Branching ratio coherent control in ultrafast bond making

Coherent control of bond making (photoassociation) is crucial for the realization of a new photochem-istry, where a lasereld is actively photo-driving the irradiated system in a coherent way from the initial state of reactants to the final state of desired products. In a significant step forward, we experimentally demonstrate here coherent control over the photoassociation branching ratio to different target states of the generated molecule. The model process is strong-field multiphoton femtosecond photoassociation of thermally hot magnesium atoms into bound magnesium dimer molecules.