Laser heating of condensed noble gases: EUV source efficiency considerations

This study describes experiments designed to assist in finding conditions for enhancing source efficiency in condensed Xe spray jet targets. A recent experimental scheme utilizes a pump-probe design where the laser-droplet plasma is diagnosed with an X-ray detector, a grazing incidence EUV spectrometer, and visible imaging diagnostics. The idea of the experiment is to heat the droplet with the pump pulse, producing the ion stages responsible for the EUV emission of interest. The variably delayed probe pulse further heats this droplet plasma, and the additional EUV emission contributed by that pulse is plotted versus the pump-probe delay. The inference from this measurement is the degree to which a pulse of fixed energy but variable width can sustainably produce efficient EUV emission.