Regular Article – Theoretical Physics
The theory of direct laser excitation of nuclear transitions
LMU Munich, 85748, Garching, Germany
2 Max Planck Institute for Nuclear Physics, 69117, Heidelberg, Germany
3 University of Bonn, 53105, Bonn, Germany
4 Max Planck Institute of Quantum Optics, 85748, Garching, Germany
5 WPI c/o Fak. Mathematik Univ. Wien, Oskar-Morgenstern-Platz 1, 1090, Vienna, Austria
6 Atominstitut, TU Wien, Stadionallee 2, 1020, Vienna, Austria
Accepted: 5 June 2020
Published online: 6 July 2020
A comprehensive theoretical study of direct laser excitation of a nuclear state based on the density matrix formalism is presented. The nuclear clock isomer Th is discussed in detail, as it could allow for direct laser excitation using existing technology and provides the motivation for this work. The optical Bloch equations are derived for the simplest case of a pure nuclear two-level system and for the more complex cases taking into account the presence of magnetic sub-states, hyperfine-structure and Zeeman splitting in external fields. Nuclear level splitting for free atoms and ions as well as for nuclei in a solid-state environment is discussed individually. Based on the obtained equations, nuclear population transfer in the low-saturation limit is reviewed. Further, nuclear Rabi oscillations, power broadening and nuclear two-photon excitation are considered. Finally, the theory is applied to the special cases of Th and U, being the nuclear excited states of lowest known excitation energies. The paper aims to be a didactic review with many calculations given explicitly.
© The Author(s) 2020. corrected publication 2021
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