# Creation and Detection of Optical Spin in a Coupled Emitter–Plasmon System

## TL;DR

This paper shows how to create and detect optical spin in a system combining a light emitter and a gold nanorod.

## Contribution

The study demonstrates net optical spin generation in an achiral system through asymmetrical emitter placement.

## Key findings

- Asymmetrical emitter placement creates net optical spin in the field inside the gold nanorod.
- Electron beam excitation effectively generates a point dipole emitter for experimental validation.
- Spin-momentum locked light in a nanofiber probe detects the optical spin as directional propagation.

## Abstract

We investigate the system of a linearly polarized dipole
emitter
coupled to the plasmonic modes of a gold nanorod (GNR). We show numerically
that asymmetrical placement of the emitter relative to the GNR axes
gives rise to a net optical spin for the field inside the rod, despite
the apparent achirality of the system. We experimentally demonstrate
this effect using electron beam excitation to create an effective
point dipole emitter and coupling luminescence evanescently to a nanofiber
probe which supports spin-momentum locked light. This converts the
net spin of the field into a net directionality of propagation in
the fiber modes, allowing detection in the far field.