Optical property of electro-tunable defect mode in 1D periodic structure with light crystal defect layer

Abstract

A liquid crystal defect layer is introduced into a one-dimensional photonic crystal and its optical distance is varied by an electric field so that the defect mode can be controlled. An optical propagation simulation is carried out for study of optical characteristics in a model in which nematic liquid crystal is introduced as a liquid crystal defect layer in a dielectric multilayer as a one-dimensional photonic crystal. We investigate whether the defect mode can be controlled by varying the optical length by way of change in orientation of the liquid crystal molecules. Based on the simulation results, a device is fabricated with a nematic defect layer introduced within a SiO2/TiO2 laminated periodic structure. The defect mode of the one-dimensional photonic crystal is measured. It is confirmed that the experimental results and the simulation results agree well. Further, it is successful in shifting the defect mode wavelength by applying a voltage. Hence, it is clear that the defect mode can be modulated by changing the optical length of the defect layer by means of control of the orientation of the liquid crystal molecules by an applied voltage. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 87(5): 24–31, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10167