Spatial Frequency Analysis of Holograms of Two Droplets in Close Proximity

抄録

Micro-droplet collision-coalescence processes can be observed more efficiently by detecting the approaching droplets in advance of the holographic reconstruction. In this study, we experimentally verify the mathematical formulation of the relationship between the stripe pattern on the spectral distribution of the hologram of two micro-droplets and their relative displacement. This relationship enables us to directly estimate the droplet displacements from the spectral distributions of holograms. We record holograms with two dot-printed glass plates while varying the inter-dot distance and confirm that the stripe pattern appears and varies with the distance between the dots. We also confirm that the detected stripe spacings of recorded holograms fit well with the theoretical spacing values calculated with our formula when the two dots are close but not colliding. Our method contributes to a better understanding of cloud microphysical processes, which can lead to more accurate precipitation prediction.