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SUMMARY:Efficient and intuitive modelling of electromagnetic nanoresonator
 s and complex metasurfaces - Kevin Vynck\, LP2N\, CNRS\, Institut d'Optiqu
 e Graduate School\, Univ. Bordeaux\, 33400 Talence\, France
DTSTART:20191128T091500Z
DTEND:20191128T101500Z
UID:TALK135370@talks.cam.ac.uk
CONTACT:Femi Ojambati
DESCRIPTION:Controlling the interaction of light with nanoresonators is on
 e of the spearheads of research in modern optics and photonics. Important 
 efforts are dedicated to the design of individual nanoresonators (Mie reso
 nators\, plasmonic nanoantennas) to scatter light with tailored directiona
 lity\, phase and polarization. The design is generally made by series of e
 lectromagnetic simulations realized at many incident angles\, polarization
  and frequencies. Besides being computationally heavy\, this strategy hard
 ly brings physical insight into the problem at hand. The designed nanoreso
 nators are then often placed in planar geometries\, creating the so-called
  metasurfaces. The interaction of resonators with a stratified medium and 
 between themselves can further enrich their optical properties\, leading f
 or instance to the a spectrally-selective angle-independent absorption or 
 to controlled coupling between free-space modes and guided modes. These me
 tasurfaces can sometimes be made by bottom-up approaches\, relying on coll
 oidal chemistry and self-assembly techniques. Theoretically predicting the
  optical properties of complex\, disordered metasurfaces are however remai
 ned elusive up to now due to the difficulty to consider simultaneously the
  coherent phenomena occurring at the level of the individual nanoparticle 
 (nano-scale) and at the level of the nanoparticle ensemble (meso-scale).\n
 In this seminar\, I will present powerful numerical methods that are curre
 ntly being developed in the “Light in Complex Nanostructures” group at
  LP2N . In a first part\, I will present a formalism based on the concept 
 of quasinormal modes that allows analysing individual nanoresonators with 
 great physical insight and strongly reduced computational cost [1]. I will
  show how this formalism can be used to analyze the multipolar behavior of
  nanoresonators and reach designs that are tolerant to variations in frequ
 ency and incident angles [2]. In the second part\, I will introduce a new 
 numerical method that enables an efficient modeling of large\, disordered 
 ensembles of complex (non-spherical) resonators in stratified media\, incl
 uding in cases of strong near-field interactions [3].\n\n[1] P. Lalanne et
  al.\, “Light interaction with photonic and plasmonic resonances”\, La
 ser Photon. Rev. 12\, 1700113 (2018).\n\n[2] T. Wu et al.\, “Intrinsic m
 ultipolar contents of nanoresonators for tailored scattering”\, arXiv:19
 07.04598 (2019).\n\n[3] M. Bertrand et al.\, “Global polarizability matr
 ix method for efficient modelling of light scattering by dense ensembles o
 f non-spherical particles in stratified media”\, arXiv:1907.12823 (2019)
 .
LOCATION:Ryle Seminar Room\, Cavendish Laboratory
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