1. Department of Optical DevicesLe Quy Don Technical University 236 Hoang Quoc Viet Hanoi 100000 Vietnam
2. Division of Physics and Applied PhysicsSchool of Physical and Mathematical SciencesNanyang Technological University Singapore 637371 Singapore
3. Centre for Disruptive Photonic Technologies (CDPT)Nanyang Technological University Singapore 637371 Singapore
4. MajuLabCNRS‐UCA‐SU‐NUS‐NTU International Joint Research Unit Singapore 637371 Singapore