(June 2, 2015) Take gold spirals about the size of a dime…and
shrink them down about six million times. The result is the world’s smallest
continuous spirals: “nano-spirals” with unique optical properties that would be
almost impossible to counterfeit if they were added to identity cards, currency
and other important objects.
Students and faculty at Vanderbilt University fabricated
these tiny Archimedes’ spirals and then used ultrafast lasers at Vanderbilt and
the Pacific Northwest National Laboratory in Richland, Washington, to
characterize their optical properties. The results are reported in a paper
published online by the Journal of Nanophotonics on May 21.