Science Buddies: "Ask an Expert"

I always wondered what it would be like to have and infinite light source.
If in a vacuum, there are two COMPLETELY PARALLEL mirrors, a light source is put in the middle, and the light is turned on and off REALLY quickly,
what would happen?
So i was thinking, since mirrors bounce off light, then two mirrors would consistently bounce off light at each other if parallel. Even so, in a vacuum, there will be no particles likely to interfere and cause a resistance towards the light waves. Then in theory, that would mean that the light waves will continuously be reflected on and on.
Is this feasible experiment? Or is there a flaw in this idea?
Please help me improve my idea.
Thanks

The experiment as you describe it probably isn't very feasible. The propagation of light is affected by the phenomena of refraction, reflection, diffraction, and interference. The divergent nature of the light wave eminating from your source would propagate out and dissipate. Additionally, microscopic flaws in the mirror would serve to further refract and reflect your beam in unknown ways. A highly focused, near flawless mirror would be extreamly expensive as well as the very technical challenge of placing them in a vacuum chamber capable of running the experiment. However, what you describe is very close to how a laser beam is formed. Photons are stimulated in a particular energy state and bounced back and forth between two mirrors achieving a very narrow, coherent beam. One mirror is just slightly less reflective than the other and at high enough photon concentrations allow the photons to pass through creating a visible beam. This all happens at the spead of...well, LIGHT. But even laser beams diverge and spread out with distance. You could do a study on the formation of lasers and the application of other "directed energy" devices. The study of light and optics is extreamly diverse and interesting with numerous applications. I would start by reading up on the 4 terms mentioned at the start of this write up. I would suggest perhaps doing a project on light propagation and/or the measure of the speed of light through various mediums. The speed of light in a vacuum is 299,792,458 m/s, but what about through air, glass, water, jello, etc...Science Buddies project guide has a few experiment suggestions dealing with light, check them out.

Ok, enough talk from me.

Let me know if you have any more questions, and have fun.