Imprinting characteristics of droplet lenses on liquid-repelling surfaces into light

Abstract

We propose an experimental method that allows the investigation of droplets on liquid-repelling surfaces. The described technique goes beyond the standard imaging approaches and reveals a plethora of spatial droplet information, which is usually unavailable. Liquid droplet lenses shape the transmitted light field of a Gaussian laser beam passing though them, thereby forming refracted three-dimensional (3D) light landscapes. We investigate numerically and experimentally these 3D landscapes which are customized depending on the droplet shape as well as its refractive index, and demonstrate the encoding of droplet information. This approach can also be applied for analyzing droplets showing high-speed dynamics, in order to reveal even minimal shape deviations. The developed technique complements and therefor extend the existing conventional tools for the investigation of the droplets formed on liquid-repelling surfaces.