The study of the properties of water droplets using a Mach-Zehnder interferometer and Mie rigorous diffraction

摘要

We studied theoretically and experimentally the interference patternof a water droplet placed in the object arm of a Mach-Zehnder interferometer, and theinfluence of heating on it. It turns out that due to special circumstances, thediffraction pattern of the sphere in the shadow area is particularly insensitive tochanges of the refractive index, because it is identical to the Fresnel diffraction of anopaque disc in the shadow area. However, this pattern is sensitive to changes of thedroplet volume caused by dilation, which is another effect of the heating. Morepromising turns out to be the Mie back- and lateral-scattering. The scattering patternin this case is sensitive to heating at certain angles. The most general and biggestproblem turns out to be the fact that the two effects of heating, the refractive indexand radius change, tend to cancel each other. Scanning the scattering angle forsensitivity provides measurement configurations where the two effects of heating donot cancel anymore.