FEMTOSECOND VACUUM-ULTRAVIOLET PULSE MEASUREMENT BY FIELD-IONIZATION DYNAMICS

Three techniques are demonstrated for measuring femtosecond pulses fro m the deep vacuum ultraviolet to the visible based on the ionization d ynamics of optical-field-ionized plasmas. A probe pulse propagates thr ough a plasma generated by an intense femtosecond KrF excimer laser-pu mp pulse. Ionization-induced defocussing or collisional absorption yie ld a cross-correlation measurement of the probe pulse. Ionization-indu ced spectral blue shifting of the probe can give an upper limit for th e probe pulse duration.