PhD in soft matter physics and photonics (M/F)

Job Description

Thesis Subject

Understanding how topological structures emerge, evolve, and can be transferred between physical systems is a central question in modern physics. Recent advances in frustrated chiral liquid crystals have shown that bulk systems can spontaneously host non-trivial 3D topological configurations [1]. These structures arise from the helical ordering of the director field n across a thickness L, and they can be observed experimentally using polarized optical microscopy, as illustrated in the figure. Such soft condensed matter systems provide a controllable and versatile platform to study topological textures in matter that is far easier to implement experimentally than one can do in solid-state condensed matter systems such as magnetic materials.

In our group, we have developed an expertise to optically write & erase topological structures in liquid crystals, in a directional manner with respect to various degrees of freedom of light (polarization, phase, amplitude) [2] . In this regard, understanding the morphogenesis process remains a challenge and the proposed PhD thesis will aim at addressing it by developing a novel optical imaging technique based on undisclosed yet preliminary experimental proof-of-principle.

Concretely, the developed technique will provide direct, real-time access to all three spatial dimensions, in striking contrast to existing techniques, which require tedious three-dimensional reconstruction from point-by-point scans acquired by nonlinear optical microscopy [3] . This capability will enable the investigation of the dynamics and topology of liquid crystal textures and defects, as well as phase transitions and nucleation processes, in fundamentally new ways.

We are looking for a motivated, curious, and proactive PhD candidate with a solid background in physics or optics. Experience in optical microscopy, image processing, and liquid crystals is an asset. The successful candidate will develop expertise in polarization optics, light-matter interactions, and liquid crystal physics.

In brief, the candidate will:
- design and build the experimental setup and sample chamber
- perform experiments (e.g., spatiotemporal polarimetry and pump-probe experiments) analyze data
- use and contribute to the development of models to unravel light-matter interactions in liquid crystals

[1] Wu, J.-S.; Smalyukh, I. I. Hopfions, Heliknotons, Skyrmions, Torons and Both Abelian and Nonabelian Vortices in Chiral Liquid Crystals. Liq. Cryst. Rev. 2022, 10 (1–2), 34–68
[2] Bruni, N.; Loussert, C.; Rafayelyan, M.; Orlova, T.; Coursault, D.; Brasselet, E. Rewritable Binary Recording of the Photon Spin State in Chiral Liquid Crystals. Phys. Rev. Lett. 2025, 134 (22), 223804.
[3] Lee, T.; Senyuk, B.; Trivedi, R. P.; Smalyukh, I. I. Optical Microscopy of Soft Matter Systems. In Fluids, Colloids and Soft Materials; John Wiley & Sons, Ltd, 2016; pp 165–185.

Your Work Environment

The PhD grant is funded as part of the “Light” major research program. The PhD candidate will be affiliated with the Doctoral School of Physical and Engineering Sciences and the LIGHT Sciences & Technologies (LIGHTS&T) Graduate Program
(https://doctorat.u-bordeaux.fr/en/before-phd/graduate-programs/light-S-T).
The successful candidate will join the Singular team at the Aquitaine Waves and Matter Laboratory (https://www.loma.cnrs.fr/), located on the campus of the University of Bordeaux's College of Science and Technology. The Singular team currently consists of 4 doctoral students, 3 postdoctoral researchers, and 3 permanent researchers.

Compensation and benefits

Compensation

2300 € gross monthly

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

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