 We understand light as an electromagnetic wave. The direction of the electric field is called the wave's linear polarity. Here we see the polarity at different angles from a fixed reference. It is also possible for the polarity to be rotating clockwise or counterclockwise around the line of motion. These properties hold for the basic unit of light, the photon. When light passes through a polarized lens, the amount of light that makes it through depends entirely on the angle between the incoming light's polarization and the polarization direction of the lens. To see this, here are a couple of experiments you can do at home if you have three pairs of polarized glasses. Photons leaving the background table have a wide variety of polarizations. We start with the lens that only allows light polarization in the vertical direction to pass through. All the other light is blocked. We'll call this lens A. If we bring a second lens, lens C, and orient it the same as the first, all the light that passes through A passes through C. But as we rotate lens C, we see that the amount of light passing through is going down. By the time we reach 90 degrees, C is blocking all the light that passes through A. Now if we bring in a third lens, lens B, and place it in between the first two and angle it at 45 degrees, we see that light that could not make it through C before is now coming through. In other words, lens B, designed to reduce the amount of light that reaches C, actually enables more light to get through C. To see what is happening here, we need to go down to the photon level. Classically, we calculated the percentage of light that goes through a lens. But a photon will go through or not go through. It cannot be divided. In quantum mechanics, it's the angle between the orientation of the photon's quantum state and the orientation of the lens's polarization that provides the probability for passing through the lens. In addition, the interaction between the lens and the photon will change the orientation of the photon's state to equal the orientation of the lens it passed through. With this understanding, we can examine how light made it through lens C once we added lens B. Here we have a number of photons with random polarizations trying to pass through the vertically polarized lens A. Some make it and some don't. All the photons that pass through A have now been changed to have the quantum state vertical to match the lens. With this polarization, the probability of passing through lens C which is rotated 90 degrees from the vertical is zero. No light gets through C. Now we introduce lens B, which is rotated 45 degrees from vertical. We see that some of the vertically polarized photons coming through lens A will pass through lens B. In addition, the interaction between the photons and lens B change the photon's quantum state to oriented at 45 degrees to match the lens. This enables some of the photons that passed through lens B to now pass through lens C. The key takeaway here is that objects like lenses, crystals, electric fields, etc. can and do modify the quantum states of the particles that encounter them.