Hybrid nanowire metamaterials with ultra-wideband epsilon-near-zero mode tuning for nanophotonic applications

This work investigates the linear and nonlinear optical properties and guided wave modes of hybrid nanowire metamaterials (HNW-MMs), focusing on controlling their transmission characteristics. The epsilon-near-zero and hyperbolic responses of such structures are analyzed using effective medium theory, dispersion relations, and the FDTD method, under irradiation with transverse electric (TE) and transverse magnetic (TM) beams. Our study reveals that including silicon cores within the nanowires significantly enhances the tunability of the optical response of the metamaterial, with the emergence of additional modes at higher wavelengths. Unlike conventional nanowire MMs, these hybrid structures exhibit extra guided modes that are unique to their configuration and physical structure. The results demonstrate that by adjusting the filling ratios, the new modes can be fully controlled from the visible to the infrared (IR) range. In specific configurations, one of the new modes can achieve epsilon-near-zero (ENZ) characteristics. This work introduces a novel platform that combines controllable modes with ENZ behavior, enabling advanced functionalities not achievable in traditional metamaterial designs. Using this tunability and ENZ properties as a novel approach, a band-stop adjustable optical filter within the ENZ bandwidth is designed and simulated. Furthermore, the Kerr nonlinear effect in ENZ mode is investigated, and highly efficient all-optical nonlinear switches and relays at the nanoscale are presented.