Quantum Coherent Control of Slow Electron Wave Packets with Light

Summary form only given. Interaction of a moving electron wave packet in free space with light and nanostructures have taken much attention recently, by the emergence of photon-induced near-field electron microscopy [1-2]. Electron beams can inelastically interact by laser-induced nearfield distribution of the nanostructures, opening ways in shaping the electron wave packets and characterization of plasmon polaritons. The interaction of high energy electron waves with laser-induced excitations in the sample is generally discussed within eikonal approximations, neglecting other effects which arise from the pondermotive forces and experienced elastic recoils [3-4]. In contrast, coherent control of above threshold ionization and high harmonic generation can be understood by interferences between different quantum paths, related to ponderomotive and absorptive parts in the minimal coupling Hamiltonian [5]. Here, we discuss the coherent interaction of electron wave packets with light and nanostructures. Using a recently developed self-consistent numerical scheme, the interaction will be modelled using the full minimal coupling Hamiltonian, beyond Eikonal approximations [6, 7]. We first consider the interaction within the framework of generalized Kapitza-Dirac effect, in which the elastic interaction of electron waves with standing wave pattern of light will cause the electron to be diffracted into distinct momentum orders (Fig. 1). The quantum coherent interferences between ponderomotive and absorptive channels can be used to coherently control the diffraction orders [8]. In a second part, we consider the electron wave interaction with near -field optical distributions, which leads to the coherent control in not only transverse distribution of the electrons, but also in its longitudinal gain and loss channels.