So for the sake of a thought experiment, related to what I think the OP is referring to.
Imagine you had a 1 way mirror. One way, light could move right through without a problem.
On the other end, it would be reflected at 100% efficiency. (obviously an impossible component at current technology, but lets say it was real.)
If you shined a laser into the box, where one end was the one way mirror, and every other side was 100% reflective.
They would bounce back and forth.
What would happen as more and more photons kept joining the box?