Fig. 2: Comparison between plasmonic and dielectric nanohole arrays.

a Schematic of typical spectra. The plasmonic resonance spectrum (dashed line) is based on experimental results in ref. ⁶⁵, and the dielectric resonance spectrum (dashed line) on experimental results in ref. ⁴⁴. This illustration highlights the practical differences between plasmonic and dielectric metasurfaces for sensing, presenting their respective advantages in terms of resonance Q-factor, amplitude, and sensitivity. The arrows indicate the peak shift towards higher wavelengths with increasing refractive index. This is a conceptual representation illustrating the enhanced refractometric sensitivity of plasmonic systems and is not based on empirical data. b The electric field (E) simulations show plasmonic ‘hotspot’ formation with strong near-field enhancement (top) and more extended confinement of resonances in a dielectric array (bottom). The image was adapted from⁴⁷