Microwave Spin Control of a Tin-Vacancy Qubit in Diamond

The negatively charged tin-vacancy (SnV–) center in diamond is a promising solid-state qubit for applications in quantum networking due to its high quantum efficiency, strong zero phonon emission, and reduced sensitivity to electrical noise. The SnV– has a large spin-orbit coupling, which allows for long spin lifetimes at elevated temperatures, but unfortunately suppresses the magnetic dipole transitions desired for quantum control. Here, by use of a naturally strained center, we overcome this limitation and achieve high-fidelity microwave spin control. We demonstrate a π-pulse fidelity of up to 99.51 ± 0.03 % and a Hahn-echo coherence time of $T$$^{echo}_{2}$ = 170.0 ± 2.8 μs, both the highest yet reported for SnV– platform. This performance comes without compromise to optical stability, and is demonstrated at 1.7 K where ample cooling power is available to mitigate drive-induced heating. These results pave the way for SnV– spins to be used as a building block for future quantum technologies.