That staple of science-fiction, the biological barcode labeling every person, plant and animal, may be one step closer thanks to a new optical tagging technique developed at Southampton University in the UK, says a repot at optics.org.

"Our main vision for the use of these barcodes is as tags in combinatorial chemistry, tagging individual molecules with labeled micro-beads," said researcher Sam Birtwell.

"Also, biological applications, marking of plants, animals, birds, insects and even individual cells can benefit. However, the potential for such tags is also huge in security applications: banknotes, credit cards, product marking, and marking of small electronic components on chips."

The team used electron beam lithography to deposit 60 nm thick, 50x50 micron chromium diffraction gratings onto glass substrates at a resolution of 100 nm. Birtwell explains that the code for each tag is stored as the periods of the grating and is read by detecting the angle of the first order beam diffracted from the tag. (photo Sam Britwell)