Photonic band gaps in self-assembled colloidal structures

An intriguing feature of colloids is their ability of self-assembly, i.e., colloidal particles arrange themselves into an ordered structure. Using computer simulations, we explore the effect of thermal disorder on the photonic band gap in a self-assembled photonic crystal. We find that photonic band gaps can exist over a large range of intermediate packing fractions and that the widest gap does not necessarily appear at the densest packing fraction. Further, we show that with judicious choices of particle shape, packing fraction, and particle internal structure, self-assembly can be a promising method to make photonic crystals with large band gaps despite the presence of disorder.