Microwave determination of electron-hole recombination dynamics from spontaneous to stimulated emission in a quantum-well microcavity laser

By studying the optical microwave frequency response of a microcavity quantum-well vertical cavity surface-emitting laser (VCSEL) in the transition, over a low (a spread-out) mode density, from spontaneous to coherent operation, we resolve the dynamics (spontaneous to stimulated) of electron-hole recombination and reveal the existence of fast spontaneous recombination (tau(Bspon)< 159 ps) in a carrier population generally characterized by a large average lifetime of similar to 1 ns (Delta n/tau(av)=Delta n(1)/tau(fast)+(Delta n-Delta n(1))/tau(slow),tau(fast)