Magneto-optics of quantum systems and nano-imaging
Prof Jörg Wrachtrup, Universität Stuttgart
Addressing magnetic degree of freedom in solids by light is a central challenge in data storage, quantum information processing as well as metrology. Usually it is angular momentum conservation, i.e. parity, that governs interaction strength. Since solids – unlike atoms- in most cases are low symmetry system any kind of magnetism imprints low a fidelity signal on their optical response. There are notable exceptions to this rule, most importantly rare earth dopants or diamond defect centers. Here not only single spins can be read out but even quantum correlations, i.e. entanglement among spins and photons can be generated under ambient conditions. Details of the magneto optical behavior of those systems and highlight applications will be explained. For example high resolution imaging of magnetic noise fields is of use in material science and bioanalytics. Alternatively high angular momentum light beams generated for example in dedicated plasmonic structures may be used to significantly enhance the usually weak Faraday effect allowing for readout of weak magnetic moments. The talk will describe the generation of those light fields and detection of the tiny Faraday effect caused by the magnetic field of a few nuclear spins.
The Distinguished Lecturer Series (DLS) follows a colloquium format for a broad audience and will be followed by a reception to provide an opportunity for meeting the speaker.