A charged quantum dot micropillar system for deterministic light matter interactions

TL;DR

This paper demonstrates a significant polarization rotation of light caused by a negatively charged quantum dot in a low-Q micropillar cavity, indicating potential for near-deterministic light-matter interactions in quantum devices.

Contribution

It reports the first observation of a large polarization rotation in a low-Q micropillar cavity with a charged quantum dot, advancing scalable quantum information technology.

Findings

Measured a ~6° phase shift of light due to QD-cavity interaction

Large rotation achieved with low Q-factor microcavity

Demonstrates feasibility of near-deterministic light-matter coupling

Abstract

Quantum dots (QDs) are semiconductor nanostructures in which a three dimensional potential trap produces an electronic quantum confinement, thus mimicking the behaviour 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 ($\sim6^o$) phase shift of light as a result of the interaction with a negatively charged QD coupled to a low quality-factor (Q$\sim290$) pillar microcavity. This unexpectedly large rotation angle demonstrates this simple low Q-factor design would enable near deterministic light-matter interactions.