1. Center for Intelligent Sensors and MEMS, Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore, 117576
2. NUS Suzhou Research Institute (NUSRI), Suzhou, Industrial Park, Suzhou 215123, People's Republic of China
3. Division of Physics and Applied Physics, Centre for Disruptive Photonic Technologies, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371
4. Institute of Microelectronics, Agency for Science, Research, and Technology (A*STAR), 11 Science Park Road, Singapore, 117685
5. Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 119077