Polariton gap in a superconductor-dielectric superlattice

Photonic band structures explored in the past 12 years were mainly fabricat ed from dielectric materials, typically used in the semiconductor technolog y. However, we foresee novel applications and interesting possibilities by incorporating the photonic crystals concept into superconducting devices. I n this paper, we study the band structure of a non-dissipative superconduct or-dielectric superlattice using the two-fluid model. We apply the dispersi on relations in both layers of the superlattice to the transcendental equat ion for a double-layer superlattice, from which we compute the bandgap stru cture for the dielectric-superconducting superlattice. Computation results show the existence of dispersion-curve splitting similar to the phonon-pola riton case in addition to the low-frequency gap similar to the plasma-frequ ency gap. The polariton gap size is characterized by polarization and the p enetration depth, and highly dependent on temperature at the vicinity of su perconducting transition temperature. Our analysis shows that the propertie s of this material structure may have application in optical region if extr emely low relaxation time superconductor is used. This may be an asset for superconducting electronics-photonics integration. (C) 1999 Published by El sevier Science B.V. All rights reserved.