Resonant gratings in planar Grandjean cholesteric composite liquid crystals.
We propose to induce a two-dimensional (2D) periodic modulation structure into a planar Grandjean cholesteric liquid crystal (CLC) to demonstrate the intrinsic 2D photonic crystal properties of such materials. The structure combines a thin transmission grating and a Bragg reflective grating. One advantage of using CLC is the intrinsic high quality Bragg structure, which can be modulated by an electric field: shifting the wavelength band edge by changing the applied field. Another interesting property is the polarization dependence. The main difference between using CLC Bragg instead of a linear grating is the need to operate with a circularly polarized light, because the CLC modes are circular in such a regime. We present preliminary results obtained with what we believe to be the first switchable photonic CLC (PCLC) sample, made up of a polymer CLC gel.
Denisov
Alexey
A
Department of Optics, Ecole Nationale Supérieure des Télécommunications de Bretagne, Unité Mixte de Recherche CNRS, Foton, CS 83818, 29238 Brest Cedex, France. alexey.denisov@enst-bretagne.fr
de Bougrenet de la Tocnaye
Jean-Louis
JL