Learning Forum

[Tongrui Pi]

Dear Lumerical Community,

I'm simulating metal's saturable absorption in Lumerical FDTD and need to define the imaginary part of Chi3. The existing models (eg. Chi2\Chi3, Raman Kerr) seem to allow only for the real part. Any advice on how to do this?

Thanks!

[Dimitris Polyzos]

Hello, 

You are correct, the imaginary part of the existing models is not included. However, there is a workaround in order to include the absorption characteristic of a material. An option would be to create your own material model (check link #2). I have to let you know that it is quite an advanced feature that requires a very good understanding of the FDTD method as well as experience in C++ programming, meaning that it will require recompiling the C++ code, and changing the update equations. Please refer to the following links:
1. https://optics.ansys.com/hc/en-us/articles/360034394734-Advanced-and-custom-optical-material-models-in-FDTD-and-MODE.

2. https://optics.ansys.com/hc/en-us/articles/360034915213-Flexible-Material-Plugin-Framework?source=search

I hope I helped. 

Kind regards

Dimitris
  

 

 

[Tongrui Pi]

Hello Dimitris,

 

Thank you very much for the quick and informative reply. This sounds challenging. I'll try to look into creating a custom material model as suggested.

 

Best regards,

LZ

[Tongrui Pi]

 

 

[Dimitris Polyzos]

Hello Linzhi Yu,

I am glad I could help. Please let me know how it went and don't hesitate to come in contact for further help.

 

Regards

Dimitris