1. Department of Electrical and Computer Engineering, University of Toronto, 35 St. George Street, Toronto, ON M5S 1A4, Canada.
2. ICFO–Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Barcelona 08860, Spain.
3. Department of Chemistry, University of Chicago, Chicago, IL 60637, USA.
4. Chemistry Division, C-PCS, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
5. University of Tokyo, Meguro, Tokyo 153-8505, Japan.
6. Technische Universitat Dortmund, 44221 Dortmund, Germany.