What’s in Your Wallet?

It isn’t only the makers of film who should fear digital photography. It’s also the bills in your wallet, according to a recent report from the Washington-based National Research Council. The report states that counterfeiting banknotes is getting easier but that photonics could play a key role in combating future fakes, gaining markets in the process.

A study by the council’s Committee on Technologies to Deter Currency Counterfeiting concluded that printing advances driven by digital photography could ensure that counterfeiters win the battle of the printed image. Within a decade, amateurs will obtain the tools to duplicate almost any two-dimensional image.

Committee chairman Robert Schafrik noted that the trend does not look good, explaining that less than 10 years ago not even 1 percent of counterfeiters were using these digital tools. Now more than 50 percent are.

However, all is not lost. Photonics technologies could play a key role in protecting currency, as outlined in the committee’s report “A Path to the Next Generation of US Banknotes — Keeping Them Real.” One suggestion is to embed a Fresnel lens into banknotes, providing a convenient way for anyone to check microprinting and determine whether a bill is genuine or not.

Another possibility involves randomly infusing small-diameter optical fiber segments into the currency. These would provide a visual cue, one that could be enhanced by scanning a section of the note during manufacturing. The captured fiber speckle pattern would be used to encode a mark on the bill itself. A reader device could later repeat the scan and compare it with the mark, thus determining the bill’s authenticity.

Schafrik noted that durability and cost of any solution are two factors that receive careful consideration. Although these are problems for some of the suggested approaches, he does not see the hurdles as insurmountable. “There are a lot of clever people in the photonics industry, and you’ve got to believe they will help find a way to solve those two problems.”

The committee’s report contains suggestions — not recommendations — and the list is not exhaustive, Schafrik noted. The final choice of what to develop and implement rests with the US Department of the Treasury. A timetable for the decision has not yet been announced.