Hello,

I am designing a Fresnel rhomb prism as a half wave plate alternative using ZnSe at 4-9um.

I calculated the phase differences as a function of TIR angle and created a polygon .POB file, inserted it as a non-sequential object and verified with CODA 123 that the polarization rotated 90 deg.

However, I tested this out across the wavelength range with no change to the merit function, while the analytical formula expects a 0.3deg difference due to dispersion.

Another issue I am having is that I don’t really know how to tolerance a polygon. The only idea I have come up with is to make many objects, “Monte-Carloing” it myself.

Please share any insights or guidance.

Note:

The additional reflection facets at half angles are for PBS coating, the prism will be used as a beam combiner. I intended to simply use a table coating file Tp Ts Rp Rs, and make two configurations for the two sorces but I am unsure if this is correct for a tilted incidence angle or if there is a better way to model the beams combination.

Thanks