Design of phoxonic filter using locally-resonant cavities

Abstract

A phoxonic crystal structure with a full phononic and photonic band gap is designed in this study, which is capable of conducting sound waves and also light waves with transverse magnetic (TM) polarization. Materials used in the structures are nylon and molybdenum, both of which have adequate difference in refractive index and elastic constants. It is worth of noting that the filling factor is considered to be 28% in all of the structures, in order to ease of fabrication. The final phoxonic filter structure is obtained by the comparison of several phoxonic filter structures in a similar condition. Since it is difficult to coordinate light and sound in phoxonic structures, the proposed structure has some advantages compared to other filters. This structure shows the optical and acoustical transmission linewidths equal 3.8 KHz in phononic and 0.06 nm in photonic modes, respectively. Also, the output quality factor is 23699 in phononic and 21201 in photonic modes. Finite element, plane wave expansion, and finite-difference time-domain methods are utilized for simulation.