Population transfer to high angular momentum states in infrared-assisted XUV photoionization of helium
Abstract
An extreme-ultraviolet (XUV) laser pulse consisting of harmonics of a fundamental near-infrared (NIR) laser frequency is combined with the NIR pulse to systematically study two-color photoionization of helium atoms. A time-resolved photoelectron spectroscopy experiment is carried out where energy- and angle-resolved photoelectron distributions are obtained as a function of the NIR intensity and wavelength. Time-dependent Schrödinger equation calculations are performed for the conditions corresponding to the experiment and used to extract residual populations of Rydberg states resulting from excitation by the XUV + NIR pulse pair. The residual populations are studied as a function of the NIR intensity (3.5 × 1010 − 8 × 1012 W cm−2) and wavelength (760–820 nm). The evolution of the photoelectron distribution and the residual populations are interpreted using an effective restricted basis model, which includes the minimum set of states relevant to the features observed in the experiments. As a result, a comprehensive and intuitive picture of the laser-induced dynamics in helium atoms exposed to a two-color XUV–NIR light field is obtained.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jun 29, 2020
- Source ID
- 10.1088/1361-6455/ab9495
Entities
People
- David M. Villeneuve
- Hiromichi Niikura
- Marc J J Vrakking
- Misha Ivanov
- Nicola Mayer
- Oleg Kornilov
- Peng Peng
- Serguei Patchkovskii
Organizations
- Air Force Office of Scientific Research
- Japan Society for the Promotion of Science
- Natural Sciences and Engineering Research Council