@FumiyaK

You could define additional fields in the system to create such an entrance slit. If you consider the one-dimensional case along the small dimension of the slit, you can have a field at the center of the slit and two other fields on either side at a distance of half the slit width. For that, I’d use the Field Type: Object Height with a Normalization: rectangular. For a slit of 100um, you can have a field at 50um, and another one at -50um (consider using a pick-up such that you only need to change one value, as shown below).

Does that make sense?

Take care,

David

@FumiyaK 

Indeed, the spectrometer images the slit onto the detector. Therefore, by imaging the field at the edge of the slit, you know how where the edge of the slit will be on the detector, which gives you the spectral resolution. You could also define more fields and give them intensities that correspond to your light profile in the entrance slit such that you get a more accurate picture of the spectral resolution, but the edge fields will give you a first approximation assuming the light is homogeneous in the entrance slit.

I hope I understood your question correctly.

Take care,

David

I’m trying to do something similar. Found the guidance here useful: Spot Size VS Spectrometer Slit Width | Zemax Community

So far I’ve stuck with Image Simulation but am getting differences that I don’t yet understand between using a filled square input IMA file and placing a rectangular aperture after the object, and generating an IMA representation of the slit (like this: How to simulate a slit width for Geometric Image Analysis? | Zemax Community)