COHERENT REPOPULATION OF HYPERFINE-STRUCTURE LEVELS IN THE FIELD OF ABICHROMATIC RESONANT RADIOFREQUENCY WAVE

We consider the resonant interaction between atoms with hyperfine ener gy levels and a bichromatic radio-frequency field. Nuclear Zeeman leve ls of an impurity center in a magnetic host form a structure of this k ind. Using the spin-density-matrix formalism, we solve the problem of coherent repopulation of a system of three of these levels under the a ction of a bichromatic resonant radio-frequency wave, taking into acco unt transverse relaxation, and note the connection between this effect and the well-known phenomenon of coherent population capture when a l aser bichromatic field interacts resonantly with a three-level system. We discuss various possibilities for observation of this effect exper imentally. (C) 1997 American Institute of Physics.