Tunable full bandgap in a three-dimensional photonic crystal modulated by a nematic liquid crystal

Photonic crystals (PCs) have many potential applications because of their ability to control light-wave propagation. We have investigated the tunable full bandgap in a three-dimensional PC structure modulated by a nematic liquid crystal (LC). Numerical simulations show that the band gaps can be continuously tuned in a diamond dielectric structure consisting of air spheres by infiltrating nematic LCs. Then we can control the full bandgap of a PC structure. We analyzed the variations of full gap by considering various index modulations of LCs. Such a mechanism of bandgap adjustment should open up a new application for designing components in photonic integrated circuits.