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PML does not work during wavelength sweep

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I was simulating the scattering from a nanodisk by normal incidence.

With a spherical PML, the scattering field should be basically symmetric below and above the disk plane. It is indeed so when I simulate 400 nm and 430 nm.

However when I start to sweep the wavelength, 400 nm to 430 nm, the 430 nm case behave very unexpectedly with the PML. Field penetrates half of the PML and a very strong reflection is observed.

I start to think this is a bug of the comsol 4.3, where the PML somehow did not recognize the new wavelength during sweeping. Maybe I did something stupid, I don't know anyone else experienced this before?

3 Replies Last Post 2013年1月22日 GMT-5 22:42

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Posted: 1 decade ago 2013年1月22日 GMT-5 20:52
I simulated PML with wavelength sweeps many times and it's working just fine. I remember someone reported a problem with spherical PML and geometry units set to nm. Something was not working correctly in this case. Maybe it's your case as well. This thread is somewhere in the forum, search for it.
I simulated PML with wavelength sweeps many times and it's working just fine. I remember someone reported a problem with spherical PML and geometry units set to nm. Something was not working correctly in this case. Maybe it's your case as well. This thread is somewhere in the forum, search for it.

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Posted: 1 decade ago 2013年1月22日 GMT-5 20:59
Thanks. That might be the problem.

I found this thread talking about this. I believe it is a very common scenario in plasmonics and people should be aware of it.
www.comsol.com/community/forums/general/thread/26840/
Thanks. That might be the problem. I found this thread talking about this. I believe it is a very common scenario in plasmonics and people should be aware of it. http://www.comsol.com/community/forums/general/thread/26840/

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Posted: 1 decade ago 2013年1月22日 GMT-5 22:42
It is indeed this problem. It works after i changed it to [m]
In fact, the bug is really bad. Previous release does not allow you to calculate if you set the nm scale. Unlike the previous version, it does not show error, but gives unreasonable solutions for spherical PML. One might believe the wrong solution if not careful.
It is indeed this problem. It works after i changed it to [m] In fact, the bug is really bad. Previous release does not allow you to calculate if you set the nm scale. Unlike the previous version, it does not show error, but gives unreasonable solutions for spherical PML. One might believe the wrong solution if not careful.

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