Rabi oscillations and adiabatic rapid passage measured in the 2s-3p transition of atomic hydrogen

The transitions to the 3p/sub 1/2/ and 3p/sub 3/2/ levels of H have been observed by transverse CW laser excitation of the metastable component of a hydrogen atomic beam. The velocity of the atomic beam ( nu ~4*10/sup 4/ cm/s) was chosen to avoid spontaneous decay during the interaction time. The energy separation between the 1/2 and 3/4 levels is larger than the Doppler and transit time broadening and allows measurements of the two excitation processes separately, according to their transitions dipole moments. The authors report measurements of Rabi oscillations and adiabatic following created by spatial modulation of the laser field.