A nano-spiral that is only visible through an electron microscope has been developed, which its developers say has unique and usable properties for issues such as identity theft and protection on currency and identity cards.
Developed at Vanderbilt University in the US by doctorate student Roderick Davidson II, the research team’s findings, which were published online, show that the nano-spiral developed appears to show unique optical properties that other attempts had yet to create.
Previous attempts at creating nano-spirals had only created them in a pattern like a dot-matrix, but Davidson’s effort is not only smaller in size, but also solid in its structure, with a square array of 100 nano-spirals on one side being less than one hundredth of a millimetre wide.
According to the university, when infrared laser light is shone on them, they emit a clearly visible blue light and produce four times as much light as the most brilliant frequency doubling effect created by the synthetic crystal beta barium borate.
Computer simulation of the harmonic emissions produced by a nano-spiral when it is being illuminated by infrared light. Image via Haglund Lab/Vanderbilt
With a combination of its frequency doubling and response to polarised light characteristics, Davidson and his team say that it could allow for the creation of a highly-customisable signature that would be incredibly difficult to counterfeit.
With the potential to be made out of inexpensive materials, it could be effective on the smallest of security items, such as a credit cards or any substance that might want to be tracked, like explosives, chemicals or drugs.
“If nano-spirals were embedded in a credit card or identification card, they could be detected by a device comparable to a barcode reader,” said the director of the research, Professor Richard Haglund.
Spiral staircase image via Shutterstock
