Enhancement of the line X-ray emission from iron plasma is investigated by simulating laser irradiation of both porous and solid targets. Spectral line intensities are calculated for selected lines of the iron plasma within the extreme ultra-violet lithography wavelength range 13.3–13.7 nm. The calculations show that X-ray yield in porous targets can be enhanced significantly in comparison with solid density targets. The results also show that for specified conditions of the driving laser, there are optimums conditions of the porous target in which maximum yield can be obtained.

The absolutely calibrated K-shell spectra emitted from short-living aluminum plasmas at laser intensities of 5 × 1015–4 × 1018 W/cm2 are reported. The experiments performed with the constant energy, variable-length laser pulses (1.5 ps–1 ns) are modeled by the one-dimensional (1D) hydrodynamics code, including nonlinear resonance absorption of the laser radiation, fast electron acceleration, and energy transfer into the target. The characteristic features of the measured and the postprocessed spectra are outlined. The spatial and temporal profiles of the emitted spectra are presented; the scaling rules for the conversion efficiency of the laser radiation into the line X-ray emission are discussed.