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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 nanoresonators), to the microsystem level (nanoresonators possibly dressed by quantum emitters, small nanoresonator assemblies), towards the mesoscopic scale (metasurfaces with many nanoresonators on thin film stacks and  forming complex macrosystems).

Some early and recent designs: from left to right, metasurfaces for imaging (1998), single photon sources (2010), fast, slow and evanescent mode tapering (2000-2010) and disordered metasurfaces for appearance harnessing (2022).



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


  • Denis ARRIVAULT (CNRS Research Engineer, now at INRIA-Bordeaux)
  • Maxime BERTRAND (PhD student, now at SharpEye, Paris)
  • 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 Facebook, California, USA)
  • Xiaorun ZANG (PhD student, now at Tampere University of Technology, Finland)



The group has launched 3 freeware packages: MAN, RETOP and RETICOLO. The graph shows the download statistics since January 2020.


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.

Interested users are encouraged to read a publication in Computer Physics Communications presenting the software capabilities and a powerpoint video providing an introduction to QNMs and MAN.

Download MAN V8.3 ; lesson a userguide video or an introduction video to the software.




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.






Link to seminars


The textbook Introduction to Nanophotonics (Oxford Univ. Press 2022) illustrates the theoretical foundations of nanophotonics, as well as the major advances in the field based on artificial metallic and dielectric nanostructures. The material is aimed at graduate students with a background in physics and electrical engineering. Quite uniquely, it presents a comprehensive overview of modes, be them of guided, Bloch or quasinormal types, a concept that aroses many subfields of nanophotonics, from photonic and plasmonic waveguides, to photonic crystals, microcavities and nanoantennas.

Introduction to Nanophotonics is more than a treatise on photons ans electrons being lost on tiny islands or in a jungle of nano-structured materials; the authors discuss numerous useful configurations while ensuring the reader does not lose sight of te underlying principles, includind an unprecedentedly clear description of the role of plasmons." Dieter Pohl, University of Basel


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

  1. Non-Hermitian physics with quasinormal modes (theory, computational physics), see our recent reviews: Normalization, orthogonality, and completeness of quasinormal modes of open systems: the case of electromagnetism in 2022, Nanoscale Light Confinement: the Q’s and V’s in 2021 and Light interaction with photonic and plasmonic resonances in 2018.
  2. Visual appearance of disordered metasurfaces (theory, numerical analysis and experiments): Visual appearances of disordered optical metasurfaces in 2022 and Fundamental limitations of Huygens’ metasurfaces for optical beam shaping in 2021.


BIOGRAPHY Philippe Lalanne

Philippe Lalanne is a CNRS Research Director. He 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 developped new modal theories and launched new numerical tools for analysing nanostructured surfaces [JOSAA96], photonic-crystal waveguides [JOSAA01,OExpress07] and nanoresonators [LPR18,PRB18]. He has used these developments to provide deep insight into the physical mechanisms involved in key nanoscale optical phenomena and devices, e.g. the confinement of light in photonic-crystal cavities [Nature04,LPR08], the extraordinary optical transmission [Nature08,Nature12], and the light interaction with localized plasmons [PRL13,ACSPhoton21]. He has designed and demonstrated novel nanostructures with record or completely novel performance in their time, e.g.  photonic-crystal cavities with tapered mirrors, slow light injectors, directional plasmon launchers, broadband single-channel photon sources. He has pionnered the field of metasurfaces in the 90's, showing the first metalenses with large numerical aperture and large efficiencies (>80%) [JOSAA99,LPR17], with designs that are basically the same as those used nowadays.

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, OPTICA and SPIE.



  • 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.


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