Excitation-Transfer Plasmonic Nanosensors based on Dynamical Phase Transitions

TL;DR

This paper introduces a novel plasmonic sensor based on dynamical phase transitions in metallic nanoparticle arrays, enabling on-off switching behavior with high sensitivity for specific environmental parameters.

Contribution

It demonstrates how dynamical phase transitions can be exploited to design plasmonic sensors with unique on-off switching capabilities, deviating from traditional plasmon ruler equations.

Findings

Sensor exhibits on-off switching at specific distances and dielectric constants.

High sensitivity achieved near the dynamical phase transition point.

Potential for environmental condition-specific plasmonic device activation.

Abstract

Dynamical Phase transitions (DPTs) describe the abrupt change in the dynamical properties of open systems when a single control parameter is slightly modified. Recently we found that this phenomenon is also present in a simple model of a linear array of metallic nanoparticles (NPs) in the form of a localized-delocalized DPT. In this work we show how to take advantage of DPTs in order to design a new kind of plasmonic sensor which should own some unique characteristics. For example, if it were used as plasmon ruler it would not follow the so called universal plasmon ruler equation [Nano Letters 2007, 7, 2080-2088], exhibiting instead an on-off switching feature. This basically means that a signal should only be observed when the control/measured parameter, i.e. a distance in the case of plasmon rulers, has a very precise and pre-determined value. Here, we demonstrate their feasibility and unique characteristics, showing that they combine high sensitivity with this on-off switching feature in terms of different distances and local dielectric constants. This property has the potentiality to be used in the design of new plasmonic devices such as plasmonic circuits activated only under certain environmental conditions.