Tunable reflectance spectra of multilayered cholesteric photonic structures with anisotropic defect layers.
In this paper, we investigate the spectral characteristics of normal incident light reflected by a multilayered structure composed of an alternated sequence of single-pitch cholesteric liquid-crystal (ChLC) and anisotropic layers. Using the Berreman 4x4 matrix formalism, we numerically obtain the reflection spectrum and the chromaticity diagram as a function of the anisotropic layers thickness d. For d-->0 , the structure behaves like a single ChLC layer, showing a single reflection band. As the anisotropic layer thickness increases, the reflection band shifts toward high-wavelength spectral regions, while new reflection bands appear. As a consequence, the reflection chromaticity continuously changes with d . It is observed that a suitable choice of the anisotropic layer thickness can produce a threefold reflection band with a red-green-blue associated color for both polarized and unpolarized incident lights.
Nascimento
E M
EM
Instituto de Física, Universidade Federal de Alagoas, Maceió, AL 57072-970, Brazil.
Zanetti
F M
FM
Lyra
M L
ML
de Oliveira
I N
IN
D016880:Anisotropy; D002784:Cholesterol / Q000737:chemistry*; D003198:Computer Simulation; D050866:Liquid Crystals / Q000737:chemistry*; D008956:Models, Chemical; D017785:Photons; D012031:Refractometry / Q000379:methods*
D002784:Cholesterol