Hi, all.

I tried to simulate the effect of a beam propagating through a plexiglass with a hole. I tried two configurations. The first one is the beam goes through the plexiglass with a hole directly, and I observe the intensity distribution at a certain distance after the plexiglass. The second is the beam goes through the plexiglass with the hole first, then it goes forward and is reflected by a retroreflector, I observe the effect of the reflected intensity distribution at the place where the source is located. The origional files are attached. For the first case, I can't see the effect of the hole at all, wherever the detector and the plexiglass are placed and however much the hole is , while for the second case the effect of the hole is that obvious. I just can't figure out why it is like that. Someone could give me some tipps? Thank you in advance!

All the best,