I'm a physicist working in the field of optics and engineering.
I use Blender personally both for some simple CAD applications (like modelling for my 3D-printer), and to explore its use for optical simulation tasks.

For this, I developed my own addon OptiCore, the main purpose of which is to easily and accurately create lens geometries in Blender.
A few months ago, I also took an active role in the LuxCoreRender engine project to help continue its development.