Expérimental et théorique
Condensed matter systems often exhibit symmetries that make their response to electromagnetic stimuli dependent on those stimuli polarization. Dichroic responses, whether linear or circular, are therefore invaluable for studying various physical properties such as structural, morphological, electronic or magnetic. Historically, dichroism has been studied using polarized photons, mainly in the visible to X-ray range. However, these techniques often lack spatial resolution. Electron spectroscopy, in particular with electron energy loss spectroscopy (EELS), enables atomic resolution, surpassing optical methods. Challenges remain, however, particularly with regard to the creation of electron waves mimicking optical polarization. Recently, we have developed a new theoretical framework showing that the local density of polarized electromagnetic states, can be measured with tools (“phase plate”) that can manipulate the incident beam electronic wave function. This project aims to use this tool to produce electronic wavefunctions that mimic polarization states, and to test these methods on nanometric optical or magnetic structures. It will cover instrumental, experimental and theoretical aspects, appealing to a curious and motivated candidate.