Resolution of Optoacoustic Transducers

Abstract

An optoacoustic transducer (OAT) is a multilayer planar device which produces a focused acoustic field distribution by trans- forming a focus-inducing optical pattern into a corresponding acoustic pattern. One measure of the effectiveness of such a device is its in- herent resolving ability, which is determined by the sharpness of its focal-plane distribution. me resolving ability of the OAT has been studied by analyzing its spatial transfer function. This transfer func- tion, called the optoacoustic spatial transfer function (OASTF), has been shown to be the product of two factors: an aberration-limited transfer function and a diffraction-limited transfer function. The aberration-limited transfer function, derived in an eariier paper, has been modified to include the effect of a photoconductive backing layer. By comparing the aberration and diffraction-limited transfer functions, optimum OAT size has been determined. Simulated images produced by an optimum-sized OAT have been obtained using the OASTF, and maximum resolution has been calculated.