Congratulations to Dr. Chris Körner for completing his PhD with highest grades!

During his PhD, Chris explored optical methods to study magnetization dynamics.

Title: “Optical Microscopy of Magnetic Phenomena Beyond the Diffraction Limit”

Chris’s thesis investigates optical methods for studying magnetization dynamics, emphasizing approaches that overcome the optical diffraction limit. In the first part, it reports the discovery of a six-octave magnonic frequency comb generated in a NiFe thin film driven by MHz radio waves. The dynamics are characterized using confocal NV-center magnetometry, SNS-MOKE microscopy, and micromagnetic simulations. A model is developed in which synchronized switching in film regions—enabled by symmetry breaking—produces the high harmonics. Scanning NV magnetometry is then used to achieve higher-resolution imaging, suited to microstructured devices. The second part presents the development of a new optical instrument combining BLS and SNOM for future nanoscale spin-wave imaging. The setup features a stabilized narrow-band laser and a custom high-throughput spectrometer. The near field system provides a spatial resolution in the 20 nm-range, far below the optical diffraction limit.