Authors: A. Sinitskii, V. Abramova, T. Laptinskaya and Yu. Tretyakov
Affilation: Moscow State University, Russian Federation
Pages: 161 - 164
Keywords: photonic crystals, self-assembly, inverse opals, laser diffraction
We discuss the experimental data on laser diffraction in tungsten oxide photonic crystal films with an inverse opal structure. The samples were prepared using deposition of monodisperse polystyrene microspheres onto a vertical glass substrate, infiltration of voids with WO3 sol followed by its gelation, and final removal of the polymer microspheres by annealing. Scanning electron micrographs revealed that the films consisted of 25-500 μm2 domains isolated by cracks. Diffraction patterns were recorded by illuminating the samples with a 532 nm laser beam and projecting the patterns onto a screen. When using laser diffraction, it was possible to examine the sample areas of about 70000 μm2 and to visualize whether or not different domains have the same orientation. This method of quality control takes on special significance for inverse photonic crystals, for which average domain size is noticeably less than that of conventional opals.