Nanostructured chiral silver thin films: A route to metamaterials at optical frequencies
2011 (English)In: THIN SOLID FILMS, ISSN 0040-6090, Vol. 519, no 9, 2650-2654 p.Article in journal (Refereed) Published
We present a study of the optical properties of three-armed square nanospirals made of silver and realized as nanostructured thin films with Glancing Angle Deposition. Optical property variations with polarization were investigated using numerical simulations. For each polarisation case, two principal resonances were determined corresponding to excitation of plasmonic modes of nanospirals which resonances frequency depended on the dimensions of the nanospirals. Calculation of current flows in the nanospirals showed patterns resembling those observed in U-shaped resonators. In particular, a mode with anti-parallel current flow in opposite arms indicates the existence of a magnetic-like resonance in the square nanospirals. We present also generalized spectroscopic ellipsometry measurements obtained on one sample at an incidence angle of 25, and evidence conversion between polarization states even for light polarized in the plane containing one of the arms. The measurements showed good agreement with the results of calculations for an ideal structure. The differences in the conversion of polarization between measurements and calculations were mainly attributed to the existence of structural non-idealities in the actual sample.
Place, publisher, year, edition, pages
ELSEVIER SCIENCE SA, PO BOX 564, 1001 LAUSANNE, SWITZERLAND , 2011. Vol. 519, no 9, 2650-2654 p.
Ellipsometry, Metamaterials, GLancing Angle Deposition, Thin films
National CategoryEngineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-67701DOI: 10.1016/j.tsf.2010.12.078ISI: 000289174200018OAI: oai:DiVA.org:liu-67701DiVA: diva2:412615