Vector nematicons

TL;DR

This paper investigates vector solitons in nematic liquid crystals using a coupled nonlocal nonlinear Schrödinger system, revealing various dark and bright soliton pairs through multiscale expansion methods.

Contribution

It introduces analytical methods to identify dark-dark, antidark-antidark, and dark-bright solitons in the defocusing regime, expanding understanding of vector solitons in nematic liquid crystals.

Findings

Existence of dark-dark and antidark-antidark solitons governed by an effective Korteweg-de Vries equation.

Discovery of dark-bright solitons described by an effective Mel'nikov system.

Soliton amplitudes are linked to physical parameters, enabling mutual guiding.

Abstract

Families of soliton pairs, namely vector solitons, are found within the context of a coupled nonlocal nonlinear Schrodinger system of equations, as appropriate for modeling beam propagation in nematic liquid crystals. In the focusing case, bright soliton pairs have been found to exist provided their amplitudes satisfy a specific condition. In our analytical approach, focused on the defocusing regime, we rely on a multiscale expansion methods, which reveals the existence of dark-dark and antidark-antidark solitons, obeying an effective Korteweg-de Vries equation, as well as dark-bright solitons, obeying an effective Mel'nikov system. These pairs are discriminated by the sign of a constant that links all physical parameters of the system to the amplitude of the stable continuous wave solutions, and, much like the focusing case, the solitons' amplitudes are linked leading to mutual guiding.