Robert Magnusson, University of Texas at Arlington, Arlington, TX
Optical sensors are needed in many high-value fields including medical diagnostics, biomarker discovery, drug development, food safety, industrial process control, and environmental monitoring. Here, we summarize the physical basis, fabrication process, and functional characteristics of an efficient sensor modality grounded in optical resonance effects. The sensor operates with quasi-guided waveguide modes induced in periodic layers by a beam of light. The resonance is enabled by one- or two-dimensional nanopatterns that can be fabricated in large formats in a reliable, repeatable, and cost-effective manner making this method commercially viable. Optical thin films play a major role in this technology as a main practical fabrication method is to deposit dielectric films on nanoimprinted plate modules. We invented and experimentally demonstrated the guided-mode resonance biosensor more than two decades ago. Since then, there have been steady developments in technology and implementation. Label-free photonic sensors are immune to electromagnetic interference and permit effective light input and output which is key to achieving compact architectures. These sensors are economic due to material sparsity and simple interrogation with unpolarized light. We summarize resonance sensor fundamentals, unveil the various technological expressions of this sensor class, and give examples of viable applications.