A subpicosecond deep UV-laser source: Two-photon two-color ionization pump-probe experiments in the VUV

Summary form only given. It is well established, that the generation of higher harmonics, plasma sources or higher order wave-mixing schemes provide ultrashort VUV-pulses in a broad spectral range on ultrashort timescales. Our scheme, the two-photon near-resonant four-wave difference-frequency mixing (FWDFM) in a noble gas has the unique property to generate continuously tunable subpicosecond VUV pulses down to the 100 nm wavelength region on a high pulse energy level which is sufficient for nearly every common spectroscopic technique. The aim of the present work is to characterize the obtained sub-picosecond VUV-pulses especially at 155 nm, to discuss the actual limitations of our setup and to demonstrate the intrinsic potential of our source by investigating small molecular systems of interest (toluene, CS/sub 2/, NO, ...).