Anti‐counterfeiting White Light Printed Image Multiplexing By Fast Nanosecond Laser Processing

Nicolas Dalloz (1) , van Doan Le (1) , Mathieu Hebert (1) , Balint Eles (1) , Manuel a Flores Figueroa (1) , Christophe Hubert (1) , Hongfeng F Ma (1) , Nipun Sharma , Francis Vocanson (1) , Stéphane Ayala , Nathalie Destouches (1)

1 LHC - Laboratoire Hubert Curien

Passive plasmonic metasurfaces enable image multiplexing by displaying different images when altering the conditions of observation. Under white light, three-image multiplexing with polarization selective switching has been recently demonstrated using femtosecond-laser-processed random plasmonic metasurfaces. Here, the implementation of image multiplexing is extended, thanks to a color search algorithm, to various observation modes compatible with naked-eye observation under incoherent white light and to four-image multiplexing under polarized light. The laser-processed random plasmonic metasurfaces enabling image multiplexing exhibit self-organized patterns that can diffract light or induce dichroism through hybridization between the localized surface plasmon resonance of metallic nanoparticles and a lattice resonance. Improved spatial resolution makes the image quality compatible with commercial use in secured documents, as well as the processing time and cost thanks to the use of a nanosecond laser. This high speed and flexible laser process, based on energy efficient nanoparticle reshaping and self-organization, produces centimeter-scale customized tamper-proof images at low cost, which can serve as overt security features.

Domaines: Sciences de l'ingénieur [physics]

Nicolas Dalloz, van Doan Le, Mathieu Hebert, Balint Eles, Manuel a Flores Figueroa, et al.. Anti‐counterfeiting White Light Printed Image Multiplexing By Fast Nanosecond Laser Processing. Advanced Materials, 2021, pp.2104054. ⟨10.1002/adma.202104054⟩. ⟨ujm-03409454⟩