Use of the acoustooptic light deflector as an optical isolator

In many uses of lasers, the minimization or elimination of power reentering the laser is necessary to ensure its stability. It is pointed out here that the frequency-shifting properties of an acoustooptic light deflector can be used for this purpose. By using the deflected beam from a Bragg deflector, stability of the laser is obtained when the frequency of the acoustic wave is chosen such that the frequency(ies) of the light reentering the laser, shifted by twice the acoustic frequency from the light leaving the laser, does not correspond to a cavity resonance. Experimental results demonstrating this isolation property are presented and are found to be in general agreement with other results of injection locking of lasers.