[Zhang, Gui; Wang, Xin-Jun; He, Meng-Dong; Li, Jian-Bo] Cent South Univ Forestry & Technol, Inst Math & Phys, Changsha 410004, Hunan, Peoples R China.
[Liu, Jian-Qiang] Jiujiang Univ, Coll Sci, Jiujiang 332005, Peoples R China.
[Huang, Zhen-Rong; Wang, Lingling] Hunan Univ, Key Lab Micronano Optoelect Devices, Minist Educ, Changsha 410082, Hunan, Peoples R China.
[Chen, Xiaoshuang] Chinese Acad Sci, Shanghai Inst Tech Phys, Natl Lab Infrared Phys, Shanghai 200083, Peoples R China.