Hannover 2020 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 14: Poster Session - Atomic Physics II
A 14.18: Poster
Dienstag, 10. März 2020, 16:00–18:00, Empore Lichthof
Towards high-precision spectroscopy of the 1S–2S transition in He+ — •Fabian Schmid1, Akira Ozawa1, Johannes Weitenberg1,2, Theodor W. Hänsch1,3, and Thomas Udem1,3 — 1Max-Planck-Institut für Quantenoptik, Garching — 2Fraunhofer-Institut für Lasertechnik ILT, Aachen — 3Ludwig-Maximilians-Universität München
Accurate tests of a physical theory require a system whose properties can be both measured and calculated with very high precision. One famous example is the hydrogen atom which can be precisely described by bound-state quantum electrodynamics (QED) and whose transition energies can be accurately measured by laser spectroscopy.
We are currently setting up an experiment to perform spectroscopy on the narrow 1S–2S transition in hydrogen-like He+ ions. Due to their charge, He+ ions can be held near-motionless in the field-free environment of a Paul trap, providing ideal conditions for a high precision measurement. Furthermore, interesting higher-order QED corrections scale with large exponents of the nuclear charge, making this measurement much more sensitive to these corrections compared to the hydrogen case.
Driving the transition requires narrow-band extreme-ultraviolet (XUV) radiation at 61 nm. Our approach is to apply direct frequency comb spectroscopy with an XUV frequency comb which is generated from an infrared source using intracavity high harmonic generation. The target He+ ions will be trapped in a linear Paul trap and sympathetically cooled by co-trapped Be+ ions.