Optics Design

Our range of services

Fraunhofer ILT offers its clients comprehensive expertise in customized geometric-optical laser systems. Among others, it focuses its research and development on beam shaping, fiber coupling as well as simulating the generation and propagation of radiation.

Given power density distributions can be generated with customized freeform optics through the redistribution of power through refraction and reflection. For this purpose, Fraunhofer ILT develops complex optimization algorithms with which virtual prototypes are created, the properties of which are then checked with simulation software. Freeform optics are used, for example, in LED lighting or in laser systems. Even materials with special properties are used for other optical systems. Thanks to the high refractive index of 2.4 and the high thermal conductivity, diamond allows, for example, dimensions of laser optics to be reduced drastically. Together with the Fraunhofer institutes IAF and IPT, Fraunhofer ILT has developed a laser cutting head that is 90% lighter than conventional components compared with glass optics and is very suitable for laser cutting processes.

The range of services offered by Fraunhofer ILT cover R&D in design and simulation, experimental studies on laboratory models, the development of industry-related, certified prototypes and comprehensive technology consulting as well as market research and feasibility studies.

Lens made of synthetic monocrystalline diamond.
© Fraunhofer ILT, Aachen, Germany.
Lens made of synthetic monocrystalline diamond.
Prototype of a line optics.
© Fraunhofer ILT, Aachen, Germany.
Prototype of a line optics.
Free-form optics made of plastic.
© Fraunhofer ILT, Aachen, Germany.
Free-form optics made of plastic.

Optics Design

  • Imaging and non-imaging optical systems for coherent and incoherent systems
  • Micro optical systems
  • λ from UV to IR and average power up to multi kW
  • Tolerance analysis
  • Design for production and assembly

Opto-mechanical Design

  • FE analysis of opto-mechanical assemblies
  • Calculation and correction of laser-induced thermal lenses
  • Mechanical design of high power optics
  • Fast scanning systems for high power lasers

Tailored Intensity Profiles

  • Beam transformation
  • 1D and 2D homogenization
  • Application-specific optics for pumping, hardening, polymer welding, brazing and cleaning

Assembly of Optical Systems

  • Production measurement technology for optical systems
  • Algorithms and methods for automated alignment and assembly
  • Qualification of optical systems


Our brochures offer a quick view onto our service portfolio. Find more detailed information in the “project results“ tab.


“Design of Freeform Optics“


“Optics Design and Diode Lasers“


Laser technology can solve demanding tasks in many different industries. Whether as a tool in automotive production, as measuring equipment in the environmental sector, as a diagnostic or therapeutic instrument in medical technology or as a communication medium in space technology, the laser provides multiple uses with high productivity and high efficiency.

Read up about the innovations of the Fraunhofer ILT in a few selected industries and convince yourself!


Research with us!

Please do not hesitate to contact us if you have any questions about general topics! Our contact persons are happy to get in touch with you.


Lüttgenau, B., Brose, S., Choi, S., Panitzek, D., Danylyuk, S., Lebert, R., Stollenwerk, J., Loosen, P.:
Design and realization of an industrial stand-alone EUV resist qualification setup.
SPIE Photomask Technology + EUV Lithography, 2020, Online Only. Extreme Ultraviolet Lithography 2020 (Proc. SPIE 2020), 115171 , 115171F (12 S.),(2020)

Prochnau, M., Holzbrink, M., Wang, W., Holters, M., Stollenwerk, J., Loosen, P.:
Measurement methods to build up the digital optical twin.
SPIE LASE, 27 January-1 February 2018, San Francisco, California, United States. Proceedings Volume 10513, Components and Packaging for Laser Systems IV; 105131I (10 S.) (2018).

Holters, M., Dirks, S., Stollenwerk, J., Loosen, P.:
Automated and model-based assembly of an anamorphic telescope.
SPIE OPTO, 22 February 2018, San Francisco, California, United States. Proc. SPIE 10538, Optical Interconnects XVIII, 105380U (10 S.) (2018)

Prochnau, M., Stollenwerk, J., Loosen, P.:
Approach towards the digital optical twin. International Optical Design Conference - IODC 2017,09-13 July 2017 Denver United States. Proc. SPIE 10590, International Optical Design Conference 2017, 1059021, (6 S.) (2017)

Traub, M., Holly, C., Hoffmann, D., Widmann, C., Zuerbig, V., Nebel, C.:
Synthetic Mono-Crystalline Diamond Lenses for High Power Laser Materials Processing Applications.
OSA Optical Design and Fabrication Congress, IODC 2017, 09 - 13 July 2017, Denver, Colorado, United States.Optics InfoBase Conference PapersVolume Part F56-OFT 2017, 2017, (3 S.) (2017)

König, G., Chen, C., Holters, M., Stollenwerk,J., Loosen, P.:
Comparison of Different Methods for Robustness Estimation of Simple Lens Systems.
OSA Optical Design and Fabrication Congress, IODC 2017, 09 - 13 July 2017, Denver, Colorado United States.Optics InfoBase Conference PapersVolume Part F51-IODC 2017, 2017, (2 S.) (2017)

Holters, M., Stollenwerk, J., Loosen, P. ,
Ermittlung der Montagereihenfolge für Präzisionsoptiken
118. DGaO (Deutsche Gesellschaft für angewandte Optik e. V.) Jahrestagung. 6.-10. Juni 2017 in Dresden. DGaO-Proceedings 2017. B 31. (S.1-2) (2017)

Pütsch, O., Stollenwerk, J., Loosen, P.:
Integrated optical design for highly dynamic laser beam shaping with membrane deformable mirrors.Proc. SPIE 10090, 1009010 (8 S.) (2017)

