Surface-plasmon-enhanced MeV ions from femtosecond laser irradiated, periodically modulated surfaces

Abstract

Enhanced emission of high energy ions is measured from sub-wavelength metallic grating targets under irradiation by intense (10 15-10 16 W cm -2), p-polarized, 50 fs, 800 nm laser pulses. The maximum ion energy is 55 higher and the ion flux is 60 higher for the modulated surface in comparison with polished surfaces of the same atomic composition. The ion emission, a result of enhanced light coupling and hot electron production in the grating targets, is correlated with enhancement in hard x-ray bremsstrahlung emission. The results are well reproduced by particle-in-cell simulations. The study reveals that the enhanced laser coupling by surface plasmon excitation on metallic gratings is directly responsible for the enhancement of ion energies. © 2012 American Institute of Physics.