Borislav Vasic, G. Isic, Rados Gajic, Kurt Hingerl,
"Controlling electromagnetic fields with graded photonic crystals in metamaterial regime"
, in Optics Express, Vol. 18, Nummer 19, OPTICAL SOC AMER, Seite(n) 20321-20333, 2010, ISSN: 1094-4087
Original Titel:
Controlling electromagnetic fields with graded photonic crystals in metamaterial regime
Sprache des Titels:
Englisch
Original Kurzfassung:
Engineering of a refractive index profile is a powerful method for
controlling electromagnetic fields. In this paper, we investigate
possible realization of isotropic gradient refractive index media at
optical frequencies using two-dimensional graded photonic crystals.
They consist of dielectric rods with spatially varying radii and can be
homogenized in broad frequency range within the lowest band. Here they
operate in metamaterial regime, that is, the graded photonic crystals
are described with spatially varying effective refractive index so they
can be regarded as low-loss and broadband graded dielectric
metamaterials. Homogenization of graded photonic crystals is done with
Maxwell-Garnett effective medium theory. Based on this theory, the
analytical formulas are given for calculations of the rods radii which
makes the implementation straightforward. The frequency range where
homogenization is valid and where graded photonic crystal based devices
work properly is discussed in detail. Numerical simulations of the
graded photonic crystal based Luneburg lens and electromagnetic beam
bend show that the homogenization based on Maxwell-Garnett theory gives
very good results for implementation of devices intended to steer and
focus electromagnetic fields. (C) 2010 Optical Society of America
Forschungs-