Excitation-Transfer Plasmonic Nanosensors Based on Dynamical Phase Transitions

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 in the form of a localized–delocalized DPT. In this work we show how to take advantage of DPTs to design a new kind of plasmonic sensor which should own some unique characteristics. For example, if it were used as a 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 be observed only when the control/measured parameter, that is, a distance in the case of plasmon rulers, has a very precise and predetermined 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.