Detection of biomolecules with 1D photonic crystals based on porous silicon

Fabrication of different porous silicon structures, namely rugate filters and rugate filters with porous silicon monolayers on top, as well as the characterization of both their reflectivity spectrum and their sensing performance are presented. The focus of this work is on a thorough analysis of the different optical features in the reflectivity spectrum and their utilization in biosensing experiments. Here, changes in the position and intensity of the rugate peak upon infiltration/adsorption of biomolecules into/on the porous structure are compared to variations of these two parameters in the fringes, resulting from Fabry-Pérot interference at the porous silicon layer interfaces. Depending on the size of the investigated biomolecules different information can be extracted from the rugate peak and the Etalon fringes in the reflectivity spectrum, facilitating the sensitive detection of analytes.