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[zzp2002]

Hello, everyone

Due to the special properties of graphene, its absorption gradually reaches saturation under high light intensity. So, how to reflect this nonlinear effect in FDTD？

Especially in the simulation of my self built resonant structure with or without graphene, there is a significant difference in the transmittance of light (-43dB and -13dB). This unreasonable data makes me doubt whether there is a problem with my simulation or due to the nonlinear effects mentioned above. Can anyone help me answer this? Thank you very much!

[Dev]

Hello,

Sorry for the delay in  response.

From what I understand, graphene exhibits intensity-dependent absorption. At low light intensities, it absorbs strongly, but as the intensity increases, the absorption saturates and gradually decreases. This is a nonlinear optical behavior and therefore cannot be accurately modeled using the standard built-in materials in FDTD, which are inherently linear.

One approach to address this is to implement a custom nonlinear material model using the Flexible Material Plugin Framework – Ansys Optics

 

Additionally, I recommend reviewing the nonlinear optics examples available on our website for reference and inspiration:

Nonlinear optics - list of examples – Ansys Optics

 

For the second question: pleasey check your mesh size, time step, and simulation duration when modeling intensity-dependent behavior.

Best regards

[zzp2002]

Thank you for your reply. I have another question, can the code extract the electric field and other information of each grid in the definition of nonlinear material plugins? In this way, the light intensity of each region can be calculated to achieve differential absorption of graphene. May I ask if there are any relevant code examples? I couldn't find them in the link you provided. Thank you very much!

[Kirill]

Dear Subscriber,
This topic appears to be a duplicate of the discussion happening in another thread 材料编写问题 and will be closed.