Generation of ultrafast terahertz radiation pulses on metallic nanostructured surfaces.
A resonant "incoherent" rectification process is presented relying on the excitation of surface plasmons on a nanostructured metal surface. Excitation of gold and silver films with 800-nm femtosecond laser pulses results in the emission of terahertz radiation with an angle-dependent efficiency and an approximately third-order power dependence. It is shown that the source of this terahertz pulse generation is the surface-plasmon-assisted multiphoton ionization and ponderomotive acceleration in the evanescent field of the surface plasmon. Simple models are used to understand the forces and dynamics near the surface.
Welsh
Gregor H
GH
Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG, Scotland, UK. g.welsh@strath.ac.uk
Wynne
Klaas
K
D003198:Computer Simulation; D006046:Gold / Q000737:chemistry*; D007259:Infrared Rays; D008872:Microwaves; D008956:Models, Chemical; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D012834:Silver / Q000737:chemistry*; D020349:Surface Plasmon Resonance / Q000379:methods*
D012834:Silver; D006046:Gold