Spin exchange collision mixing of the K and Rb ac Stark shifts

TL;DR

This paper investigates how spin exchange collisions in a hybrid K-Rb vapor cell influence the AC Stark shifts, revealing that the shifts are a combination of individual atomic shifts and can be mitigated in a co-magnetometer setup.

Contribution

It demonstrates the mixing of AC Stark shifts due to spin exchange collisions and shows how this effect can be used to reduce shifts in a K-Rb-21Ne co-magnetometer.

Findings

AC Stark shift of Rb includes contributions from both Rb and K atoms.

Fast spin exchange causes mixing of light shifts between K and Rb.

Using collision mixing, the AC Stark shift in Rb can be reduced.

Abstract

In a hybrid pumping alkali vapor cell that both K and Rb are filled, K atom spins are optically pumped by laser and Rb atom spins are polarized by the K spins through spin exchange. We find that the AC Stark shift of the Rb atoms is composed of not only the AC Stark shift of the Rb atoms caused by the far off resonant pumping laser which is tuned to the K absorption lines, but also the AC Stark shift of the K atom spins. The mixing of the light shifts through fast spin exchange between K and Rb atoms are studied in this paper and we demonstrate a K-Rb-21Ne co-magnetometer in which the AC Stark shift of the Rb atoms are reduced by the collision mixing.