Optics and Photonics Journal, 2012, 2, 105-112 doi:10.4236/opj.2012.22014 Published Online June 2012 (http://www.SciRP.org/journal/opj) Comparative Study of the One Dimensional Dielectric and Metallic Photonic Crystals Arafa H. Aly 1,2 , Mohamed Ismaeel 3 , Ehab Abdel-Rahman 2,3 1 Department of Physics, Faculty of Sciences, Beni-Suef University, Beni-Suef, Egypt 2 YJ-STRC, The American University in Cairo, New Cairo, Egypt 3 Department of Physics, The American University in Cairo, New Cairo, Egypt Email: arafaaly@aucegypt.edu Received February 22, 2012; revised April 2, 2012; accepted April 22, 2012 ABSTRACT The optical transmission properties of two types of photonic crystals have been analyzed by using the transfer matrix method. The first one is the dielectric photonic crystal (DPC), and the second is the metallic photonic crystal (MPC). We found the dielectric and metallic photonic crystals have different transmission spectra. The effect of the most pa- rameters on the transmission spectra of the dielectric and metallic photonic crystals has been studied. Keywords: Transmission; Metallic Photonic Crystals; Dielectric Photonic Crystals; Photonic Band Gap 1. Introduction Photonic crystals (PCs) are macroscopic media which arranged periodically with different refractive indices and their periodicities are in the range of the incident light [1]. In such structures the permittivity is a periodic function in space. In this case, the dielectric permittivity function repeats itself in one dimension (1D) the struc- ture called one dimensional photonic crystal (1D-PC), if it repeats itself in 2D or 3D the structure called 2D or 3D PC. The one dimensional photonic crystal (Figure 1) is a multilayered media. It is worthy to mention that, the propagation of photons in the PCs is similar to the propagation of electrons in the semiconductor crystals, where the effect of the periodic dielectric function on the propagating photon in PCs is much like the effect of the periodic potential function on the propagating electron in semiconductor crystal. Consequently, a photonic band is created in PCs similar to the electronic bad gap in semi- conductor crystal [2]. On the other hand, when electromagnetic waves (EM) incident on the PCs Bloch states create in the crystal, if the Bloch wave falls in the so called forbidden bands (photonic band gap) such a wave is evanescent and can’t propagate in the crystal. Thus the light energy is ex- pected to be totally reflected, and the crystal acts as a high reflectance reflector for the incident wave. The pho- tonic band gap of the photonic crystal makes us able to control the light even the spontaneous emission [3]. In this paper, we are going to do comparative study between the 1D-DPCs and -MPCs pointing to the general applica- tions of each kind according to its characteristics. 2. Analysis 2.1. Dielectric Photonic Crystals (DPCs) In the last decades dielectric photonic crystals have at- tracted much research interest due to their various appli- cations for example, optical filters, waveguides, and op- tical fibres [4-7]. In this section, we restrict our commu- nications on the characteristics of the 1D-DPC showing its various applications. The reflection of the EM waves through DPCs exhibit resonance reflection very much like the diffraction of x-rays by crystal lattice planes, therefore it’s called Bragg reflector. We have designed 1D-DPC composed of a low index material (Cryolite = 1.34) and a high index material (Sili- con = 3.4) stacked alternatively on a glass substrate. The number of periods, lattice constant, effective refractive index, and the filling factors of the low and the high in- dex materials are taken to be 10, 250, 2.389, 0.6, and 0.4 nm, respectively. The filling factor (f) of a material in a 1D-PC can be given by [8]; substrate Figure 1. Schematic diagram shows a one dimensional pho- tonic crystal. Copyright © 2012 SciRes. OPJ