You can have my lightsabre when you pry it from my cold, dead hands.
Shalom.
I'm series.
A lightsabre blade shouldn't be hard to figure out. have a stream of positrons emit in a, "Waterfall," pattern from the hilt. A positron blade would cut through any matter, except another positron blade, because they're positively charged electrons; whereas matter is surrounded by negatively charged electrons.
We can do this with electrons, why not positrons?
(Slight problem with radiation from the effect, but it'll work)
It could be marketed as a replacement for, "The Jaws Of Life," because it can cut through anything to rescue trapped people. Concrete. Steel. Glass. Anything made of matter can be severed with it.