You can get an idea of the amount of light energy required to change the apparently color of the moon. Elsewhere I am well known for my 'thumbnail calculations', so try this one.
The solar Flux on the ground at the equator on earth is about 750w/m^2. The moon is essentialy the same distance form the sun as the earth, so the solar flux on the moon would be about the same as it is on the earth (actually somewhat higher because there is no atmosphere on the moon).
The diameter of the moon is about 3500 Km, So the area of the apparent disc to illuminate would be 1750km x 1750km x pi kilometers^2. Roughly 10 million square kilometers or 10^14 square meters, making the solar incoming energy on the moon about 750 x 10^13 watts. There are roughly 10^10 inhabitants or earth, so to just reach the same order of magnitude as the sun shinning on the moon, you would need each earthling to point a laser with an energy of about 75,000 watts at the moon, to match the solar flux, 750,000 watts per earthling. That of course ignores the problems involved in simply providing sufficient energy to power all of those lasers, let along building enough multi-megawatt lasers. This of course ignores amospheric losses, which would only make things worse.
When I was a University Student, I once had a homework problem in thermodynamics called the 'meaning of never'... This one falls within the parameters of never. You cannot generate anywhere near enough light energy to even change the apparent color of the moon while illuminating it with millions of lasers, even if each one has output in the megawatt class.
