One-Way Transmission And Mode Conversion Of Elastic Waves By A Hybrid Phononic Crystal Structure

We study the one-way transmission and mode conversion of elastic waves by a hybrid phononic-crystal structure that consists of two mutually perpendicular phononic-crystal waveguides connected by a resonant cavity. Based on the mode matching mechanism between the cavity and waveguides, the symmetrical waves incident on the waveguide entrance are converted into antisymmetric modes and exit the waveguide. However, for the same waves incident on the structure from the waveguide exit, no output waves are transmitted toward the waveguide entrance because the modes in the waveguides and the cavity are mismatched. On the basis of this unique property, we designed a polarization-sensitive composite structure to measure the angle between two components of incident mixed elastic waves.