Hot ion generation from nanostructured surfaces under intense, femtosecond irradiation

We present the effect of a nanostructured surface on the emission of ions and electrons from intense (5-36 Petwatt per sq.cm) femtosecond laser produced plasmas. Electrons from optically polished copper targets coated with copper nanoparticles (CuNP) are observed to be hotter than those from uncoated polished targets. A nearly two-fold enhancement is observed for ions in the range 14-74 keV, while ion yield decreases by a factor of 2 in the 74-2000 keV range. The total ion yields measured using a large area Faraday cup are more from CuNP targets than those from polished Cu targets, indicating increased ion beam divergence due to surface modulations.