Study: Acoustic Virtual Vortices with Tunable Orbital Angular Momentum for Trapping of Mie Particles Citation: Asier Marzo, Mihai Caleap, Bruce W. Drinkwater.

Study: Acoustic Virtual Vortices with Tunable Orbital Angular Momentum for Trapping of Mie Particles Citation: Asier Marzo, Mihai Caleap, Bruce W. Drinkwater. Phys. Rev. Lett. 120, 044301 – Published 22 January 2018. Link: https://doi.org/10.1103/PhysRevLett.120.044301 https://doi.org/10.1103/PhysRevLett.120.044301 DOI: 10.1103/PhysRevLett.120.044301 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 inside 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).