Resonance switching in a large sonic crystal cavity

In this work we present an experimental realization of resonance switching inside a large, relative to the lattice constant, sonic crystal (SC) cavity. The resonances arise from a temporary trapping of the acoustical energy between two sonic crystal slabs when the frequency of the wave falls within a partial band-gap region (thus, the propagation inside the sonic crystal is inhibited for normal incidence and a total reflection occurs). We show that by modifying the geometry of the sonic crystal lattice, from square to centered rectangular, it is possible to switch some resonances on and off, for a certain frequency region corresponding to the second band-gap for normal incidence. We also study the generalization of this phenomenon for the same lattice and band-gap region, as a function of the length of the cavity and the filling fraction the lattice.