Bragg wave coupling in self-assembled opal photonic crystals

摘要

The optical properties of three-dimensionally-ordered self-assembled photonic crystals are studied in the Braggnwave coupling regime. Angle-resolved photonic stop gap measurements show the Bragg wave coupling extendingnover an angular range of 18◦. The new diffraction peak originating at the Bragg wave coupling regime is duento the (¯111) stop gap. The Bragg wave coupling regime is analyzed for photonic crystals with different latticenconstants and refractive index contrasts. For lower-index-contrast photonic crystals, Bragg wave coupling occursnat a lower angle of incidence as compared to higher-index-contrast photonic crystals of similar lattice constants.nThe exchange of energy between the diffraction peaks in the coupling regime is discussed. Experimental resultsnare compared with theoretical calculations and they are in good agreement. Furthermore, we demonstrate tunablenstop gap with high reflectance and photonic strength in the fiber-optic communication wavelength range.