Note: When Elf says "reflected" she's using the wrong word. When light is reflected, the incoming photon's motion is arrested, forcing it to transfer energy into the material of the mirror. That energy spawns a new photon moving in a different direction. 

When light is bent through gravitational lensing, the photon follows a topologically straight line on the warped topology of space, which to the distant telescopic observer looks exactly like a curved path. The important thing is that in this case it's the same photon the whole time.

Unifield shields behave more like gravitational lenses than mirrors, but there are some quantum higgledy-piggledies (that's a technical term that went into and fell out of fashion during the 28th) going on. The incoming photon might get redirected, or it might get combined with some others, forced through the boson soup (another term almost nobody uses anymore) and transduced (a popular word that's probably not the right one) into a shower of anti-electrons.

The shiny, salient point here is that you cannot use a mirror to turn ordinary (though brightly and intensely focused) light into a coherent column of sky-piercing flame, but you CAN use a unifield shield to do that. You can also use it to turn relativistic projectiles into neutronium. "So, you want to appear massive because you're fast? Here! You can be SUPER massive and very slow. Now finish your boson soup before the physicists take it away from us again."