Anomalous Reflection from Colloidal Crystals of Core–Shell Particles

Abstract

The reflection from colloidal crystals of core–shell particles is evaluated by the calculation of photonic band structures, and is compared with the prediction of the Bragg condition. Although the results of the calculation of the photonic band structures are consistent with those of the Bragg condition, generally, the photonic band structures predict another reflection which has no origin in the Bragg condition, when the shell of the particle is sufficiently thin and the difference in refractive index between the core and the shell is relatively large. Moreover, no reflection is expected in the case of moderate shell thickness and moderate refractive index difference.