Radiation pressure-induced nonlinearity in a micro-droplet.

In recent years, some of the most interesting discoveries in science and engineering emerged from interdisciplinary areas that defy the traditional classification. One recent and extensively studied example is the advent of optomechanics that explores the radiation pressureinduced nonlinearity in a solid micro-resonator. Instead of using a solid resonator, we studied a liquid droplet resonator in which optical pressure could actively interact with the fluid interface. The droplet resonator supported high-quality whispering gallery modes along its equatorial plane, which produced a radiation pressure that counterbalances the interfacial tension, resulting in a droplet with damped harmonic oscillation. A major goal of this study was to demonstrate that such a novel and all-liquid platform could lead to a single-photon-level nonlinearity at room temperature. If successful, such a highly nonlinear system may lead to new research paradigms in photonics, fluid mechanics, as well as quantum information science. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement