Plasmonics in the ultraviolet with the poor metals Al, Ga, In, Sn, Tl, Pb, and Bi

Abstract

We discuss how the poor metals Al, Ga, In, Sn, Tl, Pb, and Bi can be used for plasmonics in the near to far ultraviolet (UV) range, similar to the noble metals Ag and Au in the visible (Vis) range. We first discuss the empirical dielectric functions of the poor metals, contrasting them with Ag and Au, and also fitting them to a Drude and multiple Lorentz oscillator form. Using Mie theory, we then compare the optical responses of spherical poor metal nanoparticles to noble metal ones. Finally, nanoparticle dimers are studied using a vectorial finite element method. We show how the poor metals exhibit large electric field enhancements in the UV, comparable to Au in the Vis, which makes them particularly attractive for sensing applications, such as surface enhanced Raman spectroscopy.