1. Photonics
and Optoelectronics Group, Department of Physics and Center for Nanoscience
(CeNS), Ludwig-Maximilians-Universität (LMU), Amalienstaße
54, 80799 Munich, Germany
2. Nanosystems Initiative Munich (NIM), Schellingstraße 4, 80799 Munich, Germany
3. Soft Condensed Matter
Group, Department of Physics and Center for Nanoscience (CeNS), Ludwig-Maximilians-Universität (LMU), Geschwister-Scholl-Platz 1, 80539 Munich, Germany