Nanostructured multiple gratings become miniature barcodes

For many uses of barcodes, smaller is better. Researchers at the ­EPSRC Nanophotonics Portfolio Centre, University of Southampton (Southampton, England) are creating narrow nanostructured 100-µm-long barcodes of superimposed diffraction gratings (one, two, three, and four superimposed gratings in a test pattern are seen here from left to right).

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For many uses of barcodes, smaller is better. Researchers at the ­EPSRC Nanophotonics Portfolio Centre, University of Southampton (Southampton, England) are creating narrow nanostructured 100-µm-long barcodes of superimposed diffraction gratings (one, two, three, and four superimposed gratings in a test pattern are seen here from left to right). Although fabricated with electron-beam lithography for testing, these barcodes can be made with high-­volume nanoimprint-lithography techniques. The 1-D test versions have 68,000 distinguishable tags; a 2-D (crossed-grating) version would have up to 109 individual codes.

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The researchers’ first interest is in genomics; they are patenting an implementation based on the photoresist SU8. “Our main vision for the use of these barcodes is as tags in combinatorial chemistry, biological applications, marking of plants, ­animals, birds, insects and even individual cells. However, potential for such tags is also huge in security applications (banknotes and credit cards), product marking, marking of small electronic components on chips, and so on,” says Sam Birtwell, one of the researchers. For these other applications, gratings of clear-coated metal gratings would have long lifetimes. Contact Sam Birtwell at swb@phys.soton.ac.uk.

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