Manuscript received December 26, 2018; accepted January 17, 2019. Date of publication January 31, 2019; date of current version December 11, 2019. This work was supported in part by the National Natural Science Foundation of China under Grant 61771209 and Grant 61871209, in part by the Natural Science Foundation of Hunan Province under Grant 2017JJ3275 and Grant 2018JJ2333, in part by NSERC, and in part by the Hunan Province Key Laboratory for Ultra-Fast Micro/Nano Technology and Advanced Laser Manufacture under Grant 2018TP1041. (Corresponding author: Xianjun Deng.) L. Dai and B. Wang are with the School of Electronic, Information and Communications, Huazhong University of Science and Technology, Wuhan 430074, China.
