Femtosecond pump–shaped-dump quantum control of retinal isomerization in bacteriorhodopsin

We experimentally demonstrate molecular quantum control on the photoisomerization of retinal in bacteriorhodopsin with pump and shaped-dump femtosecond laser pulses. The objective is a reversion of regular control schemes for optimal excitation in which the pump pulse is shaped. Instead, we seek optimal de-excitation with a shaped-dump pulse. The pump–shaped-dump–probe scheme allows control of molecular systems away from the initial Franck–Condon window in regions of the potential-energy landscape where the decisive reaction step occurs. In addition, this method has the potential to provide information on wave packet evolution and underlying potential-energy surfaces.