Simple Glass-Titanium-Gold-Air Slab in 3D


#1

Hello all,

I want to determine the SPR of a 40nm gold film on glass substrate over which 4nm of Titanium film is deposited by evaluating reflection and transmission as a function of source angle. I want to do parameter sweep over the source incidence angle. This problem is similar to one of the open source lumerical example problem. Here is the link to the similar problem using silver in 2D: https://kb.lumerical.com/en/sp_spr_2d.html
Just that I am doing the same in 3D with gold film instead of silver. The problem is that the electric fields are not stabilizing and the final autoshutoff value is nowhere near to the desired minimum, i.e., 10^-5. I am using Bloch boundary condition as I am doing angled incidence analysis. The simulation file has been attached for reference.With_FDTD_p0.log (9.8 KB)
With_FDTD…fsp (255.8 KB)

Please somebody help.

Many thanks.


#2

Hi @eez168085,

I had a look at your file, and I noted a few issues:

  • You are using Block boundary conditions in x, and PML in y. This will cause some issues with the plane wave at the edges (in the y direction). The plane wave should be used with periodic or Block boundary conditions in x and y.

  • The source is partially in the glass. It would be better to have the source injecting from above the structure.

  • You’re doing a broadband simulation with an angled source. The angle will vary as a function of the wavelength. in your case, it means the higher wavelengths are injected with a 90 degree angle:

This is discussed in this page. To solve this problem, you can used the BFAST source.

I hope this will help!