Control of the production of highly charged ions in femtosecond-laser cluster fragmentation

We present the results of optimal-control experiments and calculations on the production of highly charged ions in intense laser field irradiation of large xenon clusters. Experimentally, a spectacular enhancement in the yield of highly charged ions is observed when clusters are subjected to an optimized laser field consisting of a sequence of two pulses, with a time delay that depends on the intensity of the laser and the size of the clusters. Similar results are obtained in optimal-control calculations, which demonstrate that the optimized pulse shape maximizes the efficiency of resonant heating.