Optical Spin Initialisation and Readout with a Cavity-Coupled Quantum Dot in an In-Plane Magnetic Field

TL;DR

This paper demonstrates that a cavity with a single linearly-polarized mode can enable high-fidelity spin initialisation and readout of a quantum dot in an in-plane magnetic field, guiding the design of quantum network components.

Contribution

It shows that single-mode cavities outperform bi-modal ones for spin control in a Voigt geometry, providing optimal parameters for quantum dot spin-photon interfaces.

Findings

Single-mode cavities support both spin initialisation and readout.

Single-mode cavities outperform bi-modal cavities in relevant regimes.

Optimal parameters for high-fidelity control are identified.

Abstract

The spin of a charged semiconductor quantum dot (QD) coupled to an optical cavity is a promising candidate for high fidelity spin-photon interfaces; the cavity selectively modifies the decay rates of optical transitions such that spin initialisation, manipulation, and readout are all possible in a single magnetic field geometry. By performing cavity QED calculations, we show that a cavity with a single, linearly-polarised mode can simultaneously support both high-fidelity optical spin initialisation and readout in a single, in-plane (Voigt geometry) magnetic field. Furthermore, we demonstrate that single mode cavities always outperform bi-modal cavities in experimentally favourable driving regimes. Our analysis, when combined with established methods of control in a Voigt geometry field, provides optimal parameter regimes for high-fidelity initialisation and readout, and coherent control in both cavity configurations, providing insights for the design and development of QD spin-photon interfaces as the basis of quantum network nodes and for the generation of photonic graph states.