2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/132991We consider two equations for the filling factor estimation of infiltrated zinc oxide (ZnO) in silica (SiO_2) opal and gallium nitride in ZnO opal. The first equation is based on the effective medium approximation, while the second one - on Maxwell-Garnett approximation. The comparison between two filling factors shows that both equations can be equally used for the estimation of the quantity of infiltrated nanocrystals inside opal matrix.14 pages, 7 figures, 1 table. Addendum to the article: http://arxiv.org/abs/physics/0508152OpticsInstrumentation and Detectorstext