  We study theoretically the photoelectron emission in noble gases using
plasmonic enhanced near-fields. We demonstrate that these fields have a great
potential to generate high energy electrons by direct mid-infrared laser pulses
of the current femtosecond oscillator. Typically, these fields appear in the
surroundings of plasmonic nanostructures, having different geometrical shape
such as bow-ties, metallic waveguides, metal nanoparticles and nanotips, when
illuminated by a short laser pulse. In here, we consider metal nanospheres, in
which the spatial decay of the near-field of the isolated nanoparticle can be
approximated by an exponential function according to recent attosecond
streaking measurements. We establish that the strong nonhomogeneous character
of the enhanced near-field plays an important role in the above threshold
ionization (ATI) process and leads to a significant extension in the
photoelectron spectra. In this work, we employ the time dependent Schr\"odinger
equation in reduced dimensions to calculate the photoelectron emission of xenon
atoms in such enhanced near-field. Our findings are supported by classical
calculations.
