1. Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland, Faculty of Chemistry, University of Wroclaw, Joliot-Curie 14 st, 50-383 Wrocław, Poland, and Department of Analytical Chemistry and Applied Spectroscopy, Laser Centre, Vrije Universiteit, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands