Author Affiliations

Z. D. Xie,^1,2 S.F. Li,¹ Y. X. Gong,^1,3 X. J. Lv,¹ H. B. Lin,¹ P. Xu,¹ Z. L. Wang,¹ G. Zhao,¹ and S. N. Zhu^1,*

¹National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China.

²Mesoscopic Optics and Quantum Electronics Laboratory, University of California Los Angeles, California, CA 90095

³Department of Physics, Southeast University, Nanjing, 211189, People’s Republic of China

^*Corresponding author: zhusn@nju.edu.cn