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

TL;DR

This paper investigates how correlation decay in active media affects pump-induced exceptional points, demonstrating their robustness and implications for designing advanced photonic systems.

Contribution

It reveals that pump-induced exceptional points remain stable despite correlation decay, providing new insights for system design in photonics.

Findings

Exceptional points are robust to correlation decay.

Strong coupling persists at negative population inversion.

Eigenvectors and eigenfrequencies coalesce despite correlation loss.

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 possibility of controlling strong coupling between light and matter with the aid of pumping. In such structures, the interaction of active molecules with external degrees of freedom, such as phonons or impurities, leads to the destruction of the correlation between polarizations of different molecules. We study the effect of the correlations decay on a system behavior near pump-induced exceptional point. We show that strong coupling persists and eigenvectors together with eigenfrequencies coalesce at a negative value of population inversion, regardless of correlation decay magnitude. Thus, we show that exceptional points are robust to correlation decay, which is crucial for designing systems with exceptional points.