1. Department of Biomedical Engineering The Hong Kong Polytechnic University Hong Kong China
2. Department of Applied Physics The Hong Kong Polytechnic University Hong Kong China
3. Department of Electrical and Electronic Engineering Joint Appointment with School of Biomedical Sciences The University of Hong Kong Hong Kong China
4. Key Laboratory of Sensing Technology and Biomedical Instruments (Guangdong Province) School of Biomedical Engineering Sun Yat‐Sen University Guangzhou PR China