PHOTO : Materials - DDA-modelling of nanoparticles
The Discrete Dipole Approximation (DDA) is a numerical method used to solve Maxwell equations. It is a powerful theoretical tool for the investigation of the optical and spectroscopic properties of semiconductor and metal nano-structures. The approach is based on the discretization of the materials in dipoles with polarisabilities taken from tabulated experimental ellipsometry data, eventually corrected for quantum size effects. It is particularly suitable for the modeling of localized optical resonances (plasmonic, excitonic, phononic) of isolated nano-objects. Size, shape and interaction effects between nano-objects can be described with this method.
The local electric and magnetic near-fields can be generated and used for the interpretation of various types of physical and chemical phenomena such as photocatalysis, thermo-plasmonics and plasmo-electronics. DDA is very complementary to other methods, used in the team PHOTO, like FDTD, RCWA and FEM which are more suitable for delocalized or propagating optical resonances supported by periodic nanostructures. The main limitation of the DDA method is the random access memory defined by the number of dipoles required for fully converged calculations. To overcome this limitation, and speed up the calculations by means of parallel computing, the DDA software is implemented in the CALMIP High Performance Computing Center of Occitanie region.DDA based calculations of the gap plasmon-exciton interaction energy in a hybrid MoS2/Au.
I. Abid, W. Chen, J. Yuan, A. Bohloul, S. Najmaei, C. Avendano, R. Péchou, A. Mlayah, and J. Lou, “Temperature-Dependent Plasmon–Exciton Interactions in Hybrid Au/MoSe2 Nanostructures”, ACS Photonics 4, 1653, 2017.