I consider Star Wars to belong to the fantasy genre, rather than science fiction. However, this article takes an interesting look at the technical problems faced with designing and building a real lightsaber:
"... in "Star Wars: Episode I – The Phantom Menace," Qui-Gon Jinn sticks his lightsaber in a heavy blast door, first making a long cut and then simply melting it. If you watch the sequence, assume the door is steel, and time how long it takes to heat up the door and melt the metal, you can calculate the energy the saber must have. It turns out to be about 20 megawatts (MW). Given an average household power consumption of about 1.4 kilowatts (kW) at all times, the power draw of a lightsaber could run 14,000 average American houses until the battery ran out."
http://www.mnn.com/green-tech/research-innovations/stories/could-we-build-actual-lightsaber
"... in "Star Wars: Episode I – The Phantom Menace," Qui-Gon Jinn sticks his lightsaber in a heavy blast door, first making a long cut and then simply melting it. If you watch the sequence, assume the door is steel, and time how long it takes to heat up the door and melt the metal, you can calculate the energy the saber must have. It turns out to be about 20 megawatts (MW). Given an average household power consumption of about 1.4 kilowatts (kW) at all times, the power draw of a lightsaber could run 14,000 average American houses until the battery ran out."
http://www.mnn.com/green-tech/research-innovations/stories/could-we-build-actual-lightsaber
Don Lincoln is a senior scientist at the U.S. Department of Energy's Fermilab