Solid-state ring laser with diffraction acoustooptic mode feedback

An experimental investigation was made of the influence of the diffraction acoustic feedback on the stimulated emission from a YAG:Nd³ solid-state ring laser with forced acoustooptic mode locking. The feedback was created by directing beams diffracted in an acoustooptic modulator back to the ring laser resonator. A study was made of systems with a single reversing mirror and with an additional linear or ring resonator for the diffracted beams. In all cases this feedback broadened considerably the mode-locking band. It was possible to modulate in different ways the intensities of the opposite waves in the ring laser by sweeping the ultrasonic wave frequency inside the mode-locking band. In particular, the direction of the radiation emitted by the ring laser could be switched without low-frequency transients.