1. Engineering Research Center for Nanophotonics & Advanced Instrument, Ministry of Education, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, P. R. China
2. Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, P. R. China
3. School of Materials Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, P. R. China