it's meaningless to say that it's a "new beam of light with identical properties."
You can think of it as information (bits). The same information that was encoded was decoded later.
It is not as if photons are items on the macro scale, that were somehow labeled (for example, photon #134), then disappeared and reappeared and the scientists compared the label and proclaimed that its the same photon (#134).
Every time light reflects of some surface this happens. The light excites the (electrons in the) material which then gives off 'new' light.
We still call it reflected light as though the photons somehow bounce off. They don't. They get adsorbed and are then re-emitted. But they might as well be the same ones because we can not tell the difference.
There are variations on this, specular reflection (think of a mirror) and diffuse reflection (think of a wall), the difference lies in the direction of the outgoing photons.
> It is not as if photons are items on the macro scale, that were somehow labeled (for example, photon #134), then disappeared and reappeared and the scientists compared the label and proclaimed that its the same photon (#134).
You can think of it as information (bits). The same information that was encoded was decoded later.
It is not as if photons are items on the macro scale, that were somehow labeled (for example, photon #134), then disappeared and reappeared and the scientists compared the label and proclaimed that its the same photon (#134).