Hi Dr. Neha,

First off, please only post one time on the forums and do not create duplicates.  Other users trying to answer one post might be wasting their time if the second post is already answered:

Importing Zernike Fringe Sag data from MetroPro and correct normalization radius | Zemax Community

Zygo uses the same Zernike polynomial as the Zernike Fringe Sag surface rather than the Zernike Standard Sag surface; you should change your surface to Zernike Fringe Sag.

As for importing the Zernike Coefficients, it really depends on how the measurement was performed with the Zygo.  In either MetroPro or Mx, there is a scale factor.  If I remember correctly, the default is 1.0.  But, if the measurements of the surface is performed in reflection, the technician is supposed to change this scale factor to 0.5.  In the Zernike Fringe Sag surface, the sag is expressed in Lens Units, so you should not scale the coefficients by the wavelength.  The output for the ZRF file is typically in microns so you might need to convert from microns to Lens Units.

To analyze PV & RMS of the Zernike Fringe Sag surface, I would use the Surface Sag (Analyze > Surface > Sag) analysis rather than the Wavefront Map.  The Surface Sag will give you the PV & RMS without needing to place the Zernike Fringe Sag surface at the Exit Pupil (which is where the Wavefront Map is calculated).

If you still have access to the part under test and can re-run the measurement, I would suggest reading the following Knowledgebase Article and use the technique the authors talk about.

Attaching Interferograms to Optical Surfaces in OpticStudio – Knowledgebase

Hello Michael,

Thank you for your suggestion.

I have updated the surface type to Zernike Fringe Sag, but the PV value (2.6 microns) from the Zygo still does not match the PV value in Zemax. Could you confirm if it's correct to set the normalized radius to the semi-diameter of the off-axis mirror? I noticed that the PV value changes when I adjust the normalized radius.

I currently have only 36 Zernike coefficients. Using the Zernike Fringe Sag surface, I entered these coefficients directly in millimeters and kept the other parameters—such as diameter and radius of curvature—consistent with my design. I’ve attached a .doc file containing these values, which are taken directly from the Zygo .int file, for your review.

Additionally, is it acceptable to use the PV value directly from the wavefront map?

Thank you for your help!