Attosecond electron microscopy of sub-cycle optical dynamics

Free-electron Ramsey-type interferometry for enhanced amplitude and phase imaging of nearfields

“…Bucher et al (60) are the first to demonstrate this concept experimentally. The approach we presented here can be directly applied in other interferometric experiments, such as (59,61).…”

Cathodoluminescence Nanoscopy: State of the Art and Beyond

“…26,27 Because the duration of electron pulses can now be limited to hundreds of femtoseconds in ultrafast electron microscopies, further improvement in time resolution is expected, bringing dynamic studies of hot charge carriers in materials within reach. In addition, the realization of trains of attosecond pulses makes it possible for time-resolved CL to surpass the barrier of 10 fs, 151,172,173 hence allowing access to the subcycle dynamics of plasmons. It is worth noting that the temporal resolution of photon detectors is another essential factor governing the performance of this technique.…”

“…Several methods to generate structured electron beams have been described in recent experiments, making the utilization of structured electron beams as quantum electron probes possible. For instance, in the time domain, a single electron pulse can be tailored into a train of attosecond pulses via the coherent interaction of electron pulses with optical near fields (Figure a), − and it can be compressed by pulsed THz fields that is enhanced by resonators. , In the spatial domain, the phase front of electron beams is shaped into a singular spiraling phase using rotated superimposed graphene sheets, holographic gratings (Figure b), magnetic charges, , and plasmonic near fields (Figure c) . Such a vortex electron beam with orbital angular momentum reflects the similarities between electron optics and photonics, which arise from the functional equivalence between the Helmholtz equations and the time-independent Schrödinger equation.…”

“…Recent technical upgrades in ultrafast laser-driven photocathodes , and ultrafast beam blankers , have improved the spatiotemporal resolution of this technique, which has reached a time resolution of 100 ps and a spatial resolution of 12 nm in recent incoherent CL studies. , Because the duration of electron pulses can now be limited to hundreds of femtoseconds in ultrafast electron microscopies, further improvement in time resolution is expected, bringing dynamic studies of hot charge carriers in materials within reach. In addition, the realization of trains of attosecond pulses makes it possible for time-resolved CL to surpass the barrier of 10 fs, ,, hence allowing access to the subcycle dynamics of plasmons. It is worth noting that the temporal resolution of photon detectors is another essential factor governing the performance of this technique.…”

Ultrafast Condensed Matter Physics at Attoseconds

“…Another progress lies in the ATEM recently achieved by Nabben et al [53] They applied a continuous-wave laser to modulate the electron wave function into a rapid sequence of electron pulses, and used an energy filter to resolve electromagnetic near-fields in and around a nanostructure as a movie in spacetime. They investigated the spatiotemporal chirality of the near-fields around a plasmonic needle tip and the spatiotemporal response of dielectric nano-resonators [see Fig.…”