Multiband acoustic waveguides constructed by two-dimensional phononic crystals

摘要

By introducing a lattice translation of the unit cell of a phononic crystal, a general recipe to invert the acoustic Zak phase-i.e. the one-dimensional geometric phase at each phononic band-is provided and verified by surface impedance measurement. Multiband acoustic interface states are thus generated and may help the design of future acoustic waveguides. The propagation properties of these topological interface states are experimentally obtained and we believe that the methods to measure surface impedance and local sound pressure distributions inside phononic crystals developed here can further help experimental studies in acoustic metamaterials.