1. Institute for Advanced Materials and Hubei Key Laboratory of Pollutant Analysis & Reuse Technology, Hubei Normal University, Huangshi 435002, P. R. China
2. School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, U.K.
3. College of Electronic Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210023, P. R. China
4. National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, P. R. China
5. Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, P. R. China