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.

What is the physical meaning of scaling factor in PML setting?

Please login with a confirmed email address before reporting spam

Hi all,

I am currently using pml to absorb light to prevent back refletion. In my simple model, I incident the light by using a port to a mirror (using perfect electric conductor BC), and let the reflected light to enter the pml behind the port. Periodic boundary conditions are used on the sides of the rectangles, and scattering BC is used at the end of the pml. Before entering the pml, I also have a boudary to integrate the poynting vector perpendicular it.

I expect, if I do it correctly, all the light gets reflected by the mirror and I will get all of the incident light. But I also realized that there may be significant reflection if the light enters the pml with a very large angle. I started to tune the parameters in the pml settings and found that when I am using rational stretching and a very large scaling factor (~200), the results are pretty good. The settings worked well in another slightly more complicated model which I used to collect the light by using port's diffraction orders.

However, I have no idea what I have been done phyiscally by tuning the scaling factor in pml. Can anyone help me with this?

Many thanks!


0 Replies Last Post 15/08/2019, 07:00 GMT-4
COMSOL Moderator

Hello tomchan516 .

Your Discussion has gone 30 days without a reply. If you still need help with COMSOL and have an on-subscription license, please visit our Support Center for help.

If you do not hold an on-subscription license, you may find an answer in another Discussion or in the Knowledge Base.

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.