title: Tuning the effective width of the optical stop band in colloidal photonic crystals.
abstract: The optical stop band in colloidal crystals is characterized by the central frequency and bandwidth. Although the former is known to be highly tunable by changing the lattice constant, the latter is basically determined by the refractive index contrast between the particles and the background medium that is intrinsic to the materials. In this study, we show that the effective bandwidth in gelled colloidal crystals can also be tuned by controlling the fabrication conditions. Single-domain gelled colloidal crystals were prepared by photopolymerization under various photoirradiation conditions. It was observed that the width of the stop band in the transmission or reflectance spectrum could be expanded by simply adjusting the irradiation time.
authors.affiliation: National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
authors.forename: Toshimitsu
authors.initials: T
authors.lastname: Kanai
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Sawada
authors.forename: Akiko
authors.initials: A
authors.lastname: Toyotama
authors.forename: Junpei
authors.initials: J
authors.lastname: Yamanaka
authors.forename: Kenji
authors.initials: K
authors.lastname: Kitamura
mesh_terms: D003102:Colloids / Q000737:chemistry*; D050866:Liquid Crystals / Q000737:chemistry*; D013057:Spectrum Analysis
chemical_list: D003102:Colloids