Quasi-crystal or disordered regular photonic crystal?

Abstract

ABSTRACT Several studies have shown that the incremental introduction of disorder in photonic crystals results in the high frequency band gaps closing followed by the lower frequency band gaps. The level and type of disorder required to pinch off the lower band gap depends on the photonic crystal’s initial dielectric layout. Our research has shown that a rotationally symmetric 12-fold quasi-crysta l structure can be reached by introduci ng a relatively low level of dielectric disorder to the hexagonal array. A morphing algorithm has been developed that permits the transformation of the hexagonal rod array photonic crystal into a 12-fold quasi-crysta l. The intermediate dielectric profiles generated are used to examine the evolution of the band gap and central defect states during the transformation. The resulting FDTD simulations display evidence that the underlying structure of the 12-fold quasi-crystal may be closely related to the hexagonal array. Keywords: photonic crystals, photonic quasi-crystals, defect states, structural disorder