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Light in complex nanostructures

The Light in Complex Nanostructures (acronym COS) group studies the properties of coherent systems involving multiple and strong scattering of light with individual or ensemble of quantum or classical nano-objects or both. We tackle the problem starting from the elementary level (individual nanoparticles), to the microsystem level (nanoparticles possibly dressed by quantum resonators, small nanoparticle assemblies), towards the mesoscopic scale (metasurfaces with many nanoparticles forming complex macrosystems).

Light in Complex Nanostructures group, 2017
The Light in Complex Nanostructures group in 2017. From left to right: Philippe Lalanne, Wei Yan, Maxime Bertrand, Louis Bellando, Alexandre Gras, Kevin Vynck


  • Adrian AGREDA (Post-doctoral fellow)
  • Denis ARRIVAULT (CNRS Engineer)
  • Philippe LALANNE (CNRS Research Director & group leader)
  • Tong WU (Post-doctoral fellow)


  • Marie-Caroline SOLIGNAC (PhD student, collaboration SVI - Saint Gobain Recherche)
  • Loïc TRAN (PhD student, collaboration L'Oréal)


  • Maxime BERTRAND (PhD student)
  • Armel PITELET (Post-doctoral fellow)
  • Kevin VYNCK (CNRS Research Scientist, now at Institut Lumière Matière, Lyon, France)
  • Louis BELLANDO (Post-doctoral fellow, now at LOMA, Talence, France)
  • Kévin COGNEE (PhD student, now at City University of New York, USA)
  • Rémi FAGGIANI (PhD student, now at Greenerwave, Paris, France)
  • Alexandre GRAS (PhD student)
  • Wei YAN (Post-doctoral fellow, now at Westlake University, Hangzhou, China)
  • Jianji YANG (Post-doctoral fellow, now at Applied Materials, California, USA)
  • Xiaorun ZANG (PhD student, now at Tampere University of Technology, Finland)




MAN (Modal Analysis of Nanoresonators)

MAN is an open-source software for analyzing electromagnetic micro and nanoresonators. It is composed of two solvers, QNMEig and QNMPole, which compute and normalize the quasinormal modes (QNMs), i.e. the quality factor Q and mode volume V. QNMEig operates under the COMSOL Multiphysics platform; QNMPole can be used with any frequency-domain electromagnetic solver. These solvers are valued by an increasing number of toolboxes, which allow a transparent analysis of nanoresonators with analytical formulae: reconstruction of the field in the modal basis, scattering and extinction cross-section spectra, LDOS spatial and spectral maps, Purcell factor, multipolar decomposition, generation of second-harmonics, temporal domain analysis … In the present version, the toolboxes are solver dependent; this is formal and with a minor effort, the user using one solver may benefit from the toolboxes developed for the other solver. In future versions, the toolboxes will be shared.

Download MAN




RETOP is an open-source Matlab toobox that implements a near-to-far-field transformation for computing the radiation diagram. This transformation is implemented in many electromagnetic software, however for most of them, like COMSOL multiphysics, the transformation is restricted to object surrounded by uniform media (free space). RETOP operates for objects on substrates or buried in stratified media. It can be used to compute the radiation diagram in the superstrate and the substrate . The substrate may support guided modes or surface plasmon modes with metal layers. RETOP additionally computes the in-plane radiation diagram in the guided modes. It just needs the near-field (computed on a rectangular box that contains the object with any full-wave Maxwell’s solver) to compute the radiation diagrams. It is especially relevant for calculating the scattering of nanoparticle on substrates. Special attention is made to the interface with COMSOL Multiphysics.

Download RETOP




RETICOLO implements the rigorous coupled wave analysis (RCWA) for 1D (classical and conical diffraction) and 2D crossed gratings. It operates under a MATLAB environment and incorporates an efficient and accurate toolbox for visualizing the electromagnetic field in the grating. As a spinoff, version V9 launched in 2021 incorporates a toolbox to analyze thin film stacks made of uniform media with arbitrary anisotropy.





HIGHLIGTH from our recent literature

  1. Metalenses at visible wavelengths: Laser Photon. Rev. 11, 1600295 (2017). The article makes an historical perspective on high-NA metalenses, rehabilitating pionneer works well before the celebrated Report published in Science (vol. 352, June 2016) by the Harvard group, "Metalenses at visible wavelengths: diffraction-limited focusing and subwavelength resolution imaging".
  2. Structural slow waves: ACS Photon. 6, 4-17 (2019). The article provides a review on structural slow light. By providing a parallel between slow plasmon and slow photons, two facets are together explored towards a comprehensive understanding. Some wrong, albeit popular, ideas, e.g. the belief that a mode with a null group velocities (stop-light issue) does not carry any energy flow on the topic of slow gap plasmons are revisited.


We welcome applications for post-doctoral positions, PhD positions and internships mainly on two topics:

  1. Non-Hermitian physics with quasinormal modes (theory and applications), see our recent publications for more details.
  2. New visual appearance with metasurfaces (theory and experiments). Metasurfaces have been mainly used to control structural colour so far. We study how to harness disordered optical metasurfaces to create new visual apperance that have not been yet observed nor modelled.

To apply, please contact Philippe Lalanne directly by email.


  • From Mérignac airport, take a Taxi (address: Institut d'Optique graduate School, 1 rue François Mitterrand, Talence)
  • From Gare Saint Jean, there are many combinations Bus+Tram. For instance, take Bus 9 (direction Bordeaux Brandenburg, 10 stops, exit at stop Barrière St Genès) or Bus 10 (direction Gradignan Beausoleil, 14 stops, exit at stop Peixotto), and then with the same ticket take TRAM B (direction Pessac, exit at stop Arts et Métiers). All trams stops at Arts et Métiers.


Philippe Lalanne is Research Director at CNRS and is an international expert in computational and nanoscale electrodynamics. He was first involved in the group of Pierre Chavel at l'Institut d’Optique at Orsay. In 1995, he spent a sabbatical year with G.M. Morris at the Institute of Optics in Rochester.

With his colleagues, he has launched new modal theories and improved numerical tools for gratings, waveguides and microresonators. He has used these tools to provide deep insight into the physical mechanisms involved in key nanoscale optical phenomena and devices, e.g. light confinement in photonic-crystal cavities, the extraordinary optical transmission [Nature 2008], light interaction with plasmonic nanoresonators [PRL 2013,PRB 2018]. He has pioneered the development of large-NA metalenses [JOSA A 1999] and has designed and demonstrated novel nanostructures with record or completely novel performance in their time, e.g. metalens [JOSA A 1999], slow light injectors, directional plasmon couplers, or broadband single-channel photon sources.

He has supervised 17 PhD candidates and co-supervised 6 PhD candidates. He is an Associate Editor of Optica, a member of the editorial board of Laser & Photonics Reviews, and is director of GDR Ondes, a broad virtual laboratory that gathers the French community working on acoustic and electromagnetic waves. He is a recipient of the Bronze medal of CNRS and the prix Fabry de Gramont of the Société Française d’Optique. He is a fellow of the IOP, OSA and SPIE.



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