Re: Will light amplification take place in a vacuum sealed reflective sphere?

If you could find a substance with "100%" reflectivity, the sphere you 
envision would be like a photon bucket.  The light source would shine, and 
produce some flux (number/second) of photons.  Since they can not escape and 
simply reflect about the density of photons would increase as long as the light 
source was on.  Intensity is a measure of the density of photons, therefore 
"light amplification" would take place.

[note added by MadSci Admin: this is not amplification in the sense usually 
referred to with lasers, where the additional photons are stimulated to be 
emitted by pumped-up atoms by passing already-existing photons.]