Analysis of errors in optical functions calculated from the Kramers-Kronig relations

The effect of errors in the measured reflection coefficient and in the calculated phase on the accuracy of calculations of optical functions is studied in the particular case of the Bi₁₂SiO₂₀ crystal, whose reflection spectra have been measured over a wide energy range (1.5–30 eV) with the help of a synchrotronradiation source. The four most common extrapolation models are compared. The effect of the physical and mathematical components on the accuracy with which optical functions are calculated is analyzed. Corresponding practical recommendations are offered.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 25–29, March, 1989.