Sooo... is this really viable?
That's in interesting link. The essence of this device is that it puts everything inside the laser:
A laser is usually described as a device that bounces light between a pair of mirrors on either end of a gain medium, which amplifies the light with each successive pass. Usually one of the mirrors inside this cavity is partially transparent allowing some of the light to exit as a laser beam.
Wi-Charge's ingenious idea was to take this cavity, which is typically a closed device, and turn it into an "open unit" where one of the mirrors is located for example in a light fixture on the ceiling and the other one on the receiving device.
Maybe that works and maybe it doesn't, but they then say:
Powerful lasers can be dangerous, however Wi-Charge uses a class 1 infra red laser (safe under all conditions of normal use) and more importantly the "external cavity" design means that the instant anything crosses the path of the laser—your hand, your eye—amplification will stop and the energy will drop.
Perhaps I am being a bit dense, but if it is amplifying light (or anything, come to that) it doesn't matter if you're inside or outside because what leaks out of the far mirror is only what's built up inside anyway. Thus if it's all class 1 then you don't have any power to transfer, and if you have enough power then it ain't class 1 wherever you interact with it.
The only part of that which seems reasonable (to someone not versed in laser technology) is the auto-kill by interruption. It seems to me you'd still get the full beam hit but it would be for a jolly short time.
I'd be interested if someone with a real clue could comment on that link rather than just diving off the deep end of what most assume the technology to be (which, apparently, it isn't).
No expert, but indeed that is a bit of a changer from the expected laser+galvo setup. Giving the benefit of the doubt that 2 retroreflectors, free space and a small gain medium work, it would indeed be much safer, as a partial obstruction would be enough to reduce system gain enough to kill any amplification in the cavity, and it would quickly (nanoseconds) extinguish down to the seed laser intensity.
I sill have concerns over reflections though, as if you're delivering 2 watts ('watts' of energy) with the receiver mirror being 90% reflective, that's 20W of beam power in the free space cavity. Any diffuse reflections from dirt on the mirrors, if it's not enough to shut off the cavity, will reflect a lot.
If they manage to get enough gain in the gain medium to drop the reflectivity of the RX end mirror, which would mean lower power in the cavity, I'd move it from "Lol holy shit that's a bad idea" to "hmmm, doesn't seem quite right, prove it."