Chirality-dependent optical dipole potential

Abstract

In this paper, we show the possibility of spatially separating two opposite enantiomers of chiral molecules, using an optical dipole potential. Because of the broken mirror symmetry of effective potential, chiral molecules have a cyclic three-level Δ-configuration structure. Irradiation of these molecules with three femtosecond laser pulses gives rise to an enantiomer-dependent optical force. Interestingly, considerable differences in the direction of the force felt by the enantiomers have been shown to cause the chirality-dependent optical dipole potential which stably captures only one enantiomeric form. Moreover, the proposed scheme provides a complete control over what kind of molecules, the left- or right-handed ones, can be selectively trapped. Note that we have analyzed the optical force, and specifically the trapping effect, by considering the full interaction Hamiltonian, including both rotating and counter-rotating terms.

Chirality-enabled optical dipole potential energy for two-level atoms

“…In another report the existence of this field component was probed with the help of the interaction of a single molecule with a fixed dipole moment [8]. In a very recent paper the creation of a chiral optical dipole potential energy is shown in a scheme which involves the irradiation of chiral molecules with three femto-second laser beams which ensures a cyclic three-level configuration [9]. However, in [7] the chiral potential energy arises from the chiral nature of the transition matrix elements.…”

“…The explanation of this lies in Eq. (9), that the effective Rabi frequencyΩ becomes larger when the term iσℓΩ k 2 ρ ∂Ω ∂ρ is negative and this obviously depends not only on the sign of the polarization or that of the winding number but also on the gradient of the Rabi frequency.…”