1. ICFO - Institut de Ciencies Fotoniques, Mediterranean Technology Park, 08860 Castelldefels (Barcelona),
Spain
2. Department of Physics
and Nanotechnology, Aalborg University,
Skjernvej 4A. DK-9220, Aalborg, Denmark
3. NanoBiotechnology Group, Department of Health
Science and Technology, Aalborg University, Fredrik Bajers vej 7, DK-9220, Aalborg, Denmark
4. International Iberian Nanotechnology Laboratory (INL), P-4715-310 Braga, Portugal
5. ICREA - Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain