Embodying the Fraunhofer spirit

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Professor Dr Reinhart Poprawe, director of Fraunhofer ILT, has announced that he will retire this autumn. Here we take a closer look at his extensive career, and the impact he has had on the world of laser technology

This autumn will see the departure of one of the laser industry’s most significant, well-recognised and well-respected figures, Professor Dr Reinhart Poprawe, director of the Fraunhofer Institute for Laser Technology ILT and the Chair for Laser Technology LLT at RWTH Aachen University.

Earlier this year, on the eve of the Laser World of Photonics, a total of 280 experts and companions from the international laser industry gathered at a symposium to pay tribute to Poprawe’s work as a professor of laser technology, as well as to his services to fundamental research, contract research and the networking of industry and science.

Amongst those in attendance were high-ranking representatives from science and industry, including Fraunhofer President Professor Reimund Neugebauer, who remarked: ‘Professor Poprawe embodies the Fraunhofer spirit through and through: Our namesake, Joseph von Fraunhofer, was active in optical technologies and, like him, Poprawe has always viewed innovations with a focus on concrete applications. Since Fraunhofer ILT was founded in Aachen, Professor Poprawe has played a key role in shaping the leading position of the German laser industry worldwide. Back when few recognised how positive the impact of technology clusters could be, he had already laid the foundation for the Aachen institute’s emphasis on combining optical technologies, mechanical engineering and process technology.

At the symposium Poprawe took part in discussions covering digital photonic production, Industry 4.0 and what they mean for future education and research. He was also presented with a symbolic doctoral cap by around 60 of the total 200 scientists who earned their doctorates under his supervision.

Professor Poprawe was presented with a symbolic doctoral cap by around 60 of the 200 scientists who earned their doctorates under his supervision, at a symposium in his honour earlier this year. (Image: Fraunhofer ILT)

A life in lasers

Following the completion of his PhD in physics at Technical University Darmstadt, Poprawe initially joined Fraunhofer ILT in 1985, where he gained his first experience with laser-specific process developments and served as head of the laser-oriented process development department for four years. Following this, in 1989 he turned towards putting this acquired knowledge into industrial practice, working as the managing director of Aachen-based Thyssen Laser-Technik for six and a half years. Thereafter, he returned to the field of teaching and applied research in full force, becoming the director of the Fraunhofer ILT and the Chair for Laser Technology LLT at RWTH Aachen University in 1996 – beginning what will undoubtedly be referred to as ‘the Poprawe era’ of the Fraunhofer ILT going forward.

The following 23 years saw countless innovations made at the institute, ranging from the development of Innoslab lasers and the first diode-pumped multi-kW solid-state lasers for industrial applications, to the development and use of high-power ultrafast lasers, and the process and system development for laser powder bed fusion and extreme high-speed laser material deposition (EHLA). These award-winning innovations were all developed by highly motivated engineers and scientists, to whom Poprawe offered extremely creative freedom along with an outstanding infrastructure and a conducive institute culture.

During his tenure, the number of employees at Fraunhofer ILT, the associated chairs and the cluster grew from 250 to a total of around 800 laser experts and prospective scientists. In addition, according to Fraunhofer ILT, on average a patent was filed at the institute every three to four weeks during the decades of Poprawe’s leadership. Around 30 companies were also founded in this environment, which Poprawe actively supported with his networks during their critical initial phases.

Professor Poprawe discusses the education and research of tomorrow with Dr Peter Leibinger, Professor Burkhard Rauhut, and Professor Alfred Gossner. (Image: Fraunhofer ILT)

Poprawe also served as the vice-president for research, structure and young scientists at RWTH Aachen for a period, during which he co-initiated the RWTH Aachen Campus, an important international technology landscape that now harbours a photonics cluster of around 30 companies. Since 2010, under Poprawe’s leadership, this cluster has been working on new ways of generating, shaping and using light, especially as a tool for industrial production. Within the cluster, Poprawe and the university’s Digital Photonic Production Research Center also initiated a strategic network of 16 institutes from six faculties of RWTH Aachen, which now cooperate in the field of fundamental research of photonic technologies.

In addition to helping shape technological progress in photonics, Poprawe has also dedicated much of his career towards building up the next generation of young talent for the industry. In his time as a professor at RWTH Aachen, not only was he recognised as the first assessor of over 200 doctorates, but his students awarded him the teaching prize of the Faculty of Mechanical Engineering of RWTH Aachen a total of four times.

