Ripplon Laser

TL;DR

This paper demonstrates stimulated capillary scattering and coherent excitation of liquid-phase capillary resonances using a resonator that couples optical and capillary waves, bridging fluid dynamics and optics with potential optofluidic applications.

Contribution

It introduces a novel liquid-phase capillary-wave laser that coherently couples optical and capillary modes, expanding the scope of phonon laser research into liquids.

Findings

Observed stimulated capillary scattering at kHz rates

Achieved coherent excitation of capillary resonances

Demonstrated optical control of water waves

Abstract

Energy exchange between light and sound was first suggested by Brillouin in 1922. After Townes established the phonon maser theory, coherent generation of intense hypersonic waves was observed together with stimulated Brillouin Scattering. Here we repeat these experiments, but with capillary-waves that are unique to the liquid phase of matter and relates to attraction between intimate fluid particles. We fabricate resonators that co-host capillary and opticalmodes, control it to operates at its non resolved sideband, and observe stimulated capillary scattering and coherent excitation of capillary resonances at kHz rates (that one can hear in audio files recorded by us). By exchanging energy between electromagnetic and capillary waves, we bridge interfacial tension phenomena at the liquid phase boundary to optics, and might impact optofluidics by allowing optical control, interrogation and cooling of water waves.