Eli5:How do analogue night vision goggles work?
In: Technology
Generally it is considered voodoo magic, because it is quite incredible how they work.
Inside they have a little vacuum tube, on one end they have a metal that holds onto it’s electrons very weakly. So when it is hit by a bit of infrared light, electrons fly off it into the vacuum tube.
Across the vacuum tube there is a very large difference in electrical potential energy (voltage). This accelerates the electrons emitted and so they have more energy.
There is also a micro channel plate. Each time the electrons bounce through these microscopic channels, it knocks off electrons in the material. It multiplies the amount of electrons going through by several thousand times. This is a noisy process, so this is what causes the static in nvgs.
This wall has a metal who holds its electrons much stronger, so when the accelerated and
multiplied electrons hits the electrons in the atom, it excites them, and when they de-excite (due to quantum mechanics) they emit a photon. This photon is now much more energetic than the original coming in. We have turned one infrared photon into thousands of visible photons.
It is an incredible process and sort of explains why they cost 10s of thousands of pounds.
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