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How to calculate farfield by nearfield?

Posted Mar 11, 2020, 7:38 a.m. EDT Wave Optics Version 5.5 3 Replies

Chang Chang
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Hi,

I'm simulating a metalens, and I want to know the field behind the lens surface. If I just calculate the field of whole space, I would run out of memory. So is there any technics, through which I can get the field at some point behind the lens without solving every point in the mesh? I mean, is it possible that I can get the farfield through the nearfield just behind the lens, without solving the Maxwell equation?

Thanks.

3 Replies Last Post Mar 13, 2020, 6:19 a.m. EDT
Robert Koslover Certified Consultant
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Posted: 5 years ago Mar 11, 2020, 11:11 a.m. EDT

You can compute the radiating far-field using built-in routines in Comsol Multiphysics. Consult the help system. (Note: I am referring to the RF module here.) If you want to evaluate radiated fields outside the finite-element modeled region, but not in the far-field, you may be able to make use of a radiating near-field approach. For one way to implement that, see https://www.comsol.com/community/exchange/672/

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Scientific Applications & Research Associates (SARA) Inc.
www.comsol.com/partners-consultants/certified-consultants/sara
You can compute the radiating far-field using built-in routines in Comsol Multiphysics. Consult the help system. (Note: I am referring to the RF module here.) If you want to evaluate radiated fields outside the finite-element modeled region, but not in the far-field, you may be able to make use of a radiating near-field approach. For one way to implement that, see https://www.comsol.com/community/exchange/672/
Pu
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Posted: 5 years ago Mar 11, 2020, 10:02 p.m. EDT
Updated: 5 years ago Mar 11, 2020, 10:04 p.m. EDT

In case you are asking about the usual near-field to far-field transformation, that's a mature topic discussed in many books and articles. (Here I would like to advertise our recent work "On the Emission Pattern of Nanoscopic Emitters in Planar Anisotropic Matrix and Nanoantenna Structures" available at https://www.researchgate.net/publication/332961578_On_the_Emission_Pattern_of_Nanoscopic_Emitters_in_Planar_Anisotropic_Matrix_and_Nanoantenna_Structures) In particular, the built-in near-field to far-field transformation functionality could be used if inhomogeneities are localized, i.e. not extended to infinity.

However, with the limited description in the post I guess your problem may not be the traditional transform. You can provide more information for others to help.

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ZHANG, Pu
School of Physics,
Huazhong University of Science and Technology
In case you are asking about the usual near-field to far-field transformation, that's a mature topic discussed in many books and articles. (Here I would like to advertise our recent work "On the Emission Pattern of Nanoscopic Emitters in Planar Anisotropic Matrix and Nanoantenna Structures" available at https://www.researchgate.net/publication/332961578_On_the_Emission_Pattern_of_Nanoscopic_Emitters_in_Planar_Anisotropic_Matrix_and_Nanoantenna_Structures) In particular, the built-in near-field to far-field transformation functionality could be used if inhomogeneities are localized, i.e. not extended to infinity. However, with the limited description in the post I guess your problem may not be the traditional transform. You can provide more information for others to help.
Chang Chang
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Posted: 5 years ago Mar 13, 2020, 6:19 a.m. EDT

Thank you Robert, that's what I'm talking about.

Thank you Robert, that's what I'm talking about.

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