Study On Scattering Field And Mueller Matrix Of Metal And Dielectric Surface

The scattering theory of random rough surface has important research value in the field of target detection and recognition,but the light intensity information is limited by factors such as the contrast between the target and the background light intensity,color contrast,etc.,only relying on the scattered light intensity to detect and recognize the target has certain limitations.The polarization of light waves is not restricted by the environment and can better reflect the target information.Therefore,it is very important to use polarization optics to explore the modulation of the polarization characteristics of light waves at random rough surfaces.Mueller matrix,as the main means to describe the polarization changes of light waves before and after the target,contains a wealth of micro-information on the target surface,such as material,roughness,morphology,structure,etc.In view of this,under the two-dimensional random rough surface model,this paper studies the scattering field distribution of metals and dielectrics,the distribution of Mueller matrix under different incident angles and different roughness,explores the differences between metals and dielectrics,and provides a reference for detecting and identifying targets.The specific work is as follows:1.The scattering of light waves on a random rough surface is studied,and the scattering field distribution of a two-dimensional rough surface of metal,isotropic dielectric and anisotropic dielectric is numerically simulated.The Kirchhoff approximation method is used to analyze the scattering of light waves on random rough surfaces,a two-dimensional random rough surface scattering model is established,Monte Carlo method is introduced to deal with the randomness of rough surfaces,and different correlation lengths and different root mean square heights are numerically simulated.The lower vertically polarized light and horizontally polarized light are scattered on the two-dimensional rough surface of gold and nickel two metals,glass,and lithium niobate respectively,and the distribution of the spatial scattering field in the incident surface is obtained.The results show that the scattered light intensity of metal is greater than that of dielectric.When the correlation length and root mean square height change,the amplitude of the scattered light intensity of metal is larger than that of dielectric,and the peak light intensity position is almost unchanged.The peak light intensity position of the dielectric is not in the mirror image direction,and varies with the roughness.2.The scattering Mueller matrix of a two-dimensional random rough surface is studied,and the Mueller matrix of metal,isotropic dielectric,and anisotropic dielectric under different incident angles and different roughness is numerically simulated.According to the relationship between Jones matrix and Mueller matrix,the expression of the random rough surface scattering Mueller matrix is obtained,and Mueller matrix of three metals of copper,iron and nickel and the two dielectrics of glass and lithium niobate are numerically simulated under different incident angles and different roughness.The results show that the Mueller matrix |m_ij|=|m_ji| is symmetrically distributed;When the incident angle increases from 20°to 60°,the |m₀₁| and |m₁₀| of the metal and dielectric both increase,and both |m₂₂| and |m₃₃| decrease.But when the magnitude of the dielectric change exceeds 80%,the metal change range is less than 30%,the metal |m₂₃?m₃₂| increases with the incident angle,and the change range exceeds 40%,while the dielectric m_{2 3}?m₃₂ is always 0;When the relative roughness increases from 0.05 to 0.15,the metal and The four parameters of |m₀₀|?|m₁₁|?|m₂₂|?|m₃₃| of the dielectric have changed greatly,showing a decreasing trend,but the reduction of metal is more than 60%,the reduction of dielectric is less than 40%,and the dielectric material |m₂₃|?|m₃₂| is always 0,which is not affected by roughness.These differences can provide a theoretical basis for distinguishing between metals and dielectric materials.