Measurement of optical amplification and population dynamics using ultrafast XUV spectroscopy of N<sub>2</sub><sup>+</sup>
We demonstrate a very strong laser gain in the near UV, at 391 nm, involving one- and two-photon transitions between initial and final levels of the transition. This opens the way to the realization of all-optical lasers at short wavelengths. The amplifying medium is N<sub>2</sub><sup>+</sup> at low density, pumped by an intense laser source at a longer wavelength, i.e., 800 nm. It is probed by measuring with femtosecond precision the absorption of XUV high harmonics through the gas, displaying the evolution of the relevant electronic levels during the amplification process. We show the role of a third level forming a "V scheme" with the initial and final levels.
Authors
- Aurélien Houard (ORCID: https://orcid.org/0000-0002-2072-6680)
- Mykyta Redkin (ORCID: https://orcid.org/0000-0002-0976-1821)
- G. Lambert (ORCID: https://orcid.org/0000-0002-1836-7818)
- Shecheng Gao (ORCID: https://orcid.org/0000-0002-7006-5702)
- A. Couairon (ORCID: https://orcid.org/0000-0003-1883-0208)
- A. Mysyrowicz (ORCID: https://orcid.org/0000-0001-8129-1783)
- Rostyslav Danylo (ORCID: https://orcid.org/0000-0003-0112-1659)
- V. T. Tikhonchuk (ORCID: https://orcid.org/0000-0001-7532-5879)
- Yi Liu (ORCID: https://orcid.org/0000-0002-0821-7322)
- Liang Xu (ORCID: https://orcid.org/0000-0001-9515-9409)
- Xiang Zhang (ORCID: https://orcid.org/0000-0002-6340-6708)
Institutions
- Centre National de la Recherche Scientifique (FR)
- École Polytechnique (FR)
- University of Shanghai for Science and Technology (CN)
- Université de Bordeaux (FR)
- Taras Shevchenko National University of Kyiv (UA)
- Commissariat à l'Énergie Atomique et aux Énergies Alternatives (FR)
- Extreme Light Infrastructure Beamlines (CZ)
- Institut Polytechnique de Paris (FR)
Publication Details
- Journal
- Optics Letters
- Published
- 2025-09-05
- DOI
- https://doi.org/10.1364/ol.565942
- Citations
- 1
- Primary Topic
- Laser-Matter Interactions and Applications
- Type
- article
- Field-Weighted Citation Impact
- 1.25