Ultrafast lasers for metal colorization in the minting industry

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The Royal Canadian Mint (RCM) is a leader in the coin making and coin collection business. Today it stamps metal currencies for numerous countries and is renowned worldwide for its strong research and innovation. To remain a leader in the minting industry, to keep its competitive edge and to attract other countries to stamp their metal currencies, RCM is now looking into new anti-counterfeiting features and new ways to produce color designs on coins. It was recently shown that ultrafast lasers can produce surface micro and nanofeatures which could be used for new security features. With counterfeiting costing some economies up to 3% of the overall stamped value, ultrafast laser produced structures would make counterfeiting much more difficult due to the high cost of the laser system, its limited access and the knowledge required to operate it. Surface morphologies produced by ultrafast laser can also be used to colorize metals. Color changing with viewing angle and fixed colors can be produced and are of interest to RCM. For counterfeiting and colorizing techniques to be industrially viable, RCM is interested in large scale production of features on coins using stamping. In the stamping process, features are first engraved with the laser on a steel die which is then used to stamp coins and transfer the features and resulting colors onto the coin. There are several aspects currently preventing RCM from using ultrafast laser for producing security features and colors on coins which mainly come from a lack of knowledge on ultrafast laser-mater interactions. To solve these problems, RCM is interested in the expertise in ultrafast laser machining available at the University of Ottawa. The proposed collaboration between RCM and the University of Ottawa will result in new scientific knowledge in terms of laser-mater interactions, metal