Roithner Blue Laser Diode, output wavelength 430 nm, illumination power efficiency 0.3%
Photonic Infrared Laser Diode, output wavelength 785 nm, illumination power efficiency 0.6%

Not too good for power transmission, unless this is offset by cost savings elsewhere. But things would have to get very expensive to make the powerplant worthwhile. Microwaves can transmit power with greater than 60 percent. I'm not certain of course, but I think the antenna for microwave transmission has to be large to keep the power density low, e.g. to prevent incinerating anything that crosses the beam. If the power is transmitted from the ground into space, a tighter beam and small antenna may be possible. Splitting the beam somehow and transmitting numerous tight-beams might help reduce the power density near the ground, but I don't know how feasible that is.