Beam interactions in one-dimensional saturable waveguide arrays

The interaction between two parallel beams in one-dimensional discrete saturable systems has been investigated using lithium niobate nonlinear waveguide arrays. When the beams are separated by one channel and in-phase it is possible to observe soliton fusion at low power levels. This new result is confirmed numerically. By increasing the power, soliton-like propagation of weakly-coupled beams occurs. When the beams are out-of-phase the most interesting result is the existence of oscillations which resemble the recently discovered Tamm oscillations.Comment: 5 pages, 6 figures, submitted to Phys. Rev.

Influence of Light Polarization on Reorientation Nonlinearity in Nematic Liquid Crystals

Nematic liquid crystals are characterized by a giant optical nonlinearity which has its origin in the molecular reorientational phenomenon. Uniqueness of this nonlinear mechanism causes that response of the medium is dependent on many conditions. Among various circumstances, both an initial alignment of liquid crystal cell and geometry of the system are very important, but in this paper a significant role of light polarization in nonlinear effects observed in nematics is emphasized. Additionally, it is underlined that dependence on light polarization does not have only trivial aspect of initial conditions. More complex seems to be the fact that due to the high optical anisotropy of the medium the state of light polarization is changing on the way of beam propagation. As a consequence, the modifications of molecular orientation in the liquid crystal cell are strongly dependent upon light polarization

Reorientational Nonlinear Phenomena in Thin Nematic Liquid Crystals Layer

In this paper the detailed study of the self-diffraction phenomena due to reorientational optical nonlinearity in nematic liquid crystalline cell is presented. The optical nonlinear effect is additionally modified by external low-frequency electric field. The dependence of nonlinear response on light polarization is also analyzed. The theoretical investigations are compared with experimental results and the theoretical predictions are in excellent agreement with experimental data

Reorientational Nonlinear Phenomena in Thin Nematic Liquid Crystals Layer

In this paper the detailed study of the self-diffraction phenomena due to reorientational optical nonlinearity in nematic liquid crystalline cell is presented. The optical nonlinear effect is additionally modified by external low-frequency electric field. The dependence of nonlinear response on light polarization is also analyzed. The theoretical investigations are compared with experimental results and the theoretical predictions are in excellent agreement with experimental data

Modeling of Spatial Solitons in Twisted Nematics Waveguides

Theoretical analysis of light beam propagation in twisted nematic liquid crystalline waveguides is presented. Due to the optical reorientation nonlinearity, the light beam changes the direction of propagation and optical spatial soliton is formed. Modeling of such behavior is presented by using (2+1) dimensional vector beam propagation method as well as simplified (1+1) dimensional method. Although both approaches give similar results, the differences are discussed in detail