Measurement of hyperfine structure in the $ \rm D_1 $ line of Rb

TL;DR

This paper presents a precise measurement of hyperfine constants in the D1 line of rubidium isotopes using a novel laser scanning technique that reduces experimental noise and resolves discrepancies in previous data.

Contribution

The study introduces a laser scanning method for hyperfine measurements that overcomes servo-loop errors, providing more accurate values for rubidium isotopes compared to earlier results.

Findings

Measured hyperfine constants: 120.510(26) MHz for 85Rb

Measured hyperfine constants: 408.340(19) MHz for 87Rb

Results are consistent with other recent measurements but differ from previous lab data.

Abstract

We report a precise measurement of hyperfine constants in the $\rm{D_1} $ line ($ \rm {5\,P_{1/2}} $ state) of the two stable isotopes of Rb. The motivation for the work is to try and resolve discrepant values that exists in the literature. We use a technique that is different from other methods---one where the laser is not locked to a particular transition but scanned around it. This is advantageous because it overcomes frequency shifts due to servo-loop errors and other sources of noise in the experiment. The values in the two isotopes are: $ A = 120.510(26) $ MHz in $\rm {^{85}Rb}$, and $ A = 408.340(19) $ MHz in $\rm {^{87}Rb}$. These values are at variance with earlier values reported from our lab, but consistent with other published measurements.