Title “Metasurfaces For Environmental Refractive Index Sensing: Design, Fabrication And Interrogation”
Date: June 9, 2025 – 3:00 pm – Raisler Lounge 225 Towne Hall
Metasurfaces are artificial materials composed of sub-wavelength building blocks whose size, shape, periodicity and composition are tailored to engineer their optical response and achieve arbitrary control of their interactions with light. Their phase discontinuities or resonances are critically dependent upon the local dielectric or refractive index environment, thus making metasurfaces excellent candidates as refractive index sensors. A unique application of such passive metasurface refractive index sensors is in agricultural and environmental sensing to conduct in-situ measurements of crop health conditions with high spatiotemporal resolution, thus maximizing crop yield. This application necessitates compact, low-cost, biocompatible metasurface sensors that can be distributed en-masse. In this thesis we study low-cost, scalable, combined top-down and bottom-up meatasurface fabrication techniques involving nanoimprint lithography and solution-processible metallic and dielectric colloidal nanocrystals. We then study metasurface sensor monitoring or interrogation techniques utilizing conventional RGB/hyperspectral remote imaging, as well as novel polarimetry techniques, to prove the real-world implementation feasibility of these metasurface refractive index sensors and develop their evaluation metrics.