Niobium as Alternative Material for Refractory and Active Plasmonics

The development of stable compounds for durable optics is crucial for the future of plasmonic applications. Even though niobium is mainly known as a superconducting material, it can qualify as an alternative material for high-temperature and active plasmonic applications. We utilize electron beam lithography combined with plasma etching techniques to fabricate nanoantenna arrays of niobium. Tailoring the niobium antenna geometry enables precise tuning of the plasmon resonances from the near-to the mid-infrared spectral range. Additionally, the hydrogen absorptivity as well as the high-temperature stability of the antennas have been investigated. Further advantages of niobium such as superconductivity make niobium highly attractive for a multitude of plasmonic devices ranging from active and refractory perfect absorbers/emitters to plasmon-based single photon detectors.