The improved method of determination basic SAW characteristics by measurement of dynamic interference pattern intensity of +1 and -1 diffracted orders at the output of a two-beams optical interferometer

The optical scheme of the two beams optical interferometer has appeared very perspective for measurements of basic SAW characteristics, namely, phase and group velocities and steering beam angle in an anisotropic solid. The given work is proposed to utilize simultaneous measurement of diffraction efficiency of both (+1) and (-1) diffracted orders to achieve self-compensating of the change of the interferometer phase shift due to the change of external conditions. As usual this effect is eliminated by special jumping-frequency algorithm, but now the frequency switching can be monotone. As a result the time of a measurement is reduced in several times at simultaneous accuracy improving. The advantage of new multiple-beam modification of acoustooptic method that utilized simultaneous diffraction of two optical beams is examined experimentally. Measurements of basic SAW characteristics in ST-quartz have shown that possibilities of the method have increased by an one order of magnitude due to effect of self-compensation and by monotone frequency switching.