Applications of TIR
Intermediate
Optical fibres, prisms and diamonds.
Optical fibres, endoscopes, prism binoculars, reflectors on bicycles and cat's-eyes on roads, and the sparkle of cut diamonds.
A fibre loses only ~4% per km.
Fibre cladding has a lower n than the core.
In more detail
Total internal reflection is used in prisms, optical fibres, endoscopes and periscopes. It provides nearly perfect reflection without the losses of metallic mirrors.
Real-world uses
- Endoscopes allow doctors to see inside the body.
- Binoculars use right-angle prisms to invert images.
- Binoculars use prisms for total internal reflection, which turns the image the right way up without losing light.
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Frequently asked questions
Why are prisms better than mirrors?
They reflect nearly all light, while mirrors absorb a little at each reflection.
Where is TIR used in everyday life?
In fibre optic internet cables and in camera viewfinders.
Why are prisms better than mirrors here?
Total internal reflection reflects almost all the light, while a metal mirror absorbs a little at each reflection.
Related topics in Optics
Apparent depth · Critical angle · Total internal reflection · Prism and deviation · Dispersion · Rainbow formation