Winner in the category Dissertation, 2019
"Optische Kohärenztomographie mit extrem ultravioletter Strahlung"
(Optical coherence tomography with extreme ultraviolet radiation)
What induced you to your field of research and the topic of your thesis?
After my student research project about the calibration of a EUV spectrometer at the synchrotron in Triest, I heard about the idea of optical coherence tomography in the extreme ultraviolet spectral range from Prof. Paulus and Dr. Rödel. I found the topic and the potential applications of the technology in the semiconductor industry so exciting, that I was able to convince Mr. Paulus to tackle this direction, which differs from his previous field of research, in my diploma thesis. Due to the promising results of my diploma thesis, I was even more motivated to transfer the technology from the synchrotron to the laser laboratory, to develop the technology further and to eliminate the "teething troubles". Therefore, I dedicated my dissertation to these goals.
What was the topic of your thesis? What fascinated and inspired you about it?
I have developed optical coherence tomography (OCT) in the extreme ultraviolet spectral range (EUV). OCT has been known in the visible and infrared range for three decades and is used especially by ophthalmologists for cross-sectional imaging of the retina. In doing so, the axial resolution does not depend on focusing. Instead, the coherence properties of broadband radiation are used to map the axial direction. The axial resolution is thus independent of the Abbe diffraction limit. Especially in the EUV range, this is a decisive advantage. In my work, I was able to transfer the new EUV method, called XCT, from the synchrotron to specially developed laser-based EUV radiation sources. Besides, I was able to eliminate ambiguities in image reconstruction by using a novel one-dimensional phase reconstruction algorithm. XCT achieves an axial resolution of a few nanometers and finds use in the investigation of layer systems and semiconductor structures.
How did you become aware of the Applied Photonics Award and what motivated you to participate?
A friend and former fellow student won the prize last year. That is why I came up with the idea of applying. My application-relevant topic was also a good match for the selection criteria.
What does the Applied Photonics Award mean to you? Would you recommend participation in the award?
I was very pleased about winning the prize. Anyone who has a Ph.D. or is still doing it knows what effort and stamina are needed. The award is an extraordinary appreciation of my work and performance and fills me with pride. I can warmly recommend everyone to apply for this award. The effort of submission is not great. But the recognition, the positive effects on the CV, the great evening event with guests from the photonics industry and last but not least the prize money are.
What are your plans for the future?
Based on my work, numerous new continuing projects have emerged. A team of six people was formed and I was entrusted with their coordination. As a postdoc, I will remain true to the topic until further notice.