Discrete Spatial Solitons in Nematic Liquid Crystals

We investigate the linear and nonlinear light propagation in the voltage-tunable array of the waveguide channels created in undoped nematic liquid crystal layer. This novel geometry, based on the concept of the photonic structure with periodic modulation of refractive index controlled by an electric field, offers a wealth of possibilities for the study of discrete optical phenomena. Proposed structure, in conjunction with a giant, non-resonant and voltage-dependent reorientational nonlinearity, allows us to drive the system from the bulk diffraction to discrete propagation. Theoretical and experimental results, performed for near infrared light of the power of single milliwatts, show the possibility of transverse light localization, resulting in the discrete spatial soliton generation. Analyzed geometry, with its easily voltage- and optically adjustable coupling and guided-wave confinement, could find its potential applications in realization of multifunctional routers and all-optical signal processors in nematic liquid crystal cells.