 As a PhD student, he worked with Prof. Dr. G. Süssmann, mainly supervised by Prof. Marlan O. Scully and Prof. L. M. Narducci.After several years of research in New Mexico, USA, and at Imperial College, London, he worked as a Marie Curie fellow at the University of Innsbruck, Austria.In 1998, he became a SFB junior research group leader at the University of Freiburg, Germany.