Research On Transmission Characteristics Of Polarized Light In Ellipsoid Particle Smoke

The shape of particles in the atmosphere is closely related to the change of polarization state of light.Due to the non-sphericity of dust and bituminous coal in nature,the calculation of polarization propagation characteristics of light in non-spherical particles will have a big error if the calculation is based on spherical particles.In order to solve these problems,the transmission characteristics of polarized light in ellipsoidal particle smoke are studied in this paper.From the simulation of polarization propagation and the experiment of polarization propagation,the variation of polarized light with different incident wavelengths and different initial polarization states under different smoke concentrations of ellipsoidal particles was measured.In order to meet the requirements of polarization transmission test in smoke environment,an artificial simulation system was established and the experiment is carried out with a self-made smoke simulation device.Two kinds of ellipsoidal particles(yeast particles and Ganoderma spores)with 1.5 ratio of long axis to short axis were used as media,and five incident light polarization states(0 °,45 °,90 °,135 °,L-rotation)and three wavelengths(450nm,532 nm,671nm)are used as variables to study the change of laser polarization transmission characteristics under different conditions.At the same time,the Monte Carlo model of polarization transmission of ellipsoidal particles is established based on the method of random probability sampling fitting scattering phase function.The behavior of photons in ellipsoidal particles smoke is traced and statistically analyzed,and the polarization characteristics of the final state of the light are simulated.In order to establish the relationship between the simulation results and the experimental results,and solve the instability of smoke concentration,the optical depth is selected to characterize the smoke concentration.The similarity of simulation and experimental results is analyzed by three similarity measures,and the experimental conclusions are drawn.The experimental results show that the polarized light in different states appears obvious depolarization phenomenon with the increase of the concentration of the medium.Under the same conditions,the circularly polarized light has better polarization-maintaining characteristics.The linearly polarized light with different polarization angles has no obvious influence on the polarization transmission characteristics.The influence of three wavelengths in the visible band on the polarization transmission characteristics is not significant.