The Propagation Of Incoherent Solitons In Nonlocal Nonlinear Media

During the recent ten years, the propagation of incoherent solitons have drawn considerable attention. Howerver, the previous research of incoherent solitons were related to the domain of local nonlinear media which is an ideal research model. Lots of realistic media has a nonlocal nonlinear response, such as liquid cryatal which can be used for self-trapping of nonlocal incoherent soliton. The study of nonlocal incoherent solitons will greatly expand the research domain of nonlinear optics, provide theoretical foundation for understanding spatial solitons. Furthermore, it can greatly promote the exploitation of all-optics communication apparatus which based on optical solitons, predigestthe structure of the current optical communication apparatus, and has very important meaning for the optical interconnects, beam steering, and other applications.The aim of this thesis is to theoretically study the self-trapping of nonlocal incoherent solitons, inculuding the propagation of incoherent white-light solitons in nonlocal logarithmic nonliear media and in strongly nonlocal Kerr media, the propation of circular and elliptic partially incoherent solitons in strongly nonlocal Kerr media, and the coherence properties of such nonlocal incoherent solitons.The main results given by the author are as follows:(â…°) The propagation properties of white-light solitons in spatially nonlocal media with a logarithmically nonlinearity are investigated theoretically. The existence curve of the stationary nonlocal incoherent soliton is obtained and the coherence characteristics of the soliton are also described. The evolution behaviors of the nonlocal white-light soliton are discussed in detail by both approximate analytical solution and numerical simulation when the solitons undergo periodic oscillation.(â…±) We study the propagation of incoherent accessible solitons in strongly nonlocal media with arbitrary response function. Based on the linear propagation equation and the mutual coherence function approach, we obtain an exact analytical solution of such incoherent accessible solitons. The solitons radius is related to the total power as well as the coherence characteristics of the incoherent beam. We find that there is not a threshold for incoherent solitons exist in strongly nonlocal media because the model is linear. Evolution behaviors of the solitons width and the coherence radius are also described when the solitons undergo linear harmonic oscillation.(â…²) We study the propagation of elliptic incoherent accessible solitons in strongly non- local media with noninstantaneous Kerr nonlinearity. For this soliton to exist, the coherence properties of the incoherent beam should be anisotropic. The total power of the incident beam should also equal to a critical value which depend on the beam width as well as the coherence properties. When initial parameters of the beam do not satisfy the existence conditions, the elliptic incoherent accessible solitons will undergo linear harmonic oscillation in different states. Corresponding properties are studied in detail.(â…³)The propagation of elliptic incoherent beam in strongly nonlocal media with noninstantaneous anisotropic Kerr nonlinearity is systematically investigated. It is reported that both isotropic and anisotropic correlation characteristics of such elliptic incoherent beam are applicable. Evolution behaviors of the beam widths are shown by numerical calculation when the beam undergo periodic oscillation. It is also obtained that the oscillation periods of the two axis are different and the elliptic beam will become circular at some propagation distance under special conditions.(â…´) We present a theoretical investigation of incoherent accessible white-light solitons in strongly nonlocal medium with noninstantaneous Kerr nonlinearity. This soliton has elliptic Gaussian intensity profile and anisotropic spatiotemporal coherence properties. For this soliton to exist, the spatial coherence distance should be larger for lower frequencies and shorter for higher frequencies. When the incident power differs from the critical value, we demonstrate the periodic harmonic oscillations of the accessible white-light solitons.(â…µ) We study the properties of one-dimension incoherent accessible solitons in strongly nonlocal media with noninstantaneous Kerr nonlinearity. Following the coherent density theory, we obtain an exact solution of such incoherent solitons. The spatial width of the incoherent solitons is related to the incoherent angular power spectrum O0 as well as the incident power. The evolution properties of the intensity profile and the coherence characteristics are also discussed in detail when the solitons undergo periodic harmonic oscillation.