2020/06/23 by Dominique Matte, Nima Chamanara, Lauren Gingras +4
Engineering · Physics and Astronomy · #Advanced Chemical Physics Studies #Atomic physics #Condensed matter physics #Electric field #Electron #Field (mathematics) #Field electron emission #Gyrotron and Vacuum Electronics Research #Laser #Materials science #Optics #Physics #Quantum tunnelling #RADIUS #Terahertz radiation #Terahertz technology and applications #Tungsten #Ultrashort pulse #physics.app-ph #physics.optics
paper · pdf · doi:10.1103/physrevresearch.3.013137
published as Phys. Rev. Research 3, 013137 (2021) · 7 pages, 4 figures, Supplemental material (5 pages, 5 figures)
arxiv created 2020/06/23 · openalex publication_date 2021/02/11 · arxiv updated 2021/02/17 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We report on subcycle terahertz light-field emission of electrons from tungsten nanotips under extreme conditions corresponding to a Keldysh parameter K 10 -4 . Local peak THz fields up to 40 GV/m are achieved at the apex of an illuminated nanotip, causing subcycle cold-field electron emission and acceleration in the quasistatic field. By simultaneous measurement of the electron bunch charge and energy distribution, we perform a quantitative test of quasistatic Fowler-Nordheim tunneling theory under field conditions that completely suppress the tunnel barrier. Very high bunch charges of 10 6 electrons/pulse are observed, reaching maximum energies of 3.5 keV after acceleration in the local field. The energy distribution and emission current show good agreement with Fowler-Nordheim theory even in this extreme field regime. Application of this theory under such extreme THz field conditions predicts a single-shot electron energy distribution with a spectral purity reaching 10 -4 . THz field-induced reshaping and sharpening of the nanotip is observed, reducing the tip radius from 120 to 35 nm over roughly 10 9 THz shots. These results indicate THz-driven nanotips in the extreme field limit are promising electron sources for ultrafast electron diffraction and microscopy.