Abstract

Nematic liquid crystals (NLC) consist of anisotropic cigar-shaped molecules which, aligned by inter-molecular forces, macroscopically behave as a positive uniaxial with an angle-dependent refractive index for extraordinary eigenwaves. Intense electric fields can therefore induce molecular reorientation towards the field vector through dipolar interaction. Such reorientation in NLC is responsible for both electro-optic and nonlinear non local responses, the latter supporting stable two-dimensional solitons, i.e. nematicons, propagating in arbitrary directions with respect to the optic axis $\hat{n}$.[1] With reference to a standard NLC planar cell (see, e.g., Ref. 1), if the top electrode is split by a gap along p in the plane yz (see Fig. la) in two parts 1 and 2, different potentials can be applied to each region with respect to the bottom ground plane In these two NLC regions ideally separated by the plane xp, different angular reorientations ξ and ρ of the optic axis $\widehat{n}$ (Fig. lb) can be induced in and out yz, enabling the definition of a voltage-adjustable transition between two birefringent media.

© 2007 IEEE