1. Photonics Devices and Systems Group Singapore University of Technology and Design 8 Somapah Rd. Singapore 487372 Singapore
2. Electronics and Photonics Department Institute of High Performance Computing Agency for Science, Technology and Research, 1 Fusionopolis Way Singapore 138632 Singapore
3. Institute of Photonics and Optical Science School of Physics The University of Sydney New South Wales 2006 Australia
4. The University of Sydney Nano Institute The University of Sydney New South Wales 2006 Australia
5. Institute of Microelectronics A*STAR, 2 Fusionopolis Way, #08‐02, Innovis Tower Singapore 138634 Singapore