Time-resolved surface acoustic wave propagation across a single grain boundary

Using an optical technique, we present time-resolved measurements of high frequency surface acoustic waves propagating across the boundary between two single crystals. The choice of the elastically anisotropic cubic crystal copper allows the observation of anisotropic surface acoustic propagation with cuspidal wave fronts together with refraction in the presence of significant orientation mismatch. The effect of the subsurface grain boundary angle on the transmitted acoustic field is revealed.