1. Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems; School of Physics; Beijing Institute of Technology; Beijing 100081 P. R. China
2. Micro-nano Center; Beijing Institute of Technology; Beijing 100081 P. R. China
3. Department of Chemical Engineering & Material Science; Yuan Ze University; Taiwan
4. Department of Physics; National Taiwan University; Taipei 106 Taiwan
5. Western Seoul Center; Korea Basic Science Institute; Seoul 03579 Republic of Korea
6. Chuncheon Center; Korea Basic Science Institute; Chuncheon 24341 Republic of Korea
7. Division of Industrial Metrology; Korea Research Institute of Standards and Science; Daejeon 305-340 Republic of Korea
8. Institute of Plasma Physics; Chinese Academy of Sciences; Hefei 230031 P. R. China