Simon

In addition to the measurements on Monday, I took the transmission data for both S and P polarization of the Brewster Polarizer. This is to further understand the type of coating that has been manufactured for it.
Attached is the respective graph.
As can be seen, in S-pol there is a distinct minimum at 45 degrees, while for the transmission in P-pol the minimum is at around 30 degrees with a maximum at 63 degrees AoI. This result correlates quite well with the reflection measurements.

Also, I characterized a second polarizer of the same type in terms of reflection and compared it with the previous one.
The reflection curves of both polarizers are almost identical and show the same location of the minimum in P-pol (~ 63 degrees).