Highly Sensitive Non-linear Probes of Chiral Structure and Dynamics

• Applicant: Dr. Alex Harvey
• Subject Area: Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: from 2017 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 390239836

Chirality, the non-superposability of an object with its mirror image, is ubiquitous in nature, and fundamental to the description of natural processes. For chiral molecules, this mirror-symmetry breaking leads to two versions of a molecule, the left and right enantiomers, which have identical chemical and physical properties except for when interacting with another chiral object such as another chiral molecule or circularly polarized light. The growing interest in the response of chiral molecules in the time domain has motivated recent and ongoing efforts to develop ultrafast non-linear chiroptical techniques to that aim. This proposal is aimed at developing the theoretical foundations of a novel approach to observing coherent excited state dynamics in chiral molecules. The approach is highly sensitive to electronic, vibrational and rotational chiral dynamics, to various relaxation processes, and to loss of coherence. Additionally, this approach offers the possibility of extension to non-chiral molecules as it can induce 'extrinsic' chirality. The sensitivity of the detected signal to the coherence of the underlying dynamics can be low in a number of ultrafast spectroscopies based on non linear optical parametric processes, such as, e.g. high harmonic generation and 2D spectroscopy. This is because these parametric processes cause the different pathways characterizing the underlying dynamics to interfere even if the underlying dynamics are incoherent. Extrinsic chirality should allow one to overcome this limitation and to develop ultrafast measurement schemes that are exclusively sensitive to coherent dynamics.

• DFG Programme: Research Grants