Westermeier, Christian
Cernescu, Adrian
Amarie, Sergiu
Liewald, Clemens
Keilmann, Fritz
Nickel, Bert
Article History
Received: 28 February 2014
Accepted: 13 May 2014
First Online: 11 June 2014
Competing interests
: F.K. is co-founder and scientific advisor of Neaspec GmbH, manufacturer of the s-SNOM setup used in this study. All other authors declare no competing financial interests.