His work has also been recognised with numerous other awards throughout his impressive career, including the Arthur L Schawlow Award and the Peter M Baker Leadership Award of The Laser Institute (LIA), the Joseph von Fraunhofer Prize, the Innovation Prize of the State of North Rhine-Westphalia, the Fraunhofer coin, and an honorary professorship of Tshingua University in Beijing. He has also held numerous fellowships and board positions, one of which was with the LIA, for which he served as the president throughout 2012.

While Poprawe hasn’t revealed in detail what he plans to do with his retirement, it was hinted in an article by laser manufacturer Trumpf recently that at the age of 12, Poprawe was astonished to hear that there was no map of the universe, and that addressing this could well be on the cards for him over the coming years!

A moment of reflection

In advance of Professor Poprawe’s retirement, Laser Systems Europe caught up with the man himself for a moment of brief reflection on his extensive career.

LSE: What led to you to pursuing a career in laser technology?

RP: In 1977 I had the opportunity to study one year at the California State University in Fresno and San Francisco. During an excursion visit to the largest laser system in the world at this time, the National Ignition Facility (NIF) at Lawrence Livermore Laboratories, I thought: ‘This is wonderful technology, but we should be able also to do some more directly effective innovations for our economy and society.’ After returning to Germany, there were two groups working on kilowatt-class lasers for industrial materials processing. I joined the one which later came to be the core of today’s Fraunhofer Institute for Laser Technology ILT in Aachen.

LSE: How has the role of laser technology in materials processing and manufacturing progressed throughout your career?

RP: The applications have grown significantly. Today, we talk about a market of approximately $14 billion worldwide; 20 years ago, it was maybe one tenth of that. In addition, totally new markets have started, like the additive manufacturing of metals, cleaning, polishing and lately ultrafast ablation by sub-picosecond laser systems. We started in this technology with 1W average power in 1996 and quickly led the world record in average power, today at the multi-kilowatt level.

LSE: How would you say the relationship between research institutes, universities and industry has developed throughout your career?

RP: Fraunhofer represents the inherent model of integrating education in a university institute with an applied research infrastructure under national governance. The model was established 70 years ago and has proven to be extremely successful.

In the meantime, we have extended this model in Aachen to what we call the Aachen Campus, the idea of ‘company matriculation’, which is based on a cooperation between university and research needs. The vision is endorsed by the idea ‘Research tomorrow means knowing, where which kind of knowledge is created’. In the cluster ‘Digital Photonic Production’, which I founded and have led until today, we combine ten university transdisciplinary institutes, four laser RWTH Aachen university chairs and Fraunhofer ILT with about 20 strategically cooperating companies. Altogether, about 800 people work in this model, on fundamental, new processes to generate industrially relevant market innovations in lasers and their applications.

LSE: Could you give an example of one of the many highlights of your time in the laser industry?

RP: Definitely a highlight about how flexible and contact-free laser applications can be was the treatment of approximately 200-disc rotors as built in the German high-speed trains in the 1990s. The discs were non-symmetric and needed cuts in the suspension to allow for thermal expansion during operation. For several months, one train was treated in the MRO terminals of Hamburg every night. Not one cut failed and all trains now run safely!

LSE: Going forward what do you think are some important developments or trends taking place in laser technology that will have a significant impact on future materials processing and manufacturing?

RP: Additive manufacturing and high-rate ultrafast material removal/ablation are of course future core subjects. In medical applications we expect much higher impact in therapy and analysis due to the advent of flexibly selectable wavelengths. The bio-printing of cells and organic materials are also on the horizon and, last but not least, the exploitation of quantum properties of entangled photons will lead to totally new applications.

LSE: And finally, what would you say to the young physicists and engineers out there considering a career in laser technology?

RP: If you have a strong curiosity for ‘what’s next’ in the world, photonics and lasers are an extremely rewarding field for scientific studies. If you are looking for entrepreneurial activities and come from the other side – the markets – and encounter the unique manufacturing characteristics of digital photonic production, you should take a close look at what we are accomplishing in laser technology and join us. Lots of innovations wait to be put to life. We have spun off about 40 companies in the last 30 years – as we say in Germany: ‘Es ist immer Gründerzeit!’.







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