1. Department of Physics and Technology, University of Bergen, Allégaten 55, 5007 Bergen, Norway
2. Lace Lithography AS, Allégaten 55, 5007 Bergen, Norway
3. Department of Physics and Astronomy, Living Systems Institute, University of Exeter, EX4 4QD, Exeter, UK
4. Freiburg Center for Interactive Materials and Bioinspired Technologies (FIT), University of Freiburg, D-79110 Freiburg, Germany
5. Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg, Germany