science

There's a paper from 1984 that worked out the math for a two-sail system that could get a spacecraft to Alpha Centauri, and slow down and end up in that gravity well, with a 41-year mission time. It would do so by discarding a reflector that points backward at the actual payload with its own sail. The paper also proposes a mechanism for a round trip mission, too, using 3 sails.

That's actually not that big of a deal!

Since these craft would be small, they wouldn't have the power to transmit back to Earth anyway. So with something like this, you would actually want a string of these kind of crafts that you would propel along the same vector so that they could send the data back using each following craft as the next point in the network back to Earth. So each one can take additional pictures to get a resolvable image at the end!

Now, getting them on the same vector is the hard part, since we're constantly moving through space and won't have the same launch conditions on subsequent launches, but this is all theoretical at this point anyway.

The scientist Robert L. Forward discussed possible ways to handle this in his novel Rocheworld. The fiction part wasn't about the light sail, more the general AI, life extension tech, and the aliens.