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Help, Plasmonic grating transmission!

Posted Apr 7, 2012, 7:24 p.m. EDT RF & Microwave Engineering Version 4.2a 10 Replies

Qiao Ma
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Dear guys,

First of all, thanks for concerning my discussion!

Based on the model of plasmonic wire grating, i rebuilt a plasmonic rectangle grating, to calculate the transmission. The model parameters are set as the attached literature.

Unfortunately, the transmission obtained is almost same, excluding a prominent different for the wavelength range of 600-900nm, I try to find the problems many times, and failed again and again!


By the way, during the simulation, another question is presented, when I change the length of simulation region along the propagation direction, the results are changed. But in my opinion, the result should keep unchanged. I really do not know the reason.

The model is too big to upload, could any friend help me to check it and show me the right direction? I will email you the model and the related paper! Million thanks!

My email: mayouqiao188@hotmail.com


Million thanks!
10 Replies Last Post Apr 12, 2012, 6:12 p.m. EDT
Alexander Kuznetsov
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Posted: 1 decade ago Apr 9, 2012, 1:07 p.m. EDT
You might have problems that were discussed here: www.comsol.com/community/forums/general/thread/27390/
You might have problems that were discussed here: http://www.comsol.com/community/forums/general/thread/27390/
Qiao Ma
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Posted: 1 decade ago Apr 10, 2012, 7:14 a.m. EDT
Hi, Alexander,

Thanks for your answer!

I have changed the port to be the scattering boundary condition, then the results are almost in the whole range of the calculated wavelength.

However, based on your discussion with Justin, I would like to add PML+Scattering BC to explore the results. Unlucky, I really do not know how to deal with it.

In my opinion, the PML should be outside the scattering BC, the calculate region should be as follows:

Simulated structure---scattering BC------PML (from inside to outside)

However, when I add a PML layer, all the boundary inner can not be defined as Scattering BC. When I try to add the scattering BC to the boundary of PML, then the calculation will be stopped, gives me some problems.

Could you or any other friend do me a favor to give me some advices?

Million thanks!
Hi, Alexander, Thanks for your answer! I have changed the port to be the scattering boundary condition, then the results are almost in the whole range of the calculated wavelength. However, based on your discussion with Justin, I would like to add PML+Scattering BC to explore the results. Unlucky, I really do not know how to deal with it. In my opinion, the PML should be outside the scattering BC, the calculate region should be as follows: Simulated structure---scattering BC------PML (from inside to outside) However, when I add a PML layer, all the boundary inner can not be defined as Scattering BC. When I try to add the scattering BC to the boundary of PML, then the calculation will be stopped, gives me some problems. Could you or any other friend do me a favor to give me some advices? Million thanks!
Alexander Kuznetsov
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Posted: 1 decade ago Apr 10, 2012, 12:38 p.m. EDT
The correct setup is Top boundary with excitation (preferrably port), Structure, PML, Scattering. Last scattering layer is not really necessary but won't hurt. But in this setup you can't measure transmission directly as you would using Port on bottom.
The correct setup is Top boundary with excitation (preferrably port), Structure, PML, Scattering. Last scattering layer is not really necessary but won't hurt. But in this setup you can't measure transmission directly as you would using Port on bottom.
Qiao Ma
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Posted: 1 decade ago Apr 10, 2012, 5:52 p.m. EDT
Hi, Alexander,

Thanks for your answer!

Based on your reply, if I want to get the reflection and transmission, the simulation arrangement should be

Top boundary with port (light excitation and the reflection record S31), PML, structure, PML, bottom boundary with Port (the transmission record S21)

I am very very stuck that:

Does the top PML allow the incident wave and prevent the reflected wave to pass?
If does, is it the regulation in COMSOL?
Or we should make some special settings to realize it? How?

Similarly to the bottom boundary.

Thanks very much!





Hi, Alexander, Thanks for your answer! Based on your reply, if I want to get the reflection and transmission, the simulation arrangement should be Top boundary with port (light excitation and the reflection record S31), PML, structure, PML, bottom boundary with Port (the transmission record S21) I am very very stuck that: Does the top PML allow the incident wave and prevent the reflected wave to pass? If does, is it the regulation in COMSOL? Or we should make some special settings to realize it? How? Similarly to the bottom boundary. Thanks very much!
Alexander Kuznetsov
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Posted: 1 decade ago Apr 10, 2012, 8:38 p.m. EDT

Based on your reply, if I want to get the reflection and transmission, the simulation arrangement should be


No. If you want both transmission and reflection, no PML layers at all (same as plasmonic grating example). If reflection is enough, then use PML on the bottom and port on the top.
[QUOTE] Based on your reply, if I want to get the reflection and transmission, the simulation arrangement should be [/QUOTE] No. If you want both transmission and reflection, no PML layers at all (same as plasmonic grating example). If reflection is enough, then use PML on the bottom and port on the top.
Qiao Ma
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Posted: 1 decade ago Apr 11, 2012, 5:37 p.m. EDT
Hi, Alexander,

Thanks for your answer!

I will make the related modification, and expect to discuss with you later!

Regards!
Hi, Alexander, Thanks for your answer! I will make the related modification, and expect to discuss with you later! Regards!
Qiao Ma
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Posted: 1 decade ago Apr 12, 2012, 7:11 a.m. EDT

You might have problems that were discussed here: www.comsol.com/community/forums/general/thread/27390/


[QUOTE] You might have problems that were discussed here: http://www.comsol.com/community/forums/general/thread/27390/ [/QUOTE]
Qiao Ma
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Posted: 1 decade ago Apr 12, 2012, 3:30 p.m. EDT
Hi, Alexander,

I checked my code again and again, and the simulation results are still incorrect based on the literature.
Is it easy for you to leave your email to me? I will send you my code.
Or you can contact me by email: mayouqiao188@hotmail.com

Million thanks!

Hi, Alexander, I checked my code again and again, and the simulation results are still incorrect based on the literature. Is it easy for you to leave your email to me? I will send you my code. Or you can contact me by email: mayouqiao188@hotmail.com Million thanks!
Alexander Kuznetsov
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Posted: 1 decade ago Apr 12, 2012, 5:00 p.m. EDT
Hi,

Please post your model on the forum after clearing solutions and meshes.
Hi, Please post your model on the forum after clearing solutions and meshes.
Qiao Ma
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Posted: 1 decade ago Apr 12, 2012, 6:12 p.m. EDT
Hi, firstly I would like to upload my code, however, i do not know how clean the solutions and meshes.
I will do a new code without any solutions again and upload it ASAP!

Regards!
Hi, firstly I would like to upload my code, however, i do not know how clean the solutions and meshes. I will do a new code without any solutions again and upload it ASAP! Regards!

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