Three-dimensional metallic nanostructures synthesized by Glancing Angle Deposition

Glancing Angle Deposition has been used to synthesize silver square nanospirals over large surfaces. It is shown numerically that such nanospirals exhibit the resonant plasmonic modes necessary to produce metamaterials at optical frequencies. The resonances remained as long as the angle of incidence of light did not vary by more than 20°. Samples were realized with different size of nanospirals. For the dimensions allowing for excitation of a magnetic-like mode at optical frequencies, generalized ellipsometric measurements have been performed. A good agreement between measurements and calculations was obtained.