(2+1)-dimensional photonic crystals from Langmuir-Blodgett colloidal multilayers

Angle-resolved transmission spectra of multilayers of two-dimensional colloidal crystals prepared by the Langmuir-Blodgett technique have been studied. In contrast to the light diffraction in three-dimensional colloidal crystals, optical spectra revealed only very weak correlation between layers in the Langmuir-Blodgett multilayers. Two reasons for the observed transmission minima have been identified: the diffraction at a stack of layers and the scattering of the incident beam by guided modes of the two-dimensional colloidal crystals. (c) 2006 American Institute of Physics. (DOI:10.1063/1.2234568

Understanding of transmission in the range of high-order photonic bands in thin opal film

Diffraction in the face centered cubic lattice cannot explain some minima observed in the transmission spectra of self-assembled opal films. Here, we compared them with minima observed in the transmission spectra of a hexagonal close packed monolayer of spheres of the same diameter. The identity of the sphere packing on the surface of the opal film and in the sphere monolayer was demonstrated by the light diffraction at the sample surfaces. It was shown that excitation of surface propagating modes in the opal film is responsible for the formation of additional minima in opal film transmission. (C) 2008 American Institute of Physics. (DOI: 10.1063/1.2920443

Erasing diffraction orders: Opal versus Langmuir-Blodgett colloidal crystals

The optical transmission of photonic crystals self-assembled from colloidal nanospheres in opals and assembled from two-dimensional colloidal crystals in a periodic stack by the Langmuir-Blodgett technique has been compared. Elimination of all related zero order diffraction resonances other than that from growth planes and broadening and deepening of the remaining one-dimensional diffraction resonance have been observed for samples prepared by the Langmuir-Blodgett approach, which are explained in terms of the partial disorder of a crystal lattice. (c) 2007 American Institute of Physics.(DOI:10.1063/1.2714198

Modification of emission of CdTe nanocrystals by the local field of Langmuir-Blodgett colloidal photonic crystals

A light source on the surface of a slab of 2+1-dimensional photonic crystal has been prepared by the Langmuir-Blodgett deposition of a colloidal crystal on top of a thin film containing CdTe nanocrystals. The directional enhancement of the light emission intensity in the spectral range of the photonic bandgap has been revealed through the comparative examination of the angle-resolved transmission, diffraction, and photoluminescence spectra of the prepared structures. Changes in the emission spectrum have been tentatively explained in terms of the acceleration of the radiative recombination due to the increase in the local field strength at photonic bandgap resonance and changes in the emission diagram-as arising from the wavelength dependence of the topology of the local field pattern