High-resolution saturation spectroscopy of singly-ionized iron with a pulsed uv laser

TL;DR

This paper presents a high-resolution uv laser spectroscopy method for singly-ionized iron (Fe II) using a pulsed laser and buffer-gas cooled plasma, achieving sub-Doppler resolution of about 250 MHz.

Contribution

It introduces a novel scheme combining buffer-gas cooled plasma and pulsed-laser saturation spectroscopy for high-resolution Fe II measurements.

Findings

Achieved a linewidth of about 250 MHz for Fe II transition near 260 nm.

Demonstrated the method's suitability for measuring transition frequencies and hyperfine structures.

Potential to measure small isotope shifts in isotope-enriched samples.

Abstract

We describe the design and realization of a scheme for uv laser spectroscopy of singly-ionized iron (Fe II) with very high resolution. A buffer-gas cooled laser ablation source is used to provide a plasma close to room temperature with a high density of Fe II. We combine this with a scheme for pulsed-laser saturation spectroscopy to yield sub-Doppler resolution. In a demonstration experiment, we have examined an Fe II transition near 260 nm, attaining a linewidth of about 250 MHz. The method is well-suited to measuring transition frequencies and hyperfine structure. It could also be used to measure small isotope shifts in isotope-enriched samples.