Aperiodic Structure With PML

[HiHatDoDot]

Hi all,

I am trying to run a simulation with S4 in python for an aperiodic structure ;
This is something quite old in the use of RCWA, the strategy is to define the structure from top to bottom (z-axis) so that it is replicated periodically on the sides (x- and y-axes).
To isolate each replicated structure and field, Perfectly Matched Layers must be added on each side to avoid refraction and reflection.
This is widely documented, to make a long story short, you need several layers with complex eps.

I was able to define a simple 2D waveguide as beginning, I set firstly a large layer of Air then with SetRegionRectangle a block for my waveguide. Also with SetRegionRectangle, I put several blocks on the side of the lattice.
However python crashes as soon as I call the GetPowerFlux...

What I am doing wrong ?
Is this method feasible with S4 ?

Thank you for any response

Romain

[HiHatDoDot]

Hi there,
I still don't know if this is possible with S4.
However, I have found this software RETICOLO made by the authors that generalise RCWA to aperiodic structures with PML.
I could contact them and they send me the version of RETICOLO that can perform this kind of simulation.

[xpdong22]

I wonder if you can send me the RETICOLO codes with PML? My email is [email protected] you!

[HiHatDoDot]

I have no more, you should contact Jean Paul HUGONIN

[mfschubert]

Hi @xpdong22, @HiHatDoDot, you might be interested in fmmax, which implements FMM/RCWA and supports anisotropic magnetic materials and uniaxial PML.

We have one example involving PML, which consists of a dipole located above a metal substrate. Here is a cross section of the electric field amplitude from that calculation; the PML layers are to the left and right sides of the figure.

https://github.com/facebookresearch/fmmax/blob/main/examples/metal_dipole.py