Extended Data Fig. 1: Photoelectron spectrum of Xe ionized by the narrow bandwidth feature around 12.365 eV.
From: Extreme-ultraviolet spectral compression by four-wave mixing
The kinetic energy spectrum is calculated from Abel-inverted photoelectron momentum distribution by angular integration between 85∘ and 95∘. A non-linear least squares fit of a Gaussian profile yields a FWHM of 4.0 +/- 0.3 meV (solid line). For more information see Supplementary Information.
