1. Division of Physics and Applied Physics; School of Physical and Mathematical Sciences; Nanyang Technological University; 21 Nanyang Link Singapore 637371 Singapore
2. Centre for Disruptive Photonic Technologies; The Photonics Institute; Nanyang Technological University; 50 Nanyang Avenue Singapore 639798 Singapore
3. Institute of Microelectronics; 11 Science Park Road Singapore 117685 Singapore
4. Department of Electrical & Computer Engineering; National University of Singapore; 4 Engineering Drive 3 Singapore 117576 Singapore
5. Center for Intelligent Sensors and MEMS (CISM); National University of Singapore; E6 #05-11F, 5 Engineering Drive 1 Singapore 117608 Singapore