Unidirectional reflectionlessness and nonreciprocal perfect absorption in optical waveguide system based on phase coupling between two photonic crystal cavities

Abstract

We demonstrate the unidirectional reflectionlessness at exceptional points (EPs) and nonreciprocal perfect absorption near EPs based on phase coupling between two photonic crystal cavities (PCCs) in optical waveguide. In our scheme, when distance [Formula: see text][Formula: see text]nm ([Formula: see text][Formula: see text]nm), the reflectivities for forward and backward (backward and forward) directions are closed to [Formula: see text] and [Formula: see text] ([Formula: see text] and [Formula: see text]), respectively, and absorptances of the nonreciprocal perfect absorptions for forward and backward directions are [Formula: see text] and [Formula: see text] with the high quality factors of [Formula: see text] and [Formula: see text], respectively.