Magneto-optical effects in hyperbolic metamaterials based on ordered arrays of bisegmented gold/nickel nanorods.

Hyperbolic metamaterials (HMM) based on multilayered metal/dielectric films or ordered arrays of metal nanorods in a dielectric matrix are extremely attractive optical materials for manipulating over the parameters of the light flow. One of the most promising tools for tuning the optical properties of metamaterialsis the application of an external magnetic field. However, for the case of HMM based on the ordered arrays of magneto-plasmonic nanostructures, this effect has not been clearly demonstrated until now. In this paper, we present the results of synthesis of HMM based on the highly-ordered arrays of bisegmented Au/Ni nanorods in porous anodic alumina templates and a detailed study of their optical and magneto-optical properties. Distinct enhancement of the magneto-optical (MO) effects along with their sign reversal is observed in the spectral vicinity of epsilon-near-zero and epsilon-near-pole spectral regions. The underlying mechanism is the amplification of the MO polarization plane rotation initiated by Ni segments followed by the light propagation in a strongly birefringent HMM. This stays in agreement with the phenomenological description and relevant numerical calculations.