Annular interdigital transducer focuses piezoelectric surface waves to a single point

摘要

We propose and demonstrate experimentally the concept of the annularinterdigital transducer that focuses acoustic waves on the surface of apiezoelectric material to a single, diffraction-limited, spot. The shape of thetransducing fingers follows the wave surface. Experiments conducted on lithiumniobate substrates evidence that the generated surface waves converge to thecenter of the transducer, producing a spot that shows a large concentration ofacoustic energy. This concept is of practical significance to design newintense microacoustic sources, for instance for enhanced acouto-opticalinteractions.