How to merge matter and light

Georg Richard Schwartz, a Ph.D. student at the Institute of Applied Physics in Prof. Stefan Nolte’s Ultra Optics research group, has been awarded the ZEISS Ph.D. Award in Modern Optics. The award was presented by the Faculty of Physics and Astronomy during the PAF Alumni Day on June 5, 2026, and was sponsored by ZEISS.

The award recognizes Schwartz’s research on so-called chirped pulse amplification (CPA) ultrashort-pulse lasers—a key technology for applications in science, industry, and medicine. These laser systems require highly precise control of dispersion, i.e., the frequency-dependent speed of light propagation. This is precisely where his work comes in: Georg Schwartz developed and investigated novel chirped fiber Bragg gratings that allow the dispersion of optical systems to be adjusted in a targeted and customized manner. This adjustment is achieved by softening the strict periodicity in the refractive index modulation of the fiber core.

A particular focus is on mitigating so-called group delay ripple effects, which lead to spectral phase noise and can significantly degrade the quality of laser pulses. Using high-resolution measurement methods and a deep understanding of the underlying laser-matter interactions, he is able to systematically address these limitations. The goal is to realize fiber Bragg gratings with significantly improved properties—regardless of material composition or wavelength range.

Challenges

Ph.D. candidate Georg Schwartz on the difficulties: “The hardest part is definitely pinpointing the exact physical causes of certain phase errors. When writing with femtosecond lasers, we’re operating in an extremely sensitive and highly coupled parameter space—changing a single parameter has a massive impact on the physical properties of the chirped fiber Bragg gratings. That’s why, for me, the scientific goal wasn’t simply to experiment to find a better component. Our aim was to understand the processes so precisely that we could not only somehow attenuate the phase noise, but systematically prevent its occurrence from the outset.

This work pushes the boundaries of current laser technology and makes an important contribution to the further development of modern optical systems. It combines fundamental physical questions with concrete technological applications.

“After all, science thrives on collaboration”

In addition to his research, Schwartz is also involved in academic self-governance and scholarly exchange. Among other things, he has been active in the student council and the faculty council, and in 2025 he assumed the chairmanship of the DokDok conference. He has received numerous awards for his scientific contributions, including the Best Student Award at the BGPP conference in 2024.

Georg Schwartz on his motivation for his involvement beyond research: “Research is often so detailed and complex that you quickly run the risk of losing yourself completely in your own work in the lab. That is precisely why this involvement has always been an extremely important balance for me—I simply enjoy actively helping to shape things beyond my own experiments. After all, science thrives on collaboration. It is important to me to foster an environment where open exchange, transparent structures, and mutual support matter. For me, a well-connected community is the absolute foundation for good research. Because you don’t just need state-of-the-art technology, but also functioning structures and a genuine dialogue that extends far beyond your own research group.”

With the ZEISS Ph.D. Award, the Faculty of Physics and Astronomy honors outstanding doctoral projects in modern optics. The award is endowed with 5,000 euros and is made possible by the ZEISS company.