1. Nanophotonics and Metrology Laboratory
2. École Polytechnique Fédérale de Lausanne
3. CH-1015 Lausanne
4. Switzerland
5. Centre for Nanostructured Media
6. School of Maths and Physics
7. Queen's University
8. Belfast BT7 1NN
9. UK
10. Electrical Division Building
11. Engineering Department
12. Cambridge University
13. Cambridge CB3 0FA