Magneto-optical trap for sodium atoms operating on the D1 line

Abstract We report on the observation of magneto-optical trapping of sodium atoms in the 3 S 1 2 → 3 P 1 2 transition (D 1 line). There are four combinations of atomic transitions within the D 1 line which produce trapping: two of them are achieved with the usual orthogonal circular polarizations used in the trap operating on the D 2 line, while the other two are just observed with reversed polarizations. The need of reversing the polarizations is attributed to the negative Zeeman shift of the lower hyperfine levels of the D 1 transition in alkalis. We have confined 10 5 to 10 7 atoms, depending on the atomic transitions involved.