Influence of the correlations in an active medium on the pump-induced exceptional points and strong coupling

Abstract

Exceptional points show great prospects for applications such as imaging, sensing, and designing lasers. Recently, systems with amplifying active medium exhibiting pump-induced exceptional points have attracted much attention due to the possibility of controlling the strong coupling between light and matter with the aid of pumping. In such structures, the interaction of the active molecules with external degrees of freedom, such as phonons or impurities, leads to the destruction of the correlations between the polarizations of different molecules. We study the effect of the correlation decay on system behavior near a pump-induced exceptional point. We show that exceptional points and strong coupling are robust to correlation decay and disappear only at very high rates of correlation decay, much larger than other relaxation rates. The obtained result is crucial for designing systems with exceptional points and strong coupling.