Characteristic measurement of surface acoustic wave using a heterodyne interferometer

A new method for measuring a wavelength and standing wave ratio of a surface acoustic wave(SAW) is presented, which is based on a heterodyne interferometer using first-order diffracted light beams from a SAW device and a grating. Phase and amplitude distributions of a beat signal from the interferometer by moving the substrate or the grating give such characteristics of the SAW. Experimental verifications are presented in two cases of the movements of the object and grating. Two-dimensional measurements around an interdigital transducer of a SAW device are also given.