I know that light takes longer to travel in a denser material, like diamond and I know that black holes also attract light. I was wandering what would happen if you would make a ring out of diamond, spin it up at high speed and put it around a black hole. If I got this right the speed of light inside a diamond object is half of light in vacuum. My question is, could you make a prison for the light outside the black hole? Would the light that enters the ring just go down to the black hole, instead of continuing it's path like it would do if there was no ring? Would the ring be like an extension to the black object that the black hole is or something else would happen?
Edit: Well, I guess most of the light would be reflected off so I think that my question now is a little silly but this is mainly what I had envisioned. Mostly a ring that would spin with enough speed that it doesn't get sucked into the black hole and it stays close enough and it has enough thickness so that objects that go at half of the speed of light near it will be directed back into the black hole.
The yellow lines are light rays. The blue parts are the diamond. On the left is a 'top' view of the black hole with it's ring and on the right there is a small portion of the ring where the doted line is the path that light would take without gravity involved.