Ultrafast Coupling of Optical Near Fields to Low-Energy Electrons Probed in a Point-Projection Microscope.
Nano Lett
; 23(12): 5528-5534, 2023 Jun 28.
Article
en En
| MEDLINE
| ID: mdl-37278447
We report the first observation of the coupling of strong optical near fields to wavepackets of free, 100 eV electrons with <50 fs temporal resolution in an ultrafast point-projection microscope. Optical near fields are created by excitation of a thin, nanometer-sized Yagi-Uda antenna, with 20 fs near-infrared laser pulses. Phase matching between electrons and near fields is achieved due to strong spatial confinement of the antenna near field. Energy-resolved projection images of the antenna are recorded in an optical pump-electron probe scheme. We show that the phase modulation of the electron by transverse-field components results in a transient electron deflection while longitudinal near-field components broaden the kinetic energy distribution. This low-energy electron near-field coupling is used here to characterize the chirp of the ultrafast electron wavepackets, acquired upon propagation from the electron emitter to the sample. Our results bring direct mapping of different vectorial components of highly localized optical near fields into reach.
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Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
Nano Lett
Año:
2023
Tipo del documento:
Article
País de afiliación:
Alemania
Pais de publicación:
Estados Unidos