Unlocking plasmonic nanolaser performance via exciton–plasmon interaction dynamics

Plasmonic nanolasers are transitioning from empirical optimization to a new paradigm driven by physical mechanisms. Owing to the lack of guidance from internal mechanisms, this transformation process remains highly challenging. Therefore, elucidating the governing nanoscale light–matter interactions has become essential for unlocking their full performance potential. In this paper, we establish a framework that connects the strength of exciton–plasmon interactions with plasmonic nanolaser performance. The evolution of the laser spectrum under increasing pumping fluence, reflected by variations in intensity, spectral peak position, and full width at half maximum, provides clear evidence of exciton–plasmon interactions. These interactions are further verified by changes in the emission lifetime with incident fluence, and it is found that the lifetime variation correlates with the change in spectral full width at half maximum. Furthermore, we calculate and analyze various loss mechanisms in plasmonic nanolasers, revealing how the strength of exciton–plasmon interactions actively modulates optical loss channels and fundamentally controls the lasing threshold. Understanding exciton–plasmon interaction dynamics is not merely a theoretical pursuit but a critical step toward realizing truly practical and scalable nanophotonic devices.