Optical pumping effect in absorption imaging of F=1 atomic gases

TL;DR

This paper develops an analytic model for the optical pumping effect in absorption imaging of F=1 atomic gases, validated by experiments with sodium Bose-Einstein condensates, aiding precise spin state measurements.

Contribution

It provides a new analytic expression for the optical signal in F=1 absorption imaging, enabling improved quantitative analysis of spinor condensate images.

Findings

Analytic expression accurately describes optical pumping effects.

Experimental validation with sodium BECs in various spin states.

Applicable to other alkali atoms with I=3/2 nuclear spin.

Abstract

We report our study of the optical pumping effect in absorption imaging of $^{23}$Na atoms in the $F=1$ hyperfine spin states. Solving a set of rate equations for the spin populations in the presence of a probe beam, we obtain an analytic expression for the optical signal of the $F=1$ absorption imaging. Furthermore, we verify the result by measuring the absorption spectra of $^{23}$Na Bose-Einstein condensates prepared in various spin states with different probe beam pulse durations. The analytic result can be used in the quantitative analysis of $F=1$ spinor condensate imaging and readily applied to other alkali atoms with $I=3/2$ nuclear spin such as $^{87}$Rb.