# Revealing Low-Radiative Modes of Nanoresonators with Internal Raman Scattering

## TL;DR

This paper introduces a novel experimental method using intrinsic incoherent Raman scattering to identify low-radiative modes in nanoresonators, demonstrated on silicon nanoparticles, revealing modes difficult to detect with traditional optical techniques.

## Contribution

The paper proposes and experimentally validates a new approach for revealing dark modes in nanoresonators using Raman scattering, overcoming limitations of existing optical methods.

## Key findings

- Successfully identified a low-radiative magnetic quadrupole mode in silicon nanoparticles.
- Demonstrated the method's effectiveness on nanoparticles on a gold substrate.
- Provided theoretical prediction and experimental confirmation of the mode detection.

## Abstract

Revealing hidden non-radiative (dark) of resonant nanostructures using optical methods such as dark-field spectroscopy often becomes a sophisticated problem due to a weak coupling of these modes with a far-field radiation, whereas methods of dark-modes spectroscopy, e.g. cathodoluminescence or elastic energy losses, are not always convenient in use. Here, we suggest an approach for experimental determining the mode structure of a nanoresonator basing on utilizing intrinsic incoherent Raman scattering. We theoretically predict the efficiency of this approach and realize it experimentally for silicon nanoparticle resonators possessing strong Raman line at 520 cm^-1. With this method, we studied a silicon nanoparticle placed on a gold substrate and reveal the spectral position of a low-radiative magnetic quadrupole mode which is hardly observable with common dark-field optical spectroscopy.