50 years GSI



The new accelerator facility FAIR is under construction at GSI. Learn more.


GSI is member of


Funded by




Laser project wins start-up prize

Helmholtz spin-off develops high power lasers for science and industry



Working in the field of high power lasers for science and industry, a joint spin-off of DESY and the Helmholtz Institute Jena, a branch of GSI Helmholtzzentrum für Schwerionenforschung, won the Start-up Challenge prize organised by OptecNet Deutschland e.V. The spin-off company, Class 5 Photonics, is currently in its founding phase and competed against 14 other top-class start-up companies. The competition took place at the Optatec trade fair in Frankfurt. The physicists from Class 5 Photonics convinced the jury with their new innovative laser technology and outstanding business model.

“Today, lasers are universal tools to process all kinds of different materials, from automotive industry to medical technology,” said Dr. Michael Schulz from the Class 5 Photonics team. Schulz and his colleagues Dr. Franz Tavella, Dr. Robert Riedel and Dr. Mark J. Prandolini developed high power lasers with pulses in the femtosecond range. One femtosecond is a quadrillionth of a second. Shorter laser pulses allow more precise working of materials.

“In addition, these short laser pulses open up new innovative applications; for example, 3D nanostructuring. In science, this technology is also extremely important; for example, efficient table-top laser systems in the XUV range can be realised for the first time,” said Riedel.

“Our systems can provide from 10 to 100 femtosecond-short pulses at an average power from one to 100 watts,” Schulz said. During 10 femtoseconds, light travels a distance of only 0.003 millimetres. This is just about one twentieth of the width of a human hair. For their flexible high power femtosecond laser, the physicists used an innovative technology, which is much more compact than existing systems. The prototype of the new high power laser with a planned output power of 20 watts has the size of only 80 by 80 centimetres.

“First, we separate a small part from an intensive Ytterbium:YAG laser pulse,” DESY scientist Schulz illustrated the functional principle. “The smaller part of the pulse is then converted by nonlinear spectral broadening into a broadband laser pulse, the larger part of the pulse is frequency-doubled.” Subsequently, the physicists simultaneously shoot both parts of the pulse onto a nonlinear crystal, where the larger part of the pulse amplifies the smaller one.

This principle, called optical parametric amplification, does not need a classical laser medium, which must first store energy within the medium before it is discharged as a laser pulse. Optical parametric amplification also requires less maintenance for the novel high power lasers; the developers assure. Conventional titanium:sapphire lasers lose about a third of the input energy as wasted heat, which may cause strong heating of the system. “The optical parametric amplification solves this problem,” said Schulz, “there is only minimal heating.”

When all wavelengths of the amplified laser pulses are temporally superimposed, this produces an extremely short and intensive laser pulse. Moreover, the new system allows tuning over a broad wavelength range, in this case 700 to 900 nanometres. The users can then choose the most suitable wavelength for processing a particular material. “With this technology, it is possible to build a turnkey system which serves a broad spectrum with ultrashort pulses,” said Schulz. “We want our system to become a key-technology on the laser market.”

"A successful innovation and a great achievement for our young Helmholtz Institute", Professor Thomas Stöhlker, director of the Helmholtz Institute Jena, congratulates the awardees. "In only a few years we managed to give impressive impulses to fundamental research as well as applications of high-energy lasers."

With their development, the physicists won first place in the finals of the OptecNet Start-up Challenge. The prize is endowed with 10 000 euros and includes a cost-free “HansePhotonik” network membership and a company presentation in the trade journal “Photonik”.

Award ceremony
Laser system
Dr. Mark J. Prandolini, Dr. Robert Riedel und Dr. Michael Schulz (from left to right)
Foto: Class 5 Photonics
Foto: M. Schulz