High-order harmonic generation in large molecules and atomic clusters

Summary form only given. Our recent studies of the soft x-rays produced from the intense irradiation of large atomic clusters (100-10,000 atoms per cluster) suggested that these clusters, which form in the adiabatic expansion of a gas jet into vacuum, may be a unique medium for high-order harmonic generation. We have studied the characteristics of the harmonic generation from these clusters and found that, unlike small molecules, clusters can dramatically affect the behavior of the high-order harmonics. We have carefully compared the harmonics generated in single atoms with those produced from clusters with intense, 100-fs laser pulses.