Polarization Controlled Directional Scattering for Nanoscopic Position Sensing

TL;DR

This paper presents a novel nanoscopic position sensing method using polarization-controlled directional scattering from silicon nanoantennas, achieving Angstrom-scale lateral resolution through interference of magnetic and electric resonances.

Contribution

It introduces a new approach for position sensing based on directional scattering controlled by polarization, utilizing high-refractive-index silicon nanoantennas and focused radially polarized light.

Findings

Achieved Angstrom-scale lateral resolution in position sensing.

Demonstrated control of directional scattering via interference of resonances.

Proposed application in nanometrology and super-resolution microscopy.

Abstract

Controlling the propagation and coupling of light to sub-wavelength antennas is a crucial prerequisite for many nanoscale optical devices. Recently, the main focus of attention has been directed towards high-refractive-index materials such as silicon as an integral part of the antenna design. This development is motivated by the rich spectral properties of individual high-refractive-index nanoparticles. Here, we take advantage of the interference of their magnetic and electric resonances, to achieve remarkably strong lateral directionality. For controlled excitation of a spherical silicon nanoantenna we use tightly focused radially polarized light. The resultant directional emission depends on the antenna's position relative to the focus. This approach finds application as a novel position sensing technique, which might be implemented in modern nanometrology and super-resolution microscopy setups. We demonstrate in a proof-of-concept experiment, that a lateral resolution in the Angstrom regime can be achieved.