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Dear Professor,

My simulation structure consists of an SiO2 substrate, graphene, and a metal layer with a plane wave incident perpendicularly. I monitor the electric field, transmission, and reflection. The issue I am encountering is that in the continuous waveband of 3-5 µm, the simulation converges normally. However, at individual wavelengths, the simulation diverges; for instance, it works fine at 4 µm but diverges at 3.5 µm. To address this, I have made the following efforts:

1. Based on the suggestions from this post (https://optics.ansys.com/hc/en-us/articles/11277217507603-Troubleshooting-diverging-simulations-in-FDTD), I tried changing to metallic boundaries and adjusting the time step, which largely ruled out these common issues.

2. I modified the parameters of the graphene, such as lowering the Fermi level, which made the divergence at 3.5 µm converge.

Could you please advise what might be causing this divergence? Is it related to the properties of graphene, or is it influenced by the wavelength of the light source? How should I analyze and resolve this issue?

Thank you very much!

Best regards,

Wang

[Guilin Sun]

参见 https://innovationspace.ansys.com/forum/forums/topic/fangzhenfasandewenti/#post-370536