[1] Univ Elect Sci & Technol China, Sch Optoelect Sci & Engn, Chengdu 610054, Peoples R China
[2] Nanyang Technol Univ, Sch Elect & Elect Engn, Ctr OptoElect & Biophoton, Singapore 639798, Singapore
[3] Nanyang Technol Univ, Sch Phys & Math Sci, Singapore 639798, Singapore
[4] Nanyang Technol Univ, Photon Inst, Singapore 639798, Singapore
[5] Univ Elect Sci & Technol China, Yangtze Delta Reg Inst Huzhou, Huzhou 313001, Peoples R China