Mode repulsion and mode coupling in random lasers

TLDR

In random media with inhomogeneously broadened gain, most lasing modes repel each other in frequency, while some couple via photon hopping or electron absorption and reemission. The study investigates the interaction of lasing modes in random media through experimental and theoretical analysis. The authors examined mode interactions experimentally and theoretically in random lasers. Weak coupling synchronizes two modes under pulsed pumping, whereas strong coupling produces antiphased intensity oscillations.

Abstract

We studied experimentally and theoretically the interaction of lasing modes in random media. When optical gain spectrum is inhomogeneously broadened, most lasing modes repel each other in the frequency domain. Some lasing modes are coupled through photon hopping or electron absorption and reemission. Under pulsed pumping, weak coupling of two modes leads to synchronization of their lasing action. Strong coupling of two lasing modes results in antiphased oscillations of their intensities.