Spectral curve fitting of dielectric constants

Optical constants are important properties governing the response of a material to incident light. It follows that they are often extracted from spectra measured by absorbance, transmittance or reflectance. One convenient method to obtain optical constants is by curve fitting. Here, model curves sho...

Full description

Saved in:
Bibliographic Details
Published inAIP advances Vol. 7; no. 1; pp. 015042 - 015042-13
Main Authors Ruzi, M., Ennis, C., Robertson, E. G.
Format Journal Article
LanguageEnglish
Published Melville American Institute of Physics 01.01.2017
AIP Publishing LLC
Subjects
Curve fitting
Dielectric properties
Fourier series
Harmonic oscillators
Incident light
Line shape
Optical properties
Permittivity
Quantum theory
Reflectance
Spectral bands
Online AccessGet full text

Cover

More Information
Summary:Optical constants are important properties governing the response of a material to incident light. It follows that they are often extracted from spectra measured by absorbance, transmittance or reflectance. One convenient method to obtain optical constants is by curve fitting. Here, model curves should satisfy Kramer-Kronig relations, and preferably can be expressed in closed form or easily calculable. In this study we use dielectric constants of three different molecular ices in the infrared region to evaluate four different model curves that are generally used for fitting optical constants: (1) the classical damped harmonic oscillator, (2) Voigt line shape, (3) Fourier series, and (4) the Triangular basis. Among these, only the classical damped harmonic oscillator model strictly satisfies the Kramer-Kronig relation. If considering the trade-off between accuracy and speed, Fourier series fitting is the best option when spectral bands are broad while for narrow peaks the classical damped harmonic oscillator and the Triangular basis fitting model are the best choice.
ISSN:2158-3226
2158-3226
DOI:10.1063/1.4975398