Anisotropic optical response of elongated Pb islands in the infrared spectral region

Niall McAlinden, Jing-Jing Wang, John McGilp

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Lead forms elongated islands when grown on vicinal Si(111) surfaces. Polarized infrared transmittance studies have shown a strong anisotropic optical response associated with antenna-like plasmonic resonances, whose spectral position in the region of 0.25 eV is sensitive to the length of the islands. Reflection anisotropy spectroscopy (RAS) using a photoelastic modulator (PEM) should be more sensitive to such optical anisotropies, but becomes difficult below ∼0.5 eV for instrumental reasons. Measurements of the anisotropic response, in reflectance, of Pb islands grown on Si(557)-5 × 1–Au are extended down to ∼0.12 eV by combining sample rotation with tuneable femtosecond laser irradiation from a difference frequency generator. The extended RAS spectral range allows the full anisotropic nanoparticle plasmon-polarition optical response in the surface plane to be explored for this type of material system. Reasonable agreement with a simple nanoantenna model of the resonance maximum is obtained, but calculating the full line profile of the RAS response of supported nanoparticles remains challenging.
Original languageEnglish
JournalPhysica Status Solidi B
Early online date21 Feb 2012
DOIs
Publication statusPublished - Feb 2012

Keywords

  • lead
  • nanoparticles
  • reflection anisotropy spectroscopy
  • surface plasmon-polaritons
  • silicon

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