Non-leaky, piezoelectric, quasi-shear-horizontal type SAW on X-cut LiTaO3

It is shown both theoretically and experimentally that, besides a conventional piezoelectric Rayleigh -type surface acoustic wave (R-SAW), there exists a nonleaky , piezoelectric, quasi-shear-horizontal-type surface acoustic wave (SH-SAW) on X-cut LiTaO₃. Both of these waves are accompanied by all of the field components. This is very different from the situation on the substrate supporting a Bleustein-Gulyaev-Shimizu wave and a nonpiezoelectric R-SAW. Fr a specific propagation direction, SH-SAW on the metallized surface concentrates its energy within two or three wavelengths from the surface and its electromechanical coupling factor k² is comparable to that for R-SAW propagating in the same direction. On the free surface, SH-SAW exists only in a very narrow range of propagation direction, and its poor energy concentration close to the surface results in negligible k². Experimental results are shown to be in good agreement with the theoretical calculation