Investigation of one-way absorption properties in an asymmetric photonic crystal containing a semiconductor defect.

We theoretically study the one-way absorption in two 1D defective asymmetric photonic crystals, air/(DB)N A(BD)M /air and air/(DB)N A(BD)M A(DB)N A(BD)M /air, where A and B are dielectrics, D is the semiconductor, n-InSb, and N, M are stack numbers with N≠M. It is revealed that their absorption spectra exhibit one-way properties. We also find that the number of one-way absorption peaks depends on the symmetry and number of defect layers, which are similar to the defect modes in the transmittance spectra of the usual symmetry photonic crystals. Additionally, effects of the incident angles for both TE and TM waves on the one-way feature are also presented. At a large incident angle, the TE wave is almost reflected, whereas the TM wave can have a partial absorption.