Investigating new materials plays a very important role for advancing the field of nanofabrication and nanoplasmonics. Even though niobium nitride (NbN) is mainly known for its superconducting properties when fabricating superconducting nanowire single-photon detectors, we demonstrate that it is also a material for plasmonic nanoantenna applications. In this work we measure physical properties of thin NbN films, such as permittivity and superconductivity, and demonstrate the feasibility and tuning of the plasmonic nanoantenna resonance throughout the near- and mid-infrared spectral range. Therefore, we fabricate NbN structures, using electron beam lithography in combination with Ar ion-beam etching. Additionally, we determine the refractory properties of the NbN nanoantennas, namely their high temperature stability. We find that they are stable up to 500°C under ambient conditions. These aspects make them attractive for a multitude of plasmonic applications ranging from refractory emitters/absorbers to candidates for plasmonically improved superconducting single-photon detectors.

中文翻译：

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氮化铌等离子体纳米天线在近红外和中红外光谱范围内的光学特性

研究新材料对于推进纳米制造和纳米等离子体学领域起着非常重要的作用。尽管氮化铌 (NbN) 在制造超导纳米线单光子探测器时主要以其超导特性而闻名，但我们证明它也是等离子体纳米天线应用的材料。在这项工作中，我们测量了 NbN 薄膜的物理特性，例如介电常数和超导性，并证明了在整个近红外和中红外光谱范围内等离子体纳米天线共振的可行性和调谐。因此，我们使用电子束光刻与 Ar 离子束蚀刻相结合来制造 NbN 结构。此外，我们确定了 NbN 纳米天线的耐火性能，即它们的高温稳定性。我们发现它们在环境条件下高达 500°C 的温度是稳定的。这些方面使它们对多种等离子体应用具有吸引力，从耐火发射器/吸收器到等离子体改进的超导单光子探测器的候选物。