Investigation of crossed SAW fields by scanning acoustic force microscopy

We used multimode scanning acoustic force microscopy (SAFM) for studying no ncollinearly propagating Rayleigh and Love wave fields. By analyzing torsio n and bending movement of SAFM cantilever, normal and in-plane wave oscilla tion components are accessible. The SAFM principle is the down-conversion o f surface oscillations into cantilever vibrations caused by the nonlinearit y of the tip-sample interaction. Through mixing of complementary oscillatio n components, phase velocities of crossed Rayleigh waves on GaAs and crosse d Rayleigh and Love waves on the layered system SiO2/ST-cut quartz were obt ained simultaneously. Now, it is possible to investigate elastic properties of submicron areas through multimode SAFM measurements. Finally, we presen t mixing experiments of four SAWs on GaAs and discuss the various influence s on the measured SAFM amplitude and phase contrast.