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Circular Polarization with Gaussian Beam
Posted 17 mag 2024, 09:22 GMT-4 Electromagnetics, Wave Optics, Physics Interfaces Version 6.2 2 Replies
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I have been working to get a circularly polarized Gaussian beam. I found that this solution does indeed work for the user defined waves but using the (built in) function for a Gaussian beam, the result is elliptically polarized light. I have combed through the equations and cannot see anything amiss. I have also tried to counteract the ellipticity using various methods, but to no avail. I believe there must be a way to simulate an circularly polarized beam in COMSOL, but thus far I cannot find it. I have attached a simple model which demonstrates the difference in the two methods despite the same inputs.
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I don't have the wave optics module, but I ran your model using the RF module instead, replacing your terms with their equivalents. And yes, I saw ~what you saw. But then I realized that I was not looking at the incident (i.e., "background") fields, but rather the computed fields within the computational volume, which are impacted by the imperfect boundary conditions. That impact includes reflection from boundary walls and ends. This led to a partial standing wave in the cylinder. In the RF wave module, plotting emw.Ebx, emw.Eby, and emw.Ebz yields the background fields, while plotting emw.Ex, emw.Ey, and emw.Ez yield the field in the presence of the actual boundary conditions. May I assume you have a similar option available for looking at the background field components, in the wave optics module? If so, I sugggest you try that.
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Indeed this is an option in the wave optics, and indeed it does show that the background field is circular. Obviously, this is a simplified model but seeing the effect everywhere else I looked and not noticing the background option I had run out of solutions. Thank you.
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