Coherent Control of Relativistic Electron Dynamics in Plasma Nanophotonics

Abstract: Intense femtosecond laser pulses interacting with solids can drive electrons to relativistic energies, enabling miniaturized particle accelerators and bright extreme-ultraviolet light sources. In-situ space-time control of these electrons is crucial for developing next-generation laser-based accelerators but remains extremely challenging. We present a novel approach to achieve such control by manipulating the local fields driving these electrons using a nanoengineered dielectric nanopillar target. We demonstrate via experiments and simulations that this sub-femtosecond and nanometer-scale control enables enhanced electron acceleration and control of the directionality of relativistic electrons over a wide angular range and predicts the coherent formation of sub-femtosecond electron bunches from the nanopillars. This research bridges nanophotonics and strong-field plasma physics, offering new opportunities for in-situ control of high-energy particles and advancements in plasma technology.