Surface acoustic wave guiding in a diffractionless high aspect ratio transducer

We demonstrate efficient three-dimensional surface acoustic wave guidance and confinement in a high-aspect ratio electrode transducer. Each electrode acts as an elastic resonator that is evanescently coupled to its neighbors. We observe high amplitude displacement fields confined within the high aspect ratio electrodes. The stored surface waves are found to present a general shear polarization instead of the sagittal polarization expected for classical Rayleigh waves. The elastic energy is mostly distributed in the mass-loaded areas, and waves propagate within the transducer without diffraction, even for very low acoustic apertures.