Speaker
Description
We propose a new on-chip optical color filter of nanostructured metallic thin film for multispectral imaging based on surface plasmon resonance. This plasmonic color filter consists of periodic corrugated metallic nano-grating with sub-wavelength single aperture. Selected wavelength of incident light excites surface plasmon resonance by the concentric periodical corrugation on metal surface. The wavelength coupled with surface plasmons transmits through the sub-wavelength aperture with beaming light. The beaming light transmission has the advantage to suppress the spatial color cross-talk between pixels in the conventional image sensor. We calculated the transmission spectrum dependence of structural parameters such as corrugation period and groove depth by using the finite-difference time-domain algorithm, and designed periodic corrugated metallic thin film with filtering functionality in visible to near-infrared. Our structure is easily fabricated by the standard techniques of electron beam lithography, vacuum evaporation, and focus ion beam milling. Here, we demonstrated the transmission color selectivity from visible to near-infrared range of the fabricated metallic color filters. Integrating the proposed plasmonic color filters on image sensor device leads to simultaneous imaging of visible and near-infrared light, and it is expected to provide improved image recognition in vehicle mounted camera, security, and biological tissue engineering, and so on.
