Annular interdigital transducer focuses piezoelectric surface waves to a single point

TL;DR

This paper introduces an annular interdigital transducer design that focuses surface acoustic waves to a diffraction-limited spot on piezoelectric materials, demonstrated experimentally on lithium niobate.

Contribution

It presents a novel transducer shape that concentrates surface waves, enabling new microacoustic source designs for enhanced acousto-optical interactions.

Findings

Surface waves converge to a single point with high energy concentration

Experimental validation on lithium niobate substrates

Potential for improved microacoustic source applications

Abstract

We propose and demonstrate experimentally the concept of the annular interdigital transducer that focuses acoustic waves on the surface of a piezoelectric material to a single, diffraction-limited, spot. The shape of the transducing fingers follows the wave surface. Experiments conducted on lithium niobate substrates evidence that the generated surface waves converge to the center of the transducer, producing a spot that shows a large concentration of acoustic energy. This concept is of practical significance to design new intense microacoustic sources, for instance for enhanced acouto-optical interactions.