Pattern Definition in Self-assembled Photonic Crystals

Introduction Colloidal self-assembly has been widely explored as a route to photonic materials. Theoretical work has demonstrated that a three dimensional photonic band gap can be generated from an inverse FCC structure if fairly rigorous dielectric contrast conditions are met. It is because of this finding that a multitude of research groups are investigating the self-assembly of colloidal particles followed by high dielectric constant replication strategies as a route to photonic band gap materials. The formation of low dielectric contrast three-dimensional nanoand microperiodic structures through colloidal templating is now relatively straightforward, but fabrication of high dielectric contrast structures as required for three-dimensional photonic band gap materials remains quite challenging. Furthermore, the functionality of self-assembled photonic crystals will be greatly enhanced if complex nanoscale features including wave guides and optical cavities are defined within the interior of photonic crystals. It is structures such as these that will be necessary for the integration of photonic crystals into optical and optoelectronic devices.