Freiburg 2024 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 56: Poster VII
Q 56.28: Poster
Thursday, March 14, 2024, 17:00–19:00, KG I Foyer
Two-Photon Frequency References for Optical Clocks and Hyperfine Spectroscopy — •Moritz Eisebitt1,2, Julien Kluge1,2, Daniel Emanuel Kohl1,2, Klaus Döringshoff1,2, and Markus Krutzik1,2 — 1Ferdinand-Braun-Insitut, Leibniz-Institut für Höchstfrequenztechnik — 2Institut für Physik, Humboldt-Universität zu Berlin
We present our monochromatic two-photon frequency references at 778 nm, operating on the 5S1/2→ 5D5/2 transition in Rubidium. We use inherently Doppler-free frequency modulation spectroscopy of the approximately 500 kHz broad transition, with detection via the fluorescence at 420 nm. The fractional instability, derived from a beat-note between two independent references, is below 1.7·10−13/√τ, reaching 6·10−15 for an averaging time τ of 1000 s. We present details on the noise analysis including the influence of residual amplitude modulation and fluctuations in the optical power.
Further, measurements of the dipole, quadrupole and octupole hyperfine structure constants of Rb 5D5/2 are presented which surpass the precision of the current state-of-the-art values by one order of magnitude.
This work is supported by the German Space Agency (DLR) with funds provided by the Federal Ministry for Economic Affairs and Climate Action (BMWK) due to an enactment of the German Bundestag under grant numbers 50RK1971, 50WM2164.
Keywords: Two-Photon; Frequency Reference; Rubidium; Hyperfine Structure