In the Star Wars films, lightsabers (also called laser swords by the uneducated) are depicted as a one-handed or two-handed weapon that have a polished metal hilt (between about twenty and thirty-five centimeters in length typically) which projects a blade of plasma energy (suspended in a force containment field) about 39 inches long (one meter). The blade did not radiate heat or expend energy until it came into contact with a solid object, although it could cut through almost anything (except for a few lightsaber-resistant materials). The field contained the immense heat of the plasma, protecting the wielder, and allowed the blade to keep its shape. The plasma was projected through a set of focusing crystals (three crystals would usually be used, although only one was required) that lent the blade its properties and allowed the adjustment of the blade length and power output.
In the Expanded Universe, lightsabers had many blade and hilt variation. Each lightsaber was designed to meet the user’s specific needs, preferences, and styles. They were primarily used during combat and rituals.
In real-life, light cannot be formed and utilized into a solid blade (as it is designed to travel continuously and not be stopped, in this case, at three feet without completely restricting the strength of the rest of the blade), there are other alternatives; however, including plasma swords (similar to those in Halo), black holes, and carbon nanotubes.
Many commandos can easily die from blood loss from traumatic wounds due to gunfire, shrapnel, or from even grenades. That is why, the military has already started field-testing a Plasma Knife. It will be used for emergencies when the commandos are without the luxury of medical backup while in the field.
The knife’s blade consists of heated, ionized gas, which easily cuts through flesh and cauterizes the wound on contact. Through cauterization, the damaged flesh can be protected from excessive bleeding and infection. A normal medical Plasma Knife relies primarily on a strong power source, but the commando version’s only drawback is it’s low-power although it is wearable and easily transported.
While it can not be used as a weapon very easily (as it would quickly run out of power), it is still pretty close to a ‘real’ lightsaber like the ones shown in the movies.
A thin, carbon nanotube wire (a nano is a billionth of a meter), strong enough to not break, but thin enough to cut through a solid object could be used to make a weapon that could slice through almost anything.
The problem with this idea is that, the user or the victim could not see the ‘blade’ because of its small size resulting in an accidental injury or fatality, or even the possibility of it being misplaced. In order for it to be handled properly, a handle would be needed at one end; however, it would throw off the balance of the whole weapon itself because of the lack of a equal amount of weight on the opposite end. This could possibly be solved if the ‘sharp end’ had a magnet on it and the handle end had an electromagnet stretching the carbon nanotube out; however, it would only be able to be used for slicing or cutting not stabbing.
A wedge-like blade would not work because it bends the top of what it is slicing, often creating cracks in the object or victim instead of a sharp clean cut.
A small black hole could not be used, at this point, because it is too heavy to wield and because of its short lifespan (resulting in a massive ball of fire).
It has also been suggested that a lightsaber could use glass filaments that extend when gigawatts of laser energy (stored in a non-existent power source) are pumped through it when it is turned on.
The Spyder III Pro Arctic is one (if not, the one) of the most lightsaber-like weapon that actually exists in real-life. The Spyder III, made by Wicked Lasers, is also the most powerful portable laser that uses only 1 Watt released that costs a mere $200. The blue-laser diode is from a dismantled Casio projector (the new mercury-free Green Slim projector, specifically) that Wicked Lasers used to make it. They are also throwing in a free pair of safety-glasses with the purchase of the Spyder III.
Wicked Lasers mentioned that, “Extremely dangerous is an understatement to the power of 1W of laser power. It will blind permanently and instantly and set fire quickly to skin and other body parts, use with extreme caution and only when using the included eye protection. Customers will be required to completely read and agree to our Class IV Laser Hazard Acknowledgment Form.”
If you are not trained in the Jedi arts, then this is not for you.
While there needs to be quite a lot of development in these kinds of technology, we can still dream, and maybe someday some brilliant scientist or student could eventually make one without making it completely out of plastic (or paper). Who knows, maybe we could find a way to make lasers to stop at a point (without it being fatal) for a real, practical, working lightsaber.