What would it take to store/feedback the gained (converted) energy to power the lasers? Sort of like a bootstrap with a very inefficient source of power, and ov

What would it take to store/feedback the gained (converted) energy to power the lasers? Sort of like a bootstrap with a very inefficient source of power, and over time transition to the produced clean energy? Armchair scientisting aside, this news seems like the most exciting news over the past few years - a great way to end this year (/pandemic). We are far out from a production-ready thingy, but if it took decades for brilliant scientists to conjure up this initial clunky toy thingy, I am sure an army of scientists/companies would work at building the real thing much, much faster: we had only a freaking 8086 not 30 years ago!! We have the basic blueprint from government funded research no less.