Stimulated chiral light-matter interactions in biological microlasers

Chiral light-matter interactions have emerged as a promising area in biophysics and quantum optics. Remarkable progress in enhancing chiral light-matter interactions have been investigated through passive resonators or spontaneous emission. Nevertheless, the interaction between chiral biomolecules and stimulated emission remains unexplored. Here we introduce the concept of a biological chiral laser by amplifying chiral light-matter interactions in an active resonator through stimulated emission process. Green fluorescent proteins or chiral biomolecules encapsulated in Fabry-Perot microcavity served as the gain material while excited by either left-handed or righthanded circularly polarized pump laser. Owing to the nonlinear pump energy dependence of stimulated emission, significant enhancement of chiral light-matter interactions was demonstrated. Detailed experiments and theory revealed that lasing dissymmetry factor is determined by molecular absorption dissymmetry factor at its excitation wavelength. Finally, chirality transfer was investigated under stimulated emission process through Forster resonance energy transfer. Our findings elucidate the mechanism of stimulated chiral light-matter interactions, providing new prospects for understanding light-matter interaction in biophysics, chiral sensing, and quantum photonics.