Optical response of Lorentzian nanospheres in the quasistatic limit

Gulen D.

JOURNAL OF LUMINESCENCE, vol.132, no.3, pp.795-800, 2012 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 132 Issue: 3
  • Publication Date: 2012
  • Doi Number: 10.1016/j.jlumin.2011.11.014
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.795-800
  • Middle East Technical University Affiliated: No


Significance of the Lorentzian dispersion relationship in controlling the optical response of the nanospheres surrounded by a homogeneous non-absorbing dielectric medium is examined. Nanospheres with size much smaller than the wavelength of the incident light are considered as prototype systems that can cover the generic optical response of Lorentzian nanoparticles. Absorption cross-section of the Lorentzian nanospheres is treated in the quasistatic approximation of classical electrodynamics and the resulting optical resonance is evaluated in terms of its dependencies on the parameters of the system. It has been illustrated that the underlying dispersion governs both the amount and the direction of the shift experienced by the optical resonance of nanospheres. Contrary to Drude nanospheres (well-known red shifters), Lorentzian nanospheres are shown to be blue shifters of the optical resonance. The amount of blue shift is dominated by the increase in the oscillator strength of the nanosphere material. Embedding media with higher dielectric constant and/or materials with larger high frequency dielectric constant lead to a suppression of the amount of blue shift induced by the oscillator strength. Further quantification of the blue shift characteristics against the red shift characteristics of Drude nanospheres is provided. The results can be instrumental for manipulating the optical response of plexcitonic nanophotonic devices. (C) 2011 Elsevier B.V. All rights reserved.