Charged quantum dot micropillar system for deterministic light-matter interactions

Quantum dots (QDs) are semiconductor nanostructures in which a three-dimensional potential trap produces an electronic quantum confinement, thus mimicking the behavior of single atomic dipole-like transitions. However, unlike atoms, QDs can be incorporated into solid-state photonic devices such as cavities or waveguides that enhance the light-matter interaction. A near unit efficiency light-matter interaction is essential for deterministic, scalable quantum-information (QI) devices. In this limit, a single photon input into the device will undergo a large rotation of the polarization of the light field due to the strong interaction with the QD. In this paper we measure a macroscopic (∼6°) phase shift of light as a result of the interaction with a negatively charged QD coupled to a low-quality-factor (Q∼290) pillar microcavity. This unexpectedly large rotation angle demonstrates that this simple low-Q-factor design would enable near-deterministic light-matter interactions.