Statistical Properties Of Partially Coherent Scalar And Vector Beams In Turbulent Atmosphere

Study on statistical properties of partially coherent scalar and vector beams inturbulent atmosphere is a topic that is considerable theortical and practical interest becauseof their potential and important applications in laser optics, remote sensing, opticalimaging, particle capture, nonlinear optics, free-space optical communication and so on. Inthe past several years, numerous efforts have been paid to the propagation properties ofpartially coherent beams and it has been shown theoretically and experimently that thepartially coherent beams are less sensitive to the effects of turbulence than fully coherentones. In this paper, we mainly concentrate on two types of laser beams: one is aLaguerre-Gaussian Schell-model beam which is one of partially coherent scalar beams andanother is a cylindrical vector partially coherent LG beam which is one of partiallycoherent vector beams. The main works are summarized as follows:1. Analytical expressions for the CSD and the second-order moments of a LGSMbeam in turbulent atmosphere are derived. And then we studied the statistical properties,such as the drgree of coherence and the propagation factor with the help of the derivedformulae. It was found that a LGSM beam with larger mode order n is less affected byturbulence than a LGSM beam with smaller mode order or a GSM beam under certaincondition, which is useful in free-space optical communication.2. We derived the realizability conditions for a CV partially coherent LG beam. Thenwe derived the analytical expressions for CSD matrix of a CV partially coherent LG beamon propagation in turbulent atmosphere with the help of the extended Huygens-Fresnelprinciple. The average intensity, the modulus of CDC and the DOP of a CV partiallycoherent LG beam have been studied numerically in detail. It was found that these statistical properties are closely related to the strength of turbulence and the initial beamparameters. The stronger the atmospheric turbulence is, the smaller the beam orders andthe correlation coefficients are, the faster the speed of the transition from its initial beamprofile to a Gaussian profile is. Furthermore, the distribution of DOP of a CV partiallycoherent LG beam turns nonuniform, and a dip appears on propagation in turbulentatmosphere. By modulating the coherence and polarization of a CV beam, we can expect toreduce the negative influence of turbulence.