Ultrafast optical rotation for extremely sensitive enantio-discrimination

TL;DR

This paper introduces a highly sensitive, all-optical method for enantio-discrimination and control of chiral molecules using ultrafast laser pulses, leveraging nonlinear optical activity driven by electric-dipole interactions.

Contribution

It demonstrates a novel nonlinear optical technique that achieves giant enantio-sensitivity in the near UV-visible range through purely electric-dipole interactions.

Findings

Giant enantio-sensitivity achieved in the near VIS-UV domain.

Efficient chiral discrimination using elliptically polarized light.

Ultrafast imaging and control of chiral dynamics with standard optical technology.

Abstract

Sculpting sub-cycle temporal structures of optical waveforms allows one to image and even control electronic clouds in atoms, molecules and solids. Here we show how the transverse spin component arising upon spatial confinement of such optical waveforms enables extremely efficient chiral recognition and control of ultrafast chiral dynamics. When an intense few-cycle, linearly polarized laser pulse is tightly focused into a medium of randomly oriented chiral molecules, the medium generates light which is elliptically polarized, with opposite helicities and opposite rotations of the polarization ellipse in media of opposite handedness. In contrast to conventional optical activity of chiral media, this new nonlinear optical activity is driven by purely electric-dipole interactions and leads to giant enantio-sensitivity in the near VIS-UV domain, where optical instrumentation is readily available. Adding a polarizer turns rotation of the polarization ellipse into highly enantio-sensitive intensity of the nonlinear-optical response. Sub-cycle optical control of the incident light wave enables full control over the enantio-sensitive response. The proposed all-optical method not only enables extremely efficient chiral discrimination, but also ultrafast imaging and control of chiral dynamics with commercially available optical technology.