Order to disorder optical phase transition in random photonic crystals

Transition process of optical modal properties induced by the introduction of randomness into random photonic crystals is investigated by a computational method. We analyze an impulse response of two-dimensional triangular photonic crystals, in which the positions of the air holes are slightly deviated to random directions. It is shown that the appropriate degree of random departure from a perfect crystal state gives rise to multiple scattering of low group velocity band-edge modes and supports their strong Anderson localization. The achieved confinement efficiency of light exceeds the one obtained in the perfect photonic crystal state.