Gain medium with saturation support for laser cavity simulation applications.

[FilipeFcp]

A user asked about a gain medium that supports saturation for applications in laser simulations.

Currently, we can simulate gain, but without saturation, it will eventually diverge for longer runtimes. I believe we can still analyze transient states in laser cavities, but it would be interesting if we had a way to simulate something as a 4-level system, as implemented in other solvers.

Priority is up for discussion, I think. I have seen one user interested at this moment. Maybe @tomflexcompute can add more about this.

[tomflexcompute]

So far I've heard one additional user brought it up. @FilipeFcp is it critical for this particular user or they can live without it?

[caseyflex]

I agree it would be nice to support this. @FilipeFcp If I implement this, would you be able to make an example notebook? Do you have something in mind there?

[FilipeFcp]

@tomflexcompute It is not critical for this user. He had experience with Tidy3D and he says it is his preferred tool.

@caseyflex Sure, I could work on a notebook about it. I have nothing specific in mind. I took a quick look and found a few papers that could be promising. But most papers just simulate the cavity (the Bragg mirrors, or photonic crystal mirrors, things like that)