1. Laboratory of Photonics and Interfaces, École Polytechnique Fédérale de Lausanne, Lausanne 1015, Switzerland
2. Laboratory of Magnetic Resonance, École Polytechnique Fédérale de Lausanne, Lausanne 1015, Switzerland
3. Center for Nanophotonics, AMOLF, Amsterdam 1009 DB, The Netherlands
4. Laboratory of Organic Chemistry, ETH Zurich, Zurich 8093, Switzerland