Sensitivity of Collective Plasmon Modes of Gold Nanoresonators to Local Environment

TL;DR

This study experimentally investigates how collective plasmon resonances in gold nanoresonator arrays respond to changes in the local environment, revealing enhanced phase sensitivity compared to traditional sensors.

Contribution

It provides the first experimental analysis of the environmental sensitivity of collective plasmon modes in nanoresonator arrays, highlighting their potential for highly sensitive detection.

Findings

Collective plasmon modes show significant phase sensitivity to refractive index changes.

Phase sensitivity exceeds that of amplitude sensitivity and traditional SPR sensors.

Resonance quality is greatly improved due to diffractive coupling in nanoresonator arrays.

Abstract

We present the first experimental study of optical response of collective plasmon resonances in regular arrays of nanoresonators to local environment. Recently observed collective plasmon modes arise due to diffractive coupling of localised plasmons and yield almost an order of magnitude improvement in resonance quality. We measure the response of these modes to tiny variations of the refractive index of both gaseous and liquid media. We show that the phase sensitivity of the collective resonances can be more than two orders of magnitude better than the best amplitude sensitivity of the same nanodot array as well as an order of magnitude better than the phase sensitivity in SPR sensors.