Yeah, I was thinking space or moon based solar or solar + nuclear on this side. Why beam that energy down through atmosphere to earth, convert it to laser, then beam it back out? On destination side, I was thinking solar-powered (or whatever you call it when the star isn't Sol), but I like the idea of the sail storing laser energy (or would that break down - can a photon both impart momentum and have it's energy stored?) Your waves wouldn't have to be equal or limited to 2 waves : 1000 100MW wave 1 reverse-pushers could aim at slowing down 1 wave 2 probe, or a series of waves until wave N is slow enough to be caught by the star. Sounds like we're not slowing down at another star any time soon, but interesting to think about.