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How to run a Gaussian beam in 3D

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Hello, I would like to run a Gaussian beam in 3 Dimensions. I know that this can be done in the Physics model emfd. However I am cnofused about how to implement it. Would I modify a port? Or would I modify a scattering boundary conditions?

Wat other rescources can I use for this?


1 Reply Last Post Mar 11, 2020, 11:09 a.m. EDT
Lars Dammann COMSOL Employee

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Posted: 4 years ago Mar 11, 2020, 11:09 a.m. EDT

Hi, there are different ways to define gaussian beams. One is to define them as a background field. Here is an example of that: https://www.comsol.com/model/nanorods-14693 This model is 2D, but it works in the same way in 3D. You can also define them on a scattering boundary condition, matched boundary condition, and perhaps others, I don't remember them all. Modifying a port is probably not a good idea, since a port assumes that you have an infinite waveguide with a fixed wave number behind the port. A gaussian beam violates that assumption.

Here are two blogs that may interest you: https://www.comsol.de/blogs/understanding-the-paraxial-gaussian-beam-formula/ and https://www.comsol.de/blogs/the-nonparaxial-gaussian-beam-formula-for-simulating-wave-optics/

Hi, there are different ways to define gaussian beams. One is to define them as a background field. Here is an example of that: https://www.comsol.com/model/nanorods-14693 This model is 2D, but it works in the same way in 3D. You can also define them on a scattering boundary condition, matched boundary condition, and perhaps others, I don't remember them all. Modifying a port is probably not a good idea, since a port assumes that you have an infinite waveguide with a fixed wave number behind the port. A gaussian beam violates that assumption. Here are two blogs that may interest you: https://www.comsol.de/blogs/understanding-the-paraxial-gaussian-beam-formula/ and https://www.comsol.de/blogs/the-nonparaxial-gaussian-beam-formula-for-simulating-wave-optics/

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