Cavity-Enhanced Emission and Absorption of Color Centers in a Diamond Membrane With Selectable Strain

TL;DR

This paper demonstrates strain-tunable cavity-enhanced emission and absorption in diamond color centers, significantly increasing ground-state splitting and enabling efficient spin-photon interfaces at cryogenic temperatures.

Contribution

It introduces a method to increase ground-state splitting via strain in diamond membranes and couples the centers with a microcavity for enhanced optical interactions.

Findings

Ground-state splitting increased by up to an order of magnitude

Achieved cavity-assisted spectroscopy with strain-tunable coupling

Observed Purcell-enhanced emitter lifetime reduction below 1ns

Abstract

Group IV color centers in diamond are among the most promising optically active spin systems with strong optical transitions and long spin coherences. The ground-state splitting of the center is particularly important to suppress the interaction with coherence-limiting phonons, which improves the coherence properties and sets the upper limit for the operating temperature. Negatively charged silicon-vacancy centers have an ordinary ground-state splitting of only 48GHz, resulting in required temperatures below one Kelvin, which can only be achieved by dilution refrigerators. Here, we increase the ground-state splitting by up to an order of magnitude by induced strain in a single-crystal diamond membrane. Furthermore, we demonstrate cavity-assisted spectroscopy enabled by coupling the emitter ensemble with a selectable strain to the mode of a Fabry-Perot microcavity. Calculation of the absorption cross-section yields $\sigma_{ens} = $4.9*10^-11 cm^2. Together with the Purcell-enhanced twofold reduction in emitter lifetime below 1ns, this makes the system a promising spin-photon interface at moderate temperatures of 4K.