Discussion Forum

Hi all,

I'm a Master student which is studying mid-IR, far-IR performance of metal nanoantennas.

Gold, for example, has a relative permittivity which is around -3000 -1000 i in mid-IR

So, a very first step would be to recover the analytical Mie solution of the perfectly conducting sphere. This model is solved in one of the examples, but I find this model very tricky, because if you choose the field in another point -at one of the final steps- you are unable to recover the result. See image.png to see what happens when you choose another point rotated 90º, blue is correct, green is choosing the other point -It's even worse if you rotate 180º -. And that's only one of the problems, for example, the model I want to study lacks of rotational simmetry and so on.

So, when I make a model, either I use Impedance Boundary Conditions (with very negative epsilons), Perfect Electric Conductor or a volume with very negative epsilons, the final solucion always resemble something like scatteringIII.png.

It doesn't go to 1 -as it should- and the peaks and minimum are not as deep. I think that I tried everything but nothing works.

The Sccatering is measured using

emw.relPoavx*nx+emw.relPoavy*ny+emw.relPoavz*nz

around the sphere, on the antenna, little far from the antenna and very far of the antenna.

The las image is meshing.png, using epsilon from -10000 to -10e6 i'm trying to recover Mie Scattering
I thick is good enough, with lambda/5 in the exterior space, 5 layers of PML and 8 nm resolution on the sphere and 15 layers in 2 nm.

Have you recovered perfectly conducting sphere Mie Scattering in a robust way or it is imposible?