We demonstrate the quantized transfer of photon energy and transverse momentum to a high-coherence electron beam. In an ultrafast transmission electron microscope, a three-dimensional phase modulation of the electron wave function is induced by transmitting the beam through a laser-illuminated thin graphite sheet. This all-optical free-electron phase space control results in high-purity superpositions of linear momentum states, providing an elementary component for optically programmable electron phase plates and beam splitters.

• Received 10 March 2020
• Accepted 31 August 2020

DOI:https://doi.org/10.1103/PhysRevResearch.2.043227

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Published by the American Physical Society