Micro-optical 1D moirés as anti-counterfeiting features

Moirés have been increasingly applied to create novel security features typically implemented by means of printing techniques, which achieve a resolution up to 2000 dpi. However, this resolution is not sufficient to effectively prevent counterfeits by desktop scanners and printers. In this paper we propose and demonstrate the design and cost-efficient fabrication of moiré-based security features with a new record resolution of 9754 dpi by means of micro-fabrication techniques. The moirés presented in our work are designed to exhibit macroscopic visible distortions for small deviations (~1 μm in period) from the ideal design, increasing drastically the difficulty to counterfeit them.