小斜率近似在粗糙面激光散射BRDF计算中的应用  

Application of Small Slope Approximation in BRDF Calculation of Laser Scattering from Rough Surface

作　　者：于海山[1] 任宏光[1] 霍力君[1] 梅浩[1] 张京国[1] 

机构地区：[1]中国空空导弹研究院,河南洛阳471009

出　　处：《光子学报》2015年第6期183-188,共6页Acta Photonica Sinica

基　　金：中国空空导弹研究院科技创新基金(No.201308S04)资助

摘　　要：基于小斜率近似法建立了粗糙面激光散射双向反射分布函数的数学模型,采用该模型计算了粗糙度参量已知的合金铝样片的双向反射分布函数值,计算结果与实测结果吻合良好,验证了模型的正确性.研究了粗糙度参量和样片光学常量对双向反射分布函数的影响,结果表明,粗糙面激光散射的双向反射分布函数与表面高度起伏均方根、自相关长度及样片光学常量相关.当入射波长一定时,高度起伏均方根越大,或者自相关长度越小,粗糙面粗糙度越大,入射激光的漫反射特性越强,双向反射分布函数峰值越小且分布越分散;当粗糙度一定时,样片光学常量对双向反射分布函数影响较大,粗糙面对入射激光复折射率的虚部越大,样片双向反射分布函数的峰值越小,当粗糙度参量增大时,样片光学参量对双向反射分布函数的影响逐步减弱.Mathematical model to calculate the Bidirectional Reflectance Distribution Function（BRDF） of laser scattering from rough surface was established based on small slope approximation. The model was used to calculate BRDF of alloy aluminum with given roughness. Theoretical data and experimental data were found in good agreement, which verifies the correctness of the model. Further study of the effects of roughness and sample optical parameters on bidirectional reflectance distribution function was carried out. Results show that the BRDF of laser scattering is related to root mean square height, correlation length of rough surface and optical parameters of the sample. As the incident wavelength is fixed, the diffuse reflectance of incident laser is stronger when the RMS height is greater, or when the correlation length is smaller, and the value of BRDF is more dispersed with smaller peak. As the surface roughness is fixed, the optical parameters of the sample have great influence on the value of BRDF. The peak value of BRDF is smaller while the imaginary part of refractive index is larger. With the increment of roughness, the effects of optical parameters on BRDF decrease gradually.

关 键 词：粗糙面 激光散射 小斜率近似 双向反射分布函数 光学常量 

分 类 号：O432.1[机械工程—光学工程]