Rabi splitting and exciton dynamics in MoSe₂ monolayers and (Ga,In)As quantum wells: a comparative study of light–matter coupling regimes

We investigate Rabi splitting and exciton dynamics in hBN-encapsulated MoSe₂ monolayers and (Ga,In)As quantum wells using femtosecond pump–probe spectroscopy at cryogenic temperatures. While (Ga,In)As exhibits clear Rabi oscillations, coherent gain, and symmetric exciton splitting due to moderate Coulomb interactions, MoSe₂ shows slightly sublinear splitting and suppressed coherence, driven by strong many-body effects and exciton–biexciton transitions. A microscopic many-body theory based on excitonic Bloch equations explains the observed dynamics, revealing how the ratio of Rabi energy to exciton binding energy governs the nonlinear optical response. Our results highlight the contrasting regimes of light–matter coupling in 2D van der Waals semiconductors and III-V quantum wells, offering pathways to control excitonic processes for future optoelectronic and quantum technologies.