Photoelectron emission control with polarized light in plasmonic metal random structures

We report on the possibility of switching the emission rate of photoelectrons by polarization changes in the plasmon excitation light. Photoelectron emission is strongly enhanced in the near-field of localized surface plasmons and occurs from areas with typical diameters of 20-70 nm. The underlying physical process involves excitation of a localized surface plasmon polariton with a femtosecond laser pulse, and a subsequent multi-photon photoemission process. The non-linearity of this process leads to a sharp polarization dependence that allows efficient switching of the emission. We demonstrate that a 90 degrees polarization change can result in on/off ratios of similar to 100 for electron emission. (C) 2011 American Institute of Physics. [doi:10.1063/1.3615783]