Optical generation of continuous 76-MHz surface acoustic waves on Y Z LiNbO3

The efficient generation of continuous surface acoustic waves (SAW) by focusing the radiation of a synchronously pumped mode-locked cw dye laser (mode-locking frequency 76.44 MHz) on the surface of a YZ LiNbO3 crystal is reported. The surface acoustic waves were generated on a small absorbing surface area under varying excitation conditions and detected piezoelectrically by means of a narrowband interdigital SAW transducer, which yielded a voltage responsivity of 1.5 μV/mW cw laser power. The detected electrical signal verified the expected square law dependence of the acoustic power on the incident laser power.