Miniature light-driven nanophotonic electron acceleration and control

Abstract

Dielectric laser accelerators (DLAs) are fundamentally based on the interaction of photons with free electrons, where energy and momentum conservation are satisfied by mediation of a nanostructure. In this scheme, the photonic nanostructure induces near-fields which transfer energy from the photon to the electron, similar to the inverse-Smith–Purcell effect described in metallic gratings. This, in turn, may provide ground-breaking applications, as it is a technology promising to miniaturize particle accelerators down to the chip scale. This fundamental interaction can also be used to study and demonstrate quantum photon-electron phenomena. The spontaneous and stimulated Smith–Purcell effect and the photon-induced near-field electron-microscopy (PINEM) effect have evolved to be a fruitful ground for observing quantum effects. In particular, the energy spectrum of the free electron has been shown to have discrete energy peaks, spaced with the interacting photon energy. This energy spectrum is correlated to the photon statistics and number of photon exchanges that took place during the interaction. We give an overview of DLA and PINEM physics with a focus on electron phase-space manipulation.

Asymmetric Dual-Grating Dielectric Laser Accelerator Optimization

“…There is no Alternating Phase Focusing [16,17] or ponderomotive-based focusing [18] scheme, but the laser field phase is tapered to match the energy gain of the accelerated electrons. In practice, this tapering could be accomplished via soft-tuning the laser phase with a spatial light modulator (SLM); although, so far this has not been experimentally demonstrated [15,19]. Without an incident field, 99.3% of particles are transmitted; this drops to 57.2% with the addition of an input field.…”

Capturing the non-equilibrium state in light–matter–free-electron interactions through ultrafast transmission electron microscopy

“…The electron wave function after the interaction is sinusoidally modulated in phase, enabling manipulation of both longitudinal and transverse components by the electromagnetic field. Phase-space manipulation in the longitudinal direction has been adopted for attosecond electron pulse trains [112,113] and electron acceleration, [114] and in the transverse direction for electron wavefront shaping. [115,116] The classical view is that the longitudinal phase modulation is based on the tailoring of the electron wave function in the time domain.…”

Free-electron Brewster-transition radiation

“…Nevertheless, at the base of all these is still a weak particle-matter interaction. The weak interaction severely impedes the development of many more enticing applications of free-electron radiation, such as the miniaturization of free-electron radiation sources ( 22 , 30 – 32 , 38 , 39 ) and high-energy particle detectors ( 18 , 19 , 40 ). The realization of such applications could boost the on-chip integration of free-electron light sources (e.g., in the terahertz/x-ray regimes) and to facilitate the direct detection of high-energy particles in outer space.…”