Modeling And Mechanism Analysis Of Polarized Light Reflection On Multilayer Coating Surfaces

When light interacts with the object surface,not only the direction of light propagation will be changed,but also the polarization of light will change.The polarization characteristics of reflected light are closely related to the incident angle,incident light wavelength,surface optical characteristics and surface physical structure,etc.The polarization characteristics are generally analyzed by establishing the polarization bidirectional reflection function(PBRDF)model of the target surface.In this paper,the PBRDF model of multilayer coating surface is constructed based on the theory of micro-surface element,polarization ray tracing technique and Monte Carlo statistical method from the point of view of simulating and solving the physical process of light propagating on the target surface formed by coating and substrate.Based on the PBRDF model,the effects of incident angle,incident wavelength,surface roughness and substrate material on the polarization characteristics of the target surface are studied.The specific contents of this paper are as follows:(1)Based on the fast Fourier transform method and the physical structure of the target surface,the three-dimensional reconstruction of the target surface is realized by using computer technology.On this basis,the parameters of the 3D reconstructed surface are analyzed to ensure that the statistical characteristics of the surface are reasonable and the reconstructed surface can be used to simulate the light scattering process.(2)Based on the theory of micro-surface element and the probability distribution function of the target surface normals,the normal vectors of the scattering light intersecting the surface element are sampled randomly in each layer,and then the reflected or refracted light propagating inside the coating is selected randomly according to the Fresnel equation.Then,the PBRDF model of reflected light in hemispherical space above the target surface is obtained by using polarized ray tracing technique and Monte Carlo method.The PBRDF model is simulated and verified experimentally.(3)Aiming at the single-layer rough surface,the influences of the incident angle,surface roughness and relative azimuth angle on the polarization characteristics of reflected light are simulated and analyzed according to the model built in this paper,taking into account the physical structure characteristics of the surface.(4)On the basis of the PBRDF model of a multilayer coating surface,and according to the physical structure characteristics of the coating surface,the incident angle,incident light wavelength,surface roughness,substrate material,coating thickness and the number of coating layers reflect the coating surface.The effect of light polarization properties.