S. Krapick,1,* M. S. Stefszky,1 M. Jachura,1,2 B. Brecht,1 M. Avenhaus,1,3 and C. Silberhorn1,3 1Department of Physics, University of Paderborn, Warburger Str. 100, 33098 Paderborn, Germany 2Faculty of Physics, University of Warsaw, Hoża 69, 00-681 Warsaw, Poland 3Max-Planck-Institute for the Science of Light, Günther-Scharowsky-Str. 1, 91058 Erlangen, Germany (Received 25 September 2013; publi...