Nematicons: Spatial Optical Solitons in Nematic Liquid Crystals

Chapter 2: Features of Strongly Nonlocal Spatial Solitons

Qi Guo, Wei Hu, Dongmei Deng, Daquan Lu, Shigen Ouyang

Laboratory of Nanophotonic Functional Materials and Devices, School of Information and Photoelectronic Science and Engineering, South China Normal University, Guangzhou, China

2.1 Introduction

Spatial optical solitons are self-trapped optical beams that exist by virtue of the balance between diffraction and nonlinearity. There are various members in the spatial optical soliton family [1–4]. Among them, nonlocal spatial solitons—that is, spatial optical solitons existing in nonlocal nonlinear media—have greatly held one's interest during the recent years [5–8]. Nonlocal spatial solitons can be modeled by the nonlocal nonlinear Schrödinger equation (NNLSE) [5, 9, 10], where the nonlinear term assumes a nonlocal form (convolution integral) with a real-valued response kernel, whereas the NNLSE also describes several other physical situations [11, 12]. Snyder and Mitchell [5] simplified the NNLSE to a linear model in the strongly nonlocal limit, and found an exact Gaussian-shaped stationary solution known as accessible soliton. Their work was highly appreciated by Shen [13], who pointed out that “Such theoretical advances will undoubtedly encourage more experimental research on solitons. Thus Snyder and Mitchell's work could be the stimulant for a new surge of soliton activities in the near future.” So far, it has been confirmed that nematic liquid crystals (NLC) [14, 15], ...