Spotlight small bundle of light

[Sauron The King]

Hello,

I want to make a spotlight, which emits a reall small bundle of light, just like a laser.
You have to see it clearly, in the air. How can you make that?
And, does there exist a mirror of some kind, maybe a custom entity. Because ingame I want the light to reflect. Of course it won't reflect by itself, but I need something that would reflect it in real. If there isn't, I will use a bottle or something like that.

Grtz,
Brian