Plasmonic Color Filters as Dual‐State Nanopixels for High‐Density Microimage Encoding

• Published in: Advanced functional materials Vol. 27; no. 35
• Main Authors: Heydari, Esmaeil, Sperling, Justin R., Neale, Steven L., Clark, Alasdair W.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 20.09.2017
• Subjects: Coding; Color imagery; color printing; Counterfeit; Filtration; High resolution; image encoding; Image resolution; Materials science; metasurfaces; nanopixels; plasmonic color filters
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.201701866

Plasmonic color filtering has provided a range of new techniques for “printing” images at resolutions beyond the diffraction‐limit, significantly improving upon what can be achieved using traditional, dye‐based filtering methods. Here, a new approach to high‐density data encoding is demonstrated using full color, dual‐state plasmonic nanopixels, doubling the amount of information that can be stored in a unit‐area. This technique is used to encode two data sets into a single set of pixels for the first time, generating vivid, near‐full sRGB (standard Red Green Blue color space)color images and codes with polarization‐switchable information states. Using a standard optical microscope, the smallest “unit” that can be read relates to 2 × 2 nanopixels (370 nm × 370 nm). As a result, dual‐state nanopixels may prove significant for long‐term, high‐resolution optical image encoding, and counterfeit‐prevention measures. Using nanostructured metal surfaces to separate discrete colors from white light shows tremendous promise for enabling the next generational leap in image sensors, “printing” techniques, and display technologies. Here, the use of two‐color nanopixels for optical image encoding is explored: employing them as dual‐state nanopixels to generate surfaces encoded with two sets of optical information using just one set of pixels.