Polarisation

Polarisation: Polarised reading sunglasses have lenses that react to sunlight, which consists of a broad range of frequencies. The lights electro-magnetic fields point in many different directions. Certain materials have the property of only allowing the passage of the fields pointing in a particular direction. These polarising materials have the effect of greatly reducing the brightness of the light. Some reading glasses are tinted with polarizing properties.

Effect: Light reflected from a horizontal surface goes through the process of horizontal polarisation. Polarised sunglasses are made to allow through only vertically polarised light, thus reducing reflection and glare. Normal sunglasses decrease the intensity of everything by the same amount but polarising reading sunglasses can selectively eliminate reflected light.

Applications: The ability of certain substances to polarise light has an application in sunglasses. The glare of the sun on the sea and other surfaces is highly horizontally polarised depending on the height of the sun. Polarised sunglasses make water appear darker and more transparent, which is ideal for anglers. Because polarisation has the effect of cutting down the glare of reflected light, these lenses are ideal for those participating in water-sports. Polarised sunglasses can be of benefit to drivers in that they filter bright sun reflections on the vehicle ahead and road surfaces, attenuating the dazzle significantly.

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