[1] E China Normal Univ, Minist Educ, Lab Polar Mat & Devices, Shanghai 200241, Peoples R China
[2] Chinese Acad Sci, Shanghai Inst Tech Phys, Natl Lab Infrared Phys, Shanghai 200083, Peoples R China
[3] Chinese Acad Sci, Shanghai Inst Tech Phys, Res Ctr Adv Mat & Devices, Shanghai 200083, Peoples R China