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Analytical definition of electromagentic field

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Dear all,

does somebody know how to define an electromagnetic field in RF/Waveoptics (comsol v.4.3a) module ANALYTICALLY using solution of Fresnel equations, not using ports?

For air-glass interface for instance. I need it for later to solve scattering on nanoparticle (does not want to do like in "scatterer on the substrate", want to have precise analytic solution for background field in the absence of scatterer).

I tried sending analytic solution of Fresnel equations from the side using "Ports" or "Electric field" option in "Full field interface" as well as typing in the analytic expressions for the field in "Background field" in "Scattered field interface", but it does not work.

Does smb have an idea? Thanks in advance

Best regards
Pavel


4 Replies Last Post 15 juil. 2017, 11:05 UTC−4
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Hello Pavel Kliuiev

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Mohammad Parvinnezhad Hokmabadi

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Posted: 10 years ago 30 août 2014, 22:23 UTC−4
Hi,
Do you still need?
I am working on the same and I know how to set.
If you still need let me know.

Thanks,
Mohammad
Hi, Do you still need? I am working on the same and I know how to set. If you still need let me know. Thanks, Mohammad

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Posted: 9 years ago 22 oct. 2015, 02:20 UTC−4
Hello! Mohammad,
I'm also very confused about how to set the background scattering field when a substrate exists and this step is aimed to solve the next scattering field when there is a gold nanoparticle on it. I tried to solve the problem refer to the example "scatter on substrate" but the result of extinction cross section at long wavelength is very large. So, I guess the background must be set in a wrong way. Would you tell me how to solve the problem? The plane wave at the normal incidence.
Thank you very much!
Ran Jia
Hello! Mohammad, I'm also very confused about how to set the background scattering field when a substrate exists and this step is aimed to solve the next scattering field when there is a gold nanoparticle on it. I tried to solve the problem refer to the example "scatter on substrate" but the result of extinction cross section at long wavelength is very large. So, I guess the background must be set in a wrong way. Would you tell me how to solve the problem? The plane wave at the normal incidence. Thank you very much! Ran Jia

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Posted: 7 years ago 12 avr. 2017, 02:01 UTC−4
Mohammad Parvinnezhad Hokmabadi,

Can we define the source like dark field source a cone like a source into the COMSOL, if so can you help me to do so???

Thanks
Mohammad Parvinnezhad Hokmabadi, Can we define the source like dark field source a cone like a source into the COMSOL, if so can you help me to do so??? Thanks

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Posted: 7 years ago 15 juil. 2017, 11:05 UTC−4
Dear Mohammad,

I am trying to find the scattering,absorption and extinction cross sections of a gold nano disk with 50 nm height and 80 nm diameter on glass substrate. I followed the 'scatterer on substrate' tutorial for COMSOL 5.1 but failed. It gave correct result for total field solutions, power reflection coefficients in the first part i.e. Air glass interface without scatterer but for the 2nd part, i.e. scatterer with background field as superposition of reflected, incident and transmitted field of first part, it gave scattering cross sections as zero for all wavelengths. The absorption and extinction cross sections are also wrong but non zero and decreasing with wavelength increment. Is it possible to input the background field analytically and only using PMLs than ports. Could you please help me that how can I analytically assign the superposition of reflected and incident field in upper side and transmitted field in substrate side for the scatterer (then no need of ports and first part complexity can be overcomes) ? For my case it is normal incidence of light and the 'scatterer on substrate' tutorial is much complex and (unnecessarily critical) for normal incidence case. i find also that Floquet condition seems not needed for normal incidence.

Could you please share your experience on it.
Dear Mohammad, I am trying to find the scattering,absorption and extinction cross sections of a gold nano disk with 50 nm height and 80 nm diameter on glass substrate. I followed the 'scatterer on substrate' tutorial for COMSOL 5.1 but failed. It gave correct result for total field solutions, power reflection coefficients in the first part i.e. Air glass interface without scatterer but for the 2nd part, i.e. scatterer with background field as superposition of reflected, incident and transmitted field of first part, it gave scattering cross sections as zero for all wavelengths. The absorption and extinction cross sections are also wrong but non zero and decreasing with wavelength increment. Is it possible to input the background field analytically and only using PMLs than ports. Could you please help me that how can I analytically assign the superposition of reflected and incident field in upper side and transmitted field in substrate side for the scatterer (then no need of ports and first part complexity can be overcomes) ? For my case it is normal incidence of light and the 'scatterer on substrate' tutorial is much complex and (unnecessarily critical) for normal incidence case. i find also that Floquet condition seems not needed for normal incidence. Could you please share your experience on it.

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