Electronically Tunable Photonic Crystals

3D photonic crystals have the ability to act as omnidirectional reflectors for certain wavelength ranges dependent on geometrical features and refractive index. Thus if the geometrical features could be dynamically controlled and the structure was designed to operate in the visible wavelength range a tunable colour reflector could be obtained. Such a device could form the basis for a pixel within full colour displays or signage depending on the speed of tunability. This paper presents initial experimental and theoretical results for a 2D implementation of such a system based on arrays of colloidal polymer spheres which have electronically tunable particle spacing.