Optically assisted trapping with high-permittivity dielectric rings: Towards optical aerosol filtration

TL;DR

This paper proposes using high-permittivity dielectric rings to trap nanoparticles optically, offering a contactless and efficient method for nanoparticle filtration, supported by semi-analytical and full-wave simulation results.

Contribution

Introduction of dielectric rings as a novel, contactless optical trapping mechanism for nanoparticles, overcoming limitations of plasmonic nanostructures.

Findings

Dielectric rings can strongly localize optical fields for trapping.

Nanoparticles can be trapped without contact using these rings.

Potential application in optical aerosol filtration.

Abstract

Controlling the transport, trapping, and filtering of nanoparticles is important for many applications. By virtue of their weak response to gravity and their thermal motion, various physical mechanisms can be exploited for such operations on nanoparticles. However, the manipulation based on optical forces is potentially most appealing since it constitutes a highly deterministic approach. Plasmonic nanostructures have been suggested for this purpose, but they possess the disadvantages of locally generating heat and trapping the nanoparticles directly on surface. Here, we propose the use of dielectric rings made of high permittivity materials for trapping nanoparticles. Thanks to their ability to strongly localize the field in space, nanoparticles can be trapped without contact. We use a semi-analytical method to study the ability of these rings to trap nanoparticles. Results are supported by full-wave simulations. Application of the trapping concept to nanoparticle filtration is suggested.