The evanescent optical field scattering simulation of a‐Se nanoparticles was obtained by the Maxwell equation solver FullWAVE and correlated to experimental a‐Se films nanoprofiles obtained by Differential Evanescent Light Intensity Imaging (DELI). The DELI method was used as an experimental imaging method of depth profiles for large areas, i.e., hundreds of mm2 of nanometer thick a‐Se layers. The comparison of light scattering simulation and thickness profiles obtained from the experiments corresponds to an optical scattering mechanism leading to evanescent light extraction by the a‐Se nanoparticles. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)