Comparison of high-order harmonic generation from various cluster- and ion-containing laser plasmas

摘要

We apply the technique of high-order harmonic generation from laser-produced plasma to investigate the harmonics generated from a medium that contains an abundance of micron- and sub-micron-sized structures. We compare harmonic efficiencies from the plasma plumes containing silver nanoparticles (110 nm spherical), colloidal silver (blocks of 100-1000 nm), aluminium particles (2-14 μm) and copper oxide nanorods (50 nm thick, few μm long). We compare these results with those obtained using solid bulk targets. We show that plasma media that are abundant with small-sized structures have higher harmonic generation efficiencies. Results also reveal that the harmonic cutoff is not affected significantly by using the nanostructured targets. The maximum conversion efficiency we observe is 4 x 10~(-5) using silver nanoparticles.