Canada has a history of creating high-tech banknotes, with many security features embedded in its colourful polymer bills. We wrote previously about the hologram hidden in the frosted maple leaf window of Canada’s original 2011 release of polymer bills and the fascinating science behind it. Since then, even more futuristic science has been going into the race to stay ahead of counterfeit bills.
While the hidden hologram is simple enough to check, it’s not easily visible at a glance, and most Canadians who handle cash payments regularly aren’t even aware it’s there. In practice, it’s too hidden. At the register, a user might have only seconds to spot a counterfeit and keep customers moving, so these are not ideal characteristics for a security measure.
Imagine instead that the entire portrait on a banknote was a 3D moving hologram, and that it could turn its head and give you a smile or a wink. It wouldn’t just be a futuristic point of pride for Canadians, it would also be a security feature that would be impossible to miss.
The technology needed to replicate it would also take a $100-million investment in equipment and years of reverse engineering. This would be the worst case scenario for would-be forgers of counterfeit bills.
Unlike the 2D holographic strip on our current banknotes, which can be copied using a standard laser printer, pulling this off would require the ability to print details on the nanoscale with pixels that are smaller than the wavelength of light.
Only a few machines in the world are able to achieve this resolution at the scale that would be needed to cover a large area of a banknote. Vancouver-based company Nanotech Security, with research and development housed at Simon Fraser University’s 4D Labs, owns one of these rare machines: an electron beam lithography machine that can print images up to 10 by 10 centimetres each day.
The resulting colourful holograms come from nanoscale ridges of varying heights, which are invisible until light cascades over them. This technology was inspired by biology, where the signature vibrant blues of the blue morpho butterfly also rely on nanostructures, not on pigments, for their brilliant colours.
