Determination of excitation profile and dielectric function spatial nonuniformity in porous silicon by using WKB approach

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We develop an analytical model based on the WKB approach to evaluate the experimental results of the femtosecond pump-probe measurements of the transmittance and reflectance obtained on thin membranes of porous silicon. The model allows us to retrieve a pump-induced nonuniform complex dielectric function change along the membrane depth. We show that the model fitting to the experimental data requires a minimal number of fitting parameters while still complying with the restriction imposed by the Kramers-Kronig relation. The developed model has a broad range of applications for experimental data analysis and practical implementation in the design of devices involving a spatially nonuniform dielectric function, such as in biosensing, wave-guiding, solar energy harvesting, photonics and electro-optical devices.


Original languageEnglish
Pages (from-to)27123-27135
Number of pages13
JournalOptics Express
Issue number22
Early online date24 Oct 2014
Publication statusPublished - 3 Nov 2014