Studies on the excitation mechanism and ionization probability of atomic multi-channel photo-excitation and ionization processes
Year: 2025
Type: article
Abstract: Atomic selective ionization processes provide critical ionization probability and isotopic selectivity in laser isotope separation, especially for the non-zero nuclear spin isotope. The semi-classical density matrix theory is established with the consideration of magnetic sublevels of near-resonantly excited hyperfine levels. For determining the dimensionless transition cross sections of hyperfine transition channels are proposed in this article, i.e. the saturated excitation line-shape comparison method and weak excitation signal strength method, and a good agreement is achieved between numerical transition cross sections and experimental results for several isotopes of non-zero nuclear spin. The dependence of saturated ionization probability on laser polarization is studied systematically, and the hyperfine transition of ΔF=+1 is found to be superior to ΔF=-1, 0 in terms of saturated ionization probability. A general formula of oversaturated ionization probability is summarized for different hyperfine transitions. An interesting phenomenon that we call it “magnetic sublevel coherence trapping” is employed to explain the inadequate ionization probability under the oversaturated excitation condition for the ΔF=-1 hyperfine transition, and its mechanism is discussed by the temporal evolution of the density matrix equations. These numerical studies can provide beneficial references for laser isotope separation researches.
Authors: Xiaoyong Lu, Lide Wang, Junyao Zhang
Language: English
Topic: Atomic and Molecular Physics
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $2,870
Award: G202902634
OpenAlex ID: W4409671594