Application of carbon cluster-contained extended plasmas for the high-order harmonic generation of ultrashort pulses

We present the studies of the high-order harmonic generation of 802-nm, 64-fs pulses in the extended plasmas contained the carbon-based clusters (fullerenes, nanofibers, nanoparticles, and nanotubes). Our studies show that the 11th–19th harmonics in the 15–33 eV range may originate from the low-sized nanoparticles produced during ablation of large clusters and agglomerates. The conversion efficiency of the 11th harmonic generated from the 5-mm-long fullerene plasma was estimated to be 2 × 10−5.