A Hybrid Photonic-Plasmonic Sensing Platform for Differentiating Background and Surface Interactions Using an Array of Metal-Insulator-Metal Resonators

In this paper, a hybrid photonic-plasmonic sensor structure based on an array of metal-insulator-metal resonators is presented. The structure is designed to improve detection and temporal resolution by increasing sensitivity and intensity as well as reducing full-width at half-maximum of the photonic and plasmonic modes. The electromagnetic fields (EMs) of the plasmonic mode are highly confined in the cavity, while the EM fields of the photonic mode are mainly distributed in the background solution. Our numerical analysis predicts a fivefold surface sensitivity and about one-half background refractive index sensitivity of the plasmonic mode in comparison with the photonic mode. Thus, the surface and background refractive index variations can be differentiated. By reducing the background index fluctuation, this high-resolution hybrid photonic-plasmonic sensor provides a platform for sensing very low concentration of target molecules in complex solutions.