1. Department of Materials Science and Engineering, and Center for Functional Photonics (CFP), City University of Hong Kong, Hong Kong SAR, 999077People’s Republic of China
2. Department of Physics, Hong Kong University of Science and Technology, Hong Kong SAR, 999077People’s Republic of China
3. Institute of Automation and Control Processes, Far-Eastern Branch of Russian Academy of Sciences, Vladivostok, 690041Russia