Cavity quantum electrodynamics with charge-controlled quantum dots coupled to a fiber Fabry–Perot cavity

We demonstrate non-perturbative coupling between a single selfassembled InGaAs quantum dot and an external fiber-mirror-based microcavity.Our results extend the previous realizations of tunable microcavities while ensuring spatial and spectral overlap between the cavity mode and the emitter by simultaneously allowing for deterministic charge control of the quantum dots.Using resonant spectroscopy, we show that the coupled quantum dot cavity system is at the onset of strong coupling, with a cooperativity parameter of C ≈ 2.0 ± 1.3.Our results constitute a milestone in the progress toward the realization of a high-efficiency solid-state spin-photon interface.