Why aren't interference filters also polarizers?

[Neo_Anderson]

After all, the un-passed light reflects off a transparent medium with a definite index of refraction, right?
HELP!

 

[sophiecentaur]

I think the only reason that you don't get significant polarisation is that the light strikes a polarising filter very near the Normal.

 

[Neo_Anderson]

...Well, I did get one answer...

Interference filters are poly chromatic, depending on viewing angle. Polychromatic, but not polarizing in any significant way.

Anyone else?

 

[Andy Resnick]

The filters I use (dichroics) have different efficiencies depending on the polarization of the incident light (s- or p- polarization), so I expect they can indeed polarize the incident light somewhat. The polarizing efficiency of the dichroic filter is much lower than a polarizer, tho.

It's possible to design filters to have very high pass efficiencies for both the s- and p- states, so they would not induce any large amount of polarization.