Measuring and monitoring optically induced thermal or orientational non-locality in nematic liquid crystal

Nonlinear propagation in nematic liquid crystals and spatial optical quasi-soliton can be generated via either thermal or orientational nonlinear process. These particular propagation modes can potentially be used in photonic and telecom devices, on the condition that they are well controlled, thus first to be properly measured. We first briefly review the measurements techniques, focussing on the newest one, based on a Raman scattering measurement. Then, it is demonstrated that there are two main ways to control the non-locality in spatial optical soliton either by using a time dependent source, or by playing with boundary conditions. Examples are given for each case.