%0 Journal Article %T Annular interdigital transducer focuses piezoelectric surface waves to a single point %A Vincent Laude %A Davy G¨Śrard %A Naima Khelfaoui %A Carlos F. Jerez-Hanckes %A Sarah Benchabane %A Abdelkrim Khelif %J Physics %D 2007 %I arXiv %R 10.1063/1.2891055 %X 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. %U http://arxiv.org/abs/0712.3899v1