Electromagnetoelastic transport through a piezoelectric slab: Selective parity interplay of electromagnetic and acoustic resonances

Abstract

We present the complete solution concerning to transport properties of coupled transverse electromagnetic and shear acoustic waves propagating via a piezoelectric slab embedded into a homogeneous dielectric medium. Since the electroacoustics of our setup is governed by four electromagnetoelastic eigenmodes, we had to succeed in developing a 4 × 4 transfer matrix method to analytically resolve the problem. As a result, the exact frequency spectra of the transmission, reflection, and transformation transport coefficients were obtained and analyzed in detail for two basic cases where the piezoelectric slab subjected by electromagnetic/acoustic perturbation generates acoustic/electromagnetic response. We establish that wave transformation is effectively realized in vicinities of electromagnetic and acoustic Fabry–Pérot resonances. Surprisingly, as a consequence of the problem geometry and accepted 4 mm symmetry of the piezoelectric medium, the phenomenon of the resonant parity selection arises: in the vicinity of an electromagnetic Fabry–Pérot resonance of the given (odd/even) parity, only acoustic Fabry–Pérot resonances with opposite (even/odd) parity are excited in the coefficient of generation. The piezoelectric coupling vanishes when the parities of both resonances coincide. The changes in transmission and reflection spectra turn out to be more sophisticated. The phenomenon is observed due to quite great distinction between electromagnetic and acoustic wave numbers provided by the fundamental difference between light and sound velocities. In our analysis, particular attention is also paid to the ability of increasing the mutual transformation of electromagnetic and acoustic fluxes.