The containment not so easy.
Even in a galaxy far, far away?
Beams of light or lasers can't terminate mid-air of their own volition in our galaxy, bulldribble. In a galaxy far far away, maybe they might....we'll never know!
This is how to make a light saber in our galaxy (Disclaimer though, if this is made, it would be an instant prohibited dangerous weapon, and you might get shot by a cop if using it wrongly in public)
The lightsaber is an extendable metal baton which extends electronically. It would have an extendable heating element down the middle which super heats the metal, causing it to glow either bright red, blue, or green, depending on the coating on the metal.
It would behave exactly like a lightsaber in appearance, you could have light saber fights, and due to the super generated heat, would injure or kill, just like in the movies. It would also be great at putting holes in snow or cutting down icicles as Luke Skywalker does in Empire Strikes Back.
A great Christmas gift for the ice sculptor in the family!