on GHz ultrasound generation in GaAs E. Morozov, Y. Laamiri, P. Ruello, D. Mounier and V. E. Gusev Eur. Phys. J. Special Topics, 153 (2008) 239-241 Published online: 12 March 2008 DOI: 10.1140/epjst/e2008-00435-3