1. School of Materials Science and Engineering; Nanyang Technological University; Singapore 639798 Singapore
2. Centre for Disruptive Photonic Technologies; School of Physics and Mathematics Sciences; Nanyang Technological University; Singapore 637371 Singapore
3. Department of Physics; Boston College; Chestnut Hill MA 02467 USA
4. NOVITAS, Centre for Micro-/Nano-electronics School of Electrical and Electronic Engineering; Nanyang Technological University; Singapore 639798 Singapore
5. CINTRA CNRS/NTU/THALES; UMI 3288; Research Techno Plaza; 50 Nanyang Drive, Border X Block Level 6 Singapore 637553 Singapore
6. National Synchrotron Radiation Laboratory; University of Science and Technology of China; Hefei Anhui 230026 P. R. China
7. Department of Materials Science and Nanoengineering; Rice University; Houston TX 77005 USA
8. Center for Programmable Materials School of Materials Science and Engineering; Nanyang Technological University; Singapore 639798 Singapore