Studies on nonlinear beam dynamics in uniaxial nematic liquid crystals under the influence of temperature, diffractive radiation, and potentials

Abstract

This thesis investigated the nonlinear beam dynamics in uniaxial nematic liquid crystals under the influence of temperature, diffractive radiation, and potentials.The study emphasizes the role of diffractive radiation in ensuring unclisturbed nematicon propagation by utilizing both variational and numerical rnethods. A key aspect of the research is the competition between focusing reorientational and defocusing thermal nonlinearities, which results in the formation of multi-peak nematicous. [t also iuvestigates how parabolic potential influences the generation of higher harmonics of nematicons. The stability of steady-state solutions against small perturbations is studied by applying the Bogoliubov-De-Gennes equations- The study has been extended to the thermal response of nematicons in a parabolic potential. Single-peak nematicons exist ouly in the absence of thermal response coefficients. The presence of both focusing reorientational and defocusing thermal nonlinearities creates multiple maxima in the energy landscape, allowing for the stabilization of doublepeak nematicous as equilibrium states. Periodic oscillations are observed in nematicons within a parabolic potential, with their wavelength being influenced by thermal response coefficients. The linear stability analysis reveals that single-peak and periodically oscillating double-peak nematicons are stable, whereas non-oscillating double'peak nematicons are unstable. The research also extends to study the formation and stability of gap nematicons. Finally, the study explores the effects of thermal response and difiractive radiation on multi-peak gap nematicons.