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Research outputs

As an application-oriented research organisation, Fraunhofer aims to conduct highly innovative and solution-oriented research - for the benefit of society and to strengthen the German and European economy.

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Projects

Fraunhofer is tackling the current challenges facing industry head on. By pooling their expertise and involving industrial partners at an early stage, the Fraunhofer Institutes involved in the projects aim to turn original scientific ideas into marketable products as quickly as possible.

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Researchers

Scientific achievement and practical relevance are not opposites - at Fraunhofer they are mutually dependent. Thanks to the close organisational links between Fraunhofer Institutes and universities, science at Fraunhofer is conducted at an internationally first-class level.

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Institutes

The Fraunhofer-Gesellschaft is the leading organisation for applied research in Europe. Institutes and research facilities work under its umbrella at various locations throughout Germany.

Recent Additions

  • Publication
    High fidelity laser beam shaping using liquid crystal on silicon spatial light modulators as diffractive neural networks
    Spatial light modulators (SLMs) based on liquid crystal on silicon (LCoS) are powerful tools for laser beam shaping as they can be used to dynamically create almost arbitrary intensity distributions. However, laser beam shaping with LCoS-SLMs often suffers from beam shaping artifacts in part caused by unconsidered properties of the LCoS devices: astigmatism that stems from the non-normal incidence of the laser beam on the SLM and the effect commonly referred to as the ’0-th diffraction order’ that is caused by both the crosstalk between neighboring pixels and the direct reflection at the cover glass of the SLM. We here present a method to consider and compensate for these inherent properties of LCoS devices by treating the SLM as a diffractive neural network.
  • Publication
    Selective laser-induced etching for novel 3D microphotonic devices
    ( 2024)
    Beckmann, Lara Christina Ive
    ;
    Bi, Toby
    ;
    Thoms, Julian M.
    ;
    Wenk, Max
    ;
    Zhang, Shuangyou
    ;
    Kratz, Martin Thomas
    ;
    Del'Haye, Pascal
    In this work, we evaluate the advantages and limitations of the Selective Laser-induced Etching (SLE) process for the fabrication of novel three-dimensional microresonator structures. Microresonators are resonant optical structures with the ability to store light of a specific wavelength. They are used as non-linear optical components, in sensors or even in integrated photonic devices. These structures are characterized by the optical quality factor Q as a measure of the optical storage capabilities. Q is significantly influenced by a high-quality optical surface with low surface roughness. In addition to surface quality and small dimensions, from tens of microns to millimeters, high optical nonlinearity is a key requirement in these fields. The fabrication of 3D fused silica parts fulfilling these requirements is an ongoing challenge in the field of microfabrication in quantum technology. The SLE process is used to fabricate three-dimensional parts of transparent materials such as fused silica with a high degree of geometric freedom in a two-step process. In the first step, a model of the part is written into the material using Ultrashort Pulse (USP) laser radiation. In the second step, the laser-written shape is wet-chemically etched in aqueous KOH to expose the part. The fabrication of 2D disk microresonators with high Q-factors is evaluated by studying the surface roughness of the SLE process followed by polishing. The polished samples are characterized and Q-factors >107 are achieved. In addition, the extent to which dimensions and geometry differ between design and real SLE components is analyzed. The SLE process will thus be investigated as a possible process for the future fabrication of three-dimensional microresonators.
  • Mainwork
    Laser-based Micro- and Nanoprocessing XVIII
    (SPIE, 2024)
    Kling, Rainer

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