Why does reflection cause polarization of light?

[maxbur]

Hello all

I know that polarisation of light can occur from reflection, and when the reflected ray is 90degrees from the refracted ray the relfected light is 100% plane polarised.
So, my question is why is it that reflection causes polarisation of light?

Thanks

 

[fadly]

because the light on the vertical plane were annihilated through phase differential.

 

[maxbur]

Ok, and what is phase differential?