Interplay between multiple scattering and optical nonlinearity in liquid crystals

Temperature control of nematicon trajectories

Using modulation theory, we develop a simple [(2+1)-dimensional] model to describe the synergy between the thermo-optical and reorientational responses of nematic liquid crystals to light beams to describe the routing of spatial optical solitary waves (nematicons) in such a uniaxial environment. Introducing several approximations based on the nonlocal physics of the material, we are able to predict the trajectories of nematicons and their angular steering with temperature, accounting for the energy exchange between the input beam and the medium through one-photon absorption. The theoretical results are then compared to experimental data from previous studies, showing excellent agreement.

Generation of multiple solitons using competing nonlocal nonlinearities

We discuss the dynamics of fundamental Gaussian beams launched in saturable and nonlocal nonlinear media. Solely in the presence of a self-focusing saturable nonlinearity, the breathing solitons undergo strong deformation. The addition of a defocusing nonlinearity leads to the generation of couples of solitons. Experimentally, we demonstrate in nematic liquid crystals the formation of multiple spatial solitons starting from a bell-shaped input, with both direction and the number of filaments depending on the input power, confirming the theoretical predictions.

Electro-optic quenching of nematicon fluctuations

Employing a low-frequency external electric field bias in nematic liquid crystals with negative dielectric anisotropy, we demonstrate that the trajectory fluctuations of reorientational spatial solitons can be substantially reduced, improving confinement and polarization purity of the output beams.