THz metamaterials made of phonon-polariton materials

• THz superlensing due to hyperbolic dispersion relation response.
• THz superlensing due to backward radiation in polaritonic waveguides of small negative permittivity.
• Total transmission and subwavelength guiding exploiting Mie resonances in a polaritonic host with epsilon near zero.
• Toroidal response in polaritonic metamaterials made by clusters of scatterers, due to the high index response of the scatterers.

In this paper, we demonstrate numerically various phenomena and possibilities that can be realized in THz metamaterials made of phonon-polariton materials. Such phenomena include hyperbolic dispersion relation, subwavelength imaging using backward propagation and backward radiation, total transmission and subwavelength guiding exploiting Mie-resonant scattering in permittivity near zero host, and toroidal dipolar response. The systems that we use to demonstrate most of these phenomena are two-dimensional periodic systems of μm-scale rods in a host, where both rods and host are made of polaritonic alkali-halide materials.