Influence of orbital angular momentum of light on photoionization processes

A theoretical PhD position is available for three years at CELIA laboratory in Bordeaux (www.celia.u-bordeaux.fr). It deals with the interaction of structured light beams with atomic and molecular targets, with particular emphasis on chiral molecules.
Chiral molecules are of paramount importance in biology because they are building blocks of organic matter, including human beings. Chiral molecules appear in pairs of left- and right-handed enantiomers, where their nuclear arrangements present non-superimposable mirror twins. It is of paramount importance to distinguish the enantiomers since they interact differently with their environment as soon as this latter presents a chiral character, which is the case of most chemoreceptors of living organisms. Enantiomers are generally identified through their interaction with circularly polarized light carrying spin s=±ℏ. Beyond the usual circular dichroism related to the different absorptions of ±ℏ spin photons, a larger chiral response appears in the photoelectron angular distribution resulting from the ionization of enantio-pure chiral samples [1]. However, we actually know how to generate light pulses which carry orbital angular momentum l=±nℏ additionally to s. This gives rise to helical light beams, or optical vortices, which have been shown to influence the magnitude of the strong-field ionization probability in atomic and molecular systems [2]. It is therefore likely that the angular momentum of light should also allow to enhance the discrimination of enantiomers through momentum exchange between between light and matter.
This will be theoretically studied in the framework of the PhD, focusing of the angular distribution of the photoelectrons, beyond [2]. Before tackling the case of intricate chiral systems, achiral targets will first be considered, in ionization regimes encompassing one-photon, multiphoton and strong-field interactions. The results of the calculations will be compared to experiments performed at CELIA, involving one- and two-color ionizing pulses.
Candidates should have skills in atomic and molecular physics, including ideally light-matter interactions. They can apply by sending an email to Bernard Pons (see the email above).
References:
[1] S. Beaulieu et al., New. J. Phys. 18, 102002 (2016) ; V. Wanie et al., Nature 630, 109 (2024)
[2] J.-L Bégin et al, Nat. Commun. 16, 2467 (2025)

Center for Intense Lasers and Applications (CELIA) - Bordeaux, France: CELIA is a center of excellence for lasers and their interaction with matter. Research is conducted on laser developments and ultrafast laser-matter interactions with atoms, molecules, plasmas, and solids. The candidate will be hosted by a dynamic group of researchers (http://harmodyn.celia.u-bordeaux.fr) and will benefit from the very supportive environment at CELIA. We are committed to creating an inclusive environment for all.

The position is located in a sector under the protection of scientific and technical potential (PPST), and therefore requires, in accordance with the regulations, that your arrival is authorized by the competent authority of the MESR.

Knowledge of atomic and/or molecular physics - Appetite for theoretical simulations - Master 2 in Physics or Chemical Physics -- obtained or being finalized