VISUALIZATION OF THE CROSS SECTION OF A SOUND BEAM BY BRAGG DIFFRACTION OF LIGHT

Abstract

This Letter reports on a novel way of imaging, in amplitude and phase, the cross section of a sound beam. Because of the phase retention, any arbitrary cross section can be brought into focus by optical manipulation without changing the relative position of light beam and sound beam. The process is explained in terms of ray optics and various pertinent features are illustrated. Following a discussion about resolution, the experimental setup is described. Results show photographs of a 22-MHz sound field behind various objects placed in the sound beam. In conclusion, the application to sound microscopy at higher sound frequencies is pointed out.