Polariton dynamics under strong light-molecule coupling.

We present a comprehensive experimental study of the photophysical properties of a molecule-cavity system under strong coupling conditions, using steady-state and femtosecond time-resolved emission and absorption techniques to selectively excite the lower and upper polaritons as well as the reservoir of uncoupled molecules. Our results demonstrate the complex decay routes in such hybrid systems and that, contrary to expectations, the lower polariton is intrinsically long-lived.