1. Centre for Ultrahigh Bandwidth Devices for Optical Systems (CUDOS) and Nonlinear Physics Centre; Research School of Physics and Engineering, Australian National University; Canberra 0200 Australian Capital Territory Australia
2. CUDOS, the Institute of Photonics and Optical Science (IPOS); School of Physics, University of Sydney; New South Wales 2006 Australia
3. Ostbayerische Technische Hochschule Regensburg; Prüfeninger Strasse 58 93049 Regensburg Germany
4. Institute of Applied Physics; Abbe Center of Photonics, Friedrich-Schiller-Universität Jena; Max-Wien-Platz 1 07743 Jena