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 d = 744 nm (d = 780 nm), the reflectivities for forward and backward (backward and forward) directions are closed to similar to 0 and similar to 1 (similar to 0: 8 and similar to 0), respectively, and absorptances of the nonreciprocal perfect absorptions for forward and backward directions are similar to 0: 98 and similar to 0: 92 with the high quality factors of similar to 1100 and similar to 310, respectively.