Chapter 8 - Light transport in three-dimensional photonic crystals

Abstract

Photonic crystals constitute a class of nanophotonic structure characterized with a periodically altered refractive index along one, two, or three orthogonal directions. In this chapter, we discuss the formation of photonic stopgaps, control of photon density of states, and different techniques for making photonic crystals along with some important applications. We elaborate on the light transport in three-dimensional opal photonic crystals through polarization-dependent reflectivity measurements. These opal photonic crystals possess low refractive index-contrast and therefore exhibit only photonic stopgaps. The branching of stopgaps at high-symmetric points in opal photonic crystals with face-centered cubic symmetry is also discussed. Optical reflectivity measurements show prominent branching of stopgaps at the K point for TE polarized light. In contrast, the TM polarized light exhibits quasi-collapse of the stopgap at the K point until the Brewster angle. Unlike the case of the K point, stopgap branching is apparent at the W point for both TE and TM polarizations. The polarization anisotropy factor is estimated to enumerate the 0non-identical stopgap formation at the K and W points. The estimated polarization anisotropy values are in good agreement with the theoretical calculations for ideal opal phoer.tonic crystals with fcc symmetry.