- #36
xts
- 885
- 0
No. Read (e.g. wiki: http://en.wikipedia.org/wiki/Evanescent_wave) about TIR mechanism or very good explanation in Feynman Lectures on Physics.Misr said:How could this happen?does the refractive index of the dirt higher than that of the core?
The light is not reflected "sharp" on the boundary between media. The light enters to the lower index medium on some depth (order of magnitude its wavelength). If the lower index medium is not transparent, the light gets absorbed or scattered, rather than reflected.
It is a perfect demonstration: you send a laser beam through a glass prism such, that it is reflected by TIR. Then you blow some cigarette smokeinto the area behind the "reflecting" surface. You may see the smoke glowing, and if you have precise photometer, you may also notice that reflected beam gets a bit dimmer.
Similar demonstration is with total reflection between glass and water - then you add some milk or ink to the water: in both cases the reflected beam gets dimmer to such extend you may see it by naked eye.
Almost parallel to fibre axis. Even in multimode fibre the angle is much lower than 1°.Misr said:you mean high??hmm that's confusing