Sub-wavelength focusing and negative refraction along positive-index and negative-index plasmonic nano-transmission lines and nano-layers

Following our recent works on the concept of plasmonic nano-inductors and nano-capacitors and related complex circuits, here we analyze the possibility of designing nano-transmission-lines (NTL) made of these basic nano-elements. We show that in the limit in which these basic circuit elements are very close to each other, they can be regarded as planar stacks of plasmonic and nonplasmonic slabs, which may be designed to act as forward (right-handed) or backward (left-handed) NTL. Negative refraction and left-handed propagation are shown to be possible in these planar plasmonic configurations, potentially applicable in several innovative setups for sub-wavelength focusing, imaging and waveguiding applications.