Chapter 6: Dynamics of Optical Solitons in Bias-Free Nematic Liquid Crystals
Nonlinear Physics Centre, Research School of Physics and Engineering, The Australian National University, Canberra, ACT, Australia
We present a review of our experimental work on spatial optical solitons in nematic liquid crystals (NLCs) in a planar cell without external fields. We investigate the nonlocal interaction of two mutually incoherent copropagating (CO) and counterpropagating (CP) bias-free nematicons; the analysis of the dynamics of CP solitons versus their relative separation and excitation shows the existence of stable vector solitons composed of two oppositely propagating nematicons. Efficient steering of nematicons is achieved by introducing defects in the liquid crystal layer: we demonstrate significant bending as well as large-angle total internal reflection of nematicons interacting with a curved interface between NLCs and air. Nematicons induce guiding channels capable of confining a weak signal: we identify experimentally the domains of nematicon power where higher order guided modes are supported. Finally, we present recent results on the astigmatic transformation of vortex beams in NLCs into spiraling dipole azimuthons accompanied by power-dependent charge-flipping of on-axis phase singularity.
Spatial optical solitons have been studied extensively in diverse nonlinear media, in both one- and ...