APPLIED PHYSICS: Scanning Nanobarcodes

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Science  10 Mar 2006:
Vol. 311, Issue 5766, pp. 1349a
DOI: 10.1126/science.311.5766.1349a

Screening technologies for biological and chemical monitoring often depend on the ability to identify and track labeled substrates. Although carrier beads can be encoded optically with fluorescence, infrared, or Raman spectroscopic signatures, the number of discriminable markers or tags available via these techniques is limited.

To expand the pool of markers, Galitonov et al. introduce an alternative method, based on the characteristic diffraction patterns produced by nanostructured barcodes. The operating principle relies on the distinctive image that results when laser light is scattered from a periodic grating, with the diffraction angles of the first and higher-order lines determined by the grating's periodicity. Each grating thus encodes a unique signature; moreover, superposition of two or more gratings creates a complex pattern, distinct from the image produced by either grating alone. By fabricating 100-μm-long barcodes from just three superposed gratings, the authors demonstrate the capacity to create a library of 68,000 distinctive tags, each readily readable by a helium-neon laser. With library sizes expected to increase as more gratings are superposed and fabrication resolution is improved, the method should find use in a variety of high-throughput screening applications. — ISO

Opt. Express 14, 1382 (2006).

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