Low‐Cost and Large‐Area Strain Sensors Based on Plasmonic Fano Resonances

This study presents a strain sensor based on plasmonic Fano resonances. The investigated system consists of U‐shaped aluminum nanowires that are fabricated at wafer scale with hot embossing and oblique metal evaporation. The proposed process is compatible with roll‐to‐roll manufacturing. The observed Fano resonance is very sensitive to the spacing between the wires and responds to strain with a spectral shift as well as attenuation of the resonance amplitude. This relation between nanoscopic displacement and optical properties is investigated with scanning electron microscopy and numerical simulations. Finally, a clearly visible color change from purple to green is achieved through optimization of the structural parameters, which enables colorimetric or even visual sensing and hence remote read‐out for example using a camera.