Optimal Control of Molecular Femtochemistry

We describe the method of adaptive femtosecond quantum control. In this technique, ultrashort laser pulses are manipulated in pulse shapers to realize complex temporal intensity and phase profiles of the electric field on a femtosecond time scale. The optimal field parameters are determined in an optimization algorithm which uses direct feedback from experimental observables. Examples of this "closed-loop" scheme discussed here include automated laser pulse compression, gas-phase photodissociation control, selective photoexcitation in liquids, and ultrafast manipulation of the polarization state of light. But also other objectives can be realized, and adaptively shaped laser pulses can be regarded as a very flexible spectroscopic tool.