  Nanometric metallic stripes allow the transmission of optical signals via the
excitation and propagation of surface-localized evanescent electromagnetic
waves, with important applications in the field of nano-photonics. Whereas this
kind of plasmonic phenomena typically exploits noble metals, like Ag or Au,
other materials can exhibit viable light-transport efficiency. In this work, we
demonstrate the transport of visible light in nanometric niobium stripes
coupled with a dielectric polymeric layer, exploiting the
remotely-excited/detected Raman signal of black phosphorus (bP) as the probe.
The light-transport mechanism is ascribed to the generation of surface plasmon
polaritons at the Nb/polymer interface. The propagation length is limited due
to the lossy nature of niobium in the optical range, but this material may
allow the exploitation of specific functionalities that are absent in
noble-metal counterparts.
