Hi,

A previous post discussed how to model a Fabry-Perot cavity with planar mirrors by using the FP coating (Fabry-Perot cavity | Zemax Community)

I’m interested in modelling a FP cavity in a confocal configuration i.e., two spherical mirrors separated by the mirrors’ radius of curvature (~10 mm). In the post, Mark mentioned that a tapered coating could be (only) way to model a varying coating thickness. At first that seemed to be the way to go, but I’m not sure that approach will work in this case, see the ray trace below when the incoming ray is not exactly on axis.

Any suggestions are welcome

/Hans