Investigations On Optical Spatial Solitons In New Materials

Optical spatial solitons supported by some presently new optical materials are investigated, which include non-spontaneous optical solitons in organic polymers that experience photoisomerization, Bessel solitary wave in strongly nonlocal nonlinear media and Jacobian elliptical function solution to Gross-Pitaevskii (G-P) equation governing the evolution of matter wave in management system. The research contents and the obtained results are as follows:1. The formation and characters of spatial solitons associated with photoisomerization are studied, and a new method of light-controlling-light is put forward. It is found that a background light can greatly effect the propagation of dark solitons and gray solitons. The most important and interesting find is the presentation of background light can realize the dark soliton-bright soliton transformation. And then it is predicted that the propagation of a signal light can be controlled by adding a background light. This idea is applicable to both the cases of single-photon-isomerization and two-photon-isomerization.2. Incoherently-coupled bright-dark soliton pairs in organic polymer that experience photoisomerization are investigated, and another idea of light-controlling-light is proposed. Research results show that a bright soliton can be obtained by coupling a dark soliton and forming a bright-dark vector soliton although a single beam can only spontaneously form a gray soliton or a dark soliton through photoisomerization. Therefore it is predicted that the propagation of a bright light beam can be controlled using a dark light beam.3. The propagation of Bessel solitary wave in strongly nonlocal nonlinear media with distributed parameters is researched. This is a new analytical solution to the strongly nonlocal nonlinear Schrodinger equation, prior to which Hermite-Gaussian solitary wave solution; Laguerre-Gaussian solitary wave solution and Kummar-Gaussian solitary wave solution were obtained by our group. The characters of this solitary wave are compared with that of the other solitary waves.4. The general nonlinear Schrodinger equation (or G-P equation) is investigated using the method of Jacobian elliptic function expandation, and the analytical solutions of such equations, namely elliptical function solutions are obtained. These precise solutions include single-function solutions and hybrid-function solutions. The standard hyperbolic secant bright soliton solution and the hyperbolic tangent dark soliton solution are just the special cases of single-elliptic function solutions. Some periodic functions such as trigonometric functions are also included in single-elliptic function solutions. Hybrid elliptic function solutions, which are always periodic functions, are totally different from the previously obtained solutions.5. Issues 3 and 4 involve with the research of spatial solitons in a management system or a system with varying coefficients. It is for the first time for us to study spatial solitons in a management system, which is expected to stimulate the investigation on optical spatial solitons in management systems.6. The necessary conditions for elementary solitons to be formed are studied, and the conclusion is derived for the first time to our knowledge that dark-like bright solitons cannot be formed in media with monotonic nonlinearities, which is expected to help comprehending the notion of elementary solitons.