Mode selective excitation mechanisms in molecules using shaped pulses

Summary form only given. A major goal of coherent control is to enable mode-selective excitation of molecules. Pulse shaping combined with learning control loops has been demonstrated to be a highly effective technique for coherent control. For many experiments however, the mechanism behind the control is not well understood. Moreover, previous work on controlling molecular vibration has largely been limited to molecular beams or cryogenically cooled systems. Here we present results on controlling nuclear vibrations in atmospheric density, room temperature (/spl sim/300K), molecular gases. By using very broad-bandwidth pulses, we can impulsively excite selected vibrations, and also shape the light pulse to suppress or enhance specific modes in SF/sub 6/ and CO/sub 2/. This work extends the reach of previous experiments to macroscopic quantities of gas at room temperatures. In addition, accurate characterization of optimized pulses provided by FROG allows us to interpret the control mechanism.