Surface plasmon polaritons with plasma frequencies above 1 eV in Sn‐doped In2 O3

Abstract

AbstractSn‐doped In2 O3 films with free‐electron concentration varied up to 1.710cm are prepared by molecular beam epitaxy. In this way, a metallic Drude‐type dielectric function with a negative real part extending beyond = 1050 nm is created. Despite essentially polycrystalline structure of the layers, the plasmonic damping is found not to exceed 70 meV in the entire doping range making excitation of low‐loss surface plasmon polaritons at frequencies fully covering the telecommunication band feasible. A monotonically increasing discrepancy between the carrier concentration obtained from Hall‐effect and the concentration extracted from fitting the optical spectra hints at a change of the band‐structure related parameters of In2 O3 with increasing Sn‐doping.