1. College of Physics and Optoelectronics Engineering, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, Shenzhen University, Shenzhen 518060, China
2. Department of Biomedical Engineering, The Chinese University of Hong Kong, Shatin 999077, Hong Kong
3. Department of Bioengineering and COMSET, Clemson University, Clemson, South Carolina 29634, United States