Isolating photons is a strange terminology.
However, there are single photon sources, for example the one mentioned http://www.sciencemag.org/cgi/content/abstract/290/5500/2282" (to read the full article, you might need a subscription).
And as said before, putting photons in particle accelerators won't help much. In vacuum they are already moving at c. You won't be able to accelerate them.
If you choose to collide 2 photons, nothing much happens. In the visible range, there will be no interactions unless you go to really high photon densities (like in extremely powerful lasers). In the high energy range, photons might behave differently, but there are people around here, who know more about high energy and particle physics than I do