Mie 3d scattering

I am studying the scattering cross section of Ge nano particles.

when i first simulated the scattering cross section as described in Mie 3D exampe on lumerican webpage i got this result.

However, i would like to change the index of the background so i used a cube extended through the PML region where i get negative Qscat which i think is not true.

in order to check that whether the simulation set up is correct or not i used a cube of index one to resemble the air’s back ground and i still get negative Qscat.

I am wondering is there something wrong in the simulation setup?Ge-250 - idex 1.2.fsp (324.7 KB)

Hi @maisaad,

The problem is due to the mesh order. The mesh order defines what material is used when 2 objects are overlapping. In your simulation, both the sphere and the rectangle have the same mesh order (2), so it is their position in the object tree that defines what index is used. In this case it is the rectangle, so when you run the simulation, it is like there is no sphere.

To change that, you can either move the rectangle (using the orange arrows) so it is above the sphere, or you can change the mesh order of the rectangle to a higher value than the one of the sphere. It should solve the issue.

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