Skip to main content

Hi All,

I’m working on a Batch Ray Trace tool using the ZOS-API and need the optical path length of each ray I trace. When I look on the docs there appear to be three options
1) “None” : which returns optical path length of the ray
2) “Current” : which returns the path difference between the current ray and the previous ray
3) “CurrentAndChief”: which returns the path difference between the current ray and the chief ray

I was seeing results that were inconsistent with my expectations so I ran a test. If “None” returns the optical path length of the ray, and I subtract the mean value of all the computed OPL’s from each ray trace, then I should see a result that is similar to the Wavefront Map. 

 



What I found is that the shape is similar, but the amplitude greater by a factor of ~10
 


What causes this difference?
 

Hi Jaren,

 

Nice to see you here! Didn’t know you were looking to use Zemax for your project. I think we are working towards a similar goal, let’s have a chat one day (I’ll write you an email).

In the meantime, have a look at this reply from @MichaelH. Perhaps it can help you. From Michael’s answer, it seems None gives you the absolute path length, probably in lens unit (at least not in waves, that’s what he’s saying in his reply).

Take care,

 

David

Hi Jaren,

The wavefront map is a plot of the OPD (in waves) over the pupil.  The OPD for an arbitrary ray is simply the difference between the optical path length of the ray minus the optical path length of the chief ray (again, typically expressed in terms of waves).

To compute the wavefront map in ZOS-API, it seems that the best way would be to use either the “Current” mode if the chief ray does not change, or “CurrentAndChief” if the chief ray happens to change.  The predecessor to the NormUnpol batch raytrace in ZOS-API was the Mode 0 version in Extensions (which are now deprecated).  Here’s what the help documentation says about this older mode of doing the same thing:

 

 

Regards,

Jeff

 

Reply


Community Posting GuidelinesCookie settings


Zemax Community

Need more help?

To Chinese users:

Do not provide any information or data that is restricted by applicable law, including by the People’s Republic of China’s Cybersecurity and Data Security Laws ( e.g., Important Data, National Core Data, etc.).


不要提供任何受适用法律，包括中华人民共和国的网络安全和数据安全法限制的信息或数据（如重要数据、国家核心数据等）。



Privacy policy   License Agreements    Terms of use    Cookie Policy   Zemax Account Licensing Policies