Photonic band gap in a superconductor-dielectric superlattice

Abstract

We foresee applications and interesting possibilities of incorporating the photonic crystals concept into superconducting electronics. In this paper, we present interesting features of the computed lower band structure of a nondissipative superconductor-dielectric superlattice using the two-fluid model and the transcendental equation ͓Pochi Yeh, Optical Waves in Layered Media, Wiley Series in Pure and Applied Optics ͑Wiley, New York, 1988͔͒. The necessary conditions for approximating the complex conductivity by an imaginary conductivity is derived and the feasibility of achieving the conditions are discussed. The superlattice dispersion obtained is similar to that of the phonon-polariton dispersion in ionic crystal. We found a nonlinear temperature-dependent ''polariton gap'' and a low-frequency ͑plasma͒ gap, and suggested the existence of a photon-superelectron hybrid around the polariton gap. The polariton gap may be observed in an infraredmicrowave regime using a high-T c superconductor with sufficiently low normal-fluid relaxation time (Ϸ10 Ϫ15 s), and in an optical regime using lower penetration depth ͑Ϸ50 nm͒ and extremely low relaxation time (Ϸ10 Ϫ17 s). I. Introduction.Much work has been done on the computation of the band structures of electromagnetic waves propagating in two-and three-dimensional dielectric periodic structures since it was shown 1 that these periodic structures can be designed to produce the required band structures. The band structures explored were mainly fabricated from dielectric materials, 2-4 typically used in the semiconductor technology. Dielectric periodic structures can be designed to mold the light propagation in integrated semiconductor optoelectronics where electronic and optical signals coexist and transform between each other.Recently, combinations of various materials for the design of photonic crystals have been studied. Sigalas et al. 5 found wider photonic band gaps when dielectric constant and relative permeability have their maximum values in different materials and suggested using magnetically tuned ferrite materials. Electric-and magnetic-field-dependent materials like ferroelectrics, ferromagnets, and ferrimagnets were investigated in two-dimensional photonic crystals. 6 Frequencydependent dielectrics 7 and metallic 8 photonic crystals have been studied, too. We foresee novel applications and interesting possibilities of incorporating the photonic crystals concept into superconducting devices. From this motivation, in this paper we study the band structure of a onedimensional nondissipative superconductor-dielectric superlattice.We describe the electromagnetic response of a typical nonmagnetic superconductor using the two-fluid model 9,10 via the complex conductivity. The necessary and sufficient conditions that reduce the complex conductivity to imaginary conductivity are derived, since we are interested in a nondissipative superlattice. The superconductor satisfies the Gorter-Casimir relation. 11 The dielectric layer is characterized by a real dielectric consta...

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

“…This strong coupling produces a superpolaritonlike narrow band such that the wave can propagate through the system. 9 For TE polarization, however, the resonant dips do not exist since there is no normal component in the electric field. Moreover, the bandwidth shown in Fig.…”

“…7 Periodic multilayer structures consisting of superconducting and dielectric materials have been reported recently. [8][9][10][11][12] It has been explored that such a periodic structure has two fundamental distinctions compared with the dielectric-dielectric and metal-dielectric ones: ͑1͒ a lowfrequency band gap exists for both TM and TE polarizations, and ͑2͒ a superpolariton band gap is found for TM polarization. 10 Both of the above mentioned band gaps lie in the optical frequency range.…”

Temperature dependent resonances in superconductor photonic crystal

“…The use of superconducting materials in photonic crystals opens up new possibilities, due to the dependence of the optical properties of superconductors on temperature and magnetic field. Recent work shows the existence of a superpolariton gap in a superconductor-dielectric superlattice 3 only for light with H-polarization or TM mode. It was realized that the gap falls in the infrared regime.…”

Finite-difference time-domain studies of low-frequency stop band in superconductor-dielectric superlattice

“…The advantage of this superconductor structure is its low loss which is much less than that of a metallic superlattice, because the imaginary part in the dielectric constant of superconductor is much less than that of metalic material. [8] In the present paper, we apply the shift operator finite difference time domain (SO-FDTD) method to the superconductor structure. For validation purpose, the results from the method are compared with the analytical solutions by calculating the transmission and reflection coefficients of a superconductor slab, and then this new FDTD formulation is used to calculate the low-frequency stop band of superconductordielectric superlattice.…”