Low Dimensional Nanostructure-Assisted Long-Range Surface Plasmon Resonance Sensors With High Figure of Merit.

Long-range surface plasmon resonance (LRSPR) sensors have been extensively studied by virtue of their extremely narrow full width at half maxima (FWHM) characteristics, but their low sensitivity remains an important factor limiting the figure of merit (FOM), making the sensors have difficulties in detecting small refractive index changes accurately. To address this problem, this paper proposes and demonstrates a low dimensional nanostructure (Au nanospheres, WS2) assisted LRSPR sensor to achieve an effective enhancement of the sensor interfaced electric field and thus improve the sensitivity. The performance parameters of the two sensors are compared with the LRSPR sensor by finite element method analysis, and the results showed that the assistance of the low dimensional nanostructure has a positive effect on the sensor. The first refractive index sensing experiment of the WS2-assisted LRSPR sensor was realized with a 25.47% increase in sensitivity and a 7.13% increase in FOM simultaneously, and the Au nanospheres-assisted LRSPR sensor with a 29.23% increase in sensitivity and a 15.95% increase in FOM simultaneously. The introduction of low dimensional nanostructures provides a flexible and effective means of sensitization for LRSPR sensors, making the plasmon resonance sensors combine high sensitivity, narrow FWHM and high FOM, which have promising applications in biochemical sensing.