Coupling of optical far-fields into aperture-less plasmonic nanofibre tips

TL;DR

This study demonstrates how gold-coated nanofibre tips can efficiently couple surface plasmons to optical fibers via side-illumination, with potential applications in quantum optics and nanoscale sensing.

Contribution

It introduces a method for exciting surface plasmons on nanofibre tips and coupling them to optical fibers, advancing nanoscale light manipulation techniques.

Findings

Coupling efficiency depends strongly on incidence angle.

Maximum coupling efficiency is a few percent.

Nanofibre tips can be used as scanning probes for beam waist measurement.

Abstract

This paper reports on the excitation of surface plasmons on gold-coated nanofibre tips by side-illumination with a laser beam and the coupling of the surface plasmons to the optical fiber. The measurements show a strong dependence of the coupling efficiency on the incidence angle with a maximum coupling efficiency on the order of few percent. Moreover, the fibre tip was used as scanning probe device for measuring the beam waist of a focussed laser beam. This work is motivated by the goal to use such plasmonic nanofibre tips in quantum optics experiments with cold atoms.