Non-local optics of the near field lens

The effects of non-locality on the focusing properties of a thin metal slab, with the real part of the permittivity equal to -1, are evaluated. Non-local effects are introduced by employing the wavenumber-dependent plasmon energy of the hydrodynamic model. Non-locality affects the dispersion of the surface plasmons, the transmissivity of the slab, and hence also its imaging ability. The results of numerical calculations for silver slabs are presented.