Title :
On the Low-Order Partial-Fraction Fitting of Dielectric Functions at Optical Wavelengths
Author :
Michalski, Krzysztof A.
Author_Institution :
Dept. of Electr. & Comput. Eng., Texas A&M Univ., College Station, TX, USA
Abstract :
Low-order partial-fraction (PF) fitting of optical dielectric functions from tabulated frequency data is investigated. Two rational function identification techniques are examined, viz., the Sanathanan-Koerner iteration and vector fitting, and it is found that these methods generate PF models of similar quality and both provide excellent starting solutions for further improvement by nonlinear optimizers. High-quality, wide-band PF models are obtained for several metals frequently encountered in plasmonic applications. These models are stable and well-suited for the finite-difference time-domain (FDTD) simulation of light interaction with nanostructures. An efficient FDTD updating scheme for PF media is also demonstrated.
Keywords :
curve fitting; dielectric function; dispersive media; finite difference time-domain analysis; iterative methods; vectors; FDTD simulation; Sanathanan-Koerner iteration; finite-difference time-domain simulation; light interaction; low-order partial-fraction fitting; nanostructures; nonlinear optimizers; optical dielectric functions; optical wavelengths; plasmonic applications; rational function identification techniques; tabulated frequency data; vector fitting; wideband PF models; Data models; Dielectrics; Gold; Nonlinear optics; Polynomials; Time-domain analysis; Vectors; Curve fitting; FDTD methods; dispersive media; rational approximation; vector fitting;
Journal_Title :
Antennas and Propagation, IEEE Transactions on
DOI :
10.1109/TAP.2013.2282082
