Hi,

So I’ve been trying to model a system that involves using light that passes through some optical elements into the back pupil of a microscope objective, focuses onto a mirror, and then reflects back through the objective (Thorlabs - TL10X-2P 10X Super Apochromatic Microscope Objective, 0.5 NA, 7.77 mm WD). Both the forward and reverse blackbox files are directly available for download on Thorlabs website, but my attempts so far to actually model using them haven’t been successful unfortunately. 

The first pass works as expected, since that’s pretty much just taking the already available forward blackbox file. The issue comes with regards to trying to correctly define the backwards path (or if it’s even possible and instead I have to try and break the simulation up into two different setups for each pass). I’ve tried a variety of attempts that end up with either none of the reversed rays seemingly interacting with the reverse blackbox, or where the spot diagram for the image plane will only show a single point in the middle. I attached an attempt where I tried to ensure the reverse blackbox is in the same position as the forward one, as well as the available blackbox files. I’ve also tried with different objectives (with their respective forward and reverse blackboxes), and ran into similar difficulties. It feels like it’s an issue where the blackbox files (both forward and reverse) are defined in a forward thickness, so in order to place the reverse blackbox in the correct location the rays are just being traced to the beginning of the reverse blackbox without actually being able to pass through it?

Is there a best practice/trick/something straightfoward I’m missing when it comes to trying to do a simulation like this? Or is it even possible?