Electrons meet light

Abstract

The precise transverse control of electrons is at the heart of any high-resolution electron microscope where electron lenses and multipole aberration correctors have enabled sub-Angström spatial resolution. This work describes a novel way of achieving transverse control over the electrons [1]. In the specimen chamber of a modified ultrafast scanning electron microscope, the electron pulse interacts in free space with a shaped counterpropagating laser pulse, inducing on-demand phase shifts to the electron wave. We demonstrate convex and concave light-based electron lensing, whereas concave lensing is impossible with traditional magnetostatic lenses. Furthermore, we show that we can create arbitrary electron intensity patterns. In contrast to other competing electron-shaping technologies, the light-based method is programmable and avoids losses, inelastic scattering, and instabilities due to the degradation of material diffraction elements. In the future, parts of the electron microscopes might be made of optical systems to improve the resolution and contrast of electron images.