Stimulated emission from a ruby laser with an ultrasonic surface wave on a resonator mirror

An investigation was made of a new acoustic method for internal high-frequency modulation of the intensity of laser radiation by ultrasonic surface waves. Excitation of a traveling wave of 5–20 MHz frequency in one of the resonator mirrors resulted in intensity modulation of each spike and the modulation frequency was the same as that of the ultrasonic wave. The depth of modulation increased with increasing amplitude and decreasing frequency of the ultrasonic wave, and also with increasing reflectivity of the resonator mirrors. A study was made of the spectral and spatial characteristics of the modulated laser radiation. The influence of the aperture and length of the resonator on the intensity modulation process was analyzed. The mechanism responsible for the observed modulation was considered.