1. Department of Chemistry, Hong Kong Baptist University, Waterloo Road, Kowloon Tong 999077, Hong Kong S. A. R., P. R. China
2. CAS Key Laboratory of Microscale Magnetic Resonance, School of Physical Sciences, University of Science and Technology of China, Hefei 230026, P. R. China
3. CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, P. R. China
4. Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon 999077, Hong Kong S. A. R., P. R. China