Kevin Vynck

Author's posts

Publication in Nature Nanotechnology: « Single-nanotube tracking reveals the nanoscale organization of the extracellular space in the live brain »


Physicists and neurobiologists from CNRS, University of Bordeaux and Institut d’Optique Graduate School, have developped a new advanced approach based on the imaging of individual carbon nanotubes to reveal the nanostructure of the extracellular space in the brain. These advances could help to gain understanding into certain psychiatric troubles and neurodegenerative diseases.

Antoine G. Godin, Juan A. Varela, Zhenghong Gao, Noémie Danné, Julien P. Dupuis, Brahim Lounis, Laurent Groc & Laurent Cognet, Single-nanotube tracking reveals the nanoscale organization of the extracellular space in the live brain, Nature Nanotechnol. (2016) (link)

Read more here (in French)

[PhD position] Exotic optical properties of complex plasmonic nanostructures

Three-year PhD position in the group « Light in Complex Nanostructures » at LP2N


complex_optical_stack_LP2NControlling the interaction of light with metallic nano-objects is the spearhead of modern nanophotonics. Thanks to the development of nanofabrication techniques, the last decade has witnessed a proliferation of optical nanoparticles of varying shape and composition, exhibiting new optical properties. For instance, one can create nanoparticles that strongly scatter light at wavelengths that are tunable on the entire visible range and with a controllable directivity. Furthermore, when these nanoparticles are self-assembled (randomly) in a thin-film stack, new optical phenomena can take place due to the interaction between the individual nanoparticle and the planar geometry, and between the nanoparticles themselves, such as a strong light confinement in very small volumes or a very efficient extraction of light confined in the stack towards free space. These complex systems have a very strong scientific and technological potential.


To date, however, the physical understanding of these nanostructures remains very limited. This is largely due to the difficulty to model such complex systems, that mix optimized nanoparticles and engineered disorder. Our research team has the ambition to develop the theoretical and numerical tools that will allow modeling and designing complex nanostructures possessing exotic optical properties, and to validate experimentally our most interesting findings.


The PhD thesis proposed here belongs to this dynamic. The PhD student will tackle advanced concepts in electromagnetic modeling and participate to the development of new numerical codes and of optical setups to optically characterize the nanostructures fabricated by our collaborators. This project is one of the key topics of the team for the coming years.


The PhD student should have a solid background in physics, especially in electromagnetism, and a pronounced interest for theory and numerical simulations. In return, he/she will receive a top-level expertise that is very interesting to many academic and industrial partners (our team has regular collaborations with Saint-Gobain Recherche and PSA Peugeot-Citroën) and that has essentially been developed on the experimental level so far, the theoretical and numerical efforts being rare.


Candidates should send their application, including CV and last academic transcripts, to and


Starting date: October 1st, 2017


Job offer in PDF: EN

Publication in Scientific Reports: « Lower bound for the spatial extent of localized modes in photonic-crystal waveguides with small random imperfections »

Light localization in periodic waveguides due to random fabrication imperfections, even very small ones, is a well-known phenomenon in optics and photonics. It is generally attributed to the fact that light propagation becomes very sensitive to perturbations when its group velocity diminishes, for instance, at frequencies near the edge of the dispersion curve.

mode_localisé_LP2NIn a recent study published in Scientific Reports, researchers at LP2N, in collaboration with researchers at ICB (Dijon, France) and at the University of St-Andrews (UK), have revealed that the parameter that drives the size of the smallest possible localized modes is the effective photon mass, rather than the group index.

These results suggest that an engineering of photonic-crystal waveguides can make them less sensitive to imperfections, which often constitutes a strong limitation for the realization of photonic components, or inversely, enhance the spatial confinement of light for applications such as sensing or quantum optics.

R. Faggiani, A. Baron, X. Zang, L. Lalouat, S. A. Schulz, B. O’Regan, K. Vynck, B. Cluzel, F. de Fornel, T. F. Krauss, P. Lalanne, Lower bound for the spatial extent of localized modes in photonic-crystal waveguides with small random imperfections, Scientific Reports 6, 27037 (2016). (link)