Conditions for anomalous acousto-optical diffraction by backward propagating acoustic waves - art. no. 026604

Experimental evidence is given of acoustic plate waves, whose group velocit y is contradirected with respect to the phase velocity, through a determina tion of the acoustic wavelength dependence on frequency, in a limited range of frequencies. The dependence d Lambda /d Omega >0 between wavelength and frequency is experimentally verified, as the required condition for acoust o-optical diffraction, where higher frequency components would scatter ligh t into smaller diffraction angles.