Optomechanical manipulation with hyperbolic metasurfaces

TL;DR

This paper explores how hyperbolic metasurfaces can enhance optomechanical manipulation by enabling strong optical forces, including pulling forces, through tailored electromagnetic interactions near anisotropic substrates.

Contribution

It demonstrates the potential of hyperbolic metasurfaces to improve optomechanical control, highlighting their spectral properties and comparing models for practical realization.

Findings

Hyperbolic metasurfaces produce strong optical pulling forces.

Spectral decomposition reveals key interaction channels.

Homogenised models match multilayer structures under certain conditions.

Abstract

Auxiliary nanostructures introduce additional flexibility into optomechanical manipulation schemes. Metamaterials and metasurfaces capable to control electromagnetic interactions at the near-field regions are especially beneficial for achieving improved spatial localization of particles, reducing laser powers required for trapping, and for tailoring directivity of optical forces. Here, optical forces acting on small particles situated next to anisotropic substrates, are investigated. A special class of hyperbolic metasurfaces is considered in details and is shown to be beneficial for achieving strong optical pulling forces in a broad spectral range. Spectral decomposition of the Green functions enables identifying contributions of different interaction channels and underlines the importance of the hyperbolic dispersion regime, which plays the key role in optomechanical interactions. Homogenised model of the hyperbolic metasurface is compared to its metal-dielectric multilayer realizations and is shown to predict the optomechanical behaviour under certain conditions related to composition of the top layer of the structure and its periodicity. Optomechanical metasurfaces open a venue for future fundamental investigations and a range of practical applications, where accurate control over mechanical motion of small objects is required.