I’m calculating infrared power densities in w/cm² of near-diffraction limited star images from a system that has variable vignetting over the field of view. Does the diffraction EE analysis ignore or account for system vignetting and light loss due to obstructions? What would the right way be in Zemax to calculate radiometric irradiance from point source images that are affected by vignetting and that vary slightly in structure from DL over the focal plane?
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Does encircled/ensquared energy analysis account for system throughput?
Best answer by Sandrine Auriol
Hi Mike
The diffraction EE takes into account system vignetting due to obstructions, meaning that those obscured rays will not be part of the encircled energy calculation. However we still consider that the EE reaches 1 on the image plane, so the 1 doesn’t reflect the energy loss throughout your system.
I checked this on this system "{Zemax}\Samples\Sequential\Telescopes\Schmidt-Cassegrain spider obscuration.zmx".
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