CC BY
1*
ALT'23
The 30th International Conference on Advanced Laser Technologies
LM-I-23
Holographic security signs based on LIPSS: physics and technology
V.P Veiko, M.K. Moskvin, E.V. Prokofiev, G.V Odintsova
ITMO University vadim.veiko@mail.ru
Holographic security signs are an integral part of many industrial sectors, serving the purpose of protecting products against counterfeiting. However, the problem of counterfeiting is always relevant and requires improvement of protection methods. To effectively counter counterfeiters, the methods of protection must be ahead of the curve, anticipating fraudulent techniques and adapting to evolving technologies and counterfeit strategies. As the development progresses, the problem of creating security signs on products not only remains unresolved but also advances into the high technologies. This is because simple solutions are being circumvented and counterfeited through various methods. In terms of protective diffraction signs, computer calculation methods allow us to determine the necessary reliefs for the implementation of optical effects: both shape and color, kinematics, etc. However, there is a problem to achieve efficient writing that would enable to integrate all known identification features and new technical solutions into a single sign. These issues are addressed in detail in this report. The aim was to investigate the feasibility of creating high-quality holographic security signs by laser-induced periodic surface structures (LIPSS). The physical peculiarities of the LIPSS formation method and its application for creation of holographic protective signs of different degrees of complexity are discussed. Additionally, this work presents a set of visual security features for holographic signs implemented by LIPSS.
The base of realization of holographic security signs is the diffraction of white light on the LIPPS matrix with different spatial directions. A new method is presented that makes it possible to achieve control by the orientation of the LIPPS by coordinated dynamic changes in direction and type polarization with the scanning trajectory of the laser beam. Coordinated parameter adjustments allow the formation of complex diffraction grating configurations. This method opens new possibilities for the direct laser writing of holographic protective signs, on metal products ensuring durability, visual appeal, and function.
