My MTF measurements don’t match my WFE and PSF measurements. I’m trying to use a model to figure out why this is the case so I can improve the MTF measurement.
I suspect the reason for the discrepancy is that the radiance from the MTF target does not fill the pupil in the same way that the WFE and PSF measurements fill the pupil. However, I cannot figure out a way to verify this assumption with a model in OpticStudio.
The MTF test setup is a trans-illuminated reticle (not an epi-illuminated printed target). While it is possible to use apodization in an OpticStudio model, this is not the same as a trans-illuminated reticle where a condenser lens may be used to focus light onto the reticle.
Can anyone suggest a method of modeling this in OpticStudio in a manner that captures the effects in a nearly diffraction limited system?