A spectroscopic study of the cycling transition 4s[3/2]_2-4p[5/2]_3 at 811.8 nm in Ar-39: Hyperfine structure and isotope shift

TL;DR

This study uses Doppler-free spectroscopy to analyze the hyperfine structure and isotope shift of a specific transition in radioactive argon isotopes, providing data crucial for laser trapping and cooling applications.

Contribution

The paper provides new measurements of hyperfine constants and isotope shifts for Ar-39, and compares them with previous data, aiding in laser cooling techniques for radioactive argon isotopes.

Findings

Hyperfine constants A and B for Ar-39 levels determined.

Isotope shift between Ar-39 and Ar-40 derived.

Results partially disagree with previous measurements.

Abstract

Doppler-free saturated absorption spectroscopy is performed on an enriched radioactive Ar-39 sample. The spectrum of the 3s^2 3p^5 4s [3/2]_2 - 3s^2 3p^5 4p [5/2]_3 cycling transition at 811.8 nm is recorded, and its isotope shift between Ar-39 and Ar-40 is derived. The hyperfine coupling constants A and B for both the 4s [3/2]_2 and 4p [5/2]_3 energy levels in Ar-39 are also determined. The results partially disagree with a recently published measurement of the same transition. Based on earlier measurements as well as the current work, the isotope shift and hyperfine structure of the corresponding transition in Ar-37 are also calculated. These spectroscopic data are essential for the realization of laser trapping and cooling of Ar-37 and Ar-39.