米氏理论的近似及在粒度测量中的应用  

Geometric Approximation of Light Scattering in Arbitrary Diffraction Regime for Absorbing Particles: Application in Laser Particle Sizing

作　　者：徐峰[1] 蔡小舒[1] 沈嘉祺[1] 

机构地区：[1]上海理工大学颗粒与两相流测量技术研究所,上海200093

出　　处：《光学学报》2003年第12期1464-1469,共6页Acta Optica Sinica

基　　金：国家自然科学基金(50 1760 3 3 )资助课题

摘　　要：将夫琅禾费衍射理论与几何散射 (包括折射和反射 )相结合 ,给出平行光入射下圆形颗粒在前向大角度范围内的散射光强分布近似算法。由于考虑了衍射、折射和反射相互间的干涉效应和颗粒对光的吸收性 ,对于正常或非正常衍射状态下无因次参量α≥ 40的耗散颗粒 ,在前向 0°～ 60°散射之内 ,该方法对散射光强计算结果与米氏理论结果是吻合的。由于计算速度比米氏理论快 ,有效角度范围比夫琅禾费衍射理论宽 ,因而适合于大颗粒的前向光强计算。将这一计算方法应用到大角度采光时的激光粒度测量实验中 。The whole-geometric-approximation-method (WGAM) is presented to compute the forward light intensity. Since Fraunhofer diffraction and geometric scattering are combined, such a method is applicable under anomalous or normal diffraction regime. Due to the consideration of interference between the diffraction, refraction and the reflection rays, the calculable angle range is extended to 0°～60°. Because of its high calculation efficiency and wide validity range, WGAM is especially effective for light pattern calculation of the large particles with size parameter α larger than 40. Numerical calculations show that the results of WGAM are consistent with Mie theory. The experiments also find that WGAM can be applied in laser particle sizing based on large-angle forward scattering method.

关 键 词：物理光学 散射测粒 非正常衍射 夫琅禾费衍射理论 几何散射 无因次参量 米氏理论 吸收性 

分 类 号：O436.2[机械工程—光学工程]