1. University of California, Beckman Laser Institute, 1002 Health Sciences Road East, Irvine, California 92612bSichuan University, Department of Opto-Electronics, No.24 South Section 1st, Yihuan Road, Chengdu 610065, China
2. University of California, Beckman Laser Institute, 1002 Health Sciences Road East, Irvine, California 92612cUniversity of California, Department of Biomedical Engineering, 3120 Natural Sciences II, Irvine, California 92697-2715
3. Sichuan University, Department of Opto-Electronics, No.24 South Section 1st, Yihuan Road, Chengdu 610065, China