Light polarization can be in many forms, and unless you have a degree in physics is not easy to explain, so to keep it simple let’s look at the simplest form of light polarization which is reflection of light, or glare. The glare from the sun can often be temporarily blinding when it reflects from the road or water. This is especially bad when the sun is low in the sky and therefore the angle of the reflected glare is also at a low angle. Not all substances produce polarized light and it is most common from transparent surfaces such a water and glass.
A classic form of polarized light that most people will have experienced is a rainbow. However the human eye is ill equipped to determine the actual polarization of rainbows and if they are viewed through a polarizer they become much clearer. Polarized light is also used in LCD displays and many computer monitors and televisions will make use of this form of light.
If you look out across a choppy sea on a sunny day you will see the light glittering from the ripple and dancing across the surface of the water. This is another example of light polarization and is caused by the sunlight reflecting at different angles as the wave moves.
There is a distinct difference between standard sunglasses and polarized sunglasses. Standard sunglasses reduce the intensity of the light from all surfaces but do not filter out glare. They simply make everything darker depending on how dark they actually are. Polarized sunglasses have a filter in the lenses that actually cuts out the glare of polarized light. Because of this they don’t necessarily make everything darker, but can make certain things clearer to see. Of course if you buy a pair of polarized dark sunglasses they will reduce the brightness of everything and also cut glare but not all polarized sunglasses are made this way. It is also worth noting that, because of the way that the polarized filter is designed within the lens, glare will only be reduced when the polarized light waves hit the lens at certain angles. Looking straight down at a reflected surface or at a 90 degree angle will have no effect on glare reduction. Also if the lenses are turned sideways to the reflective surface the filter will not work. When wearing polarized sunglasses it is often worth nodding your head up and down a little until you get the best angle.
When purchasing polarized sunglasses the best way to tell if they are real is to look at a piece of glass at an angle so that you get a reflection. Don’t look directly at the glass so that you can see a reflection of yourself, look across it whilst it is flat on a surface. When you place the polarized lenses over your eyes you should be able to see what is behind the glass much more clearly than when you are not using the lenses.
Author Bio: Dimitar Yoldov is an optician which has worked for one of Denmark’s top eye care companies. He knows a lot about the different types of sunglasses (or solbrille as they call them in Denmark) and would be willing to share it with his readers.