Color images multiplexing by laser structuring of plasmonic materials for security and personalization of ID cards – MIXUP

One of the challenges of the proposal will be to demonstrate that the technology can be implemented to multiplex more than 2 different images. To do this we will:

Elaborate colorimetric models extrapolating the gamuts of hypercolors, i.e. le sets of colors displayed in various modes, along the dimensions related to the laser parameters.

Develop clustering and sorting algorithms to identify among big hypercolor ensembles, all the hypercolors that satisfy specific trees of color combinations enabling multiplexing.

Implement rapid laser scanning processes to go towards an industrial transfer process for printing multiplexed images, based on the optimization of material composition and other marking parameters.

Another challenge of the proposal is to carry out more fundamental studies in order to better understand the mechanisms at the origin of the transformations of such plasmonic nanocomposite systems under laser irradiation and the link between nanostructures and hypercolors. For this the proposal also aims at:

Set up in operando characterization techniques to follow the time evolution of the material color from the nanosecond timescale when thermal effects start irreversibly changing the nanocomposite film, to few seconds when new phases stabilize.

Model the physico-chemical mechanisms and simulate changes in the film nanostructure.

Model the hypercolor evolution resulting from changes in the film nanostructure using electromagnetic modeling.

The technological solution developed in the project could be considered as a new security feature that could be adopted as a new standard in the e-ID card industry. HID Global CID would then be able to attract new customers and win new markets.

Laser-empowered random metasurfaces for white light printed image multiplexing

Going beyond the ink-less color printing with lasers, this paper, published in Advanced Functional Materials, demonstrates the femtosecond-laser-induced printing of multiplexed colored information that can be revealed optically. Three images are combined in an encoded image printed on a 200 nm thick metasurface by a single laser beam and are revealed independently under white light by changing the conditions of observation. The article highlights the very interesting optical properties of still poorly appreciated laser-induced random plasmonic metasurfaces.
youtu.be/d1jstP4lCk0

See more on the project website: sites.google.com/view/anr-mixup/home

Expected breakthroughs

From a scientific and academic point of view, several breakthroughs are expected from the different parts of the project:

Multiple color image multiplexing. Develop specific strategies to demonstrate that multiple (>2) color image multiplexing can be implemented with fast laser processing on plasmonic films. Implement two-image multiplexing for naked eye and white light observation (overt security feature)

Physico-chemical mechanisms involved in the coloring process. Understanding the mechanisms involved at different timescales from the femtosecond (fs) to the second and different scales from the atomic to the macroscopic level to better explain the occurence of laser induced self-organization mechanisms.

Final product and expected results

The final product that will be produced by HID Global CID is a composite card with a clear window in which multiplexed images have been encoded and marked by laser to be displayed in different observation modes. We also expect to unveil some of the fundamental mechanisms that irreversibly drive the transformation of nanocomposite films including metallic nanoparticles upon excitation by pulsed lasers thanks to the development of in operando characterization setups and new multi-physical models.

Scientific and technical barriers to be lifted

Creating new types of composite cards with an irregular transparent window.

Developing digital image multiplexing adapted to laser marking performances.

Implementing high speed laser marking of encoded multiplexed color images.

Characterizing in operando the laser induced transformations of plasmonic nanostructured films.

Modeling the colors and spectral properties of the plasmonic random metasurfaces produced by laser processing of the initial nanocomposite films.

Articles in international peer-reviewed journals
N. Destouches, N. Sharma, M. Vangheluwe, N.Dalloz, F. Vocanson, M. Bugnet, M. Hébert, J. Siegel , Laser-empowered metasurfaces for white light printed image multiplexing, Adv. Func. Mater., 2021, 10.1002/adfm.202010430

H. Ma, S. Bakhti, A. Rudenko, F. Vocanson, D. S. Slaughter, N. Destouches, T. Itina, Laser-generated Ag nanoparticles in mesoporous TiO2 films: formation processes and modeling-based size prediction, J. Phys. Chem. C, 2019, 123, 25898-25907

Sharma, N.; Destouches, N.; Florian, C.; Serna, R.; Siegel, J. Tailoring Metal-Dielectric Nanocomposite Materials with Ultrashort Laser Pulses for Dichroic Color Control. Nanoscale 2019,11, 18779-18789

Sharma, N.; Vangheluwe, M.; Vocanson, F.; Cazier, A.; Bugnet, M.; Reynaud, S.; Vermeulin, A.; Destouches, N. Laser-Driven Plasmonic Gratings for Hiding Multiple Images. Mater. Horizons 2019, 6 (5), 978–983

Sharma, N.; Ma, H.; Bottein, T.; Bugnet, M.; Vocanson, F.; Grosso, D.; Itina, T. E.; Ouerdane, Y.; Destouches, N. Crystal Growth in Mesoporous TiO2 Optical Thin Films. J. Phys. Chem. C 2019, 123 (10), 6070–6079

See more on the project website: sites.google.com/view/anr-mixup/home

In a context where government agencies develop enhanced security policies and technologies to track and protect the correct identity of every person, the MIXUP proposal aims at developing a breaking approach in the field of physical authentication of ID documents such as passports, ID cards, driving licenses or visas. HID Global CID and the academic partners, Laboratoire Hubert Curien and Institut Fresnel, merge their expertise to develop an innovative easy and efficient manufacturing process to provide secure see-through windows in a composite card, in which a tamper-proof portrait of the ID document bearer could be engraved by laser. The transparent window will exhibit several new security features and will contain a plasmonic film embedded at the card core in which multiplexed personal information and images of the card bearer will be printed by laser as a last personalization step of the card manufacturing process, with no need to add any protection layer afterwards.

Color image multiplexing allows displaying different images depending on the mode of illumination or observation of the card. The laser process implemented to print such multiplexed images in the card core relies on complex laser-matter interactions controlled by many parameters that require internal knowledge and know-how and make the process very difficult to counterfeit. Printed information is also protected from any attempt to modify it. Thanks to the way the different images or information are encoded to create the multiplexed data, it is impossible to change the color of one image in one mode without affecting simultaneously images in all the other modes making the fraud easily detectable.

One of the challenges of the proposal will be to demonstrate that the technology can be implemented to multiplex more than 2 different images. To do this we will:
o Elaborate colorimetric models extrapolating the gamuts of hypercolors, i.e. le sets of colors displayed in various modes, along the dimensions related to the laser parameters.
o Develop clustering and sorting algorithms to identify among big hypercolor ensembles, all the hypercolors that satisfy specific trees of color combinations enabling multiplexing.
o Implement rapid laser scanning processes to go towards an industrial transfer process for printing multiplexed images, based on the optimization of material composition and other marking parameters.

Another challenge of the proposal is to carry out more fundamental studies in order to better understand the mechanisms at the origin of the transformations of such plasmonic nanocomposite systems under laser irradiation and the link between nanostructures and hypercolors. For this the proposal also aims at:
o Set up in operando characterization techniques to follow the time evolution of the material color from the nanosecond timescale when thermal effects start irreversibly changing the nanocomposite film, to few seconds when new phases stabilize.
o Model the physico-chemical mechanisms and simulate changes in the film nanostructure.
o Model the hypercolor evolution resulting from changes in the film nanostructure using electromagnetic modeling.

The technological solution developed in the project could be considered as a new security feature that could be adopted as a new standard in the e-ID card industry. HID Global CID would then be able to attract new customers and win new markets.