Advanced Structural Engineering of Nanoporous Photonic Structures: Tailoring Nanopore Architecture to Enhance Sensing Properties

In this study, we demonstrate that an optimal design of the pore geometry and shape of sensing platforms based on nanoporous anodic alumina (NAA) photonic structures is critical to develop optical sensors with improved capabilities. To this end, two types of NAA photonic structures featuring different pore geometries (i.e., pore lengths and diameters) and shapes (i.e., straight and modulated pores) were produced, and their optical characteristics were assessed systematically by reflectometric interference spectroscopy. The geometric features (i.e., pore lengths, diameters, and shapes) were systematically modified in order to establish the optimization paths for the sensitivity, low limit of detection, and linearity of these optical sensing platforms. The obtained results reveal that an optimal design of these nanoporous photonic structures can enhance their sensitivity, achieve a lower limit of detection, and improve their linearity for both nonspecific and specific detection of analytes. Therefore, as this study demonstrates, the rational design of optical nanoporous sensing platforms is critical in the development of reliable, sensitive, robust, inexpensive, and portable optical systems for a broad range of sensing applications.