Research of the influence of non-spherical ellipsoid particle parameter variation on polarization characteristic of light

Abstract

There are many non-spherical particles in the sand-dust and carbonaceous environment of the natural world, but this kind of particles are in most cases approximated by the spheres in the description of the transmission process, which cannot reflect the actual state of the transmission through the particles. For this reason, on the basis of polarization characteristic of spherical particles, a further research is made on the polarization characteristic with different refractive index, effective radius, particle shape, and other parameters of ellipsoid particles. When the non-polarized light is used as the incident light, the T-matrix method is applied to the simulation of the transmission process of the non-spherical particles, and the power-law size distribution is used to describe the size distribution condition of the particles, which is the most effective method to show the whole process of light scattering through non-spherical particles. With this method, the polarization characteristic after the transmission of the ellipsoid particles and the polarization differences between the ellipsoid and spherical particles can be obtained, and at the same time the examples of the sand-dust, marine and carbonaceous aerosols are given to show the validity of the results. Simulation results show that the smaller the real part of the refractive index and the larger the image nary part of the refractive index, the less obvious the polarization character differences between the ellipsoid and spherical particles are. When the effective radius of particle increases, the DOP (degree of polarization) variation of the spherical particles is more obvious than the non-spherical particles, and the maximum values are at the positions of the scattering angles 150 and 120 respectively. When the particle shape is different, the differences between the ellipsoid at diverse vertical-to-horizontal ratio and spherical particles are not obvious if the scattering angle is less than 60, and when the vertical-to-horizontal ratio of the ellipsoid particle is reciprocal, the polarization character of the two kinds of particles becomes the same. Through the analysis above, in the process of transmission, in most circumstances the ellipsoid particles cannot be approximated by spherical particles for computation, and the parameters of the refractive index, effective radius, shape of the ellipsoid particles can all influence the polarization character.