Fiber optics also uses _exceptionally_ clear glass.
If the ocean were as clear as your average long-distance fiber cable, you would see down to the bottom of the Mariana Trench (also in the range of visible light, AFAIK).
If the ocean were as clear as your average long-distance fiber cable, you would see down to the bottom of the Mariana Trench (also in the range of visible light, AFAIK).
Clear in certain wavelengths. Depends on the composition of the glass.
https://en.wikipedia.org/wiki/Optical_fiber#/media/File:Si_Z...
Silica glass behaves differently from ZBLAN (fluorozirconate glass).
Which goes to show how complicated EM interactions with media can be. It's generally easier to just empirically measure attenuation through some medium and use the empirical measurements as a model.
IIRC, when Corning Co. first started working on optical fibers, the best available glass would be good for sending signals about ten meters. What was improved was not the total internal reflection; it was the purity of the glass.