Metallic NanoArc Antennas – Plasmonics Building Blocks for Non-Linear Optical Metamaterials

The linear and non-linear optical properties of metallic nanoarcs were investigated. The resonance frequencies in the NIR spectrum were correlated to geometric and materials parameters, primarily the nanoarc length and the permittivity of the substrate. Metamaterials consisting of arrays of arcs were designed to display enhanced Second Harmonic Generation at a predictable frequency. The enhancement is achieved through a double-resonance matching condition between the incident and emitted light and two plasmon resonances of individual nanoarcs. Larger nanoarc central angles lead to higher linear extinction cross-section at the second longitudinal mode resonance and larger second harmonic generation signal. The metamaterial consist of common, low-cost materials with no intrinsic second-order susceptibility.