Theory of plasmon-enhanced high-order harmonic generation in the vicinity of metal nanostructures in noble gases

Max Born Institute of Nonlinear Optics and Short Pulse Spectroscopy, Max Born Str 2a, D-12489 Berlin, Germany(Dated: September 22, 2010)We present a semiclassical model for plasmon-enhanced high-harmonic generation (HHG) in thevicinity of metal nanostructures. We show that both the inhomogeneity of the enhanced local fieldsand electron absorption by the metal surface play an important role in the HHG process and leadto the generation of even harmonics and to a significantly increased cutoff. For the examples ofsilver-coated nanocones and bowtie antennas we predict that the required intensity reduces by upto three orders of magnitudes and the HHG cutoff increases by more than a factor of two. Thestudy of the enhanced high-harmonic generation is connected with a finite-element simulation of theelectric field enhancement due to the excitation of the plasmonic modes.