Our investigation uses the film-interference transmittance spectrum in the computer calculation of thin-film thickness t and complex refractive index n<sup>*</sup>=n−ik. Titanium oxide films of different thicknesses are studied, and a new approach to determine the film thickness and optical constants is proposed. This new approach is based on the use of numerical optimization methods in transmittance-spectra fitting. Various dispersion equations of the finite-power-series type are used to obtain the best fit between transmittance measurements and calculations. The best-fit results for n(λ) and k(λ) are found to agree with dispersion relations that follow from a quantum theory of light absorption.
© 1998 Optical Society of America
(070.4790) Fourier optics and signal processing : Spectrum analysis
(120.4530) Instrumentation, measurement, and metrology : Optical constants
(120.5240) Instrumentation, measurement, and metrology : Photometry
Milen Nenkov and Tamara Pencheva, "Calculation of thin-film optical constants by transmittance-spectra fitting," J. Opt. Soc. Am. A 15, 1852-1857 (1998)