Hello, this is my first post to this site. I had this idea a few nights ago, and I've been trying to wrap my head around it. Before I go ordering supplies to run some tests, I thought it would be worthwhile to gain some insight from you guys. Anyways, as you probably know, total internal reflection occurs at certain angles when light hits a medium boundary. Light bounces off this medium boundary with total energy being conserved, making this a perfect mirror. I know we utilize this with lasers in fiber optics to transmit information, but my question is this: What would happen if a laser was shown into a fiber optic that was bent to make a doughnut or torroid shape. Would the collimated beam keep bouncing along the inside of the fiber optic medium? What would happen after the laser input was removed? Would the system be self sustaining for a period of time before aberrations and losses took over? You would think this would have been done before for the pure simplicity of the idea. However I have looked all of the internet and nobody has done this. Ideas? Thanks!