Optical aspects of inhomogeneous molecular order in confined NLC systems: Monte Carlo studies

Analytical (elastic medium approximation) and numerical (Monte Carlo and molecular dynamics) modelling of an inhomogeneous spatial order in nematic liquid crystal (NLC) molecules in confined systems (e.g. in planar or twisted NLC cells) is widely used for molecular engineering of optical devices based on inhomogeneous spatial distribution of refractive index. We present an overview of recent results obtained viaMonte Carlo approach based on model Lebwohl-Lasher Hamiltonian, concerning optical aspects (index of refraction, diffraction efficiency, transmission) of inhomogeneous molecular order in nematic liquid crystals in confined geometry. The role of anchoring forces and of their fluctuations is discussed, in particular for transmission in Twisted NLC (TNLC) cells. Preliminary results on an influence of molecular order on tunable negative- and zero-index nanosphere dispersed liquid crystals (NDLC) are presented. The phase diagram for real part of effective permittivity in variables external electric (magnetic) field - anchoring strength is calculated.