The silicon vacancy centers in SiC: determination of intrinsic spin dynamics for integrated quantum photonics

TL;DR

This paper characterizes the intrinsic spin dynamics of silicon vacancy centers in SiC, providing essential data for optimizing their use in integrated quantum photonics and demonstrating feasible multi-photon entanglement generation.

Contribution

It offers a comprehensive model of the spin-optical dynamics of V_Si^- centers in SiC, including decay rates and mechanisms, advancing the understanding necessary for quantum photonic applications.

Findings

All relevant spin-dependent decay rates are measured.

The spin dynamics model enables realistic multi-photon entanglement schemes.

Up to 3-photon GHZ/cluster states are feasible with current technology.

Abstract

The negatively-charged silicon vacancy center ($\rm V_{Si}^-$) in silicon carbide (SiC) is an emerging color center for quantum technology covering quantum sensing, communication, and computing. Yet, limited information currently available on the internal spin-optical dynamics of these color centers prevents us achieving the optimal operation conditions and reaching the maximum performance especially when integrated within quantum photonics. Here, we establish all the relevant intrinsic spin dynamics of negatively charged $\rm V_{Si}^-$ center in 4H-SiC by an in-depth electronic fine structure modeling including intersystem-crossing and deshelving mechanisms. With carefully designed spin-dependent measurements, we obtain all previously unknown spin-selective radiative and non-radiative decay rates. To showcase the relevance of our work for integrated quantum photonics, we use the obtained rates to propose a realistic implementation of time-bin entangled multi-photon GHZ and cluster state generation. We find that up to 3-photon GHZ/cluster states are readily within reach using the existing nanophotonic cavity technology.