These numbers surprised me - efficiency of only 20%. I thought they were already able to send power to satellites by laser.
DARPA...new record in transmitting energy over distance...over 800 watts of power delivered for about 30 seconds with a laser beam crossing 8.6 kilometers...laser is much more focusable—you can create a narrow beam [almost] without any spreading [in ideal conditions]," he says...estimated receiver efficiency, says POWER team leader Paul Jaffe, is around 20 percent...the receiver reflects the infrared radiation from a conical mirror onto the photovoltaic cells—which, in turn, turns that beam into usable electricity...the goal...was not efficiency, but speed. "There's a number of design decisions that were made in the interest of building something quickly, not efficiently,"...timeline of three months between planning and execution.
https://spectrum.ieee.org/darpa-optical-wireless-power