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Large wavelength to feature size mismatch: Limitation of COMSOL simulations?

Posted May 30, 2020, 5:08 p.m. EDT Wave Optics, General, Introduction 3 Replies

Ann P. Physics
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Is it possible to simulate the interaction of a ~ 3000 micron beam with an object with 1 micron smallest feature size (currently using Wave Optics module)?

I read that there are limitations of conventional EM simulations when the mistmatch between the wavelength and feature size becomes very large. How can I determine when/if this is the case?

3 Replies Last Post May 31, 2020, 6:39 p.m. EDT
Edgar J. Kaiser Certified Consultant
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Posted: 5 years ago May 31, 2020, 3:55 a.m. EDT

Andrea,

best is to make a model that can be compared to an analytical solution.

Cheers Edgar

-------------------
Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
Andrea, best is to make a model that can be compared to an analytical solution. Cheers Edgar
Dave Greve
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Posted: 5 years ago May 31, 2020, 6:33 p.m. EDT

I read that there are limitations of conventional EM simulations when the mistmatch between the wavelength and feature size becomes very large.

If a student said that I would ask where he read that and why the author says it happens.

If you wanted to do a comparison between simulation and analytic solutions, then scattering of a plane wave by a sphere would be a good test problem. The Rayleigh scattering solution is valid in the limit of a very small sphere in relation to wavelength, and the Mie scattering solution is valid for larger spheres.

> I read that there are limitations of conventional EM simulations when the mistmatch between the wavelength and feature size becomes very large. If a student said that I would ask where he read that and why the author says it happens. If you wanted to do a comparison between simulation and analytic solutions, then scattering of a plane wave by a sphere would be a good test problem. The Rayleigh scattering solution is valid in the limit of a very small sphere in relation to wavelength, and the Mie scattering solution is valid for larger spheres.
Ann P. Physics
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Posted: 5 years ago May 31, 2020, 6:39 p.m. EDT

Thanks for the feedback--I think I have quite a bit more reading to do to understand this issue. I'll check out modeling the simple case of scattering from a sphere, as you mentioned, and compare this the Rayleigh scattering solution to get a better idea of the limitations of the simulation.

Thanks for the feedback--I think I have quite a bit more reading to do to understand this issue. I'll check out modeling the simple case of scattering from a sphere, as you mentioned, and compare this the Rayleigh scattering solution to get a better idea of the limitations of the simulation.

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