Porous silicon optical sensors for vapors, liquids, and biological molecules

Recently, an increasing interest has been devoted to the use of porous silicon (p-Si) in photonics and in sensing fields. In particular, the great reactivity, mainly due to its large surface to volume ratio, has demonstrated to be promising in sensing applications for the detection of gases, vapors, and biochemical molecules. In this work, we present experimental and numerical results on p-Si optical microcavities as sensing transducers in biological and chemical fields. The measures are based on the change of the cavity reflectivity spectrum induced by the exposition to the bio-chemical specimen under test. The p-Si microcavity has a Fabry-Perot structure confined between two Distributed Bragg Reflectors (DBRs) with high reflectivity in the wavelength range of interest.