On the effect of rear-surface dielectric coatings on laser-driven proton acceleration

Laser-driven ion acceleration has been experimentally investigated by irradiating, with tightly focused femtosecond laser pulses at 5 x 10(19) W/cm(2), thin metal foils, which have been back-coated with a mu m thick dielectric layer. The observation we report shows the production of MeV proton bunches with an unexpected highly uniform spatial cross section. (C) 2009 American Institute of Physics.