Michal Kwasny

Nematicons in chiral nematic liquid crystals

We report on the experimental studies of the existence of spatial solitons called nematicons in chiral nematic liquid crystal cells. The low absorption allows us to observe soliton propagation at a distance of over a few millimeters in range. The results of our experiment also show that it is possible to create independent nematicons in different layers formed by a helical structure of the liquid crystals.

Nematicon–nematicon interactions in a medium with tunable nonlinearity and fixed nonlocality

We investigate the attractive interaction between spatial solitons in nematic liquid crystals with a tunable nonlinearity and a constant nonlocality. The experimental study, carried out by controlling the orientation of the optic axis via the electro-optic response, shows how the interactions depend on reorientation, in excellent agreement with a model accounting for the anisotropic nature of the dielectric.

Nonlinear competition in nematicon propagation.

We investigate the role of competing nonlinear responses in the formation and propagation of bright spatial solitons. We use nematic liquid crystals (NLCs) exhibiting both thermo-optic and reorientational nonlinearities with continuous-wave beams. In a suitably prepared dye-doped sample and dual beam collinear geometry, thermal heating in the visible affects reorientational self-focusing in the near infrared, altering light propagation and self-trapping.

Nematicons Interaction in Chiral Nematic Liquid Crystals

Recently, it has been shown experimentally that due to the reorientational nonlinearity in nematic liquid crystals (NLCs) it is possible to generate self-trapped non-diffractive light beams for relatively low power. Such spatial solitary waves in NLCs are called nematicons. Very interesting and promising properties have nematicons in chiral nematic liquid crystals (ChNLCs), where the incident light propagates perpendicular to the helical axis. In this work we report on the experimental studies of the existence of nematicons in such ChNLCs cells. We show that it is possible to utilize multi-layers for propagation of independent and interacting nematicons.

Light beam steering in chiral nematic liquid crystals

In the paper the steering possibility of nonlinear light beam in chiral nematics film are presented. We measured the propagation of light beam at the distance of few millimeters and the nonlinear self-focusing was observed for a light power of order of few tenths of milliwatts. Additional, in a waveguide induced by the nematicon, other low-power light beam (signal beam) with different wavelength was trapped. The experimental results are in a good agreement with theoretical predictions and numerical simulation.

Self-focusing and nematicons in chiral nematic liquid crystals

In this work we present the experimental results of measurements of spatial solitons (nematicons) in chiral nematic liquid crystalline film. We measured the propagation of light beam at the distance of few millimeters and the nonlinear selffocusing was observed for a light power of order of few tenths of milliwats. The experimental results are in a good agreement with theoretical predictions.

Interplay of Thermo-Optic and Reorientational Responses in Nematicon Generation

Employing several nematic liquid crystal mixtures, we investigate how the thermo-optic response of nonlinear birefringent soft-matter affects the propagation of light beams and the features of self-induced waveguides. We address the formation of optical spatial solitons and the control of their trajectories versus temperature, comparing the measurements with the expectations based on a simplified model, showing an excellent agreement. Moreover, in a guest–host mixture with an absorbing dye dopant, we study the competition between reorientational and thermal nonlinearities, demonstrating that the two processes can be adjusted independently in order to tune the soliton properties, i.e., trajectory and confinement strength. Our results are an important contribution to better comprehend the role played by material properties on linear and nonlinear beam propagation, as well as their exploitation for signal processing and addressing.

Spatial solitons in chiral nematic liquid crystals

We demonstrate experimentally the existence of spatial solitons in a chiral nematic liquid crystal planar cell. Due to the optical reorientational nonlinearity there were created for a light power of a few milliwatts. The low absorption allows us to observe soliton propagation distance over lengths of a few millimeters.