1. Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education) Shanghai Engineering Research Centre of Ultra Precision Optical Manufacturing Department of Optical Science and Engineering School of Information Science and Technology Fudan University Shanghai 200433 P. R. China
2. Institute for Electric Light Sources Department of Light Sources and Illuminating Engineering School of Information Science and Technology Fudan University Shanghai 200433 P. R. China
3. Yiwu Research Institute of Fudan University Chengbei Road Yiwu City 322000 P. R. China