Disable auto source normalization for harmonic generation simulations

[Nikolaos-Matthaiakakis]

Hello, I am interested in running nonlinear simulations that require the source normalization to be turned off in order to obtain the harmonic intensity. Is there a way to globally do this? or even a per monitor way. Thank you

[momchil-flex]

Yeah just set normalize_index=None in Simulation.

Do you mean you are planning to use our built-in nonlinear material models? Because if so you might want to use a CW source, and explore some of our examples about this, e.g. this one

[Nikolaos-Matthaiakakis]

Thank you for the fast reply. Yes I am currently planning to use a method similar to https://docs.flexcompute.com/projects/tidy3d/en/latest/api/_autosummary/tidy3d.NonlinearSpec.html and https://docs.flexcompute.com/projects/tidy3d/en/latest/api/_autosummary/tidy3d.KerrNonlinearity.html . Ideally I need a relatively broadband pulse to see the response in the frequency domain in order to compare with experimental data that use a similar source.

[momchil-flex]

Sounds good, so you are trying to match pulsed nonlinearity and so use a similar pulse in the FDTD as the one in experiment? I believe all our nonlinear optics examples are CW. If this works well and there's data you can share it could be a great addition to the community library!

[Nikolaos-Matthaiakakis]

I will gladly do so as long as there is no sensitive data. Maybe I could provide a simplified example once it works.

[Nikolaos-Matthaiakakis]

Hello again, regarding the pre-built models included in tidy3d, chi2 is currently not available? I have found only chi3 in the documents.

[momchil-flex]

That is correct unfortunately.

[Nikolaos-Matthaiakakis]

I understand, thank you.