title: All-optical coherent population trapping with defect spin ensembles in silicon carbide.
abstract: Divacancy defects in silicon carbide have long-lived electronic spin states and sharp optical transitions. Because of the various polytypes of SiC, hundreds of unique divacancies exist, many with spin properties comparable to the nitrogen-vacancy center in diamond. If ensembles of such spins can be all-optically manipulated, they make compelling candidate systems for quantum-enhanced memory, communication, and sensing applications. We report here direct all-optical addressing of basal plane-oriented divacancy spins in 4H-SiC. By means of magneto-spectroscopy, we fully identify the spin triplet structure of both the ground and the excited state, and use this for tuning of transition dipole moments between particular spin levels. We also identify a role for relaxation via intersystem crossing. Building on these results, we demonstrate coherent population trapping -a key effect for quantum state transfer between spins and photons- for divacancy sub-ensembles along particular crystal axes. These results, combined with the flexibility of SiC polytypes and device processing, put SiC at the forefront of quantum information science in the solid state.
authors.affiliation: Zernike Institute for Advanced Materials, University of Groningen, NL-9747AG Groningen, The Netherlands.
authors.forename: Olger V
authors.initials: OV
authors.lastname: Zwier
authors.affiliation: Zernike Institute for Advanced Materials, University of Groningen, NL-9747AG Groningen, The Netherlands.
authors.forename: Danny
authors.initials: D
authors.lastname: O'Shea
authors.affiliation: Zernike Institute for Advanced Materials, University of Groningen, NL-9747AG Groningen, The Netherlands.
authors.forename: Alexander R
authors.initials: AR
authors.lastname: Onur
authors.affiliation: Zernike Institute for Advanced Materials, University of Groningen, NL-9747AG Groningen, The Netherlands.
authors.forename: Caspar H
authors.initials: CH
authors.lastname: van der Wal