Quantum control of unidirectional rotations of a chiral molecular motor

A quantum control method is presented for designing electric fields of laser pulses to drive a chiral molecular motor in desired, rotational directions. Intuitive or counter-intuitive rotational motion of a chiral motor, 2-chloro-5-methyl-cyclopenta-2,4-dienecarbaldehyde, was controlled by electric fields of ps-laser pulses with midinfrared central frequencies. The control mechanism is discussed by analyzing the time- and frequency-resolved spectrum of the electric fields of the laser pulses. Timing of laser pulses is the essential factor for controlling unidirectional motions.