1. Beijing Key Laboratory of Optoelectronic Measurement Technology, Beijing Information Science and Technology University, Beijing 100192, China
2. Beckman Laser Institute, University of California, Irvine, Irvine, California 92612, USA
3. Key Laboratory of Nondestructive Test (Ministry of Education), Nanchang Hangkong University, Nanchang 330063, China
4. Department of Biomedical Engineering, University of California, Irvine, Irvine, California 92697, USA