High Harmonic Generation Assisted by Metal Nanostructures and Nanoparticles
We present a review of our theoretical studies of plasmonic field enhanced high harmonic generation in the vicinity of various metallic nanostructures, of rough metallic surfaces or in composites containing a mixture of a noble gas and metallic nanoparticles. First we present a semiclassical model for plasmon-enhanced high-harmonic generation (HHG) taking into account both the field inhomogeneity in the hot spots and electron absorption by the metal surface. Both effects play an important role in the HHG process and lead to the generation of even harmonics and to an twofold increased cutoff. Further alternative arrangements or mechanism for field enhancement enabling higher HHG efficiencies and a lower damage threshold are studied. We simulate field enhancement and HHG spectra in the vicinity of metallic rough surfaces and predict an increased interaction volume of hot spots in the case of grazing incidence of s-polarized pump pulses with an efficiency of plateau harmonics in the range of 10−7. Finally, we investigate low-intensity high-harmonic generation enabled by the plasmonic electric field enhancement in a mixture of a noble gas with metal nanoparticles. In this case HHG efficiencies up to 10−6 are predicted.
KeywordsPump Pulse Field Enhancement Field Inhomogeneity Attosecond Pulse Field Enhancement Factor
A. H. acknowledges financial support from German Research Council, Projekt Hu 1593/2-1.
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