Tuning light-matter interaction of near-infrared nanoplasmonic scintillators

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 Lu \(_2\) O \(_3\) :Er \(³⁺\) 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 owing to its ultranarrow antenna linewidth ( \(κ\) = 3.5 meV), with observable coherent-exchange signatures appearing at the lowest tested coupling strength of g = 8 meV. These results identify near-infrared conductive nanoantennas, particularly graphene-based ones, as promising platforms for accessing hybrid scintillation regimes relevant to radiation detection.