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We present selected examples of recent experimental results in coherent quantum control of processes and products of laser atom interactions. These include control of ionization and autoionization rates, of light induced atomic structure, ionization branching ratios and frequency up-conversion. Quantum interference of atomic transitions, induced by a bichromatic electromagnetic field, is underlying all the results of this work. Since the quantum interference is induced by the field, its parameters govern control of products and processes. Thus control is demonstrated through the wavelength, intensity and phase of the field.

We report on the observation of the modification of the final status products in a photoionization of the Xe atom through the coherent process of laser-induced continuum structure (LICS). The photoionization decay of the Xe ground state into the two electronic continua, corresponding to the two fine structure levels of the ground state of the Xe ion, is varied by embedding a bound state into the two continua through a laser field (dressing laser). The dressed continua, probed from the atomic ground state through three-photon absorption, exhibit different induced structures. The experiment is performed on an atomic beam apparatus which uses a time-of-flight spectrometer for energy analyzing the emitted photoelectrons. The modified final state amplitudes are controlled by the wavelength of the dressing laser. No significant modification of the {sup 2}P{sub 3/2} continuum has been observed, in the limit of the detection efficiency. The effect is characterized by a window resonance in the slow electron continuum as the dressing laser is tuned over the LICS resonance.

We have studied the absorption of light induced by a resonant or near-resonant collision between two atoms. The calculations have been performed by taking into account also the magnetic sublevels, which makes our theoretical predictions more applicable to realistic cases. Analytical expressions for the far wing absorption cross-section have been obtained.

An experimental analysis of the structure induced by a strong laser field in the continuum of ionization of the sodium atom is reported. The experiment is performed on an atomic beam provided with a time-of-flight spectrometer, for an energy analysis of the photoelectrons. A substantial improvement in the evidence of the resonance has been obtained thanks to the selectivity of the detection system.