Optimal control of ultrafast selection

Optimal laser control for ultrafast selection of closely lying excited states, whose energy separation was smaller than the laser bandwidth, was applied on the two-photon transition of atomic cesium. Selective oxidation was carried out using pulse shaping of ultrashort laser pulses adaptively modulated in a closed loop learning system handling eight parameters representing electric field. The selectivity was measured by monitoring the two color fluorescence from the respective excited states. A pair of nearly transformed-limited pulses were obtained as an optimal pulse after fifty generations.