Coherence of a charge stabilised tin-vacancy spin in diamond
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2022-03-07 |
| Journal | Zenodo (CERN European Organization for Nuclear Research) |
| Authors | Johannes Gƶrlitz, Dennis Herrmann, Philipp Fuchs, Takayuki Iwasaki, Takashi Taniguchi |
| Institutions | Saarland University, University Hospitals of the Ruhr-University of Bochum |
Abstract
Section titled āAbstractāColour centres in diamond have recently emerged as competitive platforms in the field of QIP . In particular the G4V centres combine long spin coherence times with favourable optical properties such as large Debye-Waller factors and transform limited resonance linewidths. While the large spectral diffusion for the nitrogen vacancy centre in diamond is to be expected, G4V centres should be protected by their inversion symmetry from large first order Stark shifts. Nevertheless, spectral diffusion due to second order effects is still common to impose a strong limit on the usefulness in quantum information and simulation applications, which makes overcoming these spectral instabilities a crucial task. The origin of the unstable resonance lines is oftentimes introduced by fluctuating charges resulting from impurities or lattice defects in the vicinity of the colour centre. Furthermore, these environmental impurities and defects can act as charge traps or electron donors leading to an ill-defined charge state of the emitter. Among the G4V centres, the SnV - centre shows great promise in terms of spin coherence at easily accessible liquid helium temperatures and lifetime limited optical transitions. Unfortunately, its potential for application in QIP is suffering strongly from the termination of fluorescence under resonant excitation. In this work, we investigate the mechanism leading to the charge instability of a single SnV - centre in diamond and find it to be a single photon process. We furthermore fully explore the charge cycle of the SnV centre and use it to implement a straightforward, highly efficient initialisation of the negative charge state while preserving longterm stablility of dipole allowed optical transitions. We find that the principle of this charge cycle can also directly be applied to other G4V centres for efficient control of their charge state. Subsequently, we probe the coherence of the charge stabilised SnV - centre by an all-optical coherent population trapping (CPT) scheme, yielding a spin dephasing time of the ground state of T<sub>2</sub><sup> *</sup> = 5Āµs . By employing a proof-of-principle single shot readout protocol, we demonstrate the presence of highly cycling optical transitions even in the case of large angles between the magnetic field and the symmetry axis of the defect.