C点偶极子通过海洋湍流的演化OA

In order to find out performance of the C-point dipole nested in partially coherent stochastic vor-tex beam in oceanic turbulence,the Gaussian-Schell model vortex(GSMV)beam carrying a C-point dipole is constructed,which is used to research the evolution property of the C-point dipole in oceanic turbulence.Ac-cording to the definition of the polarization singularities in partially coherent vector beams,the GSMV beam was constructed to realize a partially coherent beam carrying a pair of C-point dipoles with opposite topolo-gical charges.According to the extended Huygens-Fresnel principle,the formula of the cross-spectral dens-ity(CSD)for the GSMV beam propagating through oceanic turbulence is deduced by using of the integral formula.In accordance with the formula of the CSD derived above,the effects of propagation distance z,the off-axis parameter s and coherent length δ on the evolution behavior of the C-point dipole is illustrated and analyzed.The position of a C point can be determined by the contour lines of phase of Stokes field S12=Si+iS2.The degree of polarization of a C point can be calculated by spectral Stokes parameters,while its topolo-gical charge can be judged by the sign principle which was proposed by Freund.It is shown that,the position and the degree of polarization of the C points may be changed with propagation of the GSMV beam.Though the creation and annihilation of C points may occur with variation of the propagation distance,the total of the topological charges of C points of the beam hold consistent.Besides,as the off-axis parameters are chosen as opposite numbers,the numbers of C points from the optical fields are equal.When the partially coherent vor-tex beam carrying a C-point dipole propagates in oceanic turbulence,the evolution behavior of the C-point dipole is affected by the propagation distance of the host beam,the off-axis parameter,turbulence intensity as well as the spatial coherent length.