Theory of self-induced back-action optical trapping in nanophotonic systems

TL;DR

This paper presents a theoretical framework for self-induced back-action (SIBA) optical trapping in nanophotonic systems, revealing its potential to create highly localized traps with lower intensities, surpassing traditional limits.

Contribution

It provides the first comprehensive theory of SIBA trapping, demonstrating its ability to reshape potentials and achieve sub-wavelength confinement.

Findings

SIBA enables dynamic reshaping of trap potentials.

SIBA allows for strongly sub-wavelength trap features.

SIBA significantly reduces the optical intensities experienced by particles.

Abstract

Optical trapping is an indispensable tool in physics and the life sciences. However, there is a clear trade off between the size of a particle to be trapped, its spatial confinement, and the intensities required. This is due to the decrease in optical response of smaller particles and the diffraction limit that governs the spatial variation of optical fields. It is thus highly desirable to find techniques that surpass these bounds. Recently, a number of experiments using nanophotonic cavities have observed a qualitatively different trapping mechanism described as "self-induced back-action trapping" (SIBA). In these systems, the particle motion couples to the resonance frequency of the cavity, which results in a strong interplay between the intra-cavity field intensity and the forces exerted. Here, we provide a theoretical description that for the first time captures the remarkable range of consequences. In particular, we show that SIBA can be exploited to yield dynamic reshaping of trap potentials, strongly sub-wavelength trap features, and significant reduction of intensities seen by the particle, which should have important implications for future trapping technologies