1. Centre for Optical and Electromagnetic Research
2. South China Academy of Advanced Optoelectronics
3. South China Normal University
4. 510006 Guangzhou
5. China
6. Department of Theoretical Chemistry and Biology
7. KTH Royal Institute of Technology
8. SE-106 91 Stockholm
9. Sweden
10. College of Biophotonics
11. 510631 Guangzhou
12. P. R. China
13. Experimental Biomolecular Physics
14. Department of Applied Physics
15. Stockholm