Acousto-optic modulator of infrared radiation operating under acoustic resonance conditions

An acousto-optic modulator of infrared radiation was built using a germanium crystal operating under acoustic resonance conditions. Optimal dimensions of the modulator were calculated. The parameters of the acoustic grating established in the crystal were stabilized using a lithium niobate transducer supplied from a self-excited oscillator. The dependences of the intensity of the diffracted light on the electrical power were investigated under standing and traveling acoustic wave conditions. The frequency characteristic of the modulator was determined in the range from 100 Hz to 100 kHz.