extended non seq sources

  • 13 April 2021
  • 3 replies
  • 281 views
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Dear Zemax Team,


I have converted a diffraction-limited optical system from sequential to non sequential mode finding that my input fields have been converted into source ellipse sources with about 1e-6 mm X,Y half width. The conversion works fine, but I would need to evaluate the effect of using and extented source (a pinhole) in the non seq mode instead of the diffraction-limited one. I was naivily setting the X,Y half width tabs of the source ellipse to a fraction mm up to 1 mm, but when I ray trace basically the PSF disappears. I did this check on object n° 43 configuration 2. Is there clever a way to represent properly an extended source for this purpouse?


At this link you can access the zar file, it has been saved with a diffraction-limited object n°43.











https://wetransfer.com/downloads/cd8e9bf0c9800be70241f93b4a9e8c9a20210413151906/9fc8114982f2d70af2a9fb5791dd3d2920210413151935/78dfb6
 

Thanks for your help.


Best regards


Gabriele


 


 

3 replies

David
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Hi Gabriele,


The conversion to non-sequential models field points as Source Ellipse objects using a Source Distance in the data specifying the Source Ellipse. From the documentation on Source Ellipse:


'Source Distance: The distance along the local z axis from the apparent source point to the location of the source object. This value may be positive or negative. If zero, the rays are collimated. If positive, the apparent source point is behind the object. Considered only if Cn, Gx, and Gy are all zero.'


So although the Source Ellipse does have a non-zero diameter, the rays appear to be emitted from a point. OpticStudio chooses the source semidiameter and the source distance so as to produce a cone of rays which simulate a point source which models the sequential field. You can use it as it is -- it  is not really an extended source.


Here is the result of converting a very simple sequential design:



And here is what it looks like if we zoom in on the Source Ellipse:



The rays are actually emitted from a point.


Kind regards,


David


 

Kind regards, David
S
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Userlevel 6
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Hi Gabriele


No problem. I had a look at your file and I think something might have gone wrong in the conversion.


If I only trace Sources 43-46 without ray splitting and scattering, I can see on the layout that no rays are reaching the Detector 50. When there is no ray splitting and scattering, this is equivalent to the sequential path. I am not sure how your sequential system is but I would check that there is not an issue with the nesting rule. The nesting rule is that when 2 objects overlap in space, the properties of the object listed last in the editor is the one that defines the properties. Check that section of the help file: 



Let me know if I misunderstood. Let us know if you'd like to share the sequential file. We can have a look.


You can also check the PSF in non-sequential. There is a flag in the Detector Rectangle for that.


 


And two final comments:



  • When you share your files, please untick this box. It will make the files smaller in size:


  • And last thing, this forum thread is open to our whole community. So if you don't want to share your files with everyone, please feel free to open a case.


Thank you.


Sandrine

Sandrine Auriol
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Thanks David and Sandrine for your suggestions, I didn't realize I was spamming the whole community, I will then move it to a case;)


Best regards


Gabriele

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