Quantum coherence, central to modern physics, underlies phenomena such as entanglement and Rabi oscillations, which lack classical analogues. This internship aims to explore a fundamental open question: can a relativistic free electron be entangled with a photon through its interaction with a plasmon? The project, which may evolve into a PhD thesis, combines experimental, instrumental, and theoretical efforts to reveal temporal correlations between ~100 keV electrons and photons mediated by surface plasmons. Using a scanning transmission electron microscope, a nanoscale electron probe will be positioned with nanometric precision on specially designed chiral plasmonic structures that emit circularly polarized photons at specific plasmonic resonances. Preliminary calculations indicate that in these conditions, each inelastic electron acquires a defined orbital angular momentum and becomes nearly perfectly entangled with a circularly polarized photon. The internship will focus on performing correlation measurements between electrons and photons to probe this entanglement, including tests of Bell inequality violations. These experiments will leverage a unique combination of advanced instrumentation, tailored nanostructures, and state-of-the-art detectors available in our group.