Investigation of surface acoustic wave scattering effects

We present measurements of surface acoustic wave (SAW) scattering from single dots, periodic and locally disturbed two-dimensional dot arrays. By using the scanning acoustic force microscope (SAFM), SAW fields of arbitrary polarization can be imaged with submicron spatial resolution and sub-Å wave amplitude sensitivity. The influence of a wavelength-sized single dot on SAW diffraction is studied. Forward- and back-scattered wave components can be imaged by insonifying the dot with a pump and a probe beam under different angles. SAW diffraction images of a regular dot array reveal a wavefield that is localized around the dots. In case of a disturbed scattering array, the localized SAW pattern vanishes in the vicinity of the distortion