Observation of terahertz-wave assisted electron scattering by Ar

Abstract

We have shown that electrons (1.0 keV) scattered by Ar in a monocycle THz-wave (0.6 THz) field gain and lose their energy through the THz-wave assisted electron scattering (TAES) and that the magnitude of the energy gain and loss reaches the energy of as many as ∼ 800 photons of the THz-wave, exhibiting the extremely high-order energy exchanges. We have also shown that observed characteristic asymmetries in the azimuthal-angle dependence of the energy spectra of TAES signals are reproduced well quantitatively by the theoretical TAES signals calculated using the modified Kroll-Watson formula and the experimentally determined THz-wave form.