Tuning light-matter interaction of near-infrared nanoplasmonic scintillators

TL;DR

This paper develops a quantum-optical framework to explore how near-infrared scintillator nanocrystals coupled with nanoplasmonic antennas transition from weak to strong light-matter coupling, revealing optimal conditions for enhanced radiation detection.

Contribution

It introduces a comprehensive model for near-infrared scintillator nanocrystals interacting with various nanoplasmonic antennas, highlighting the potential of graphene antennas for strong coupling regimes.

Findings

Strong coupling signatures depend on emitter dephasing and antenna linewidth.

Narrow-band emitters with narrow antennas facilitate strong coupling.

Graphene antennas have the lowest threshold for coherent exchange.

Abstract

Nanoplasmonic modification of scintillation has so far been explored mainly in the weak-coupling regime, where changes in the local density of optical states enhance radiative recombination via Purcell-type rate engineering. By contrast, strong light-matter coupling generates hybrid states that modify emission dynamics beyond simple decay-rate acceleration, but its implications for scintillator nanocrystals (NCs) under ionizing radiation remain poorly understood. All of these effects are beneficial for near-infrared scintillators, which are typically slow and have low brightness. Here, we present a quantum-optical framework to investigate how near-infrared scintillator NCs coupled to nanoplasmonic antennas evolve from weak coupling toward strong light-matter coupling. We compare broad- and narrow-antenna platforms with single and periodic Au nanorods and benchmark them against conductive plasmonic antennas based on indium tin oxide and graphene. As representative emitters, we consider wide-band PbS NCs and narrow-band cubic Lu2O3:Er3+ scintillators. The calculations show that the onset of strong-coupling signatures is jointly governed by emitter dephasing and the antenna linewidth, with narrow-band emitters coupled to spectrally narrow antennas providing the most favorable conditions. Among the platforms considered, graphene gives the lowest threshold (g = 4 meV) for observable coherent exchange owing to its ultranarrow antenna linewidth (\k{appa} = 3.5 meV). These results identify near-infrared conductive nanoantennas, particularly graphene-based ones, as promising platforms for accessing hybrid scintillation regimes relevant to radiation detection.