Part 1: COMSOL Multiphysics Electromagnetic Modeling Periodic Gold Nanoparticle Arrays

(If you are interested in photothermal modeling of nanoparticles check out this video: https://www.seevid.ir/fa/w/5BATzIjKwDA) In this tutorial, computational electromagnetic modeling of infinite array (or film) of plasmonic gold nanoparticles is demonstrated on COMSOL Multiphysics (electromagnetic wave module, frequency domain). Far-field and near-field optical properties are easily evaluated for this kind of simulations. Notes: The optical properties of gold were obtained from Johnson and Christy (1972) https://journals.aps.org/prb/abstract/10.1103/PhysRevB.6.4370 To upload to COMSOL, the real and imaginary parts of the refractive index needs to be in .txt (notepad) formal. Basically wavelength vs. refractive index data from excel can be pasted on a notepad for this. If dielectric constants are obtained instead of refractive index, they can be converted to refractive index by well known correlations. The post processing will be shown in another video. Post processing is shown in this video: https://www.seevid.ir/fa/w/tcDpMT3R6dI To obtain the spectra, go to global evaluations and type: ewfd.Rtotal (Reflectance) ewfd.Ttotal (Transmittance) ewfd.Atotal (Absorptance) and compute. This video may be useful for the computations where optical/electromagnetic modeling of single nanoparticles is shown with scattered field solution: https://www.seevid.ir/fa/w/8u4pNpf0N2o For infinite nanostucture arrays as shown in this video, full field solution of Maxwell's equation in unit cell computational domain with Floquet periodic boundary conditions have to be solved. The same strategy can be applied for different other dielectric or semiconductor materials. Also for the simulation of photonic crystals, this procedure can be used. We have published two works on such systems. The one that is shown in the video: https://www.nature.com/articles/s41598-022-20117-7 In another one, VOC sensing with such a nanoparticle film is demonstrated where ellipsometric modeling is also shown. But doing ellipsometric modeling can be quite simple as one easily obtains the complex reflectivites from comsol which then have to be converted to phase and amplitude data: https://pubs.acs.org/doi/full/10.1021/acsanm.2c02524 Thank you for watching. Please write your comments down below.