I don't understand how it would work. How would a single photon be sent through the atmosphere to a ground station without ever interacting with anything else? Or do they send lots of photons and somehow communicate back which particular ones they have received?
Originally posted by twhitehead I don't understand how it would work. How would a single photon be sent through the atmosphere to a ground station without ever interacting with anything else? Or do they send lots of photons and somehow communicate back which particular ones they have received?
They don't HAVE to be visible photons, maybe they are using longer wavelengths like IR or lower, maybe even high gigahertz waves. It has to be SOME kind of photon, the only question is the wavelength.
Originally posted by sonhouse They don't HAVE to be visible photons,
I realise that, but the question still stands. Can you send photons of any kind, from space to a receiver without any interaction, or am I misunderstanding something?
Originally posted by twhitehead I realise that, but the question still stands. Can you send photons of any kind, from space to a receiver without any interaction, or am I misunderstanding something?
It might be like you said, millions of photons simultaneously and the ones intact used at the other end.
I know it is possible to send this kind of photon through optical fiber at least a hundred kilometers which of course is a lot milder transmission media than atmosphere but the Chinese have claimed to be able to do so.
Of course they may be just lying and having a belly laugh at the hooplaw generated.
It has to be experimental so I don't think either China or Austria knows the outcome yet since it IS experimental. It's not like they have some boiler plate solution in hand. This is science not warfare.
Originally posted by twhitehead I don't understand how it would work. How would a single photon be sent through the atmosphere to a ground station without ever interacting with anything else? Or do they send lots of photons and somehow communicate back which particular ones they have received?
There already has been relatively long distance work like this: