Index of content:
Volume 107, Issue 6, June 2000
- TRANSDUCTION 
107(2000); http://dx.doi.org/10.1121/1.429345View Description Hide Description
Laser ultrasonics is an effective means of generating surface acoustic waves (SAWs). We have shown in previous publications how computer-generated holograms (CGHs) can be used to project optical distributions onto the sample surface. These can be used to control both the frequency content and the spatial distribution of the resulting ultrasound field. In this paper the concept is extended further to produce distributions which themselves act as diffractive acoustic elements (DAEs) for SAWs. It is demonstrated how frequency suppression, multiple foci, and frequency selective focusing of Rayleigh waves may be achieved with these elements. Agreement between the distributions predicted from the designs and those actually measured is excellent.