No, because you're not gaining anything. Lots of energy goes in (in the form of lots and lots of photons having not so much energy each) and lots comes out (in

No, because you're not gaining anything. Lots of energy goes in (in the form of lots and lots of photons having not so much energy each) and lots comes out (in the form of many fewer photons, each with a larger amount of energy), but you don't get more total energy out than in. It's not conceptually different from, say, trickle charging a LiPO battery for a week from dollar-store AAAs, then using it for a few glorious seconds flying a drone that couldn't have even lifted the AAAs. You're still using the energy from the AAAs, and suffering losses, but you're still doing something you couldn't have done with the AAAs alone. The mechanism is different - very, very different - but the idea's the same.