Tunneling properties of electromagnetic wave in slab superconducting material

Abstract

When the electromagnetic wave propagates through a slab superconducting material in microwave ranges, tunneling properties of the electromagnetic wave at critical temperature are investigated theoretically. The transmittance and the reflectance of the slab superconducting material vary with the thickness of material as well as the refractive index of substrates.The high transmittance is found for thin superconductor at low wavelength region. However, optical properties are strongly dependent upon temperature and incidence wavelength. The electromagnetic wave is totally transmitted without loss for incidence wavelength ( = 5000 nm) due to the zero refractive index and infinite penetration depth of the superconductor at the critical temperature.The studies of one dimensional photonic crystals (1D-PCs) including metallic, chiral, negative refractive index (NI) and superconducting materials, etc. have attracted much attention [1][2][3][4][5][6] . The propagation of electromagnetic waves in periodic media including metal, NI and superconducting materials has been a subject of interest because of its several useful applications in making optical devices like reflectors, super lens, etc [7][8][9][10] . One-dimensional metallic photonic crystals (1D-MPCs) have been shown to have high transmittance within a certain controllable spectral range and an enhanced nonlinear optical response in ID-MPC has also been reported [11,12] . The band structure for dielectric-dielectric photonic crystals (DDPCs) displays that the photonic band gap (PBG) between the first and second bands widens as the difference in dielectric permittivity is increased [13,14] .Recently, Thapa et al [15] has studied the enlargement of photonic band gap in heterostructure of metallic photonic and superconducting photonic crystals. They have shown that the heterostructure of the metallic-dielectric and superconductor-dielectric can have omni-directional behavior. The photonic crystals composed of superconductor and metallic layers have also been studied by Aly et al [16][17][18] . The electromagnetic wave at THz in the one-dimensional superconducting metallo-dielectric superlattice is allowed to propagate * through the structure when its frequency is higher than the cutoff frequency. However, it will be totally reflected at a frequency below the cutoff frequency. This cutoff frequency is strongly dependent on the thicknesses of the superconductor and dielectric layers, and the temperature as well. Raymond Ooi and Kam [19] have studied the transient pulse propagation in 1D-PC. The two new effects are identified: double reflection and slow-light ringing of transmitted and reflected pulses. The angle and thickness dependent photonic band structures in a one-dimensional superconducting photonic crystal have been studied by Wu et al [20][21][22] based on the framework of the Bloch theorem together with the transfer matrix method in a multilayer structure. Additionally, the effects coming from the oblique incident angle for both TE and TM modes also have been num...