Bonhoff, T., Gayer, C., Stollenwerk, J., Loosen, P.:
Simulation and measurement of thermo-optical effects in an f-theta lens at high laser power
DGaO-Proc. 117. Tagung, 2 S. (2016)

Büsing, L., Bonhoff, T., Behnke, L., Stollenwerk, J., Loosen, P.:
Theoretical and experimental analysis of scan angle-depending pulse front tilt in optical systems for laser scanners
Adv. Opt. Techn. (online first) (7 S.) (2016)

König, H.-G., Pütsch, O., Stollenwerk, J., Loosen, P.:
An improved approach for process monitoring in laser material processing
Proc. SPIE 9889, 98890T (6 S.) (2016)

Bonhoff, T., Büsing, L., Stollenwerk, J., Loosen, P.:
Modeling of optical aberrations due to thermal deformation using finite element analysis and ray-tracing
Proc. SPIE 9626, 96261V (10 S.) (2015)

Esser, D., Staasmeyer, J.-H., Weitenberg, J., Rußbüldt, T., Sartorius, T., Hoffmann, H.-D.:
Fused-silica mirror substrates with laser-microstructured openings with reduced chipping
CLEO_Europe 2015. 21-25 June 2015 in Munich. CE_10_3. (2015)

Thombansen, U., Gatej, A., Pereira, M.:
Tracking the course of the manufacturing process in selective laser melting
Proc. SPIE 8963, 89630O (7 S.) (2014)

Thombansen, U., Hermanns, T.:
In-situ measurement of the focal position in one and ten micron laser cutting
Proceedings 33rd Int. Congress on Applications of Lasers & Electro-Optics (ICALEO), October 19-23, 2014, San Diego, USA,
Paper 179, ISBN 9781940168029 (4 S.) (2014)

Thombansen, U., Hermanns, T.: Molitor, T., Pereira, M., Schulz, W.:
Measurement of cut front properties in laser cutting
Physics Procedia  56, 885-891 (2014)

Thombansen, U., Hermanns, T., Stoyanov, S.:
Setup and maintenance of manufacturing quality in CO2 laser cutting
Procedia CIRP 20, 98 – 102 (2014)

Thombansen, U., Ungers, M.:
Illumination for process observation in laser material processing
Physics Procedia  56, 1286-1296 (2014)

Thombansen, U., Ungers, M.:
Cognition for robot scanner based remote welding
Proc. SPIE  8963, 89630N (8 S.) (2014)

Pütsch, O., Bahrenberg, L., Loosen, P.:
Opto-mechatronisches System zur Erzeugung prozessangepasster Intensitätsverteilungen für die Lasermaterialbearbeitung
Mechatronik 2013, Aachen, 06.-08.03.2013, VDI, (9 S.)

Traub, M., Hoffmann, D., Hengesbach, S., Loosen, P.:
Automatic design of multi-lens optical systems based on stock lenses for high power lasers
International Optical Design Conference, Kohala Coast, Hawaii United States, June 22-26, 2014
Optimization (IW1A) (2. S.) (2014)

Pütsch, O., Bahrenberg, L., Loosen, P.:
Opto-mechatronisches System zur Erzeugung prozessangepasster Intensitätsverteilungen für die Lasermaterialbearbeitung
Mechatronik 2013, Aachen, 06.-08.03.2013, VDI, (9 S.)

Pütsch, O., Temmler, A., Stollenwerk, J., Willenborg, E., Loosen, P.:
Active optical system for laser structuring of 3D surfaces remelting
Laser Beam Shaping XIV. Ed.: Andrew Forbes, Todd E. Lizotte. Proc. SPIE 8843, 88430D (8 S.) (2013)

Crump, P., Hengesbach, S., Witte, U., Hoffmann, H.-D., Erbert, G.,
Tränkle, G.:
High-power diode lasers optimized for low-loss smile-insensitive external spectral stabilization
IEEE Photon. Technol. Lett. 24, Nr. 8, 703-705, (2012)

Gatej, A., Wasselowski, J., Loosen, P.:
Thermo-optical (TOP) analysis by coupling FEM and ray tracing
Proceedings of SPIE 8429, E-84290E-84290E-8, (2012)

Gatej, A.,  Wasselowski, J., Loosen, P.:
Using Adaptive Weighted Least Squares Approximation for Coupling Thermal and Optical Simulation
Applied Optics 51/28, 6718–6725 (2012)

Gatej, A.,  Richmann, A., Pütsch, O., Loosen, P.:
Thermo-Optical (TOP) analysis of transmissive elements for laser-systems 
Proceedings of SPIE 8490, (2012)

Pütsch, O., Loosen, P.:
Electro-optically actuated liquid-lens zoom 
Proc. SPIE 8429, 8 S. (2012)

Hengesbach, S., Witte, U., Traub, M., Hoffmann, D.:
Simulation and analysis of volume holographic gratings integrated in collimation optics for wavelength stabilization 
Proc. SPIE 7918, 79180A, 13 S., (2011)

Funck, M., Loosen, P.:
Estimating the performance gain of selectively assembled optical systems
53. Int. Wissenschaftliches Kolloquium, Techn. Univ. Ilmenau. CD-ROM
pp. 160-161, (2008)

Schnitzler, C., Hambuecker, S., Ruebenach, O., Sinhoff, V., Steckman, G., West, L., Wessling, C., Hoffmann, H.-D.:
Wavelength stabilization of HPDL array: fast-axis collimation optic with integrated VHG
Proc. SPIE 6456, 1-7, (2007)

Traub, M., Hoffmann, H.-D., Plum, H.-D., Wieching, K., Loosen, P., Poprawe, R.:
Homogenization of high power diode laser beams for pumping and direct applications
Proceedings of SPIE 6104, 61040Q.1-61040Q.10, (2006)