Plasmonic space folding: focusing surface plasmons via negative refraction in complementary media

Area of Science:

• Photonics and Metamaterials
• Condensed Matter Physics

Background:

• Surface plasmon polaritons (SPPs) are light-like waves propagating at interfaces.
• Anisotropic media present unique challenges for wave propagation and focusing.
• Perfect lenses offer theoretical sub-diffraction imaging capabilities.

Purpose of the Study:

• To extend perfect lens designs for SPP focusing in anisotropic media.
• To elucidate the role of anisotropic permittivity and permeability tensors in SPP dispersion.
• To propose a practical design for a flat SPP lens.

Main Methods:

• Theoretical analysis using coordinate transformations to derive dispersion relations.
• Three-dimensional finite element computations for simulating SPP focusing.
• Design and conceptualization of a periodic dielectric cylinder array lens.

Main Results:

• Identified specific components of anisotropic tensors governing SPP propagation.
• Demonstrated SPP focusing using flat and cylindrical perfect lenses in simulations.
• Proposed a novel flat SPP lens design with hexagonal arrayed dielectric cylinders.

Conclusions:

• Perfect lenses can focus SPPs in anisotropic media by carefully designing material tensors.
• The proposed dielectric cylinder array offers a pathway to practical flat SPP lenses.
• This work advances the understanding and application of SPPs in nanophotonics.