Optical forces, torques and force densities calculated at a microscopic level using a self-consistent hydrodynamics method

TL;DR

This paper introduces a self-consistent hydrodynamics method to calculate microscopic optical force densities in nanoplasmonic systems, accounting for quantum and non-local effects, revealing uneven force distributions and induced torques.

Contribution

The paper presents a novel self-consistent hydrodynamics approach for calculating microscopic optical forces, including quantum and non-local effects, at the nanoscale.

Findings

Calculated force density distributions in nanoplasmonic systems.

Discovered uneven force distributions can induce spinning torques.

Demonstrated the method on nanoplasmonic dimers.

Abstract

The calculation of optical force density distribution within a material is challenging at the nanoscale, where quantum and non-local effects emerge and macroscopic parameters such as permittivity become ill-defined. We demonstrate that the microscopic optical force density of nanoplasmonic systems can be defined and calculated using a self-consistent hydrodynamics model that includes quantum, non-local and retardation effects. We demonstrate this technique by calculating the microscopic optical force density distributions and the optical binding force induced by external light on nanoplasmonic dimers. We discover that an uneven distribution of optical force density can lead to a spinning torque acting on individual particles.