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.
Categories: physics.atom-ph