a d n S

204 nm are produced by a Ti:sapphire (Ti:S) oscilla-tor cavi seeded N by the The osc the Ti:S mode of ing sche delivers 15–24 ns and a 10-Hz repetition rate and in a band-width of 50 MHz. The pulse duration is physically determined by the rate of stimulated emission in Ti:S and is a function of pump power and of the ref lectivity of the output coupler, which for these measurements was taken at 90%. Although we demonstrated that it is possible to amplify the output pulses to a level Fig. 1. Layout of the laser system delivering tunable-wavelength Fourier-transform-limited pulses in the range 197–204 nm and the CRD setup. Osc., digital storage oscilloscope; PMT, photomultiplier tube; PG, pressure gauge; NV, needle valve; F, aerosol f ilter.ty that is pumped by the green output of a d:YAG Q-switched laser and injection-seeded continuous-wave (cw) output of a Ti:S laser. illator cavity contains no other elements than crystal; its cavity length is stabilized to the the cw laser via the Hänsch–Couillaud lock-me. On pumping at 10 mJpulse the cavity near-IR pulses at 1 mJpulse, at a duration ofDeep-ultraviolet cavit