Ultrafast TACOS -- Terahertz-Assisted Chiro-Optical Spectroscopy

TL;DR

TACOS combines terahertz and optical spectroscopies to enable ultrafast, efficient imaging and control of molecular chirality by inducing transient electronic orientation and detecting enantiosensitive optical responses.

Contribution

This work introduces TACOS, a novel method that uses terahertz pulses to induce and detect chiral electronic dynamics without requiring phase stability or vacuum conditions.

Findings

Enables ultrafast imaging of molecular chirality

Uses THz pulses to induce electronic orientation

Detects chiral signals via elliptically polarised light

Abstract

We bring together the advantages of terahertz (THz) and optical spectroscopies to introduce TACOS (Terahertz-Assisted Chiro-Optical Spectroscopy), a novel approach for ultrafast and highly efficient imaging of molecular chirality and control over chiral electronic dynamics. We show how, using a THz pulse, we can induce a transient electronic orientation in a medium of randomly oriented chiral molecules that breaks the isotropy of the molecular sample. This symmetry breaking twists the nonlinear response of the medium to an ultrashort linearly polarised optical pulse in a highly enantiosensitive manner. As a result, the medium emits elliptically polarised light at new optical frequencies that records the molecular handedness via purely electric-dipole interactions. The long wavelength and period of the THz pulse enable both spatial coherence across the sample and a substantial degree of electronic orientation over the duration of the ultrashort optical pulse. TACOS does not require optical carrier-envelope phase stability or working in vacuum, and it creates exciting avenues for ultrafast and highly efficient chiral sensing and manipulation.