High-Precision Measurement of the Laser-Trapping Frequencies for $^{209,210,211}$Fr Atoms

TL;DR

This paper reports highly precise measurements of laser-trapping transition frequencies for three francium isotopes, significantly improving accuracy and aiding future atomic structure tests.

Contribution

It introduces an interferometric method for accurate frequency measurement of francium isotopes, achieving an order of magnitude better precision than previous work.

Findings

Final accuracy of 8 MHz for the transition frequencies

Improved measurement precision for $^{210}$Fr

Potential for enhanced tests of atomic theory

Abstract

We present the accurate measurement of the frequency of the $7S-7P$ laser-trapping transition for three francium isotopes. Our approach is based on an interferometric comparison to deduce the unknown laser frequency from a secondary laser frequency-standard. After careful investigation of systematics, with samples of about 100 atoms the final accuracy reaches 8 MHz, an order of magnitude better than the best previous measurement for $^{210}$Fr, and opens the way to improved tests of the theoretical computation of Fr atomic structure.