SAMOP 2021 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 2: Precision spectroscopy of atoms and ions (joint session A/Q)
A 2.12: Poster
Montag, 20. September 2021, 16:30–18:30, P
Towards direct optical excitation of the nuclear clock isomer 229mTh — •Johannes Thielking, Maksim V. Okhapkin, Jascha Zander, Johannes Tiedau, Gregor Zitzer, and Ekkehard Peik — Physikalisch-Technische Bundesanstalt, 38116 Braunschweig, Germany
The transition of the 229Th nucleus between its ground state and its uniquely low-lying isomer at about 8 eV has been proposed as a frequency reference for a highly precise type of optical clock [1]. Although several advances have been made in determining the transition energy and nuclear properties [2], its optical excitation is still pending. To this end, we are currently developing a vacuum ultraviolet (VUV) laser system based on resonance enhanced four-wave difference mixing in xenon. The mixing process is driven by two pulsed dye laser amplifiers with a pulse duration of 10 ns. The amplifiers are seeded with cw ring lasers to achieve a Fourier transform limited bandwidth. The laser system provides VUV pulses with photon numbers of about 1013 per pulse and a broad tunability that covers the current uncertainty range of the nuclear excitation energy. Here we will report on the current status of the laser development, as well as future experiments to excite the isomeric state in trapped ions and a Th-doped crystal.
[1] E. Peik, Chr. Tamm, Europhys. Lett. 61, 181 (2003).
[2] K. Beeks et al., Nature Reviews Physics 3(4), 238-248 (2021).