fig9

Figure 9. Development of AEM and representative applications. (A) Momentum projection of the Wigner function showing laser-induced spectral modulations. The temporal projection yields an 82 as (FWHM) peak in the laboratory frame. Reprinted with permission^[16]. Copyright 2015, Springer Nature. (B) Generation and characterization of laser-compressed attosecond electron pulse trains at a dielectric foil. Attosecond streaking (deflect gram) and pulse retrieval give a 820 as (FWHM) peak above the background. Reprinted with permission^[165]. Copyright 2018, Springer Nature. (C) Concept and experimental layout of attosecond-resolution electron microscopy. A laser-driven modulation stage produces attosecond electron pulses that probe the specimen at a controlled attosecond dela y. Reprinted with permission^[158]. Copyright 2020, AAAS. (D) Light-cycle-resolved imaging within one optical cycle. Energy-change maps ΔE(r, Δt) provide field-cycle contrast and yield time-sequenced gain/loss images with nm-attosecond precision. Reprinted with permission^[159]. Copyright 2023, Springer Nature. (E) High-spatial-resolution free-electron homodyne detection (FREHD). A focused beam traverses the sample and a vertically displaced reference membrane, and phase-controlled interferograms from raster-scanned spectra reconstruct the complex sample-induced phase modulation. Reprinted with permission^[47]. Copyright 2024, AAAS. (F) Generation of attosecond electron coils. An optical vortex imprints a space-time-dependent momentum shift Δp to the electron wavepacket, then free-space propagation forms a chiral coil, and planar-wave attosecond gating with delay scanning enables 3D reconstruction. Reprinted with permission^[166]. Copyright 2024, Springer Nature.