Femtosecond laser based on optical fiber amplifiers, are now used in many areas of industry, medicine and science. There is a great demand for ever more powerful laser sources and also laser pulses with wavelengths that differ from the standard ytterbium wavelength of about 1030 nm. However, there are physical effects that limit the performance of these sources.
Our Institute deals extensively - and also very successful - with issues relating to laser powers in the border area, as shown at the this year's world largest conference Photonics West in San Francisco from 7th -12th February.
Thus, all three first places of the best student presentation competition at the sub-conference "Fiber Lasers: Technology, Systems, and Applications" went to PhD-students of the IAP group "Fiber & Waveguide Lasers" by Jun.-Prof. Jens Limpert.
Marco Kienel got the first prize for his first realization of a in both dimensions scalable multidimensional system. By dividing a pulse in four separate times pulse copies, which were amplified in parallel in two spatially separated ytterbium-doped fibers, pulse energies were achieved, which goes far beyond the destruction of the individual fiber. This concept will open the way to a laser system with highest pulse energies in the near future. Moreover, for many applications the wavelength of the laser radiation is of high relevance.
The second prize went to the work of Christian Gaida, which deals with the development of thulium-doped fiber lasers at 2 microns wavelength with high output power. The challenge was to handle the reduced efficiency and increased heat input into the fiber. The work discussed the experimental conditions to improve the efficiency and to deal with the increased heat. As a result, an unprecedented level of output power for ultrashort pulses in these thulium-doped fiber lasers has been realized.
Arno Klenke presented the coherent combination of several femtosecond pulses in order to circumvent limitations in the average power and peak pulse power fiber lasers. Thus, the output pulses of four parallel amplifiers were combined in a pulse and so a laser system with peak powers and energies was created which are significantly higher than previously existing fiber laser systems. With additional temporal pulse division and pulse combination a further increase in the pulse peak power is possible.
Another success celebrated Felix Zimmermann at the reseach group "Ultrafast Optics" by Prof. Stefan Nolte. On the sub-conference "Frontiers in Ultrafast Optics: Biomedical, scientific and industrial applications XV", Felix presented nanogratings in glass, which were induced with ultra-short pulses. These structures show an artificial birefringence, which can be adapted by the laser parameters as desired. This allows various applications, especially because the structures can be rewritten by polarization rotation. The research on this so far poorly understood effect has now been honored at the Photonics West.

Junior Professor. Dr. rer. nat. Jens Limpert

Prof. Dr. rer. nat. Stefan Nolte

News from: 20.02.2015 13:59
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