Towards High-Order Harmonic Generation in Laser Produced Plasmas

State-of-the-art nanolithography machines use extreme ultraviolet (EUV) light, emitted by a laser-produced plasma (LPP) in tin, to print ever smaller structures on silicon wafers. The EUV emission characteristics of this LPP depend strongly on the plasma properties, which are conditioned by the laser pulse that generates the plasma. Therefore, it is useful to understand how different laser parameters affect the spatial and temporal properties of the formed plasma. For this purpose, we aim to investigate the temporal and spatial properties of laser produced plasmas from various materials under different plasma formation conditions by means of high-order harmonic generation (HHG) in the plasma of interest. Multiple experiments with HHG in various laser plasmas have been performed [1]. Such experiments have shown high cutoff energies and in some cases also high conversion efficiencies of single resonant harmonics, depending on the phase matching conditions and plasma species. Therefore we expect differences in HHG spectra depending on the plasma formation conditions.

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