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

Abstract

We report our study of the optical pumping effect in absorption imaging of Na-23 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 Na-23 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-metal atoms with I = 3/2 nuclear spin such as Rb-87.