I have couple LED monitors. Let's see what are their photons polarizations.   50% photons pass through:   Rotate filter -45 degree, image from monitor disappeared, ~0% pass through:   Rotate fllter +45 degree. Image is fully visible, ~100% photons pass through filter.   Other monitor/tv. different result:   By using polarization filters we learned what was source photons polarization.   When two polarization filters are one by another with 90 degree rotation, ~0% photons