Optical study of the pseudogap in thickness and orientation controlled artificial opals

Abstract

Artificial opals consisting of polystyrene spheres ordered into a fcc lattice are grown with control over the orientation and thickness. A thorough study of the formation of the pseudogap in these structures is carried out by means of reflectivity and transmission spectra. Special attention is paid to discriminating those features inherent to the photonic crystal, and those to the substrate on which the crystal is grown. Further, a characterization of the photonic band structure in the hexagonal facet of the Brillouin zone is made using angle resolved reflectivity measurements.