Aachen, Germany - The Fraunhofer Institute for Laser Technology (ILT) has developed an optical module that shortens the pulse duration of powerful ultrafast lasers by a factor of four. The compact module is suitable for use in lasers with up to 1kW average power and energy from 10 to 200µJ. A 1ps pulse can thus be compressed to about 250fs, during which less than 10% of energy is lost and the beam quality is maintained.
The patent-pending technology of the pulse-shortening module was funded by the Federal Ministry of Education and Research (BMBF) as part of the FOCUS project. In further development of the module, significantly higher pulse energies are to be achieved.
The pulse-shortening module can be combined with a femtosecond laser in the 150W power range. The module has been fine-tuned for robustness and economy, thanks to its particularly simple design. This laser is characterized by its almost diffraction-limited beam quality.
Also, by combining thin-disk and INNOSLAB amplifiers, Fraunhofer ILT has set a new record for ultrafast lasers: the system delivers 1.5kW average power at a pulse duration of 710fs. Further optimization, specifically of the thin-disk amplifier system, should enable power beyond the 2kW limit. This development has been supported by the BMBF as part of the FOCUS Project, as well as by the TRUMPF Group.
Industrial laser systems in this power class are particularly suitable for the processing of large parts; for example, those made of carbon fiber-reinforced plastic (CFRP).
New beam sources at wavelengths of 1.5 to 3.5µm (shortwave infrared [SWIR]) provide an example of ultrafast laser technology solutions by Fraunhofer ILT, tailored for specific applications. Many technically and economically interesting material classes have an extremely high absorption in SWIR, which makes a series of innovative applications possible. So far, however, there has been a lack of sufficiently powerful lasers in this range.
Scientists at Fraunhofer ILT have now developed a test system that delivers laser power even over 20W at 1.6-3.0µm. The pulse duration can be between 900fs and 1.5ns. They are currently working on power scaling to more than 50W. The test system can be adapted to different drive lasers and, thus, provide a wide range of application parameters. The new system allows users to make both feasibility studies and provides process-optimized beam parameters for production.
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