Background and project goals:

In times of complex production processes with increasing safety and quality of products, the Product tracking as well as the Distinguishing inferior plagiarism More present than ever. For example, in segments such as cosmetics and pharmaceuticals, counterfeits and originals are often barely distinguishable from one another for end users. With regard to product tracking, there is enormous industrial interest in being able to assign processes even years later and to easily identify selected products.

that Objective of the joint project LaserImplant consisted in the development of a laser process with which high-quality glass products can be marked forgery-proof, permanently and non-destructively. The developed process should be applicable to (various) industrial glasses. From a technical point of view, the marking should be in the form of a so-called computer-generated hologram (CGH) , which is calculated using an iterative Fourier transform algorithm (IFTA). The CGH had to be inscribed in the glass material just below the surface in order to produce a mark that was permanently protected against abrasion and could not be manipulated.

The process is based on the laser-based production of metallic nanoparticles made of gold or silver, which have a characteristic light absorption, the so-called surface plasmon resonance (English Surface Plasmon Resonance (SPR)). Defined diffraction patterns produce an ideal contrast, which enables readout at a suitable wavelength. By means of a directed (coherent) light source, for example in the form of a green (wavelength 532 nm) or a red (wavelength 650 nm) laser pointer, the hologram information encoded in the CGH is visibly projected in the form of a logo, lettering, code or the like and can be read out both manually and by machine, depending on the application.