Design Of Broadband Omnidirectional Band Gap In The One-dimensional Ternary Photonic Crystals

Having omnidirectional broadband gap of photonic crystal can for any of the polarization of light and any Angle of the incident show100%of reflection. All get broadband gap has become the researchers pursuit and the object of study.Some methods to enlarge the frequency range of omnidirectional photonic band gap have been proposed, such as increasing the contrast of dielectric functions between the PC composites, using a chirped PC or photonic heterostructure, or introducing the disorder into the periodic structures.One-dimensional photonic crystal dispersion relation expression is derived expression sidebands around the band gap of one-dimensional dual photonic crystals and photonic crystal band gap bandwidth obtained the structure of the photonic crystal photonic crystal dispersion.Finally according to the expansion of the photonic crystal, this paper put forward two extended band gap method.(1)On the band gaps in the visible and infrared area, a theoretical research to the layers of a metal embedded one-dimensional dual photonic crystal.Research found that the structure of the band gap wider than by layers of one-dimensional dual photonic crystal, by three medium consisting of one dimension of three ternary photonic crystal and by a medium layer and a metal layers of one-dimensional dual photonic crystal the band gap.In normal incident, embedding a thin layer of metal band gap is significantly expand.In inclined incidence band gap also be expanded.In inclined incidence upper band edges of the wavelength with TM polarization is less than the wavelength with TE polarization.lower band edges of the wavelength with TM polarization is larger than the wavelength with TE polarization. Finally caused the whole structure of the band gap All depends on TM polarization. This is all similar with the band gap of the traditional one-dimensional dual photonic crystal mirror depending on TM polarization(2)By adopting the transfer matrix method, we discuss the adjustable omnidirectional photonic band gap in the one-dimensional ternary photonic crystals (1DTPC) containing superconductor. It is found that the bandwidth and the photonic band-edges of the photonic band gap vary with the changing of the thickness of the superconducting material and the incident angle. Comparing to the one-dimensional binary photonic crystals, the bandwidth of the photonic band gap is broadened obviously and the frequency range of the omnidirectional band gap is enhanced apparently in the1DTPC formed by sandwiching the superconductor between two dielectric layers, these results suggest that we can realize the broadband omnidirectional reflector in this1DTPC. Moreover, the influence of the temperature of the superconducting materials layer on the bandwidth of the omnidirectional band gap in the one-dimensional ternary photonic crystals is discussed. It is shown that the bandwidth of the omnidirectional band gap, the wavelengths of upper and lower band edges and the center wavelength can be tuned by controlling the external temperature.