This begs the question (Score 1)

100kW hitting w/ "pinpoint accuracy"... what kind of heatsinkage would be necessary to dissipate all this? Assuming "pinpoint accuracy" is a figure of speech, really more on the scale of .01 m^2, says you need to dissipate 1 megawatt/m^2 to prevent the burnout. If you're partially reflective (50%), and spinning (divide power by circumference/.1m if theta=>inf) you need less heat dissipation. A small missile, C=pi m, semireflective is down to 1/63 (.016) the heat sinkage necessary. Quality CPU heatsinks dissipate, what, on the scale of 10kW/m^2? Clearly, if it really is pinpoint accurate, even if only down to the .01m range, all that is moot. But that's one hell of a fire control system, .01m error over 10km. I dont do optics, but that sounds pretty fantastically accurate to me, at least in atmospehere. Liquid nitro cooling could help sink even more. Oh, and if it wasn't the most obvious solution: the optical countermeasure. How bout a smoke trailer a few meters in front of the missile, opaque to whatever the necessary frequency was?