Method for the accurate determination of two-photon transition frequencies as demonstrated with the cesium hyperfine transitions
Phys. Rev. A 112, 052821 – Published 18 November, 2025
DOI: https://doi.org/10.1103/9jtf-dm2q
Abstract
An experimental setup for accurately determining the frequency of alkali-metal-atom two-photon transitions is proposed and demonstrated, with which we avoid laser modulation by an offset-locking technique; keep away collision shift via a high-vacuum pumping; compensate for Zeeman shift directly from the information of the spectral linewidth; remove residual Doppler background by the two-photon crossover spectra; observe the frequency reproducibility between normal days and aftershocks; and compare different approaches of counting laser frequencies, that is, different time bases from either a cesium atomic beam clock or a precalibrated rubidium clock. The frequency of cesium hyperfine transitions and the corresponding hyperfine constants are hence updated, which are both significant for improving the calculation precision of atomic parity nonconservation and for enhancing the accuracy of the two-photon transition-based optical clocks.
