Acoustic Virtual Vortices with Tunable Orbital Angular Momentum for Trapping of Mie Particles

Marzo, A., Caleap, M., & Drinkwater, B. W. (2018). Acoustic Virtual Vortices with Tunable Orbital Angular Momentum for Trapping of Mie Particles. Physical Review Letters, 120(4), 44301.

http://doi.org/10.1103/PhysRevLett.120.044301

This paper was features in Physics Synopsis and made the front cover!

Digested read (haven’t time to read the full paper…here is what it says…)

Abstract

Acoustic vortices can transfer angular momentum and trap particles. Here, we show that particles trapped in airborne acoustic vortices orbit at high speeds, leading to dynamic instability and ejection. We demonstrate stable trapping in

side acoustic vortices by generating sequences of short-pulsed vortices of equal helicity but opposite chirality. This produces a “virtual vortex” with an orbital angular momentum that can be tuned independently of the trapping force. We use this method to adjust the rotational speed of particles inside a vortex beam and, for the first time, create three-dimensional acoustics traps for particles of wavelength order (i.e., Mie particles).

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