I want to terminate the laser beam after about two metres, like the lightsabers in Star Wars. How can I do that?

It is not possible to create lightsaber like effects: You cannot "terminate" the laser beam somewhere, it can physically not be terminated without having an end-point (surface).

Light can not be ended somewhere, it can only "fade out", meaning intensity is reduced with greater distances. But this is of course not feasible for a lightsaber.

Please also read the FAQ regarding projection surfaces