Novel device structures based on colloidal photonic crystals

We describe two different ideas for novel architectures based on photonic crystals of sub-micron colloids. The first involves the formation of photonic superlattices from colloidal photonic crystals. The superlattice periodicity induces the formation of minibands due to folding of the photonic band structure. This represents the first instance in which mid-gap states have been incorporated into a colloidal photonic crystal via a specifically engineered structural modification. The second idea involves applying the superprism concept to three-dimensionally periodic structures. Near a photonic band edge, the diffraction angle is extremely sensitive to the wavelength and propagation direction of the incident light. We analyze this effect in the context of macroporous polymer thin films formed from colloidal crystal templates.