Terahertz negative refraction in a high-temperature superconducting material

The phenomenon of negative refraction at terahertz (THz) frequency for a high-temperature superconducting material is theoretically investigated based on the inhomogeneous wave theory. Negative refraction, which arises from the negative refractive angle, can occur when a p-polarized wave is incident from a dielectric to a superconductor. The dependences of negative refractive angle on the angle of incidence, the wave frequency, and the temperature have been analytically studied. The conditions for obtaining a pronounced result in negative refraction are elucidated. The study of negative refraction is of potential use in designing a tunable polarizer. In addition, it is an extended study of a transmission problem that is not treatable from the Fresnel equations in electromagnetics and optics.