Droplets Acoustics

TL;DR

This paper reports the first experimental excitation of acoustical resonances in droplets at 37 MHz with high quality factors, significantly expanding the spectral range of droplet vibrations beyond traditional capillary modes.

Contribution

It introduces the first experimental demonstration of sound-based acoustical resonances in droplets, opening new avenues for optical and acoustic studies of droplet dynamics.

Findings

Droplets vibrate at 37 MHz with a quality factor of 100.

Optical excitation threshold is 68 microWatts.

Spectral band of vibrations is 1000 times higher than capillary resonances.

Abstract

Contrary to their capillary resonances (Rayleigh, 1879) and their optical resonances (Ashkin, 1977), droplets acoustical resonances were rarely considered. Here we experimentally excite, for the first time, the acoustical resonances of a droplet that relies on sound instead of capillary waves. Droplets vibrations at 37 MHz rates and 100 quality factor are optically excited and interrogated at an optical threshold of 68 microWatt. Our vibrations span a spectral band that is 1000 times higher when compared with drops previously-studied capillary vibration.