Acoustic angular sorting of resonant subwavelength particles

TL;DR

This paper introduces an acoustic method for angularly sorting subwavelength particles based on their resonances and sizes, using ultrasound waves to achieve selective manipulation.

Contribution

It proposes a dynamical mechanism for size and resonance-based angular sorting of particles using acoustic forces, with analysis and practical examples.

Findings

Sorting efficiency depends on particle size and resonance

Detuning between ultrasound beams affects sorting precision

Feasible experimental setups are discussed

Abstract

We suggest a dynamical mechanism for angular sorting of subwavelength particles in accord with their resonances and sizes, realised with the forces imposed by acoustic (ultrasound) waves with different wavelengths. We analyse how the acoustic force acting on a small particle depends on its size relative to the ultrasound wavelength, and how the detuning between the two different beams influences the size range and angular distribution for unambiguous sorting outcomes for a given size range. We predict a range of scenarios depending on the particular materials and provide several feasible examples and discuss their practical realisation.