Study of the Frequency Range of Operation of a Piezoelectric Converter Acousto-Optical Filter Using Electrical and Optical Methods

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