Studying the Frequency Range of Operation of a Piezoelectric Transducer of an Acousto-Optic Filter by Electric and Optical Methods

The acousto-optic characteristics of a paratellurite crystal with a cut angle of α = 10.2° have been investigated theoretically and experimentally. The crystal is used in an acousto-optic filter for processing optical images in visible and infrared light. The electric range of filter tuning has been experimentally determined based on the frequency dependence of the power absorbed by the piezoelectric transducer of the filter. Estimates of the range of filter tuning with respect to optical wavelengths are made. At light wavelengths of λ = 1.15 µm and λ = 0.63 µm, the dependences of the Bragg angle of incidence on the ultrasound frequency are calculated. When measuring the diffraction efficiency in the deflector operation mode, it was found that the range of filter tuning in optical wavelengths turns out to be different from that predicted as a result of measuring the electrical characteristics of the transducer and becomes narrower.