Problem with Beam Splitter Design

  • 18 January 2023
  • 2 replies

Hi guys! So I tried to model a set up ( as shown below ) on Zemax but i seem to be having some problems. The beam splitters on the top and far right does not seem to have two rays. Is there any way i could solve this? Thank you!

(ZIP File is attached below)
What I wanted:

My Model:


My Lens Data:



Best answer by David.Nguyen 18 January 2023, 11:32

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I have looked at your file and made the following modifications for the respective configurations.

Configuration 1 - Transmitted beam

  • Surface 8 had a Thickness of 0. Therefore Surface 10 (45-deg surface) was at the same location but tilted. I made Surface 8 Thickness to 5.0.
  • Both tilted Surfaces were in the wrong orientation. I changed the Tilt About X in Coordinate Break 3 and 9 from -45 to 45. I also had to change the corresponding return Coordinate Break (5 and 11) to -45 instead of 45 because the Pick-up solve wasn’t there anymore.

Configuration 2 - Reflected beam

I’m not sure what you did here, after the beam is reflected, and transmitted to the detector, you have it propagate backwards to try and reach a second detector. I think that’s what is causing the issue. In Sequential mode, whenever you split the beam, you almost inevitably have to make a new configuration. Similar to what you did for the very first cube. And if the paths are not symmetrical, it can become a bit tedious. In general, I’d recommend modelling one path at a time, but I went ahead and tried to make something similar to your figure (file attached to my answer).

I see that you are still missing one beam from your figure. I leave it to you as an exercise. You’ll have to create yet another configuration. It Should be fairly similar to Configuration 1 except there’s a reflection at the cube. As a cosmetic improvement it might be necessary to go in the Surface properties and in the Draw tab tick Skip Rays To This Surface (I had to do it for the green path).

I hope this helps, good luck, and take care,



I got it to work! Thank you so much! Now i just need to add the apetures in! :)