Unidirectional operation of ring lasers via the acoustooptic effect

Two different techniques are described for enforcing unidirectional operation of a ring laser using the acoustooptic effect. A simple quantitative explanation for each mechanism is presented, together with a detailed analytical model which allows the difference in loss for the counter-propagating beams to be calculated. Experimental results which confirm the validity of the models are also presented. The application of these techniques for single frequency CW and Q-switched operation of miniature solid-state lasers is discussed and, based on the analytical model, strategies for optimising the design of acoustooptic modulators and ring resonators are considered.