High-Q impurity photon states bounded by a photonic band pseudogap in an optically thick photonic crystal slab

Abstract

We show that, taking a two-dimensional photonic crystal slab system as an example, surprisingly high quality factors (Q) over 105 are achievable, even in the absence of a rigorous photonic band gap. We find that the density of in-plane Bloch modes can be controlled by creating additional photon feedback from a finite-size photonic-crystal boundary that serves as a low-Q resonator. This mechanism enables significant reduction in the coupling strength between the bound state and the extended Bloch modes by more than a factor of 40. © 2012 American Physical Society.