1. Institute of Physical Chemistry and Electrochemistry; Leibniz University Hannover; Callinstr. 3 A D-30167 Hannover Germany
2. Fraunhofer Institute for Laser Technology; Steinbachstr. 15 D-52074 Aachen Germany
3. LPKF Laser & Electronics AG; Osteriede 7 D-30827 Garbsen Germany