A silicon-integrated telecom photon-spin interface

TL;DR

This paper introduces the T center in silicon as a promising matter-photon interface with long coherence times and telecom-band optical transitions, advancing quantum communication technologies.

Contribution

It demonstrates the T center's long electron and nuclear spin lifetimes and optical properties, establishing a practical silicon-based quantum interface.

Findings

Electron spin lifetime exceeds one millisecond

Nuclear spin lifetime exceeds one second

Optical lifetime of approximately 0.94 microseconds

Abstract

Long-distance entanglement distribution is a vital capability for quantum technologies. An outstanding practical milestone towards this aim is the identification of a suitable matter-photon interface which possesses, simultaneously, long coherence lifetimes and efficient telecommunications-band optical access. In this work, alongside its sister publication, we report upon the T center, a silicon defect with spin-selective optical transitions at 1326 nm in the telecommunications O-band. Here we show that the T center in $^{28}$Si offers electron and nuclear spin lifetimes beyond a millisecond and second respectively, as well as optical lifetimes of 0.94(1) $\mu$s and a Debye-Waller factor of 0.23(1). This work represents a significant step towards coherent photonic interconnects between long-lived silicon spins, spin-entangled telecom single-photon emitters, and spin-dependent silicon-integrated photonic nonlinearities for future global quantum technologies.