Extraordinary optical properties of a superconducting periodic multilayer in near-zero-permittivity operation range

Optical properties in a one-dimensional periodic multilayer structure consisting of superconducting and dielectric films are rigorously studied. Due to the temperature- and wavelength-dependent refractive index in superconducting films, the design of multiple-resonance Fabry-Perot resonators can be achievable without physically introducing any defects to break the periodicity of the structure. These extraordinary optical properties, different from the regular all-dielectric Bragg reflectors, are mainly attributed to the operation in the near-zero-permittivity range of superconductors. Additionally, while the reflection bandwidth tends to enlarge with increasing angle of incidence for transverse magnetic polarization, it remains unchanged with band edges shifted for transverse electric polarization.