Compact lasers as alternative to synchrotron facilities

15 Apr 2019 | Source: Universität Jena - News

The European Research Council (ERC) will provide close to 2.5 million euros over the next five years to fund the development of a high-performance fibre laser system at Friedrich Schiller University in Jena, to generate coherent laser pulses in the infrared, terahertz and soft X-ray range. Prof. Jens Limpert and his research team at the Institute of Applied Physics will receive one of the prestigious ERC Advanced Grants for this work. Limpert is one of the few researchers in Germany – and the only one in the state of Thuringia – who has succeeded in obtaining an ERC grant no fewer than three times. In 2009, he received a ‘Starting Grant’, followed by a ‘Consolidator Grant’ in 2014.

This is a great honour for me, but also for the entire team,” says Limpert. He sees the funding as a confirmation of his scientific work to date, which “was not only achieved by me, but together with my staff”. This success is motivating the Jena University researchers to tackle new and exciting topics and challenges and they are doing just this in the ERC-funded project ‘SALT’ (High-Flux Synchrotron Alternatives Driven by Powerful Long-Wavelength Fibre Lasers). With this project, Limpert and his team want to expand the range of applications that are currently possible with high-performance particle accelerators (synchrotrons). They aim to do this using frequency-converted fibre lasers, which can be operated in any standard laser laboratory.  

High-performance radiation in the terahertz and mid-infrared range

Such ultra-fast laser systems already have a wide variety of applications. Explaining their advantages, Limpert says: “They are capable of producing high-energy radiation pulses and they can do this even though they are very compact in size.” However, the drawback is that the radiation spectrum of the lasers is limited. “But beyond these limits, there is enormous potential for applications,” adds Limpert. For example, high-performance radiation in the terahertz range could enable innovative approaches to the non-destructive investigation of complex materials. In the mid-infrared spectral range, a pioneering application would be the detection of diseases in the human body using modern spectroscopy. Current laser-based sources are not yet capable of performing in a way that makes practical applications possible. Large-scale research facilities such as synchrotrons need to be involved for basic research.

However, access to such research facilities is very limited and is far from being available for all innovative research questions. “For this reason, we want to develop an alternative way of making such radiation sources available to a wider circle of researchers,” Limpert. Since direct emission of coherent radiation with the wavelength agility and performance of a synchrotron is not possible with conventional lasers, the physicists in Jena are adopting a different approach. They first generate laser pulses of a different frequency and focus them through a non-linear medium, which shifts the frequency into the desired range (frequency conversion). In the SALT project, they will use laser radiation with a significantly longer wavelength than it was previously the case. They want to achieve this, among other things, by using thulium-doped ultrafast fibre lasers.

One of the largest grants in the European Union

The ERC Advanced Grant is one of the largest grants in the European Union. This year, the ERC has awarded Advanced Grants to 222 researchers throughout Europe, from more than 2,000 applications.


Prof. Dr Jens Limpert
Institute of Applied Physics
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D-07745 Jena
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