Nanostructure-based optical filters for multispectral imaging applications

摘要

Multispectral imaging technologies rely on interference-based optical filters or grating structures that add cost, size and weight to multispectral camera systems. Nanostructures offer an attractive alternative since their optical properties can be specified precisely during fabrication and nanostructures are suitable for integration into present camera technologies. However, nanostructure-based optical filters have broad-band transmission properties and poor out-of-band blocking that reduce their spectroscopic performance and therefore limit their usefulness in multispectral imaging applications. In an attempt to break through these barriers, our group has developed a series of nanostructurebased optical filters with progressively improved optical transmission properties. The devices rely on the principle of index matching to reduce the transmission bandwidth and improve the out-of-band blocking. We have investigated the effect of packing the optical filters in proximity to one another, as well as the use of a tiled arrangement of several thousand optical filters for snapshot multispectral imaging in chemical analysis. Based on these studies, we conclude that nanostructure-based optical filters are suitable for multispectral imaging in the near infrared. In the future, nanostructure-based optical filters may be useful for integration into diagnostic instrumentation.