Generation of higher harmonics of femtosecond radiation in clusters

The frequency conversion of laser radiation in cluster media is studied by the method of laser ablation of surfaces containing different nanoparticles (Cr₂O₃, In₂O₃, Ag, Sn, Au, and Cu). Using plasma that contains In₂O₃ nanoparticles as an example, it is shown that the resonant amplification of certain harmonics in the plateau-like distribution of harmonics, which is characteristic of the ablation of certain solid targets, is considerably modified in the case of targets that contain cluster formations. An increase in the conversion efficiency to harmonics in nanoparticle-containing media is discussed. In order to determine optimal characteristics of laser plasma with nanoparticles, their morphology is studied before and after laser ablation.