Propagation Properties Of Polarized Light After Multiple Scatterring Through A Discrete Media

When the sunlight is going through the discrete media it will be scatterred multiplly to produce polarization, the process has an important affect on the polarization information. In this thesis the transmission characteristics of the multiple scattering are mainly studied, the vertical evolution characteristics and lateral statistical variations of polarization degree of polarized light under complex transformed with propagation and scattering is discussed. The polarized Mie multi-particle multiple scattering modle is established based on Mie scattering theory by using the Monte Carlo method. With spherical scatterers, and using parameterized description of different physical quantities as the influencing factors of polarization transfer function, we studied the multiple scattering transmission characteristics of polarized light qualitatively and quantitatively, and the transmission characteristics under different scale distribution of scatterring particles is analyzed on the basis of experimental data. The results show that:The circularly polarized light shows different characteristics in the forward and backward scattering. The degree of linear polarization and circular polarization retains their polarized character at large transmission distance from the incident light beam.They has the largest value at the propagation axis, and decrease when deviates from the axis. FWHM (full width at half maximum) of the degree of polarization increases when the scattering particle scale increases, on the contrary, the FWHM of the intensity of scattered light decreases. The main work of the thesis is as follows:(1) Mueller matrix describes the scattering of uniform spherical particles in the scattering plane, reveals the polarization characteristics of scattering particles in the medium, it affects the collision process bettwen photon and scattering medium directly, in this article the change characteristics with scattering angle of the four separate elements of Mueller matrix are analyzed.(2) The current multiple scattering modle only considers the particle size with uniform distribution, but in practice, aerosols are not a kind of particle withsingle size. In this article different particle size distribution is considered in themodeling of multiple scattering, logarithmic normal distribution and Jungedistribution are adapted to describe aerosol scale distribution, and the multiparticle multiple scattering model of polarized light is established.(3) Combined with several media environments and different impact factors,several sets of simulation experiments are designed, the transmissioncharacteristics of polarized light in scattering medium under multiple facters isanalyzed qualitatively and quantitatively. The covered factors including thewavelength of incident light, the incident polarization state, scale parameter ofscattering particles, the scattering coefficient and the transmission distance.And the vertical evolution characteristics and lateral statistical variations ofpolarization properties after experiensing propagation and scattering are mainlystudied.