Isotope shifts of the $\left(3s3p\right){{}^{3}P}_{0,1,2}\text{−}\left(3s4s\right){{}^{3}S}_1$ Mg I transitions

We report measurements of the isotope shifts of the $\left(3s3p\right){{}^{3}P}_{0,1,2}\text{−}\left(3s4s\right){{}^{3}S}_1$ Mg I transitions for the stable isotopes ${}^{24}\text{M}\text{g}$ $\left(\text{I}=0\right)$, ${}^{25}\text{M}\text{g}$ $\left(\text{I}=5/2\right)$, and ${}^{26}\text{M}\text{g}$ $\left(\text{I}=0\right)$. Furthermore, the ${}^{25}\text{M}\text{g}$ ${{}^{3}S}_1$ hyperfine coefficient $A\left({{}^{3}S}_1\right)=\left(-321.6\pm 1.5\right)\text{MHz}$ is extracted and found to be in excellent agreement with state-of-the-art theoretical predictions giving $A\left({{}^{3}S}_1\right)=-325\text{MHz}$ and $B\left({{}^{3}S}_1\right)\simeq {10}^{-5}\text{MHz}$. Compared to previous measurements, the data presented in this work are improved up to a factor of 10.

Figure 1

Level diagram for ${}^{24}\text{M}\text{g}$ showing transitions relevant for this Brief Report. There are three stable magnesium isotopes ${}^{24}\text{M}\text{g}$, ${}^{25}\text{M}\text{g}$, and ${}^{26}\text{M}\text{g}$ with nuclear spins of $\text{I}=0$, $\text{I}=5/2$, and $\text{I}=0$, respectively. Dashed line indicates the separation between the singlet and triplet spin states. Note that for ${}^{25}\text{M}\text{g}$, hyperfine structure is present.

Figure 2

(Color online) Schematic diagram of the laser system: T, telescope; DM, dichroic mirror; IF, interference filter; M, mirror; $\lambda /2$, half wave plates; BS, beam splitter; AOM, acousto-optic modulator; PMT, photomultiplier tube. A two-stage YDFA system is used for 1034 nm laser amplification and is single pass frequency doubled in a PPLN crystal. Fluorescence spectroscopy is performed on a metastable magnesium beam, approximately 40 cm from the oven orifice.

Figure 3

(Color online) Fluorescence signal from the ${{}^{3}P}_0\text{−}{{}^{3}S}_1$ transition. Blue curve represents the experimental data and red curve is a fit to the data. The hyperfine splittings of ${}^{25}\text{M}\text{g}{\left({{}^{3}P}_0\right)}_F\text{−}{\left({{}^{3}S}_1\right)}_F$ are indicated as (a)–(c).

Figure 4

(Color online) Fluorescence signal from the ${{}^{3}P}_1\text{−}{{}^{3}S}_1$ transition. Blue curve represents the experimental data and red curve is a fit to the data. The hyperfine splittings of ${}^{25}\text{M}\text{g}{\left({{}^{3}P}_1\right)}_F\text{−}{\left({{}^{3}S}_1\right)}_F$ are indicated as (a)–(g).

Figure 5

(Color online) Fluorescence signal from the ${{}^{3}P}_2\text{−}{{}^{3}S}_1$ transition. Blue curve represents the experimental data and red curve is a fit to the data. The hyperfine splittings of ${}^{25}\text{M}\text{g}{\left({{}^{3}P}_1\right)}_F\text{−}{\left({{}^{3}S}_1\right)}_F$ are indicated as (a)–(i).