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Plasmonic interconnects as well as metasurfaces manipulating the phase and amplitude of reflected and/or transmitted light, have attracted significant attention in the fields of planar optics and on-chip nanophotonics. The application space of plasmonics has recently been expanded by new materials classes including transparent conducting oxides (TCOs) and refractory transition metal nitrides (TMNs). These materials offer superior thermal stability, robustness, tailorability and CMOS compatibility, thus outperforming the conventional plasmonic components (e.g. gold and silver) in application-specific requirements. Here, we discuss recent progress in the areas of plasmonic interconnects, modulators and metasurfaces realized using TMNs and TCOs.
Ultrafast nonlinear responses near the epsilon near zero (ENZ) region have been recently demonstrated for Al doped zinc oxide (AZO) (TCO). This has spurred the development of ultrafast, on-chip modulators with TCOs as an active material. Building from on our previous work on LRSPP waveguides with ultrathin Titanium Nitride (TiN) (5.5mm propagation length) and Zirconium Nitride (ZrN), we will report solid-state hybrid mode waveguides using TiN as well as a modulator based on this waveguide which provides all-optical tunability, low optical losses at the telecommunication window, and CMOS-compatibility.
Successful integration of these alternative plasmonic components into the phase gradient metasurfaces platform without loss of performance have also been demonstrated. A metasurface employing ZrN brick antennas shows the photonic spin Hall Effect (PSHE), by reflecting the two circular polarizations in different directions. In another device, a metasurface based on nanostructures of Ga doped ZnO (TCO), functioning as a quarter-wave plate, have been realized.
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