1. School of Materials Science and Engineering, 5 Zhongguancun South Street, Beijing Institute of Technology, Beijing 100081, China
2. Department of Materials Science and Engineering, 184 College Street, University of Toronto, Toronto, Ontario M5S 3E4, Canada
3. Department of Chemistry, University of Victoria, P.O. Box 3065, Victoria, British Columbia V8W 3V6, Canada
4. Department of Chemistry, Institute for Optical Sciences, and Centre for Quantum Information and Quantum Control, 80 St. George Street, University of Toronto, Toronto, Ontario M5S 3E4, Canada