Pump-control approach to enantiospecific state transfer

Enantiospecific state transfer of chiral molecules is extremely important because enantiomers coexist in many biologically active compounds and play significantly different physiological, pharmacological, and biological roles. The inherently strong electric-dipole optical approaches based on the cyclic three-level model of chiral molecules have been extensively discussed. But, for the cases of large chiral molecules and/or chiral molecules of low asymmetry, the four-level model with two sub-loops is more realistic to describe the molecules. Based on the four-level model, we propose a pump-control approach to realize the highly efficient enantiospecific state transfer. In our approach, two pump pulses are applied to generate molecular coherence between the ground state and the first excited state of our working model. According to the coherence of the molecules, we adjust the phase and pulse area of the control pulse, then we obtain the highly efficient enantiospecific state transfer in the first excited working state. In addition, we further optimize the fraction of enantiopure samples by adjusting the area of the two pump pulses.