Coherent acoustic waves excitation and detection on subterahertz frequencies

The theory of coherent phonon radiation due to interaction of electromagnetic oscillations in Josephson junctions with mechanical displacement field caused by piezoelectric effect has been developed. We consider sound generation in Josephson tunneling structure depositing on the rather thick substrate playing the role of the high overtone (n~10⁴-10⁵) resonator for longitudinal acoustic waves propagating normally to the layers. It explains resonant sound generation in the range of 100-700GHz which was manifested as a superfine structure on current voltage characteristics with a voltage (frequency) spacing corresponding to acoustic modes frequencies spacing (about several MHz).