1. CINTRA (CNRS-International-NTU-THALES Research Alliances/UMI 3288), Research Techno Plaza, 50 Nanyang Drive, Border X Block, Level 6, Singapore 637553, Singapore
2. School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
3. Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore
4. Department of Physics, IPB University, Jl Meranti Avenue, Wing S Building, Dramaga Campus of IPB, Bogor 16680, West Java, Indonesia