Non-contact acoustic microscopy

We demonstrate a fast all-optical surface acoustic wave (SAW) microscope. This acoustic microscope may be thought of as a non-contact (hence non-perturbing) surface acoustic microscope. The key to producing a sufficiently high SAW amplitude for imaging without producing surface damage is to tailor the generating optical distribution. This can be used to spread the optical power on the sample surface (preventing damage) and to focus the acoustic waves (increasing the amplitude). This paper discusses the general and specific design features of our microscope and important new developments in the general design of such instruments. Our microscope based on this technology is capable of producing high quality, quantitative images of SAW amplitude and phase (velocity) on many materials; this and new, unique, forms of acoustic contrast are demonstrated and discussed.