Tunable spectral and spatial filters for the mid-infrared based on hyperbolic metamaterials

In this paper we present the possibility of shaping the reflectivity characteristics of tunable hyperbolic metamaterials (THMMs). Using the example of voltage-sensitive graphene-based structures, we demonstrate the existence of spectral and spatial functionalities of edge and narrowband filters, controlled dynamically over a 3-5 μm spectral range, that are important for both civilian and military applications. We also demonstrate that the adoption of apodization techniques in the THMM design leads to a reduction in the sidelobe's parasitic effect in edge filters, as well as providing the means to reshape the overall reflectivity characteristics, which not only unveiled the tunable angle aperture functionality but also significantly increased the potential for tailoring optical properties of THMM nanostructures in general.