NLSE femtosecond laser filamentation

[IvanOstr]

Hello there,
I've been playing with the beautiful application you wrote and enjoying it lately.
In my research i'm interested in the following task -
Propage a 100 fs pulse through air with external focusing (lens of 500mm) conditions and create a plasma filament.
Is this doable under your simulation?
I haven't found a way to put a lens.

Thanks,
Ivan

[NickKarpowicz]

Hi there! It should be possible - I don't have air implemented as a medium at the moment, but I've wanted to for a while... I can do it in a few days and get back to you with an example
Cheers,
Nick

[IvanOstr]

Thank you,
that sounds great.

[NickKarpowicz]

Hi again,
I worked on this a bit today - I have air in the current version of the material database now, and briefly tried it; at least qualitatively it seems to behave like one would expect a filament to work. It would need some good experimental literature to tune the plasma absorption parameters, though - do you have anything in particular in mind that you wanted to look at?

I put my saved result of a test run here if you want to load it and try: https://datashare.mpcdf.mpg.de/s/lpOr1GUSA8jtH05

Since this code is made for field-resolved things, I have to say that it's a bit inefficient at filamentation - unlike the typical NLSE, the quantity being propagated is the real-valued electric field, which must be resolved cycle-by-cycle. This is better for very broadband things, but filamentation is a case where the envelope approach would likely be faster. This result look about ten minutes on my home PC. On the plus side, it does include a dispersive nonlinearity and naturally handle things like interference with the third harmonic.