1. Centre for Disruptive
Photonic Technologies, School of Physical and Mathematical Sciences
and The Photonics Institute, Nanyang Technological University, Singapore 637371
2. School of Materials Science and Engineering, Nanyang Technological University, 639798, Singapore
3. Optoelectronics Research Centre and Centre for Photonic Metamaterials, University of Southampton, Southampton SO17 1BJ, United Kingdom
4. Division of Physics and Applied Physics,
School of Physical and Mathematical Sciences, Nanyang Technological University, 637371, Singapore