Study On The Propagation And Characteristics Of Spatial Optical Soliton Based On Nonlocal Nonlinear Media

Soliton is one of the oldest nonlinear phenomena.It has been more than 100 years since Russell discovered solitary waves.Optical solitons can be divided into time light solitons and space light solitons according to the different formation mechanisms.The time optical soliton is a precise balance between the dispersion effect and the non-linear effect of the ultra-short pulse envelope in the fiber.In the time domain,the pulse envelope does not shrink or widen with the change of the propagation distance,but keeps the waveform unchanged.The phenomenon of stable transmission.The spatial light soliton is that when the incident light is transmitted in the medium,the diffraction effect of the beam and the non-linear effect of the medium(that is,the self-focusing effect)are accurately balanced,and it appears in the space that the incident beam is on a cross section perpendicular to the propagation direction.Both the shape of the beam and the intensity distribution do not change with the change of the propagation distance.This phenomenon is called spatial light solitons.Due to the existence of the light Kerr effect,a spatial light soliton will focus on a point in the medium when it propagates in a 1 + 2 dimensional medium.The non-locality of the medium can suppress this focusing,thereby supporting the optical soliton in the 1 + 2 dimensional Stable transmission in the medium.The spatial optical soliton carrying orbital angular momentum has extensive research value in the field of all-optical communication and quantum communication because of its rotation effect and unique spiral phase structure.Because of its mechanical effects such as torque and radiation when interacting with particles,it has potential application value in the field of all-light control.In this paper,starting from the rotating elliptical optical solitons in non-local non-linear media,the soliton solutions of the rotating elliptical optical solitons are obtained by using analytical methods(mainly variational methods);and a new method is simulated by Matlab using numerical simulation The rotating sine-type elliptical optical soliton is named SSES and its transmission characteristics are studied.The main conclusions are as follows:1.By analyzing the Gaussian pulsed beams with no initial chirp transmitted through the positive dispersion medium and the anomalous dispersion medium,and comparing the intensity distribution and spectrum of Gaussian pulses with linear positive chirp an linear negative chirp,the initial chirp is obtained.A chirped Gaussian pulse transmitted through a positive dispersion medium will carry an equivalent positive chirp,and a chirped Gaussian pulse will carry an equivalent negative chirp.2.Derive the nonlinear Schr(?)dinger equation in the non-local medium through Maxwell's equations,and obtain that the energy and momentum of the beam meeting this equation are conserved during propagation.In lead glass,the variational decomposition of the elliptic space optical solitons is derived using the variational method,and it is pointed out that only in the anisotropic medium,the elliptical optical solitons can stably transmit.3.Through the distributed Fourier algorithm,we simulated a rotating elliptical optical soliton carrying the sine term and named it SSES.We studied its transmission characteristics by setting its step size and found that SSES was in the propagation process.It can maintain a stable "rotation" with the same shape,and study the influence of topological charge and ellipticity on its transmission characteristics.It is found that whether the topological load or the ellipticity increases,the stability of SESS will decrease accordingly.With the change of ellipticity and topological load,the relationship between the central singular point,critical power and orbital angular momentum of the SESS beam is studied.