Mode switching dynamics in organic polariton lasing

TL;DR

This paper investigates the complex dynamics of multimode polariton lasing in organic microcavities, revealing how mode switching and bi-modal lasing depend on coupling regimes and system parameters.

Contribution

It introduces a second-order cumulant equation approach to distinguish between bi-modal lasing and temporal mode switching in organic polariton systems.

Findings

Temporal switching occurs more widely than bi-modal lasing.

Weak and strong coupling regimes exhibit different switching mechanisms.

Gain spectra and photoluminescence reveal the origin of mode switching.

Abstract

We study the dynamics of multimode polariton lasing in organic microcavities by using a second-order cumulant equation approach. By inspecting the time evolution of the photon mode occupations, we show that if multiple lasing peaks are observed in time-integrated mode occupations, the reason can be either bi-modal lasing or temporal switching between several modes. The former takes place within a narrow range of parameters while the latter occurs more widely. We find that the origin of the temporal switching is different in the weak- and strong-coupling regimes. At weak coupling slope efficiency is the determining factor, while for strong coupling it is changes in the eigenmodes and gain spectrum upon pumping. This difference is revealed by investigating the photoluminescence and momentum-resolved gain spectra. Our results underscore the importance of understanding the time evolution of the populations when characterizing the lasing behaviour of a multimode polariton system, and show how these features differ between weak and strong coupling.