1. Department of Electrical and Computer Engineering, National University of Singapore, 117576 Singapore
2. NUS Suzhou Research Institute (NUSRI), Suzhou, Industrial Park, Suzhou 215123, People's Republic of China
3. Center for Intelligent Sensors and MEMS (CISM), National University of Singapore, 117608 Singapore
4. Division of Physics and Applied Physics, Centre for Disruptive Photonic Technologies, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371 Singapore
5. Department of Biomedical Engineering, National University of Singapore, 117583 Singapore
6. Graduate School for Integrative Sciences and Engineering, National University of Singapore, 117456 Singapore