Magneto-optics meets Transmission Electron Microscopy

Both magnetism and optics have been in use by mankind for centuries. Magnetism, originating from the cooperation of multitudes of electron spins acting as tiny magnetic dipoles in a material is invaluable to the operation of modern computers. It plays a vital role in current memory and data storage and holds promise for enabling future computing power through spintronics and quantum computing. Optics, meanwhile, is ubiquitous in everyday life, from vision correction and imaging devices to worldwide optical communication networks and speed-of-light computing. This project is situated at the unique interface of these two fields, where many engaging questions remain on the nature of the fundamental interactions between spins and light. Magnetic materials change the properties of transmitted and reflected light, leading to intriguing possibilities in creating active, ultrafast optical switches. Interactions between magnetism and light can be further enhanced using nanoscale (~10 -9 m) phenomena known as surface plasmons. Surface plasmons are waves of electron density coupled to light, akin to waves in the ocean. They are capable of confining and enhancing electromagnetic energy at length scales well below those typically obtainable with standard optics. In my research, I will study magneto-optical effects in nanoscale plasmonic devices supported by magnetic nanostructures using a transmission electron microscope (TEM). For almost a century, the TEM has been a powerhouse of materials characterization, using high energy electron beams to image single atoms and collect information across a broad spectral range. With recent advances in my host group, the Haslinger lab at TU Wien, we are able to detect and temporally resolve individual interaction events, in which a single electron causes the emission of a single photon from the sample. Using this equipment, I have the opportunity to combine magneto-optical characterization techniques with the high spatial resolution of the TEM to study the behaviour of plasmons under the influence of applied magnetic fields. Reaching down to the very fundamental level of photon-spin interactions, my research will shed light on the quantum and classical correlations between electrons, plasmons, and emitted photons. I will demonstrate new methods for studying magneto-optical properties on a truly nanoscale level, accelerating the development of spintronic and active plasmonic devices for the next generation of ultrafast technologies.