Alcohol-Infiltrated One-Dimensional Photonic Crystals

In this work, experimental results on the optical characterization of alcohol-infiltrated silicon/air one-dimensional photonic crystals (1D-PhCs), fabricated by electrochemical micromachining of silicon, are presented and compared with theoretical predictions. Infiltration of alcohols into 1D-PhCs produces reliable changes (redshift and increase of the bandgap order in the near-infrared region) in the reflectivity spectrum, with respect to air. Such changes, which can be attributed to an increase in the average refractive index of the structure, allow one to discriminate between different alcohols. Experimental data are in good agreement with numerical results calculated by using the characteristic matrix method, modified to take into account surface roughness of silicon walls.