Multi-band plasmonic color filtering through nanostructured metal thin film for RGB-NIR image sensor

摘要

We propose a novel on-chip color filter consisting of periodic corrugated metallic nano-gratings concentrically surrounding a sub-wavelength single aperture for a multispectral imaging of visible to near-infrared (NIR). NIR image sensor provides a significant information such as range measurement imaging and biological tissue imaging. By integrating our proposed RGB-NIR plasmonic color filter on a single image sensor, improved image recognition such as range image and tissue image in color will be performed. Wavelength-selected incident light coupled with surface plasmons transmits through the sub-wavelength aperture as propagating beaming light, which has the advantage to suppress the spatial color cross-talk between the pixels. We demonstrated the multi-band color filtering from visible to NIR range using our proposed plasmonic color filter, leading to spectral narrow bandwidth and higher color purity than those reported previously.