Rigorous modeling of meander-type metamaterials for sub-lambda imaging

Abstract

It has been shown that surface plasmon polaritons (SPPs) have a dominant influence on the unique properties of negative index materials (NIMs). Consequently, one could replace bulk NIMs by resonantly coupled surfaces that allow the propagation of SPPs. We show that a metallic meander structure is perfectly suited as such a resonant surface due to the tunability of the short range SPP (SRSPP) and long range SPP (LRSPP) frequencies by means of geometrical variation. Furthermore, the pass band between the SRSPP and LRSPP frequencies of a single meander sheet, induced by two Fanotype resonances, retains its dominant role when being stacked. In this report we demonstrate how a stack consisting of two meander structures can mimic perfect imaging known from Pendry's lens within this pass band region. On the other hand, to observe sub-wavelength features in the far-field more than (perfect) near-field imaging is necessary. We propose a stack of meander structures with successively increasing periodicity capable to decrease the lateral wave vector until near-field to far-field transformation is achieved. When stacking multiple meander structures with different periodicities, the pass band shifts in frequency for each sheet in a different way. We rigorously calculate the spectra of various meander designs and show that this shift can be compensated by changing other geometrical parameters of each single sheet. Such meander stacks can transfer energy resonantly over large distances with a high transmission and might enable sub-wavelength imaging.