Analysis of unidirectional broadband absorption in one-dimensional superconductor photonic crystal with an asymmetric multiple-layered structure

In this paper, the unidirectional absorption characteristics of one-dimensional (1D) superconducting photonic crystals (SPCs) with defect layers in the terahertz (THz) frequency region are theoretically analyzed by the transfer matrix method. The arrangement of such SPCs is an asymmetric multiple-layered structure (AB)D-N(BA)(M)(N not equal M). N, M are the stack numbers, respectively. The calculated results demonstrate that, in comparison with conventional 1D binary PCs, the unidirectional absorption region (UAR) of the proposed 1D SPCs can be significantly improved and the relative bandwidth can approximately reach over 20%. The effects of the parameters for the proposed SPCs on the UAR also are investigated. The computed results illustrate that the tailored and optimized UAR can be obtained in the THz regime by tuning those parameters and also demonstrate possible means to realize the THz unidirectional broadband absorber based on the SPCs. (C) 2019 Optical Society of America