The feat of having a ray of light looping back to it's source may not be impossible with the recent research of light property and how to manipulate it. Some says that light (photon) is a matter nevertheless. But the feat of dueling with a ray of light is impossible, for light does not have a physical property.
This is an article I found in the net a long time ago......
A NEW ELEMENT FOR A NEW WEAPONMaster Obi-Wan Kenobi described a lightsaber as “an elegant weapon for a more civilized age.” Contrary to what the name might imply to the uninitiated, the deadly blade of a lightsaber is not actually made up of pure light. By consulting with official records (the recently released DVD trilogy), we see that a lightsaber blade performs feats that no mere beam of light is capable of: parrying similar blades, casting shadows, and stopping in mid-air a short distance from its source (Figure A).
Lightsaber blades actually have solid metal cores. This central part of the formidable weapon is made of a single element, metachlorium (Me), number 138 on the periodic table, whose discovery shattered all materials records for melting point and cohesive energy. An energy cell powers three pumping lasers that are focused onto a coupling crystal at the base of the blade core, allowing a unique electromagnetic frequency to travel along the blade core as surface plasmons. Waste heat causes the blade core to rapidly expand by a factor of four or more, until it reaches its full size.
Magnetic suspension (which produces the weapon’s characteristic hum) physically isolates the Me rod, containing the intense surface oscillations safely on the blade exterior. Some electromagnetic energy escapes as light in a color corresponding to coupling frequency, but the core contains almost all of it until coupled to another object, at which time plasmon energy and blade heat enables it to slice through steel like a knife through butter.
Credits:
Joseph F. AuBuchon and Joel Hollingsworth
Graduate Student Researchers
Materials Science and Engineering Program
University of California, San Diego
Illustration:Oohh.. no no, I don't believe any of it. It's just another Delusion of Grandeur. :D