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arXiv · 2608.04797

High-cooperativity coupling and spin-resolved extinction of tin-vacancy centers in a diamond-like microcavity

Kerim Köster·András Laukó·Federico Rapisarda·Philipp Graßhoff·Vladislav Bushmakin·Jens Fuhrmann·Ou Wang·Dominic Reinhardt·Doğuşcan Ahiboz·Peter Knittel·Thomas Hümmer·Wolfgang Wernsdorfer·Jörg Wrachtrup·Fedor Jelezko·Tommaso Pregnolato·Tim Schröder·Jan Meijer·Cyril Popov·David Hunger
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Abstract

The tin-vacancy (SnV) center in diamond is a promising spin-photon interface for quantum networks, combining favorable optical properties with spin coherence above 1K. Unfolding the full potential requires cavity enhancement to increase photon-emitter coupling efficiency. Here, we demonstrate cavity-enhanced light-matter coupling of SnV centers in a fully tunable Fabry-Pérot microcavity operating at temperatures down to 1K with in-situ magnetic field control. We access the diamond-like regime of hybrid cavity modes through integration of low-roughness diamond membranes, where the field is concentrated inside the diamond and Purcell enhancement is maximized. Diamond-like modes deliver a more than two-fold increase in the effective Purcell factor over air-like modes, reaching $C_0 = 4.1(1)$ compared to $C_0 = 1.85(5)$ in the air-like case, while simultaneously relaxing mechanical stability requirements. Resonant probing reveals coherent cavity-emitter coupling with 96% extinction contrast and a coherent cooperativity of $C = 4.0(14)$. By applying a magnetic field, we further achieve spin-resolved cavity extinction, observing spin-selective optical transitions with a contrast of ${\cal C}_{\rm spin} = 0.91$. These results establish SnV centers in diamond coupled to open Fabry-Pérot microcavities as a promising platform for efficient spin-photon interfaces.

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Kerim Köster, András Laukó, Federico Rapisarda, Philipp Graßhoff, Vladislav Bushmakin, Jens Fuhrmann, Ou Wang, Dominic Reinhardt, Doğuşcan Ahiboz, Peter Knittel, Thomas Hümmer, Wolfgang Wernsdorfer, Jörg Wrachtrup, Fedor Jelezko, Tommaso Pregnolato, Tim Schröder, Jan Meijer, Cyril Popov, David Hunger. 2026-08-05. High-cooperativity coupling and spin-resolved extinction of tin-vacancy centers in a diamond-like microcavity. https://arxiv.org/abs/2608.04797

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