If you watched Star Wars when it first aired back in the 1970s, chances are, you've desperately wanted a light saber for the three decades. Admittedly, they do sound rather appealing: A blazing line of light that, in your righteous abandon, you use to exterminate your foes...who wouldn't want that? The major problem with this, of course, is that you are using a blazing line of light to exterminate your foes. Unlike traditional weapons, like a sword or axe, light doesn't just stop. It doesn't come to a nice, clear end.
Light goes on and on.
Consequently, one of the problems with lightsabers is confining the beam of light so that you don't destroy, well, everything that it intersects with. Of course, this is just the beginning of the problems that we'll need to surmount if we are to ever build a real lightsaber. There are many more (for example, the handle would probably be hot enough to burn your hand off). In this video, Dr. Michio Kaku, professor of theoretical physics, attempts to address these issues and create his own lightsaber using modern technology.
WATCH: Can We Make Lightsabers?