1. School of Optoelectronic and Communication Engineering, Xiamen University of Technology, Xiamen 361024, China
2. Fujian Key Laboratory of Optoelectronic Technology and Devices, Xiamen University of Technology, Xiamen 361024, China
3. Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
4. Otto von Guericke University Magdeburg, Institute of Experimental Physics, Universitätsplatz 2, 39016 Magdeburg, Germany