Discussion Forum

Hi, when I need to model scattering (or absorption) of a single particle under illumination with external wave (usually plane wave), then I use scattered field formulation - same as described in your tutorial: https://www.comsol.com/blogs/modeling-the-scattering-of-light-off-of-an-object-on-a-substrate/ For the case of a substrate I write my background field manually (with reflected and transmitted wave), and whole simulation domain is encapsulated in PML - to simulate individual particle. I am wondering, how COMSOL treats this background field. I mean, obviously it finds fields obeying Maxwell equations (simplified to Helmholtz equation), but it also needs bounday conditions (or starting point). With ports I can understand (to some extent) this boundary condition, but what is happening in scattered field? This is mainly to understand limits of applicability of this formulation (if any): for example, what if the particle will provide a huge change in fields compared to the background (i.e., it is not a small perturbation), will results still be physical? I use RF and Wave Optics modules (both do the same), v5.6.