Electrically tuned phase transition and band structure in a liquid-crystal-infilled photonic crystal

Rapid Communication

Electrically tuned phase transition and band structure in a liquid-crystal-infilled photonic crystal

P. Halevi, J. A. Reyes-Avendaño, and J. A. Reyes-Cervantes

Phys. Rev. E 73, 040701(R) – Published 28 April 2006

Abstract

We studied a nematic liquid crystal (LC) cylinder under the action of an axial electric field $E_{0}$ . Elaborate modeling of the free energy leads to the conclusion that the configuration of the molecules is “escaped radial” for low $E_{0}$ ; a phase transition, however, occurs for a critical value $E_{c}$ , the configuration becoming axial for $E_{0} > E_{c}$ . From these results, the position-dependent dielectric tensor is determined and the photonic band (PB) structure is calculated for a photonic crystal of LC cylinders. It is shown that by varying $E_{0}$ a PB gap can be fully tuned from open to closed. Also, switching to a supercritical field can give rise to interesting polarization and directional effects in the propagation of light.