Demonstration of k-vector selective microscopy for nanoscale mapping of higher order spin wave modes

Higher order spin wave modes are deconvoluted by their k-vector and directly imaged with X-ray microscopy, achieving <20 nm spatial and <40 ps temporal resolution. These real space measurements allow a direct insight into the inner workings of complex spin wave systems and reveal their fine structure and localization profi le. While confirming analytical theory on the nanoscale, design paths towards multimode signal transmission in magnonic waveguides are shown.