Laser light can modulate the kinetic energy spectrum of free electrons and induce extremely
high acceleration gradients, which are instrumental to electron microscopy and electron
acceleration, respectively. We present a design scheme for a silicon photonic slot
waveguide which hosts a supermode to interact with free electrons. The efficiency of this
interaction relies on the coupling strength per photon along the interaction length. We
predict an optimum value of 0.4266, resulting in the maximum energy gain of 28.27 keV for …

The electron beam (eBeam) emitted by the ultrafast transmission electron microscope
(UTEM) can be selected within a kinetic energy range of 80 keV to 200 keV, which
corresponds to a range of sub-relativistic velocities, 𝑣e, of 0.5 𝑐0 to 0.7 𝑐0 respectively,
where 𝑐0 is the speed of light in vacuum. The UTEM can be operated in one of the following
two modes. The thermionic emission mode delivers a flow of single electrons as random
current once the temperature reaches the work function of the material, which is useful to …