Three dimensional super-resolution in metamaterial slab lenses
  This letter presents a theoretical and experimental study on the viability of obtaining three dimensional super-resolution (i.e. resolution overcoming the diffraction limit for all directions in space) by means of metamaterial slab lenses. Although the source field cannot be actually reproduced at the back side of the lens with super-resolution in all space directions, the matching capabilities of metamaterial slabs does make it possible the detection of images with three-dimensional super-resolution. This imaging takes place because of the coupling between the evanescent space harmonic components of the field generated at both the source and the detector. 
F. Mesa, R. Marques, M. Freire, J.D. Baena