Surely to make a gamma laser, you at a minimum need a gamma mirror.
To my knowledge, such things don't exist (current gamma mirrors aren't 'shiny' - ie. they don't reflect the light, but instead diffuse it).
To my knowledge, such things don't exist (current gamma mirrors aren't 'shiny' - ie. they don't reflect the light, but instead diffuse it).
No. See free-electron lasers [1].
Edit: I mean this in terms of a maximum norm. You get a smaller maximum amount of mutually coherent photons without an optical resonator.