Quote:
Originally Posted by Richard
Water's refractive index is about 4/3. Light originating on the water side will be partially reflected (back into the water) and partially refracted (into the air) at angles given by Snell's Law. Light originating in the water and incident on the surface at an angle greater than about 49 degrees will be totally reflected back into the water.
So some underwater positions will permit better transmission of IR than others. |
I wasn't going to get into the math of it because it's highly unlikely that we'll need to transmit (or recieve) through the air/water barrier.
Also, you will most likely be able to transmit at greater angles because the surface of water will (most likely) never be a perfect plane.
Snell's law could come into play though if you tried to protect your sensor with polycarbonate ... which also makes me wonder if polycarbonate is opaque to IR ... Hmmmmm