Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

Gaussian beam illuminated on thin films

Please login with a confirmed email address before reporting spam

Hi, I got a question about setting gaussian beam in the wave-optical module.

My structure composes of a thin Fe layer (5 nm) on the SiO2 substrate, laser wavelength 800 nm.

The COMSOL tutorial "Nanorod" shows we can directly set the gaussian beam conveniently using the scattering wave formulation, and surrounding PML are adopted to absorb any reflection.

However, I am not sure if this method is correct since my structure is not a isolated scatter, but a large thin film, and I am sure how to set gaussian beam in the port function.

Any suggestions are quite welcome.


1 Reply Last Post 13.01.2020, 04:53 GMT-5
Lars Dammann COMSOL Employee

Please login with a confirmed email address before reporting spam

Posted: 4 years ago 13.01.2020, 04:53 GMT-5

Hi Song Sun,

strictly speaking, the background field formulation is only valid for isolated scatterers. It does not work for infinite substrates.

You could use the scattering boundary condition instead. Since version 5.5 it is possible to define an incoming wave in the shape of a gaussian beam on those.

Best wishes, Lars Drögemüller

Hi Song Sun, strictly speaking, the background field formulation is only valid for isolated scatterers. It does not work for infinite substrates. You could use the scattering boundary condition instead. Since version 5.5 it is possible to define an incoming wave in the shape of a gaussian beam on those. Best wishes, Lars Drögemüller

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.