Numerical optimization of metallized titania nanotube morphologies for negative index material flat lens applications

We perform numerical calculation in order to optimize the morphology of metallized ti- tania nanotubes from the point of view of flat lens application based on NIM. An efficient multiple-scattering approach is used to calculate propagation of electromagnetic waves through the materials designed. The focusing properties of a flat lens constructed from a superlattice structure of nanotube clusters were found to be better as compared to a lens with a regular arrangement of nanotubes. A disorder of 20% introduced in the position of nanotubes of the optimized superlattice does not significantly influence the focusing properties of the lens.