EUV and fast ion emission from cryogenic liquid jet target laser-generatedplasma

A liquid jet of either nitrogen or argon of 20 mum diameter was exposed to intense laser fields with pulse durations between 70 fs and 250 ps, leading to intensities of 10(16) W cm(-2) and 10(13) W cm(-2), respectively. The e mission of extreme UV light and soft X-rays shows the characteristic lines of hydrogen-like nitrogen and carbon-like argon. For nitrogen the emitted p hoton flux at 250 ps was about two orders of magnitude higher than for 70 f s pulses. A weak dependence on the laser polarization with respect to the l iquid jet axis was found. The kinetic energy of the emitted ions easily exc eeded 100 keV for nitrogen and 200 keV for argon for a pulse duration close to 2 ps.