1 MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi’an Jiaotong University, Xi’an 710049, China
2 Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
3 Shaanxi Key Laboratory of Quantum Information and Quantum Optoelectronic Devices, School of Physics, Xi’an Jiaotong University, Xi’an 710049, China
4 State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics, and Physics, Chinese Academy of Sciences, Changchun 130033, China
5 e-mail: chengwei.qiu@nus.edu.sg
6 e-mail: zhangpei@mail.ustc.edu.cn