Im still looking for the generic term, I found the name of the other flat grooved optic that comes to mind.
Fresnel Lens is what i was thinking of before. That monster can melt almost anything using solar power... what happens when you refocus almost 6ft^2 into a 1in^2 space? 738x the heat!!!!
The best idea i have come up with for replicating the concept is getting a piece of lexan and heating it, with something that has the sawtooth pateren on it (like overlaping strips of metal... but that is more .5mm every 3-4mm . Even if i could get a list of products that used this sort of lens, I could get the name probably (calling distributes for parts.)