Topological properties in a GaAs-SU8-Based phoxonic crystal with high Q factor and mechanics-optics coupling coefficient

We propose a two-dimensional GaAs-SU8-Based (SU8 photoresist is a high-contrast epoxy negative photoresist) phoxonic crystal to simultaneously exhibit topological characteristic of electromagnetic and elastic waves. By rotating the angle of SU8 holes with respect to the center of the regular hexagon, diarc cone degeneracy occurs at both photonic and phononic bandgap, accompanied by band flipping. Further, the topological transmission and robustness is verified by design three different interface channels with a 30°/-30° flip. We investigate the Q factor of both mechanics and optics in this topological system, when the ratio n = 0.2 (radius r to the lattice constant a) and a= 340μm, Q_photonic and Q_phononic achieve highest, equal to 6432 and 2508, respectively. At this time, the mechanics-optics coupling in the phoxonic cavity reaches its maximum, g_mb= 1024 Hz, g_pe= 75.2 Hz and g= 1099.2 Hz. (g_mb means the moving interface effect; g_pe means the photoelastic effect, and g means the The mechanics-optics coupling coefficient) The propose PxCs realize highly topologically protected and robust characteristics with the effect of maintaining high optical force coupling rate. Providing a model reference for the design of mechanic-optic functional devices such as liquid concentration sensor, mass sensor and micro-displacement sensor.