Precision measurement of light shifts at two off-resonant wavelengths in a single trapped Ba+ ion and determination of atomic dipole matrix elements

TL;DR

This paper precisely measures light-induced energy shifts in a single trapped barium ion at two wavelengths, enabling the determination of an unknown atomic matrix element and testing atomic theory models.

Contribution

It provides the first measurement of the ratio of light shifts at two wavelengths in a Ba+ ion and derives a key atomic matrix element from these data.

Findings

Measured the light shift ratio at 514.531 nm with 0.2% accuracy.

Measured the light shift ratio at 1111.68 nm, providing new data.

Derived the <5D||er||4F> matrix element from the measurements.

Abstract

We define and measure the ratio (R) of the vector ac-Stark effect (or light shift) in the 6S_1/2 and 5D_3/2 states of a single trapped barium ion to 0.2% accuracy at two different off-resonant wavelengths. We earlier found R = -11.494(13) at 514.531nm and now report the value at 1111.68nm, R = +0.4176(8). These observations together yield a value of the <5D||er||4F> matrix element, previously unknown in the literature. Also, comparison of our results with an ab initio calculation of dynamic polarizability would yield a new test of atomic theory and improve the understanding of atomic structure needed to interpret a proposed atomic parity violation experiment.