Mercury cadmium telluride diode... breaks all the ROHS rules and then some! And all for 4W/m^2.

For perspective, a typical (non-orbital/space/crazy-exotic) terrestrial solar panel can generate 200 to 250W/m^2 in typical mid-latitude daylight conditions. Assuming this generator worked for 8h overnight it would produce the same amount of power as the same area of solar cells would in about seven minutes in daylight. And the night time generator is a theoretical maximum while the daytime one is an achievable, long-term practical reality.

Now consider that you have 500m^2 of space to do something with - which would you choose to occupy that space? For this to be sensible it would need to swap spots with the daytime solar cell during the night - some kind of automated system that would flip over the thing to the night side, etc. Consider the cost of adding night-time functionality to a daytime solar generation system - and for what, an extra 1% in total output? It doesn't even make sense. This is a curiosity, nothing more.

I saw 4w and I thought "well maybe that is what they have now..." This isn't enough power to flip solar panels over. Maybe we can use this in space? Like on the backside of the moon? But I think a mirror bounce would be better.

Yeah, nobody is billing as a replacement for solar, but it's an interesting invention and probably has applications for space work.

Possibly for space. At 4AU or thereabouts the intensity of the sun drops to about 4W/m^2, so if you were far from the sun, on that order, and this thing still works pointing into deep space, then it would be a more viable option than a solar cell beyond a certain distance from a star.

Still, it would be big... and heavy. There you'd be competing with something like an Am231 RTG, which could give you ~4W for a couple hundred years in a package of a few kg.

Wow. "Fast Fourier Transform". I haven't seen that phrase since the days of running the SETI@Home app ... in like 2000?

Science and engineering haven't forgotten the venerable FFT - it remains a ubiquitous staple in the signal processing toolbox across countless disciplines.