I am trying to model the reflected amplitude of Chi3 for a thin film as a function of film thickness. The thin film is
that is on a SiO2/Si substrate so I want to use lumerical to account for any reflections/interference effects that might affect the reflected THG signal. I’m basing my model off the harmonic.fsp example and look at the simulated spectrum amplitude at the frequencies of interest. I have found that when I change the thickness of the material, the source
jumps around significantly as can be seen in this figure (used the original example with Chi2 and varied the mesh and material thickness simultaneously):
Is this a problem with the Fourier Transform? I’ve increased the mesh accuracy to 6 and it doesn’t seem to help. I’ve also turned off auto-shutoff thinking that maybe I need to collect spectra that all have the same simulation length. Do you have any suggestions?