[1
]Department of Physics and Technology, University of Bergen, P.O. Box 7803, NO-5020
Bergen, Norway
[2
]Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, NL-9747AG
Groningen, The Netherlands
[3
]Christian Michelsen Research AS, P.O. Box 6031, NO-5892 Bergen, Norway
[4
]ProAnalysis AS, P.O. Box 2619, NO-5836 Bergen, Norway