A grating-based magneto-plasmonic sensor considering geometrical deviations

Abstract In this work, a grating-based magneto-plasmonic sensor is designed. Subsequently, the modes in which the lattice exhibits a geometric deviation were investigated and simulated. In this sensor, gold (Au), bismuth-substituted iron garnet (BIG), and SiO2 are used for the design of the lattice, magnetic layers, and substrate, respectively. A light field with a wavelength of 630 nm with a radiation angle of 1º to 35º was used to excite the structure. An ideal grating is assumed when developing this type of sensor. Since geometric deviations can occur during the manufacture of the structure, the response is accompanied by minor or major changes. If the deviation of the response is large, the built sensor is inefficient. To understand whether this sensor is efficient or not, the conditions under which the structure can deviate were investigated. These modes include changes in width and thickness, period, slope or surface hollowness, and curvature of the edges of the grating, as well as changes in the shape of the grooves. The most consistent mode occurred with the period variation, while the worst response occurred with the grating width variation. The maximum figure of merit (FoM) and sensitivity are 8571 RIU-1 and 85 º/RIU respectively.