DETECTION OF BLEUSTEIN-GULYAEV SURFACE-WAVES PROPAGATING ON HEXAGONAL CRYSTALS USING ACOUSTOOPTIC INTERACTION

Bleustein-Gulyaev (BG) waves retain the main advantages of surface acoustic waves (SAW), while being less sensitive to surface stresses and contamination. Our aim here is to study the acousto-optic detection of this kind of SAW using a laser probe. The interaction of BG waves with light propagating in the SAW sagittal plane is investigated theoretically for zinc oxide (ZnO) and cadmium sulphide (CdS) crystals with hexagonal symmetry (6 mm). The diffraction of the reflected and transmitted beam is studied versus the angle between the light wavevector and the normal to the SAW supporting plate (the depth direction along which the SAW attenuates). Some experimental results are also reported and compared with the above theory.