Lasers
As mentioned, light is a mixture of many different wavelengths or colours.
The reason is because atoms normally give off light randomly and are mostly out of step.
Instead of containing many different types of wavelengths, the laser light has only one.
The waves are coherent. The laser light is made by feeding energy into a solid, liquid, or
gas. Atoms strike other surrounding particles when the substance takes in energy , leading
to more light being released, thus a chain reaction occurs. The light produced is then
reflected to and fro between special mirrors until the light becomes so intense that some
of it passes through the mirror to form a laser beam.
Uses of lasers
Lasers are used in operations when the operation requires great
accuracy, for example when a person's retina comes loose, and no longer able to see
clearly. A laser beam can be used to align the retina, thus reducing the risk that the
patient might loose his eye due to the operation itself.
Another use for the laser beam is to measure. One example is in tunnelling. Since the
laser beam always follow a straight line, it is used to check whether a tunnel of anything
is straight. Laser light can also be used to measure the distance between two objects.
Since long-wavelenth lasers produce intense heat when directed and focused onto a surface,
the laser beam is used in spot welding and so on. The intense heat produce by the lasers
can cut through any kind of materials, be it paper , fabric, or even steel. One of the
advantage for using laser light is that it cannot become blunt.
