van Beeck J P, Riethmuller M L
Appl Opt. 1996 May 1;35(13):2259-66. doi: 10.1364/AO.35.002259.
An experimental method is presented that detects whether a droplet is spherical. The method is based on a comparison between two droplet diameters deduced from two different optical interference patterns observed in a rainbow that is created by a droplet scattering laser light. Experimental validation has been carried out with a CCD camera. Once a rainbow pattern has been identified as coming from a spherical droplet, we can derive a reliable droplet velocity and diameter from the same interference patterns, using theories for the rainbow that are valid only for spherical droplets. Preliminary experiments have been carried out with a laser beam and a photomultiplier.
提出了一种检测液滴是否呈球形的实验方法。该方法基于从液滴散射激光产生的彩虹中观察到的两种不同光学干涉图样推导出的两个液滴直径之间的比较。已使用电荷耦合器件（CCD）相机进行了实验验证。一旦将彩虹图样识别为来自球形液滴，我们就可以使用仅适用于球形液滴的彩虹理论，从相同的干涉图样中得出可靠的液滴速度和直径。已经使用激光束和光电倍增管进行了初步实验。
