Improved spatial soliton theory on the example of photorefractive gallium arsenide

This article presents a critical look at the standard theory of bright and dark photorefractive screening solitons. We pay attention to the commonly overlooked fact of the inconsistency of the theory in the context of the accordance of soliton solution with the microscopic band transport models. Taking into account the material equations for the semi-insulating semiconductor (SI-GaAs) and including the nonlinear transport of hot electrons, a simple differential equation has been developed to determine the distribution of refractive index changes in the material for a localized optical beam. An amendment to the standard solution of (1 + 1)D solitons has been proposed, which particularly should be used for dark solitons to obtain the plausible self-consistent solutions

Evolution of rectangular and triangular initial beam profiles in positive Kerr local medium

The hyperbolic secant (Sech) shape, as the initial beam profile, is the well-know profile that compensates the diffraction and self-focusing effect during propagation in Kerr medium, and evolves as the bright spatial soliton. The Sech beam can be confined in the Kerr medium andinduces its own waveguide. In this work, two initial beam profiles, rectangular and triangular functions, that are different than Sech profile, are considered, and the propagation of these beam profiles in third-order nonlinear (Kerr) medium is investigated. As a result, the initialbeam-width played an important role in confining the beam profiles in direction of propagation. In addition, the intensity profiles change to the Sech profile after some initial step of propagation. All the calculations and simulations have been done by the Split-Step numericalmethod with MATLAB program.

Supermode spatial solitons via competing nonlocal nonlinearities

We study spatial soliton formation in a system with competing nonlinearities. In doing so, we consider a specific nonlinear response that involves both focusing and defocusing nonlocal contributions. We demonstrate that at a sufficiently high input power level, the interplay between these nonlocal nonlinearities may lead to the formation of in-phase, two-hump, fundamental spatial solitons. The conditions required for the existence of these two-peak spatial solitons are also presented. Full Text: PDF ReferencesG. Stegeman and M. Segev, "Optical Spatial Solitons and Their Interactions: Universality and Diversity", Science 286, 1518 (1999). CrossRef Y. Kivshar and G. P. Agrawal, Optical Solitons: From Fibers to Photonic Crystals (Academic, San Diego, 2003).P. Varatharajah et al., "Stationary nonlinear surface waves and their stability in diffusive Kerr media", Opt. Lett. 13, 690 (1988). CrossRef G. Assanto and M. Peccianti, "Spatial solitons in nematic liquid crystals," IEEE J. Quantum Electron. 39, 13 (2003). CrossRef G. Assanto, ed. Nematicons: Spatial Optical Solitons in Nematic Liquid Crystals (Wiley, 2012). CrossRef O. Bang, W. Krolikowski, J. Wyller, J.J. Rasmussen, "Collapse arrest and soliton stabilization in nonlocal nonlinear media", Phys. Rev. E 66, 046619 (2002). CrossRef X. Hutsebaut, C. Cambournac, M. Haelterman, A. Adamski, K. Neyts, "Single-component higher-order mode solitons in liquid crystals," Opt. Commun. 333, 211 (2004). CrossRef C. Conti, M. Peccianti, and G. Assanto, "Route to nonlocality and observation of accessible solitons," Phys. Rev. Lett. 91, 073901 (2003). CrossRef U. A. Laudyn, P. S. Jung, M.A. Karpierz, and G. Assanto, "Quasi two-dimensional astigmatic solitons in soft chiral metastructures," Sci. Rep. 6, 22923 (2016). CrossRef U. A. Laudyn, P. S. Jung, M. A. Karpierz, G. Assanto, "Power-induced evolution and increased dimensionality of nonlinear modes in reorientational soft matter," Opt. Lett. 39(22), 6399–6402 (2014). CrossRef Y. V. Izdebskaya, V. G. Shvedov, P. S. Jung, and W. Krolikowski, "Stable vortex soliton in nonlocal media with orientational nonlinearity," Opt. Lett. 43, 66-69 (2018) CrossRef P.S. Jung, W. Krolikowski, U.A. Laudyn, M. Trippenbach and M.A. Karpierz, "Supermode spatial optical solitons in liquid crystals with competing nonlinearities", Phys. Rev. A 95, 023820 (2017) CrossRef P.S. Jung, W. Krolikowski, U.A. Laudyn, M.A. Karpierz and M. Trippenbach, "Semi-analytical approach to supermode spatial solitons formation in nematic liquid crystals", Opt. Express 25, 23893 (2017) CrossRef S. Jungling and J. C. Chen, "A study and optimization of eigenmode calculations using the imaginary-distance beam-propagation method", IEEE J. Quantum Electron. 30, 2098 (1994). CrossRef P.S. Jung, K. Rutkowska and M.A. Karpierz, "Evanescent field boundary conditions for modelling of light propagation", Journal of Computational Science 25, 115 (2018) CrossRef A.A. Hardy, W. Streifer, "Coupled mode theory of parallel waveguides," IEEE J. Lightwave Techn. LT-3, 1135 (1985) CrossRef M. Matuszewski, B.A. Malomed, and M. Trippenbach, "Spontaneous symmetry breaking of solitons trapped in a double channel potential," Phys. Rev. A 75, 063621 (2007) CrossRef