Excitation of coherent atomic states by strong magnetic field pulses

An analysis is made of the action of short magnetic field pulses, sufficiently strong to "break" the hyperfine coupling, on an ensemble of noninteracting atoms. This action alters the polarized states of individual atoms and changes the polarization of the whole ensemble. The ensemble assumes coherent states which correspond to the appearance of nonzero nondiagonal elements in the density matrix. This is manifested by the modulation of resonance fluorescence and may be observed experimentally.