1. Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria 3086, Australia
2. Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
3. School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia
4. ARC Centre of Excellence in Exciton Science, Department of Chemical Engineering, Monash University, Clayton, Victoria 3800, Australia
5. Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168, Australia
6. Institut für Technische Physik, Universität Erlangen, Staudtstrasse 1, Erlangen D-91058, Germany
7. Centre for Quantum Computation and Communication Technology, School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia