1. School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China
2. Hubei Key Laboratory of Ferro &Piezoelectric Materials and Devices, Faculty of Physics and Electronic Science, Hubei University, Wuhan 430062, China
3. Department of Electrical and Computer Engineering, University of Nebraska—Lincoln, Lincoln, Nebraska 68588-0511, United States
4. Wuhan National Lab for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China