1. School of Materials Science and Engineering University of New South Wales Sydney NSW 2052 Australia
2. Centre for OptoElectronics and Biophotonics School of Electrical and Electronic Engineering and The Photonics Institute Nanyang Technological University Singapore 639798 Singapore
3. Computer, Electrical, and Mathematical Sciences and Engineering Division King Abdullah University of Science and Technology Thuwal 23955–6900 Saudi Arabia
4. Graduate School of Biomedical Engineering Faculty of Engineering University of New South Wales Sydney NSW 2052 Australia
5. School of Optical and Electronic Information Huazhong University of Science and Technology Wuhan 430074 China
6. Department of Materials Science and Engineering City University of Hong Kong Kowloon Hong Kong SAR 999077 China
7. Department of Metallurgical and Materials Engineering The University of Alabama Tuscaloosa AL 35487 USA