A New Application of a Lamb‐shift Polarimeter

With the use of a spinfilter as the most important component of a Lamb‐shift polarimeter, a beam of metastable atoms in one hyperfine state (α1 or α2) can be produced. By induced transitions it seems possible to observe any transition between the $2S1/2$ metastable hyperfine states or into the short‐lived states $2P1/2$ and $2P3/2$ of the hydrogen (deuterium) atom separately as a function of the magnetic field. According to our estimate, the Breit‐Rabi diagrams for these states can be measured with a precison of about 1 kHz $(4.2×10−12 eV)$ or even better. Furthermore, the hyperfine splittings and the Lamb shift can be observed as well.