2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/230327We report on very high enhancement of thin layer's absorption through band-engineering of a photonic crystal structure. We realized amorphous silicon (aSi) photonic crystals, where slow light modes improve absorption efficiency. We show through simulation that an increase of the absorption by a factor of 1.5 is expected for a film of aSi. The proposal is then validated by an experimental demonstration, showing an important increase of the absorption of a layer of aSi over a spectral range of 0.32-0.76 microns.4 pages, 5 figuresMaterials ScienceMesoscale and Nanoscale Physicstext