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.