1. The Institute of Technological SciencesWuhan University Wuhan 430072 China
2. School of Optical and Electronic InformationHuazhong University of Science and Technology Wuhan Hubei 430074 China
3. Wuhan National Laboratory for Optoelectronics Wuhan Hubei 430074 China
4. School of Power and Mechanical EngineeringWuhan University Wuhan 430072 China
5. Brick Nanotechnology CenterPurdue University West Lafayette IN 47906 USA
6. School of Industrial EngineeringPurdue University West Lafayette IN 47906 USA