Why is laser light special?
Lasers are a special form of light. Laser light does not exist in nature.
Ordinary light, like sunlight, is made up of many different wavelengths, or colours, of light. If you put all the different colours together, you get white light.
On the other hand, the light from a laser contains exactly one colour or wavelength rather than a lot of different wavelengths. So, laser light is said to be `monochro matic,' meaning of one colour.
In laser light, all the high points or crests of the waves, and the low points or troughs are lined up, so that the waves move together, or are said to be 'coherent.'
Moreover, while light waves from ordinary sources such a,. light bulbs, or the Sun spread out in all directions, laser light waves all travel in the same direction, exactly parallel to one another. This means that laser light beams are very narrow, and can be concentrated on one tiny spot. This property makes the laser light 'collimated.'
The focused power makes laser light useful for cutting and welding. It also makes it possible to control laser light very precisely, and make it do all kinds of useful things. Laser light is truly a wonderful thing- and only human technology can create it!
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