Effect of losses and dispersion on the focusing properties of left-handed media

By means of an analysis of the field radiated by a point source placed in front of an infinite left-handed slab, the effect off losses and dispersion on the focusing properties of continuous left-handed media are analyzed. It is shown that subwavelength focusing of point-like quasi-monochromatic sources can be achieved by using physical left-handed slabs, provided some conditions are fulfilled. These conditions tire qualitative and quantitatively analyzed. Numerical examples that show the accuracy of this analysis are provided. Finally, the proposed electromagnetic analysis and the geometrical Veselago's demonstration of over-wavelength focusing by left-handed slabs are found to be mutually consistent. (C) 2004 Wiley Periodicals, Inc.