Abstract

We image gigahertz surface acoustic waves normally incident on a microscopic linear array of triangular holes-a generic acoustic diode geometry-with a real-time ultrafast optical technique. Spatiotemporal Fourier transforms reveal wave diffraction orders in k-space. Squared amplitude reflection and transmission coefficients for incidence on both sides of the array are evaluated and compared with numerical simulations. We thereby directly demonstrate acoustic rectification with an asymmetric structure. © 2011 American Institute of Physics.