1. State Key Laboratory of Advanced Optical Communication Systems and NetworksSchool of Physics and AstronomyKey Laboratory for Thin Film and Microfabrication Technology of the Ministry of EducationShanghai Jiao Tong University 800 Dongchuan Rd. Shanghai 200240 China
2. Key Laboratory of Infrared Imaging Materials and DetectorsShanghai Institute of Technical PhysicsChinese Academy of Sciences 500 Yutian Rd. Shanghai 200083 China