Multistability Observation in Acousto-Optic Generator

The results of a multistability operation observation in the acousto-optic (AO) system with feedback circuit (FC), functioning above the self-excitation threshold in the absence of an external RF generator are presented. Feedback loop connects the optical output and the piezoelectric transducer of the AO cell. The ultrasound frequency in the AO cell and the corresponding frequency of the radio frequency signal in the FC are determined by the collinear AO diffraction phase matching condition for the chosen wavelength of incident optical radiation. It was found out that the presence of multistability depends on the magnitude of the electrical signal phase shift introduced by the phase shifter and the delay time in the FC. Both these parameters variation may influence the RF signal frequency and magnitude.