Discussion Forum

Hi, I am trying to study the scattering problem in COMSOL for a 2-D cylinder.

I used RF Module->In Plane Waves->TE Waves->Scattering Harmonic Propagation. And just made changes directly from the model library->RF module->Tutorial Models-> dielectric scattering PML. I have attached the model file and the report.

The basic drawing is: A laser beam is irradiated from the left surface (I directly use constant electric field in Boundary condition, set as 1). And a silica cylindrical rod is placed on the silicon substrate with around 50-200nm gap between them. Another cylinder surrounding the silica rod is set as vacuum and it is for mesh and scattering effect analysis. The square on the right of the rod is the silicon wafer and below the silicon is vacuum. The wavelength I used is 800 nm. The material properties are selected directly from the COMSOL library.

I am not sure about the definition of the Boundary conditions, especially for the incident laser beam. In the model I define as: for outer bounday->scattering boundary condition; for inner boundary->continuity; only the left iner surface is set as constant electric field(1 V/m) to resember the incident light. For sub domain, I use the same as the library model.

My predicted result is that there will be enhancement of electric field in the gap and I want to know the enhancement factors with different rod materials and gap distance. Later on, I will try to use n-j*k for the result.

Any suggestion would be appreciated!