| Autor: |
Dominique Matte, Nima Chamanara, Lauren Gingras, Laurent P. René de Cotret, Tristan L. Britt, Bradley J. Siwick, David G. Cooke |
| Jazyk: |
angličtina |
| Rok vydání: |
2021 |
| Předmět: |
|
| Zdroj: |
Physical Review Research, Vol 3, Iss 1, p 013137 (2021) |
| Druh dokumentu: |
article |
| ISSN: |
2643-1564 |
| DOI: |
10.1103/PhysRevResearch.3.013137 |
| Popis: |
We report on subcycle terahertz light-field emission of electrons from tungsten nanotips under extreme conditions corresponding to a Keldysh parameter γ_{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. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
|
