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Controlling size of background plane wave in optical scattering

Posted 25 ago 2016, 10:11 GMT-4 RF & Microwave Engineering, Materials, Modeling Tools & Definitions, Parameters, Variables, & Functions, Results & Visualization Version 4.3a 1 Reply

Rahim Leung
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Hi,

I am currently working on modelling the optical scattering of a plane wave on a nanocircle. I require the plane wave to only excite a select region of space, and so I multiplied it with a rectangular function with the desired width. However, the results indicate that when multiplied with the rectangular function, there are diffraction like effects that affect the scattered field that are not present when rectangular function is not applied.

I have included two images of the scattered field norm: one is when the plane wave is truncated with a rectangular function, and one is with a plane wave of infinite extent in the y-direction.

How do I remove the unwanted effects from the results with the truncated plane wave?

Thanks!

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1 Reply Last Post 25 ago 2016, 22:37 GMT-4
Robert Koslover Certified Consultant
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Posted: 8 years ago 25 ago 2016, 22:37 GMT-4
Instead of a rectangle, consider using a spatial windowing function that does not have such a sharp edge. Then you will get much less diffraction.

en.wikipedia.org/wiki/Window_function

Also, consider using Comsol's "Scattered-Field" formulation instead of the full field formulation.
Instead of a rectangle, consider using a spatial windowing function that does not have such a sharp edge. Then you will get much less diffraction. https://en.wikipedia.org/wiki/Window_function Also, consider using Comsol's "Scattered-Field" formulation instead of the full field formulation.

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