1. Department of Materials Science and Engineering, and Center for Functional Photonics (CFP), City University of Hong Kong, 83 Tat Chee Avenue, Kowloon 999077, Hong Kong S.A.R., P. R. China
2. Department of Chemistry and Center of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong, Kowloon 999077, Hong Kong S.A.R., P. R. China
3. Center of Information Optical Technologies, ITMO University, Saint Petersburg 197101, Russia
4. Shenzhen Research Institute, City University of Hong Kong, Shenzhen 518057, P. R. China