Pulse shaping and its characterization of mid-infrared femtosecond pulses: Toward coherent control of molecules in the ground electronic states

We have examined a technique of complex shaping of mid-infrared femtosecond laser pulses towards accurate and precise control of rovibrational wave packets of molecules in the ground electronic state. A Germanium acousto-optics modulator was used as a device for the pulse shaping. In order to characterize the shaped pulses precisely, sum-frequency cross-correlation frequency-resolved optical gating was introduced for the analysis of both amplitude and phase of the electric fields. The mid-infrared pulses were shaped and characterized with a frequency resolution better than 4.5 cm⁻¹. Such a resolution is supposed to be sufficient for the realization of quantum gate operations with high fidelity, which is one of the most challenging applications of rovibrational wave packet manipulation of molecules. In order to demonstrate the precision of our method of shaping and its characterization, we have generated shaped pulses that will realize Hadamard and NOT quantum gates with rovibrational states of a CO molecule.