Visualization of 10 μm surface acoustic waves by stroboscopic x-ray topography

Abstract

X-ray topographs under acoustic wave excitation were taken from LiNbO3-based surface acoustic wave devices with He-implanted waveguide layers, using monochromatized synchrotron radiation from the European Synchrotron Radiation Facility (ESRF), Grenoble. Measurements were performed in the stroboscopic mode, i.e., by synchronizing the electron bunch frequency with the resonant frequency of the acoustic wave excitation in the 300 MHz range. These x-ray diffraction images showed plane acoustic wave propagation through the LiNbO3 crystals as well as a weak wavefront distortion due to the scattering on dislocation deformation fields. In some images secondary spherical waves were observed as a result of the strong acoustic wave interaction with the submicron size density perturbations.