Maybe stupid question, but does the unit contains one '20W' power diode or maybe several smaller ones?
Marketing talk still holds the '5W delivered power' if you have 5 devices charged by 5 diodes (or maybe even 10 diodes?)
It does not mention that the 5W is per device by 1 diode.
Or am I missing something?
I did a little skimming of the patents, which are very interesting. According to the patents, is not using a regular laser diode at all but rather a "freespace" lasing system, that is the laser cavity is formed between the transmitter and the receiver (both of which have retroreflectors).
Remembering that "laser" stands for "light amplification by stimulated emission of radiation", that is in this system, light emitted from the transmitter is reflected by the receiver, then reflected & amplified by the transmitter, repeatedly.
This is a very smart idea since it means that anything interrupting the beam stops the lasing directly. Additionally they can use it with some adaptive optics to focus / track the receiver.
Theoretically multiple transmitters could be employed, afaict, since retroreflection would allow each to operate independently (though I wonder about interference?).
The biggest issue of course is if some proportion of the light is scattered or reflected away from the intended optical path.
Like Dave pointed out it all seems a little overkill for charging mobile phones, but there are likely real applications in other fields (sensor networks? micro-satellites?).