The idea is that it doesn't need cooling. It just incandesces at a certain temperature. Like the filament of an incandescent bulb the material has to be able to withstand that temperature. Overheating would imply a different temperature. You would just turn down your reactor. You are only interested in heat being dissipated through incandescence.I don't think this would work for pumped lasers because they always need cooling because they will always have high entropy heat that has to be dissipated in addition to the low entropy laser beam.I also like the idea of beamed laser light, but for this thread the subject is NEP. I can think of reasons people may want this autonomy in the future but that is way off topic. Just treat it as a technical problem.(edit)I was just thinking about my incandescent idea again. I googled around and found this:miniature power generator converts infrared to electricity