1 Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China.
2 Nanjing Institute of Astronomical Optics and Technology (NIAOT), National Astronomical Observatories, Chinese Academy of Sciences, Nanjing, Jiangsu 210018, People's Republic of China.