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The Total Internal Reflection of Light in Optical Fibres.
What is an Optical Fibre?
An optical
fibre is a long thin strand of glass
that has an outer plastic coating. See the picture
below.
How does an Optical Fibre Work?
Light
from a laser enters at one end of the fibre, striking the
surface of the
glass at an angle greater than the critical angle.
Total
internal reflection occurs at the
glass surface and the
light cannot escape until it
reaches the other end of the fibre.
Both visible light and infra-red
can be used as they can
travel long distances in glass
with very little being absorbed.
The plastic coating prevents scratches on the glass
surface
which can allow the light to
escape from the side of the fibre.
What are the Uses of Optical
Fibres?
Optical
fibres are used
for telecommunications
and to make endoscopes.
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