1. State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, International Center of Future Science, Jilin University, 2699 Qianjin Street, Changchun130012, China
2. Department of Electrical Engineering, The Pennsylvania State University, University Park, Pennsylvania16802, United States
3. Institute of Quantum Optics, Leibniz Universität Hannover, 30167Hannover, Germany