Quantum coherence in nonlinear optical processes: theory and possible application to control of chemical reaction and quantum computation

Phase dependence in nonlinear optical processes reveals an intriguing inter play between the phase coherence of a short laser pulse and the laser-induc ed quantum wave-packet dynamics, which cannot be observed in the linear res ponse regime. In this paper, the intra-pulse quantum coherence is demonstra ted with three examples: molecular pi pulses for total inversion of electro n population, unexpected chirp dependence in multi-photon absorption yield, and active control of decoherence for quantum computation. These results d emonstrate that quantum coherence is a unique method in the dynamic control of molecular systems, which cannot be achieved otherwise. (C) 2000 Publish ed by Elsevier Science B.V. All rights reserved.