Photoelectron vortices in strong-field ionization of chiral molecules with linearly polarized light

Similarly to optical vortices, electron vortices – electron waves with orbital angular momentum – have revealed a new set of possibilities out of reach for regular plane waves. Among their applications, electron vortices could be used to probe the chirality of nanoclusters and macromolecules in inelastic electron scattering. Here, we propose to use electron vortices as the fingerprint of molecular chirality in photoionization. We analyzed the orbital angular momentum (OAM) of photoelectrons emitted by a chiral target when subjected to an ultrashort intense IR field, linearly polarized along z . For an achiral target there is no correlation between the photoelectron direction p_z and its OAM. For a chiral target we found a strong correlation between p_z and the OAM. For a given enantiomer, photoelectrons with positive p_z have positive OAM and photoelectrons with negative p_z have negative OAM. For the opposite enantiomer the correlation is reversed, i.e. photoelectrons with positive (negative) p_z have negative (positive) OAM. This effect is robust across a wide range of photoelectron momenta and since it occurs within the electric-dipole approximation, it yields enantiomeric discrimination on par with the most powerful techniques, such as photoelectron circular dichroism (PECD).