All-optical control of the silicon-vacancy spin in diamond at millikelvin temperatures

TL;DR

This paper demonstrates all-optical coherent control of silicon-vacancy spins in diamond at millikelvin temperatures, revealing spin dephasing mechanisms beyond phonon effects, crucial for quantum photonics applications.

Contribution

It introduces a method for all-optical control of silicon-vacancy spins at very low temperatures and identifies nitrogen spin bath coupling as a key decoherence source.

Findings

Achieved all-optical coherent control of silicon-vacancy spins at 12mK.

Identified nitrogen spin bath as the main decoherence source.

Demonstrated spin dephasing effects beyond phonon-induced decoherence.

Abstract

The silicon-vacancy center in diamond offers attractive opportunities in quantum photonics due to its favorable optical properties and optically addressable electronic spin. Here, we combine both to achieve all-optical coherent control of its spin states. We utilize this method to explore spin dephasing effects in an impurity-rich sample beyond the limit of phonon-induced decoherence: Employing Ramsey and Hahn-echo techniques at 12mK base temperature we identify resonant coupling to a substitutional nitrogen spin bath as the limiting decoherence source for the electron spin.