@article{6901,
  abstract     = {Freeform optics belong to the increasingly important elements in optical research and industry, which pose several challenges regarding design and highly precise manufacturing. First being used in cameras and for focusing, nowadays freeform optics are used in a broad range of applications, from lighting to LiDAR, from endoscopy to photovoltaics, and from astronomical instruments to quantum cryptography. Designing freeform optics can be based on different theories and methods. Fabrication is possible by mechanical methods, such as diamond turning or high-precision milling, often followed by different polishing techniques, as well as laser-based techniques, mainly applying different lithographic techniques. Here, we give an overview of recent design and optimization methods, production methods used during the last years, and applications of freeform optics, including the possibility to combine freeform optics with tunability for different applications. We describe the opportunities of new applications as well as common problems and give an outlook towards future directions of research and development.},
  author       = {Blachowicz, Tomasz and Ehrmann, Guido and Fiedler, Johannes and Kaschuba, Reinhard and Ehrmann, Andrea},
  issn         = {2673-8023},
  journal      = {Micro},
  keywords     = {photopolymerization, tunable micro-optical freeform elements, two-photon polymerization, multiphoton lithography, direct laser writing, diamond turning},
  number       = {2},
  publisher    = {MDPI AG},
  title        = {{Freeform Micro-Optical Elements—Recent Production Techniques, Opportunities and Challenges}},
  doi          = {10.3390/micro6020035},
  volume       = {6},
  year         = {2026},
}

@article{669,
  author       = {Sudsom, Devika and Blachowicz, Tomasz and Hahn, Lothar and Ehrmann, Andrea},
  issn         = {0304-8853},
  journal      = {Journal of Magnetism and Magnetic Materials},
  keywords     = {Magnetic nanostructures, Wedges, Micromagnetic simulation, Vortex, Magnetization reversal, Iron, Permalloy, Lithography},
  publisher    = {Elsevier},
  title        = {{Vortex nucleation and propagation in magnetic double-wedges and semi-squares for reliable quaternary storage systems}},
  doi          = {10.1016/j.jmmm.2020.167294},
  volume       = {514},
  year         = {2020},
}

@article{635,
  author       = {Sudsom, Devika and Juhász Junger, Irén and Döpke, Christoph and Blachowicz, Tomasz and Hahn, Lothar and Ehrmann, Andrea},
  issn         = {2410-3896},
  journal      = {Condensed Matter},
  keywords     = {magnetic nanostructures, micromagnetic simulation, bow-tie structure, vortex, magnetization reversal, iron, permalloy, lithography},
  number       = {1},
  publisher    = {MDPI},
  title        = {{Micromagnetic Simulation of Vortex Development in Magnetic Bi-Material Bow-Tie Structures}},
  doi          = {10.3390/condmat5010005},
  volume       = {5},
  year         = {2020},
}

@article{582,
  author       = {Blachowicz, Tomasz and Kosmalska, Dorota and Döpke, Christoph and Leiste, Harald and Hahn, Lothar and Ehrmann, Andrea},
  journal      = {Journal of Magnetism and Magnetic Materials},
  keywords     = {Magnetic nanostructures Magneto-optical Kerr effect (MOKE) Micromagnetic simulation Magnetization reversal Cobalt Lithography},
  title        = {{Varying steps in hysteresis loops of Co square nano-frames}},
  doi          = {10.1016/j.jmmm.2019.165619},
  volume       = {491},
  year         = {2019},
}

@article{340,
  author       = {Ehrmann, Andrea and Blachowicz, Tomasz},
  issn         = {2372-0484 },
  journal      = {AIMS Materials Science},
  keywords     = {micromagnetic simulation, magnetic nanoparticles, nanoparticle cluster, OOMMF, stable intermediate state, lithography},
  number       = {2},
  pages        = {383--390},
  title        = {{Interaction between magnetic nanoparticles in clusters}},
  doi          = {10.3934/matersci.2017.2.383},
  volume       = {4},
  year         = {2017},
}