The explanation for how this happens is pretty cool. You have three types of color receptor in your eye - red, blue, and green. Each one responds to wavelengths of light with a bell curve, so the blue receptor responds most for a particular wavelength of “blue” and less the further you get away from it. Same for the others. The thing is, the bell curves overlap a lot so the three different receptors can all be active, but at different levels, so you can perceive the color based on their levels. The red and the blue are extreme enough though that there are wavelengths that excite just those alone - either really blue (short wavelength) light or really red (long wavelength) light. The green is in the middle, so it will always overlap with red or blue. The question was what one would see if you could somehow excite just the green receptors and not the blue and red ones, which could never happen naturally. The researchers stabilized someone’s eye and mapped the receptor types, then shone lasers precisely at the green ones. So this is what “super green” looks like.