Observation of plasmonic exceptional points

TL;DR

This paper reports the first observation of plasmonic exceptional points at room temperature, achieved through hybridized multilayered plasmonic crystals, enabling enhanced biological sensing and potential nanoscale device applications.

Contribution

It introduces a novel method to observe and utilize exceptional points in plasmonics, expanding their application to room temperature and biological sensing.

Findings

Observation of plasmonic exceptional points at room temperature

Enhanced sensing of anti-Immunoglobulin G antibodies

Potential for nanoscale sensors and devices based on topological effects

Abstract

Non-Hermitian singularities known as exceptional-points (EPs) have been shown to exhibit increased sensitivities but the observation of EPs has so far been limited to wavelength scaled systems subject to diffraction limit. We propose a novel approach to EPs and report their first observation in plasmonics at room temperature. The plasmonic EPs are based on the hybridization of detuned resonances in multilayered plasmonic crystals to reach a critical complex coupling rate between nanoantennas arrays, and, resulting in the simultaneous coalescence of the resonances and loss rates. Because plasmons shrink the wavelength of light to make it compatible with biological relevant substances, enhanced sensing of anti-Immunoglobulin G, the most common antibody found in blood circulation, is observed. Our work opens the way to novel class of nanoscale devices, sensors, and imagers based on topological polaritonic effects.