Solved

Every detector is reading true.

How light works here

Every detector wants one exact colour. Turn the optics until they all read true — and don't spill anything extra into them.

1. 1Click any piece to turn it. Right-click, or hold Shift, to turn it the other way. Emitters, walls, filters and detectors are bolted down.
2. 2Colour adds up. A red beam and a green beam arriving at the same detector make yellow. All three primaries make white.
3. 3And it comes apart again. Prisms fan a beam into its primaries, dichroic mirrors bounce one colour and pass the rest, filters keep only their own. White light is a resource.
4. 4Exactly means exactly. A cyan detector fed cyan and a stray red reads white, and stays dark.
5. 5Par is real. It is the shortest solution the generator could prove, so matching it is a genuine result.

Free play

Pick a size and a seed. The same seed always builds the same board, so a link is a puzzle.