Hyperfine Spectroscopy of Isotopically Engineered Group-IV Color Centers in Diamond

TL;DR

This paper predicts and experimentally verifies hyperfine interactions in group-IV diamond color centers, revealing strong coupling regimes that enhance quantum register applications in quantum communication.

Contribution

It provides first-principles predictions and experimental validation of hyperfine parameters in GeV and SnV centers, enabling improved quantum register design.

Findings

Hyperfine coupling causes significant optical transition splitting.

Identifies magnetic-field insensitive transitions in SnV centers.

Reveals strong coupling regime suitable for quantum information applications.

Abstract

A quantum register coupled to a spin-photon interface is a key component in quantum communication and information processing. Group-IV color centers in diamond (SiV, GeV, and SnV) are promising candidates for this application, comprising an electronic spin with optical transitions coupled to a nuclear spin as the quantum register. However, the creation of a quantum register for these color centers with deterministic and strong coupling to the spin-photon interface remains challenging. Here, we make first-principles predictions of the hyperfine parameters of the group-IV color centers, which we verify experimentally with a comprehensive comparison between the spectra of spin active and spin neutral intrinsic dopant nuclei in single GeV and SnV emitters. In line with the theoretical predictions, detailed spectroscopy on large sample sizes reveals that hyperfine coupling causes a splitting of the optical transition of SnV an order of magnitude larger than the optical linewidth and provides a magnetic-field insensitive transition. This strong coupling provides access to a new regime for quantum registers in diamond color centers, opening avenues for novel spin-photon entanglement and quantum sensing schemes for these well-studied emitters.