Thank you for your reply. I have followed all the instructions from the given websites in order to perform the THG simulation.
It works well when I performed the simulation using simple nonlinear nanostructure with 2D simulation region. However, after I added a substrate underneath the nonlinear material and changed the simulation region into 3D, the simulation didn’t work out. The electric field didn’t converge so that the spectrum didn’t show any fundamental or THG signal. I have no idea how to improve the simulation setup further.
The 2D and 3D simulation files are shown as the following:
Could you please help me check the problems and give me some advises? Thank you!