Bandgap engineering of face-centered cubic photonic crystals made of hollow spheres

Abstract

A three-dimensional photonic band structure was calculated numerically for a self-assembled face-centered cubic (FCC) lattice of hollow spheres either formed in air or embedded in a high-refractive-index dielectric medium. For the latter case, the bandgap and midgap frequency can be controlled precisely when the shell thickness, the shell radius, and the ratio of dielectric constants are changed between the shell and the interstitial medium. Eventually, we demonstrate that a FCC lattice of hollow spheres with a suitable shell thickness in a dielectric medium can be engineered to have a bandgap-to-midgap ratio as high as 4.5% and a bandgap 31% higher than for an identical structure of homogeneous spheres. (C) 2001 Optical Society of America.