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[10172100207]

I am attempting to calculate the effective index of a gap using a Finite-Difference Eigenmode (FDE) analysis. I am attempting to calculate the effective index of a gap using a Finite-Difference Eigenmode (FDE) analysis.  the simulator returns an error stating "No physical structure found." My structure consists of Au (gold) material etched with gap and a dielectric material in the gap.  

In contrast, when I choose the "metal" boundary condition, the analysis proceeds without errors.  Furthermore, I would like to know the recommended area to include in the FDE region to accurately calculate the effective index of the gap with a dielectric material film in the gap.Should the area be the the gap size?   

[Amrita Pati]

Hi,

I have simulated plasmonic slots before and I have never seen this error message. Just want to confirm if the error message is "No physical structures found" or "No physical modes found"? With metals sometimes it can be a bit tricky to find the right modes. But I am not sure why it would say that there are no structures in the geometry. Can you share a screenshot of the entire view (including x-y, y-z, and z-x planes)

Regards,
Amrita

 

[10172100207]

Hi,

The error is: 

This is the entire view:

Thank you. I have tried to expand my simulation area, but the error is still occurring. My groove width is approximately 1.5 um along the x-axis, and its height along the y-axis is about 0.3 um. The FDE range along the x-axis is 2 um, and along the y-axis is 6 um.

[Amrita Pati]

Hi,

Thanks for sharing the screenshot! It can be hard to find modes in these metallic structures sometimes due to a large number of spurious modes like the PML modes (most of the energy resides in the PML). These modes are automatically removed from the Mode List as they are not physical modes. But when the solver calculates the modes, it still counts them. So, if the solver only finds spurious "number of trial modes", then it will stop looking for physical modes. So, there are two things you can do. The first thing is you may increase the number of trial modes, so that the solver looks for more mode solutions to the eigenmode equations. Secondly, if you have a rough estimate of what the effective index of the mode would be, then you can use this value in the search near n field in the Eigensolver Analysis Window. 

Regards,
Amrita