# Quantum interference with different polarization

1. Jun 24, 2013

### gespex

Hi all,

Imagine a double slit experiment where each slit contains a polarization filter with some angle relative to each other ($\alpha$). If the polarization filters are parallel the usual interference pattern will emerge, and when they are perpendicular no interference pattern will emerge. What happens when they have different relative angles, though?
The problem is that I've read two different sources, Wikipedia states:
While someone answered a question saying that it did interfere and that the intensity would be:
$$I=I_1+I_2+2\sqrt{I_1I_2}cos(\alpha)$$

It claims that there are still the same interference pattern, but it simply gets closer to no interference.

So which is right?