COHERENCE TRANSFER IN 3-LEVEL SYSTEMS - CONTROLLED VIOLATION OF ADIABATICITY AND ANTIPARALLEL DOUBLE RESONANT IRRADIATION

It is shown by theory and experiment how coherent superpositions of quantum states in three-level systems can be manipulated by irradiating two connected transitions with two resonant fields with suitably shaped time-dependent amplitudes and phases. Three variants are discussed in detail; (i) adiabatic coherence transfer (ACT) between two transitions, which may be either allowed or forbidden; (ii) nonadiabatic transfer of coherence to a nonirradiated transition by controlled violation of adiabaticity (CVA); (iii) coherence transfer to a nonirradiated transition by antiparallel double resonant irradiation (APDRI). A geometrical representation of these experiments gives a clear physical picture of the phenomena and provides a tool for the development of new methods. The principles are illustrated experimentally by applications to magnetic resonance of deuterium (I = 1) in anisotropic phase at high magnetic field, but could also be applied to three level-systems in nuclear quadrupole resonance, optics, and other areas of spectroscopy. © 1995 American Institute of Physics.