Coherence of a charge stabilised tin-vacancy spin in diamond

Abstract

Quantum information processing (QIP) with solid state spin qubits strongly depends on the efficient initialisation of the qubit’s desired charge state. While the negatively charged tin-vacancy (SnV−) centre in diamond has emerged as an excellent platform for realising QIP protocols due to long spin coherence times at liquid helium temperature and lifetime limited optical transitions, its usefulness is severely limited by termination of the fluorescence under resonant excitation. Here, we unveil the underlying charge cycle, potentially applicable to all group IV-vacancy (G4V) centres, and exploit it to demonstrate highly efficient and rapid initialisation of the desired negative charge state of single SnV centres while preserving long term stable optical resonances. In addition to investigating the optical coherence, we all-optically probe the coherence of the ground state spins by means of coherent population trapping and find a spin dephasing time of 5(1) μs. Furthermore, we demonstrate proof-of-principle single shot spin state readout without the necessity of a magnetic field aligned to the symmetry axis of the defect.

Efficiency Optimization of Ge‐V Quantum Emitters in Single‐Crystal Diamond upon Ion Implantation and HPHT Annealing

“…[24,29] Remarkably, the saturation power is considerably reduced when the annealing temperature increases to 1500 °C (1.2 ± 0.5 mW), and it is further decreased to 0.9 ± 0.3 mW upon HPHT treatment. This observation is in line with a recently proposed model for group-IV impurities in diamond [47] relating the charge state stability with the concentration of surrounding lattice divacancies. Divacancy are introduced in the diamond lattice as a byproduct of the ion implantation process performed to fabricate GeV centers.…”

Fast optoelectronic charge state conversion of silicon vacancies in diamond

“…The arguments against optical electron-hole pair creation also hold for the PC in between the electrodes. Instead, we propose that the PC stems from free holes created by optical excitation of a VB electron into a defect level, which is in accord with recent findings on SnV charge state stabilization (13).…”

“…It shows excellent coherence times in the range of 10 ms for electron spins and several hundred milliseconds for nuclear spins at sub-kelvin temperatures and using dynamical decoupling ( 1 , 12 ). The interaction of G4V complexes with proximal impurities or defects in the diamond host can be detrimental for their charge and spectral stability, possibly hindering their use as a spin-photon interface ( 13 ). Unlike nitrogen vacancy (NV) centers, SiVs do not efficiently cycle between two charge states when pumping them with visible light.…”

‘Sawfish’ Photonic Crystal Cavity for Near‐Unity Emitter‐to‐Fiber Interfacing in Quantum Network Applications

“…The SnV − possesses a ZPL at 484.3 THz and a comparably large ground state splitting of 850 GHz rendering it a promising optically-active spin emitter. [25,26] Our spin-photon interface, however, is applicable to a large variety of solid-state quantum emitters. This allows for its integration with nanophotonic devices based on different material platforms.…”