Hybrid metasurface comprising epsilon-near-zero material for double transparent windows in optical communication band

Metasurfaces with multiple transparent windows are highly desired and epsilon-near-zero (ENZ) materials offer a good platform for different coupling effects. We propose a hybrid metasurface composed of an indium tin oxide (ITO) nanolayer and a plasmonic metasurface. This device can support two kinds of different coupling effects to achieve double transparent windows in communication band. ITO behaves as an ENZ material and can support an ENZ mode when the real permittivity crosses zero (occurring at about 1.55 μm). In addition to electromagnetic induced transparency (EIT) at 1.31 μm supported by the plasmonic metasurface, another transparent window at 1.55 μm is produced by strongly coupling between the ENZ mode and the plasmonic metasurface. Our works provide a simple way to micro-nano device for multi-transparent windows, and may find applications in filters and sensors.