We report on spectroscopy of the low-lying electronic transitions in $^{ 224}$Ra$^+$. The ion's low charge to mass ratio and convenient wavelengths make $^{ 224}$Ra$^+$ a promising optical clock candidate. We measured the frequencies of the the $^2{ S}_{ 1/2} \ $$\leftrightarrow$$\ ^2{ P}_{ 1/2}$ cooling transition, the $^2{ S}_{ 1/2}\ $$\leftrightarrow$$\ ^2{ D}_{ 5/2}$ clock transition, the $^2{ D}_{ 3/2} \ $$\leftrightarrow$$\ ^2{ P}_{ 3/2}$ electric dipole transition, and the $^2{ D}_{ 5/2} \ $$\leftrightarrow$$\ ^2{ P}_{ 3/2}$ cleanout transition. From these measurements we calculate the frequencies of the $^2{ D}_{ 3/2}\ $$\leftrightarrow$$\ ^2{ P}_{ 1/2}$ repump transition, the $^2{ S}_{ 1/2} \ $$\leftrightarrow$$\ ^2{ D}_{ 3/2}$ electric quadrupole transition, and the $^2{ S}_{ 1/2} \ $$\leftrightarrow$$\ ^2{ P}_{ 3/2}$ electric dipole transition.
Categories: physics.atom-ph