1. College of Electronic and Optical Engineering and College of Microelectronics, Nanjing University of Posts and Telecommunications, Nanjing 210026, People’s Republic of China
2. Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, People’s Republic of China
3. State Key Laboratory of Mechanics and Control of Mechanical Structures, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, People’s Republic of China