Modeling of a 3-D Tunable Photonic Crystal for Camouflage Coating

摘要

Photoresponsive polymers undergo structural changes (expansion or contraction) upon photoirradiation[1]. This group of polymers when polymerized with arrays of colloidal particles self-assembled into a crystalline colloidal array (CCA) forming a polymerized CCA (PCCA). The functionality of the CCA is enhanced by polymerizing it, due to the inclusion of specific properties of the polymer. Combining the properties of both, significant change in the lattice size is observed under external stimuli resulting in an optical response of the PCCA (either a blue or red shift of the spectrum)[2],[3].Novel tunable nanophotonic devices that enable a camouflage behavior could be realized using this technique. Camouflage behavior is achieved when an object blends into the environment, making it indiscernible from its surroundings. One approach to achieving such behavior in an object is to reflect only the wavelength that is predominant in the range of wavelengths incident from its surroundings. In this work we model and simulate a 3D polymerized photonic crystal structure which has the potential to exhibit this behavior. Simulations are performed to model the dynamic band gap tuning of the 3-D photonic crystal using the MIT Photonic Bands (MPB) and OptiFDTD optical modeling tools. These results lend a key understanding to the design of PhC's that exhibit dynamic band gap tuning, and how they can be applied in device designs.