Freiburg 2024 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 59: Lasers II
Q 59.2: Talk
Friday, March 15, 2024, 11:15–11:30, HS 1015
Methods for focusing VUV laser light onto a single 229Th ion — •Tamila Rozibakieva1, Irtiza M. Hussain1, Lilli Löbell1, Daniel Moritz1, Kevin Scharl1, Johannes Weitenberg2, Markus Wiesinger1, Stephan H. Wissenberg2, and Peter G. Thirolf1 — 1Ludwig-Maximilians-Universität München (LMU) — 2Fraunhofer Institute for Laser Technology (ILT), Aachen
Direct frequency-comb spectroscopy is a promising way for narrow-band nuclear laser excitation. The combination of a VUV frequency comb being developed at Fraunhofer ILT and a cryogenic Paul trap set up at LMU Munich as part of the ERC synergy project "Thorium Nuclear Clock", will enable us to excite the isomeric first excited state in 229Th using laser radiation of 148.7 nm wavelength, an important step towards the realization of a nuclear clock that can be used to search for new physics beyond the standard model. For the single-ion nuclear clock, a laser-cooled 229Th3+ ion must be irradiated with a single mode of a frequency comb with narrow bandwidth. When focusing to a spot with a diameter of 3 µm, we envisage sufficient laser radiation intensity for driving nuclear Rabi oscillations. For such tight focusing of a VUV beam on a single ion, it is important to choose the proper optical elements that minimize optical aberrations and power losses due to interaction with optical materials. Different methods and simulations for focusing a VUV beam down to 3 µm, such as a spherical mirror, an off-axis parabolic mirror and an achromatic lens, will be presented. Funding: ERC Synergy project, Grant Agreement No. 856415 and BaCaTec (grant 7-2029-2).
Keywords: VUV radiation; Focusing on a single ion; 229Th; Nuclear laser excitation; Nuclear Clock