[1] Zhejiang Univ, State Key Lab Silicon Mat, Hangzhou 310027, Peoples R China
[2] Arizona State Univ, Dept Appl Phys, Tempe, AZ 85287 USA
[3] Hong Kong Polytech Univ, Dept Appl Phys, Kowloon, Hong Kong, Peoples R China
[4] Chinese Acad Sci, State Key Lab High Field Laser Phys, Shanghai Inst Opt & Fine Mech, Beijing 100864, Peoples R China