High-Sensitivity Colorimetric Sensors Based on Reflective Guided-Mode Resonance Metasurfaces

This paper proposes a reflective guided-mode resonance (GMR) metasurface incorporating a secondary grating structure, designed for high-sensitivity colorimetric sensing in the visible spectrum. The proposed design significantly enhances the near field-analyte interaction, achieving improved sensing performance compared to conventional dielectric GMR metasurfaces. Specifically, the metasurface exhibits visually perceptible color shifts with an exceptional resolution corresponding to a refractive index (RI) change of 0.0097. The spectral measurements reveal a 4.36-fold increase in RI sensitivity. Furthermore, by varying the grating periods, the metasurface achieves higher resolution. This work demonstrates an innovative approach for developing highly sensitive GMR metasurface-based biochemical sensors.