Strongest Magnetically Induced Transitions in Alkali Metal Atoms with nuclear spin \(3/2\)

Abstract

The probabilities of atomic transitions \(F_e - F_g = \pm 2\) between a ground \(F_g\) and an excited \(F_e\) level of \(D_2\) line of any alkali metal atom are zero when no external magnetic field is applied. In an external magnetic field in the range \(0.1 - 3\) kG, the probabilities of these transitions called magnetically induced (MI) are highly modified. For these MI transitions, we have previously exhibited the following rule: the probabilities of MI transitions with \(\Delta F = +2\) are maximal when using \(\sigma^+\)-polarized laser radiation, while the probabilities of MI transitions with \(\Delta F = -2\) are maximal when using \(\sigma^-\)-polarized laser radiation. This difference has been termed Type 1 Magnetically Induced Circular Dichroism (MCD1). It is demonstrated for the first time that for alkali atoms with a nuclear spin \(I=3/2\) (\(^{87}\text{Rb}\), \(^{39}\text{K}\),\(^{23}\text{Na}\), \(^7\text{Li}\)) in magnetic fields \(> 100\) G, the probability of the strongest \(\sigma^+\) MI transition of the group \(F_g = 1 \rightarrow F_e = 3'\) (transition \(\ket{1,-1}\rightarrow\ket{3',0'}\)) is about 4 times higher than the probabilities of the strongest MI \(\sigma^-\)-transitions \(\ket{1,-1}\rightarrow\ket{3',-2'}\) and \(\ket{2,+1}\rightarrow \ket{0',0'}\). These properties make the \(\sigma^+\) MI transition \(\ket{1,-1}\rightarrow\ket{3',0'}\) an interesting candidate for the study of magneto-optical processes in strong magnetic fields.