Interference and spectral broadening of higher harmonics of laser radiation in plasma torches containing ions,nanoparticles, and fullerenes |
| |
Authors: | R A Ganeev |
| |
Institution: | (1) Department of Food Science, Cornell University, Ithaca, NY 14853-7201, USA |
| |
Abstract: | We analyze the interference between two processes of higher harmonic generation (HHG) in plasma containing mixtures of different
materials (silver and gold nanoparticles, as well as graphite and boron). We find that, for mixtures and individual ingredients,
the limiting orders of generated harmonics of laser radiation approximately coincide with one another. At the same time, for
plasma torches formed by the ablation of mixtures of materials, the HHG efficiency is considerably reduced compared to the
case of the frequency transformation of laser radiation in individual ingredients of these mixtures as a result of destructive
interference in the former case. We demonstrate a considerable spectral broadening of harmonics generated in laser plasma
with pulses passed through filaments formed in air. In this case, the HHG efficiency increases fourfold (from 3 × 10−6 to 1.2 × 10−5) compared to the case of radiation free of phase and frequency modulation. The generation of harmonics is also observed upon
the passage of 120-fs laser pulses through plasma containing fullerenes. In this case, the limiting value of generated harmonics
achieves the 33rd order. The efficiency of harmonics in fullerene plasma considerably exceeds a similar process in silver
plasma. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|