Disordered photonic bandgap materials, from functional deice design to self-assembly progress.

Disordered photonic band gap materials are not limited to crystalline symmetries, hence offering unprecedented freedom for functional-defect designs, an inherent advantage associated with the isotropy of the structure. Beyond our previous works in disordered photonic structures, we made further progresses in both functional device designs and self-assembling attempts. We designed hyperuniform-disordered wall-networks for coupling 1.55-micron waves effectively in and out thin Silicon slabs. We systematically studied how various design parameters can be optimized for the best total efficiency, the best directional coupling and the broadest angle coupling. This can be potentially useful for integrated photonic circuits, and large-area and wide-angle light emitters and sensors. Microscopic disordered patterns with different degrees of hyperuniformity can be experimentally realized by driving colloidal suspensions out of equilibrium in a flow with different degrees of shearing. We found a clear correlation between the easiness (minimum required index-contrast) in opening photonic bandgap with the transition of displacement amplitude. This may open new routes for bottom-up self-assemblies of functional photonic materials.