介绍了米氏(Mie)散射理论, 设计了基于米氏散射理论的云粒子探测器。该探测器使用685nm的二极管激光器照亮敏感区域的云滴粒子。光学接收部分分为前向散射和后向散射两部分, 前向散射接收云粒子立体角在4°～12°的散射而后向散射接收126°～134°之间的能量。根据前向散射信号的强度可以确定云滴粒子尺寸, 云粒子尺寸确定后, 可以利用前向散射和后向散射的比值推断被测云粒子的相态。利用米氏散射理论计算了云粒子散射能量强度随粒子尺寸的变化和前、后向散射能量比随云粒子折射率的变化。

Mie theory and design of a probe of cloud droplet based on this theory are introduced in this paper. A 685 nm diode laser is used to illuminate the cloud droplets in the sensitive area in the probe. The forward-scattering part and backward-scattering part are included in the optical receiving system. The former collects energy between the solid angle of 4°～12°, and the latter collects energy between 126°～134°. The size of the cloud droplet can be obtained by the data from the energy of the forward-scattering. When the size of the cloud droplet is known, the phase state of the cloud droplet can be inferred from the ratio of forward-scattering to backward-scattering. In the end, the intensities of forward-scattering varied with sizes of cloud droplets and the ratios of forward-scattering to back-scattering varied with the refractive indexes are presented by using the Mie theory.