Phase-control in two-dimensional phononic crystals

A theoretical model is developed to ascertain the necessary band structure and equi-frequency contour (EFC) features of two-dimensional phononic crystals (PCs) for the realization of phase control between propagating acoustic waves. Two different PCs, a square array of cylindrical polyvinylchloride inclusions in air and a triangular array of cylindrical steel inclusions in methanol, offer band structures and EFCs with highly dissimilar features. We demonstrate that PCs with EFCs showing non-collinear wave and group velocity vectors are ideal systems for controlling the phase between propagating acoustic waves. Finite-difference time-domain simulations are employed to validate theoretical models and demonstrate the control of phase between propagating acoustic waves in PC structures. (c) 2011 American Institute of Physics. [doi: 10.1063/1.3641634]