Noncontact continuous wavefront/diffractive acoustic elements for Rayleigh wave control

A laser is used to excite Rayleigh waves on a sample. The optical distribution of the laser energy as it strikes the sample is controlled using a computer generated hologram—this optical distribution determines the initial acoustic wavefront and hence the acoustic amplitude distribution. In this letter, we present two designs of acoustic elements which use diffraction of the Rayleigh waves as a means of controlling the acoustic amplitude distribution.