There are several approaches to analyze transmittance data of selenium films, from which one can extract their optical constants and other related topics.[1]
However, the algebraic method of Swanepoel seems to be trustful and need no dispersion relations in prior, but is limited to transmittance spectra that display a number of peaks (maxima and minima).
References
- ^ Jafar, Mousa M. Abdul-Gader; Saleh, Mahmoud H.; Ahmad, Mais Jamil A.; Bulos, Basim N.; Al-Daraghmeh, Tariq M. (2016-04-01). "Retrieval of optical constants of undoped amorphous selenium films from an analysis of their normal-incidence transmittance spectra using numeric PUMA method". Journal of Materials Science: Materials in Electronics. 27 (4): 3281–3291. doi:10.1007/s10854-015-4156-z. ISSN 0957-4522.