The characteristic of the stero-coupling high-Q photonic crystal slab cavity

Inspired by the idea of the stero-coupling, we propose a new sandwich-like photonic crystal microcavity which is composed of double layer photonic crystal slabs H1 (DLPCS-H1) cavity with an air layer in between. We calculate the electromagnetic field distribution and the quality factor of the dipole mode by the three-dimensional finite-difference time-domain method and the Pade approximation method. Through carefully analyzing the effect of the air layer height on the quality factor of the dipole mode, we obtain an optimized DLPCS-H1 cavity in which the height of intermediate air layer is about 0.5a (a is the lattice constant, a = 420 nm). In this cavity, the quality factor of the dipole mode is 4 times as large as that of the conventional single layer photonic crystal slab H1 cavity. Furthermore, we study the three-layer photonic crystal slabs H1 cavity, and the quality factor of its dipole mode is increased over 7 times.