Type of Photonic Crystal

Photonic crystals are regular arrays of material with different refractive indices. In photonic crystal, there are 3 types of them. There are one-dimensional, two-dimensional and three-dimensional. In other word 1D type, 2D type and 3D type. In the case where the variation is along one direction, we call it a 1D photonic crystal. Similarly, we define 2D and 3D photonic crystal’s, corresponding to the respective cases where varies along two and three independent direction. It is arrange by according to the dimensionality of the stack.


The 1D photonic crystals= It is dielectric multilayer and their optical properties are well-known. They are utilized as high-reflection mirrors and anti-reflection coating. However, most investigations related to the control of the radiation field in recent years have been concentrated on 2D and 3D photonic crystals, because they offer a rich variety of new physics of the radiation field.


The 2D photonic crystals= It intersections of air- or dielectric rod axes with a perpendicular plane form a 2D lattice. So that is how the 2D photonic crystals formed.


The 3D photonic crystals, if we design it properly, there appears a frequency range where no electromagnetic eigenmode exists. Frequency ranges of this kind are called photonic bandgaps, since they correspond to bandgaps of electronic eigenstates in ordinary crystals. Moreover, if we introduce a disorder into the regular dielectric structure of the photonic crystal, we may obtain midgap modes whose eigenfunctions are strongly localized around the disorder. These modes are called localized defect modes.