Study On Polarization Preserving Ability Of Circular And Linear Polarized Light In Non-Spherical Scattering Media

With the occurrence of industrial incineration,dust storms and forest fires,the pollution problem of the atmosphere is increasing,and how to monitor and control this status has received widespread attention.Most of the sand and dust and combustion particles in the atmosphere are non-spherical particles,and the detection technology of polarization has been applied in a large number of fields,among which linearly polarized light and circularly polarized light have different polarization-preserving performance in different environments,so it is important to study the polarization-preserving performance of circularly polarized light and linearly polarized light in non-spherical media.To investigate the polarization preserving ability of circularly polarized light and linearly polarized light in non-spherical particles,the simulation and experiment verification system of non-spherical particles was established.The polarization preserving ability of ellipsoidal particles,cylindrical particles and spherical particles with different wavelengths and aspect ratios(0.5,0.67,1.5,2)after multiple scattering by randomly oriented polarized light.The half-material simulation environment testing was established to verify the simulation algorithm,and the ellipsoidal fine particles were prepared by burning ganoderma lucidum spores.The size distribution and optical thickness of the ellipsoidal fine particles were measured by malvern spraytec and light power meter respectively.The simulation result can be proved by combining the experiment with simulation.The simulation results show that at different wavelengths,the polarization of horizontal,vertical,+45 degree linearly polarized light and right circularly polarized light of different shapes of non-spherical particles all decrease,and the polarization preservation ability of three kinds of linear polarizations are basically consistent,and the polarization preservation of circularly polarized light is generally better than that of linearly polarized light at high concentrations,but the critical point will be slightly different depending on the wavelength and aspect ratio,and the critical point will appear earlier with the increase of wavelength.The polarization-preserving properties of both circularly polarized light and linearly polarized light of spherical particles are significantly higher than those of nonspherical particles.The experimental results show that at different wavelengths,the polarization curves are decreasing with the increase of optical thickness,and the polarization-preserving performance of circularly polarized light is better than that of linearly polarized light at high concentrations;with the increase of wavelength,the depolarization value is gradually decreasing,and the critical point at which the polarizationpreserving performance of circularly polarized light is better than that of linearly polarized light is also advancing.The accuracy of the simulation model is verified by the compliance between the experiment and simulation,which is more than 84%.The results of this study can extend the environmental applicability of polarization detection and provide theoretical support for the study of polarization detection in non-spherical particulate matter environment.