Broadband demultiplexer based on the self-collimation superprism effect in sonic crystals

We propose a broadband acoustic superprism based on self-collimation in a two-dimensional sonic crystal (SC), which simultaneously exhibits both angular and frequency superprism effects with high spectral resolution. Our design not only achieves high wavelength sensitivity, but also effectively suppresses beam divergence and irregular beam generation, thereby overcoming the inherent limitations of conventional SC-based superprism. These advantages originate from the self-collimation effect and the deliberate selection of an operating region away from the Brillouin zone edge. Building on this self-collimation superprism, we further design and numerically demonstrate a two-dimensional demultiplexer capable of resolving arbitrary frequency components of the input sound beam within the operating band while preserving excellent wavefront integrity.