Determination of transition frequencies in a single $^{138}$Ba$^{+}$ ion

TL;DR

This study precisely measured transition frequencies in a single trapped $^{138}$Ba$^{+}$ ion using laser spectroscopy and an optical frequency comb, achieving sub-MHz accuracy for key energy level transitions.

Contribution

It introduces a method combining laser spectroscopy with an optical frequency comb and an eight-level optical Bloch model to accurately determine ion transition frequencies.

Findings

Achieved 0.1 MHz accuracy for two specific transitions.

Achieved 0.2 MHz accuracy for another transition.

Demonstrated a precise measurement technique for single-ion spectroscopy.

Abstract

Transition frequencies between low-lying energy levels in a single trapped $^{138}$Ba$^{+}$ ion have been measured with laser spectroscopy referenced to an optical frequency comb. By extracting the frequencies of one-photon and two-photon components of the line shape using an eight-level optical Bloch model, we achieved 0.1 MHz accuracy for the 5d $^{2}$D$_{3/2}$ - 6p $^{2}$P$_{1/2}$ and 6s $^{2}$S$_{1/2}$ - 5d $^{2}$D$_{3/2}$ transition frequencies, and 0.2 MHz for the 6s $^{2}$S$_{1/2}$ - 6p $^{2}$P$_{1/2}$ transition frequency.