1. Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
2. School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, Hubei, P. R. China
3. School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 637371, Singapore
4. State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, P. R. China
5. Frontier Science Center for Quantum Information, Beijing 100084, P. R. China
6. Collaborative Innovation Center of Quantum Matter, Beijing 100871, P. R. China
7. Beijing Academy of Quantum Information Sciences, Beijing 100193, P. R. China