Vacuum-ultraviolet laser source for spectroscopy of trapped thorium ions

authored by

J Thielking, K Zhang, J Tiedau, J Zander, G Zitzer, M v Okhapkin, Ekkehard Peik

Abstract

A tunable vacuum-ultraviolet (VUV) laser source based on four-wave frequency mixing in xenon is presented. Using seed radiation from two continuous-wave lasers, the system allows for precise control of the VUV frequency and is developed for the resonant laser excitation of the Th-229 nucleus to its low-energy isomeric state. The system is prepared to operate in a wide scanning range from 148 nm to 155 nm. The source produces pulses of 6-10 ns duration with up to 40 µJ energy and is coupled via a vacuum beamline to a linear radiofrequency ion trap. In a first implementation of VUV laser spectroscopy of trapped Th

⁺ ions we excite three previously unknown resonance lines near 149 nm wavelength to electronic levels that are close to the Th-229 isomer energy. The resonances are detected and analyzed via fluorescence of the excited Th

⁺ ions. An analysis of the lineshape is used to estimate the linewidth of the VUV radiation to be in the range of ⩽ 6 GHz, dominated by phase noise that is enhanced in harmonic generation and in the four-wave mixing process. The prospects for the use of the system in nuclear laser spectroscopy of Th-229 are discussed.

External Organisation(s)

Physikalisch-Technische Bundesanstalt PTB

Type

Article

Journal

New journal of physics

Volume

Pages

083026

ISSN

1367-2630

Publication date

14.08.2023

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

General Physics and Astronomy

Electronic version(s)

https://doi.org/10.1088/1367-2630/aced1b (Access: Open)

BibTeX

@article{5ba3fcb05705488b9a9cd10c6beef399,
title = "Vacuum-ultraviolet laser source for spectroscopy of trapped thorium ions",
abstract = "A tunable vacuum-ultraviolet (VUV) laser source based on four-wave frequency mixing in xenon is presented. Using seed radiation from two continuous-wave lasers, the system allows for precise control of the VUV frequency and is developed for the resonant laser excitation of the Th-229 nucleus to its low-energy isomeric state. The system is prepared to operate in a wide scanning range from 148 nm to 155 nm. The source produces pulses of 6-10 ns duration with up to 40 µJ energy and is coupled via a vacuum beamline to a linear radiofrequency ion trap. In a first implementation of VUV laser spectroscopy of trapped Th + ions we excite three previously unknown resonance lines near 149 nm wavelength to electronic levels that are close to the Th-229 isomer energy. The resonances are detected and analyzed via fluorescence of the excited Th + ions. An analysis of the lineshape is used to estimate the linewidth of the VUV radiation to be in the range of ⩽ 6 GHz, dominated by phase noise that is enhanced in harmonic generation and in the four-wave mixing process. The prospects for the use of the system in nuclear laser spectroscopy of Th-229 are discussed.",
keywords = "nuclear laser excitation, trapped ions, VUV laser",
author = "J Thielking and K Zhang and J Tiedau and J Zander and G Zitzer and Okhapkin, {M v} and Ekkehard Peik",
note = "Publisher Copyright: {\textcopyright} 2023 The Author(s). Published by IOP Publishing Ltd on behalf of the Institute of Physics and Deutsche Physikalische Gesellschaft.",
year = "2023",
month = aug,
day = "14",
doi = "10.1088/1367-2630/aced1b",
language = "English",
volume = "25",
pages = "083026",
journal = "New journal of physics",
issn = "1367-2630",
publisher = "IOP Publishing Ltd.",
number = "8",
}