Noncontacting optical generation of focused surface acoustic waves using a customised zoneplate

Abstract

The use of computer generated holographic zoneplates to enhance the generation of laser ultrasound is described. An amplitude grating capable of focusing laser light onto an arc which in turn generates a near diffraction limited focus of 82 MHz Rayleigh surface waves is also described. The application of zoneplates for ultrasonic nondestructive evaluation and imaging is considered.