Quantum dot lasing in the strong coupling regime in semiconductor microcavities

Summary form only given. The coexistence of low threshold lasing in the strong coupling (SC) regime in a high-quality semiconductor microcavity under quasi-resonant optical pumping is reported. In this study, a clear evidence of the simultaneous presence of the perturbative and non-perturbative regimes under the same optical excitation in semiconductor microcavities is observed. An unambiguous anti-crossing behavior of the coupled bare cavity and exciton modes, characteristic of the strong-coupling regime is obtained. Between these eigenstates of the system a new strong line appears whose intensity is exponentially dependent on the pumping power. An intermediate regime in semiconductor microcavities is identified, where this unexpected lasing mode, which fulfills the characteristics of the weak coupling mode, coexists with the free polariton modes. It is shown that this extra mode results from the population inversion of highly localized exciton states that behave as quantum-dot-like trap in the plane of the quantum well. Thus, simultaneous operation of a VCSEL and strongly coupled exciton-polaritons in a cavity is achieved.