Hamdy Mohamed Elshorbagy, MahmoudCuadrado Conde, AlexanderAlda, Javier2023-06-162023-06-162020-01-031557-195510.1007/s11468-019-01105-6https://hdl.handle.net/20.500.14352/6096Received: 12 september 2019; Accepted: 04 december 2019; Published: 03 january 2020We present a refractometric sensor realized as a stack of metallic gratings with subwavelength features and embedded within a low-index dielectric medium. Light is strongly confined through funneling mechanisms and excites resonances that sense the analyte medium. Two terminations of the structure are compared. One of them has a dielectric medium in contact with the analyte and exploits the selective spectral transmission of the structure. The other design has a metallic continuous layer that generates surface plasmon resonances at the metal/analyte interface. Both designs respond with narrow spectral features that are sensible to the change in the refractive index of the analyte and can be used for sensing biomedical samples.engjournal articlehttps://doi.org/10.1007/s11468-019-01105-6https://link.springer.com/article/10.1007%2Fs11468-019-01105-6open access535.5NanophotonicsPlasmonicsOPtical sensorsRefractometryÓptica (Física)2209.19 Óptica Física