High-resolution optical probing of SAW and leaky SAW structures

A nondestructive high-resolution technique for the optical detection of surface acoustic wave (SAW) devices is presented. The laser probing technique allows for the measurement of the phase and amplitude of microacoustic fields and waves of SAW components in operation. The phase velocity can be determined directly from the measurements with a relative accuracy of up to 1.5.10/sup -5/. We present new experimental results of microacoustic wave propagation phenomena including anisotropic and temperature dependent phase velocity /spl upsi/, diffraction, and attenuation and compare them to full-wave analysis computations. The minimum detectable surface displacement of less than 1 pm//spl radic/Hz allows for the detection of different acoustic modes such as Rayleigh waves and leaky SAWs.