热辐射偏振建模与仿真

Modeling and Simulation of Thermal Emission Polarization

针对传统热辐射偏振模型忽略物体表面微观分布的问题,进行红外热辐射偏振特性建模仿真研究,基于微面元偏振双向反射分布函数(p BRDF),结合微观结构分布情况建立红外热辐射偏振度模型。利用红外热辐射发射率的平行和垂直分量的和分之差来表示偏振度,根据基尔霍夫定律和微面元双向反射分布函数(BRDF)得到发射率与半球空间反射率之间的关系,最后将微面元BRDF偏振化计算定向半球空间反射率,继而得到定向发射率矩阵并计算偏振度。仿真结果表明,模型仿真得到的红外热辐射偏振度与发射角的关系曲线与实际测量结果基本保持一致,并且与传统红外热辐射偏振模型仿真结果相比较更符合实测值,在表面粗糙度较大的情况下,能够更准确地反映物体的红外热辐射偏振特性。

Traditional thermal emission polarization model ignores the microscopic distribution, and taking this into consideration to expand modeling and simulation research of infrared thermal emission polarization characteristics. Model of the degree of polarization of the infrared thermal emission is built based on the microfacet polarized Bidirectional Reflectance Distribution Function （pBRDF） and the microstructure distribution. Utilizing the difference between the parallel and perpendicular components of the emissivity of the infrared thermal emission divided by the sum of them represent the degree of polarization. And the relationship between emissivity and hemispherical reflectance is obtained according to the Kirchhoffs law and the microfacet BRDF. Polarizing the microfacet BRDF to calculate the directional hemispherical reflectance and then directional emissivity matrix, and last to get the degree of polarization. The simulation results show that the curves of the relationship between the polarization and the emission angle of the infrared thermal emission are consistent with the actual measurement results, and compared with the simulation results of traditional thermal emission polarization model, is closer to the measured value, especially in the case of the surface roughness is larger, can more accurately reflect the infrared thermal emission polarization characteristics.