The Study Of Spatial Optical Solitons In Complex Potentials

Spatial optical solitons are essentially the result of the combined action of the spontaneous diffraction effect and the nonlinear effect of the propagation medium during light wave transmission.Spatial solitons can keep their waveforms unchanged during transmission,and when they meet each other,they can behave like elastic collisions of particles,so they have great application value in all-optical devices,light-controlled light technology,and optical information processing.In recent years,the study of spatial optical solitons in parity-time（PT）symmetric complex potentials has been continuously reported,proving that stable solitons can exist in complex potentials.The research in this paper is also based on the spatial optical solitons in complex potentials.The main research contents are as follows:The properties of solitons in a focused Kerr medium supported by a two-dimensional non-PT symmetric complex potential are first studied.It is found that the soliton family is continuous and that a stable region can exist.There are several discrete eigenvalues in the linear spectrum of these complex potentials.Fundamental solitons bifurcate from the largest discrete eigenvalue,while dipole solitons bifurcate from the second or third largest discrete eigenvalue.We further find that the eigenvalues of the linearly stable spectrum of the soliton appear in the form of conjugate pairs.The effects of different complex potential parameters on the stability of the solitons are discussed in detail,and the lateral energy flow vector of the solitons in these complex potentials are also given.Second,this paper also studies nonlocal solitons in PT-symmetric optical lattices with fractional-order diffraction.The fundamental soliton family exists in the semi-infinite gap and there are stable regions.In a general degree of nonlocality,there are two stable regions of the fundamental solitons.The study also found that the out-of-phase dipole solitonsare stable in the low-power region in the first gap.And as the Lévy index increases,the dipole solitons are closer to the lower edge of the second Bloch band.Fractional-order diffraction has modulation effect both on fundamental and dipole solitons.In general non-local degree,with the decrease of the Lévy index,the stability region of solitons becomes wider.But in a strong degree of nonlocality,the fractional-order diffraction has little effect on the stability region of the solitons.An increase in the degree of nonlocality reduces the stability region of the solitons,but the power of the soliton increases significantly.