Nonlinear photoluminescence spectra from a quantum-dot-cavity system: Interplay of pump-induced stimulated emission and anharmonic cavity QED

We investigate the power-dependent photoluminescence spectra from a strongly coupled quantum dot-cavity system using a quantum master equation technique that accounts for incoherent pumping, stimulated emission, pure dephasing, and fermion or boson statistics. Analytical spectra at the one-photon correlation level and the numerically exact multiphoton spectra for fermions are presented. Master equation models that neglect stimulated emission processes are shown to lead to unphysical predictions at high powers, such as negative mean photon numbers. We compare to recent experiments on a quantum dot-micropillar cavity system and show that an excellent fit to the data can be obtained by varying only the incoherent pump rates in direct correspondence with the experiments. Our theory and experiments together show convincing evidence for stimulated-emission induced broadening and anharmonic cavity quantum electrodynamics.