Optimal design of diamond-air microcavities for quantum networks using an analytical approach

TL;DR

This paper develops an analytical framework to optimize diamond-air microcavities, enhancing emission into desired modes for quantum networks by balancing Purcell factor, stability, and outcoupling.

Contribution

It introduces an analytical approach to design hybrid diamond-air microcavities, enabling better trade-offs among Purcell enhancement, stability, and outcoupling efficiency.

Findings

Analytic descriptions of hybrid cavities guide optimal design parameters.

Trade-offs between Purcell factor, cavity stability, and outcoupling are quantitatively analyzed.

The approach provides a practical tool for improving quantum network emitter interfaces.

Abstract

Defect centers in diamond are promising building blocks for quantum networks thanks to a long-lived spin state and bright spin-photon interface. However, their low fraction of emission into a desired optical mode limits the entangling success probability. The key to overcoming this is through Purcell enhancement of the emission. Open Fabry-Perot cavities with an embedded diamond membrane allow for such enhancement while retaining good emitter properties. To guide the focus for design improvements it is essential to understand the influence of different types of losses and geometry choices. In particular, in the design of these cavities a high Purcell factor has to be weighed against cavity stability and efficient outcoupling. To be able to make these trade-offs we develop analytic descriptions of such hybrid diamond-and-air cavities as an extension to previous numeric methods. The insights provided by this analysis yield an effective tool to find the optimal design parameters for a diamond-air cavity.