Observation of double-resonant laser-induced transitions in the v=n-l-1=2 metastable cascade of antiprotonicHe4atoms

Another laser-induced resonant transition in the v=n-l-1=2 metastable cascade of antiprotonic ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ atoms has been found by using a double-resonance technique. This was done by setting the first laser to the already known 470.724-nm resonance [(n,l)=(37,34)→(36,33)], while the (38,35)→(37,34) transition was searched for with the second laser. The resonant transition was found at a wavelength of 529.622±0.003 nm, showing excellent agreement with a recent prediction of Korobov.