Department of Physics, Tampere University of Technology, Tampere, Finland.|VTT Technical Research Center of Finland, Espoo, Finland.|Department of Physics, Tampere University of Technology, Tampere, Finland.|Department of Physics, Tampere University of Technology, Tampere, Finland.|Department of Physics, Tampere University of Technology, Tampere, Finland.|Department of Physics, Tampere University of Technology, Tampere, Finland, MEMPHYS - Centre for Biomembrane Physics, University of Southern Denmark, Odense, Denmark.