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Plasmon propagation length modeling

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Hello,

I have modeled a plasmon grating coupling periodic 2D model with success and now I want to model the propagation length of different gratings. This means a none periodic problem - half of the model is the excited grating that couples the plasmon and the other half is just the metal/dielectric interface where the plasmon propagates. I used scattering boundary conditions on all boundaries but the results is not logical and I am sure it is due to inappropriate boundary conditions.

Can someone help?

Thank you.
Itai.

9 Replies Last Post Aug 4, 2011, 4:41 a.m. EDT

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Posted: 1 decade ago Aug 2, 2011, 5:03 p.m. EDT
Can you upload a copy of your code?
Can you upload a copy of your code?

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Posted: 1 decade ago Aug 4, 2011, 1:56 a.m. EDT
Try to make metal dieletric interface very long so plasmon will be damped by losses. (Although it will need very big mesh.)

Or use Perfectly matched layers.
Try to make metal dieletric interface very long so plasmon will be damped by losses. (Although it will need very big mesh.) Or use Perfectly matched layers.

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Posted: 1 decade ago Aug 4, 2011, 3:31 a.m. EDT
Hi Guys,

Thank for your responses but I found the problem - it seems the COMSOL demands that the complex nature of losses be negative! it is due to definitions of the coordinate directions and wave propagation. this does not appear in the documentation but this issue resolves correct losses and propagation directions.

FYI!
Hi Guys, Thank for your responses but I found the problem - it seems the COMSOL demands that the complex nature of losses be negative! it is due to definitions of the coordinate directions and wave propagation. this does not appear in the documentation but this issue resolves correct losses and propagation directions. FYI!

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Posted: 1 decade ago Aug 4, 2011, 3:57 a.m. EDT
I am sorry but I do not understand what you mean by "COMSOL demands that the complex nature of losses be negative!"
I am sorry but I do not understand what you mean by "COMSOL demands that the complex nature of losses be negative!"

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Posted: 1 decade ago Aug 4, 2011, 4:18 a.m. EDT
In order for the metal to show losses you must define its epsilon as complexed. and the sign of the complex part must be defined as negative to creae losses, if you define it as positive it will generate power and not absorb it. this also effect the propagation direction of waves since the wave is EXP(i*k*x).

Itai.
In order for the metal to show losses you must define its epsilon as complexed. and the sign of the complex part must be defined as negative to creae losses, if you define it as positive it will generate power and not absorb it. this also effect the propagation direction of waves since the wave is EXP(i*k*x). Itai.

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Posted: 1 decade ago Aug 4, 2011, 4:21 a.m. EDT
It is specified at pages 121-122 of RFModuleUsersGuide.pdf
It is specified at pages 121-122 of RFModuleUsersGuide.pdf

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Posted: 1 decade ago Aug 4, 2011, 4:33 a.m. EDT
I am sorry, I dont see it, what version are you using?
I am sorry, I dont see it, what version are you using?

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Posted: 1 decade ago Aug 4, 2011, 4:34 a.m. EDT
Version 4.2
Version 4.2

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Posted: 1 decade ago Aug 4, 2011, 4:41 a.m. EDT
I am using 3.5a so maybe they added that...
I am using 3.5a so maybe they added that...

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