Anti-counterfeiting security markings for metal goods

We present a laser-based process for the fast generation of ‘tamper-proof’ security markings on the flat surface of metals, such as stainless steel, nickel, brass and nickel-chromium Inconel® alloys. The markings which are in the form of phase holographic structures are generated using 35ns long laser pulses of wavelength 355nm. These laser pulses are capable of producing very shallow (<0.5μm deep) optically-smooth deformations with the depth control of ±25nm; as a consequence of localised laser melting and vaporisation of the metal surface. The security markings are resistant to abrasion and tampering because they are generated directly on the metal surface. In this talk, we are going to discuss the design and fabrication process of the security markings and demonstrate their use on commercially-available metal components.