Total internal reflection occurs when light traveling through a dense medium hits a boundary with a less dense medium at an angle steeper than the critical angle. Instead of refracting through the boundary, 100 percent of the optical power reflects back into the dense medium. This is the primary guiding mechanism that keeps light trapped inside the core of optical fibers and inside reflecting prisms.
Heard on the job
We're losing power at the bend because the angle exceeds the limit for total internal reflection.
Insider tip
TIR is lossless in theory, but surface roughness or contamination at the boundary will scatter light and degrade the reflection.
Also heard as
- TIR