Reconfigurable Phononic-Crystal Circuits Formed by Coupled Acoustoelastic Resonators

Reconfigurable phononic circuits can be created by the selective fluid filling of holes in a solid phononic crystal. For frequencies within a complete band gap of the bare phononic crystal, the filled holes become cavities that sustain acoustoelastic defect modes. Those cavities couple evanescently with a strength that depends on their separation. We investigate the dispersion relation and the transmission properties of coupled-resonator acoustoelastic waveguides formed by a chain of cavities. While the dispersion relation is strongly dependent on the separation between cavities, transmission properties are only weakly dependent on the details of the phononic circuit for a fixed separation. Furthermore, depending on the polarization of the source of waves, defect modes can be excited selectively. As a result, rather arbitrary phononic circuits can be created, such as multiply bent waveguides or wave splitters.