Cluster-size distribution effects in laser-cluster interaction experiments

Measurements of the ion energies resulting from irradiation of Xe clusters with 800 nm laser pulses in the intensity range 2×10¹⁵--5×10¹⁶Wcm^-2 are reported. The maximum ion energies as a function of mean cluster size and laser intensity were determined at a constant laser-pulse duration of {~}65 and 90 fs respectively---a factor of 3 shorter than previous scaling studies. Comparisons made between experimental results and numerical simulations of the laser-cluster interaction have shown the importance of considering a distribution of cluster sizes. We have found the addition of a log-normal size distribution to simulations using the nanoplasma model of cluster excitation improves the agreement between numerical and experimental data.