Problem with grid phase

  • 10 December 2021
  • 3 replies

Hello! I want to use grid phase to generate arbitrary regulation of wavefront and have some attempts following the method in handbook. But there are some problems. The same .DAT file which I succeeded to run in the Zemax2013 did not work in the Zemax OpticStudio. All non-zero values turned to 1.989965E-312. It really confused me and I sincerely thank you for your answer!

3 replies

Userlevel 5
Badge +2

Hi Hanukkah,


I guess backward compatibility has its limits sometimes, and I definitely can’t help with that. But if you tell us what you’d like to achieve, I’m sure somebody will likely help you fix your problem.

How does your *.DAT file look like?

The current format your *.DAT file should be in is described in the Help File of OpticStudio under: The Setup Tab > Editors Group (Setup Tab) > Lens Data Editor > Sequential Surfaces (lens data editor) > Grid Phase. This section of the Help File points differences with respect to the Grid Sag Format found here: The Setup Tab > Editors Group (Setup Tab) > Lens Data Editor > Sequential Surfaces (lens data editor) > Grid Sag. An excerpt from that Help Section reads:


The proper file format is as follows:

 nx ny delx dely unitflag xdec ydec z dz/dx dz/dy d2z/dxdy nodata... 


Does that somehow look similar to your *.DAT file, and if not, could you convert it?

Take care,



Thank you for your response Mr. Nguyen.


In fact, I use the example .DAT files in the \Zemax\Objects\Grid Files folder. And it perform well in Zemax13. I prefer to agree that the compatibility has some limition. Grid phase is used to arbitrarily regulate the phase of the light field, for example, to generate the vortex beam. Maybe I’ll select Zemax13 to accomplish my design. Besides, grid sag is available in all versions and the sag looking can be shown correctly in Analyze...Surface...Surface Sag. It’s really amazing! 


Thanks again for your promptly reply!

Userlevel 2

Was there a problem other than changing the zero values to 1.989965E-312? I ask because this sounds like mainly an aesthetic issue. A number that small is basically zero for any possible purpose known to physics, but because of floating point precision in digital chips, sometimes numbers are rounded funny. Can you let us know if any additional problems are occurring?