All-optical initialization, readout, and coherent preparation of single silicon-vacancy spins in diamond

TL;DR

This paper demonstrates high-fidelity optical control and readout of single silicon-vacancy spins in diamond, achieving long spin relaxation times and coherent superposition states, advancing quantum information applications.

Contribution

It introduces a method for optical initialization, readout, and coherent control of SiV- spins with detailed characterization of their coherence properties.

Findings

Achieved spin relaxation time of 2.4 ms.

Demonstrated coherent population trapping with 35 ns coherence time.

Established SiV- centers as solid-state spin-photon interfaces.

Abstract

The silicon-vacancy ($\mathrm{SiV}^-$) color center in diamond has attracted attention due to its unique optical properties. It exhibits spectral stability and indistinguishability that facilitate efficient generation of photons capable of demonstrating quantum interference. Here we show high fidelity optical initialization and readout of electronic spin in a single $\mathrm{SiV}^-$ center with a spin relaxation time of $T_1=2.4\pm0.2$ ms. Coherent population trapping (CPT) is used to demonstrate coherent preparation of dark superposition states with a spin coherence time of $T_2^\star=35\pm3$ ns. This is fundamentally limited by orbital relaxation, and an understanding of this process opens the way to extend coherences by engineering interactions with phonons. These results establish the $\mathrm{SiV}^-$ center as a solid-state spin-photon interface.