Design of a one-way multichannel and wide-angle absorber based on the one-dimensional superconductor photonic crystals with the cascaded quasi-period structure

In this paper, a one-way multichannel and wide-angle absorber based on the one-dimensional superconductor photonic crystals (SPCs) in the terahertz regime is realized via splicing the classical quasi-period sequences and manipulating the ambient temperature properly, whose characteristics and mechanisms are theoretically in- vestigated by the transfer matrix method. The preeminent absorbing features of the proposed SPCs are ascribed to the temperature and frequency-dependent refractive index of the superconductor components, whose ima- ginary part plays a role in giving rise to the high dissipation. Additionally, when the thickness of the whole structure is of the order of the incident electromagnetic wavelength, the one-way absorption and the reflection in the opposite direction can be perfectly obtained. The calculated results demonstrate that the relative bandwidths of the one-way effective absorption regions in our proposed SPCs can reach to 51.94%, 30.18%, and 19.12%, respectively, and the maximum angle where the wide-angle absorption region can sustain is up to 84 degrees for TM wave by controlling the related parameters. Moreover, the impacts of the external factors such as temperature and incident angle and the interior elements including the thicknesses of diverse layers and the recursive numbers of the cascading sequences on the absorbing performance are also taken into account. To explicitly verify the reliability of our model, the impedance matching and the average refractive index are introduced for explaining the splendid multichannel absorption. As a whole, our research offers effective guidance for the theoretical excogitation of the multichannel and wide-angle absorber in the optical field.