1. Robert Bosch GmbH, Bosch Research, Postbox 30 02 40, D-70442 Stuttgart, Germany
2. Photonik-Zentrum Kaiserslautern e.V., Kohlenhofstr. 10, D-67633 Kaiserslautern, Germany and Research Center OPTIMAS, University Kaiserslautern, Erwin-Schrödinger-Strasse, D-67663 Kaiserslautern, Germany