Can a real fighting lightsaber be built with current technology?

The Star Wars saga borrowed (some say outright stole) its mythological theme from Budo (the art of the warrior) which was the societal philosophy behind the ancient Japanese culture of bravery, loyalty, and technical mastery of weaponry. The influence of Budo is especially evident in the preferred weapon of the Jedi and Sith lead characters… the lightsaber. The outward appearance and functionality of this fictional weapon is clearly an homage to the ultimate personal weapon of Japanese antiquity, the Samurai sword (katana). With a length of approximately one meter, deadly slicing efficiency, and prerequisite dexterity and training, it is obvious that there are many similarities shared between the lightsaber of science fiction and the very real katana of old.

The ancient Japanese weapon was forged from the best technology of its day with a precise mixture of carbon steel that was hammered thin, tempered, and folded up to 15 times resulting in 32 768 layers for optimal strength, elasticity, and durability. The time and craftsmanship involved in a katana’s construction made the best examples cost as much as a Japanese homestead. In the hands of a sword master, a katana could cleanly slice through copper pipe, armor, or a human torso. One can imagine that limbs must have been especially vulnerable to the sword in battle, as in the Star Wars series.

Can a fighting lightsaber be built with existing technology? There have been several “expert” scientific opinions on the Internet which have concluded that the answer is “No”. Their argument is that a purely photon-based weapon would look more like a laser beam of infinite length extending into space with no mass or momentum. In a photon sword duel, the blades would merely pass through each other with no ability to block, parry, or riposte (the basic maneuvers in swordplay). There are also the practical problems of energy generation and heat transfer in the handle (hilt).

During the production of the Star Wars movie series, the lightsaber scenes were filmed using non-edged wooden dowels coated with Scotchlite retroreflector material and inserted into battery pack hilts. The glow lighting and sound effects were post-production enhancements. Because of the fragility of the wooden dowels, the actors had to pull back to prevent full force contact. Therefore, the movie props were thin, fragile, and blunt wooden sticks, that were certainly not capable of slicing through metal or flesh.

However, if you can do without one Hollywood cinematic feature, it is possible to build a real and deadly lightsaber with currently available technology. Inside the hilt would be a lithium battery pack and a laser light generator. Handheld laser pointers have existed for decades, so this technology is merely a matter of power scaling. The blade would be ceramic nanotube material capable of sustaining super-high temperatures. NASA-developed ceramic tiles are what protected the US Space Shuttle from the 3 000 °F (1 649 °C) heat generated by the friction of reentry into Earth’s atmosphere. Nanotube technology would overcome the inherent brittleness of ceramics. The laser light emanating from the hilt would heat the hollow core of the nanotube shaft and create a super-hot cutting weapon.

Shaft heating would occur quickly but not instantaneously, resulting in an activation sound when the button is pushed as the surrounding air super-heats. The low heat-conductivity of the ceramic material would allow the hilt to remain at a manageable temperature, so you could hold it without needing a glove. The solid material of the shaft would enable combatants to engage in full-contact swordplay with traditional defensive and offensive fencing techniques. The nanotube microstructure could be designed to mimic the strength and flexibility of a Japanese katana. The super-heated blade would be very deadly and capable of cutting through metal and human flesh, similar to a plasma torch if temperatures of 50 000 °F (27 760°C) could be attained. Unlike the bloody aftermath of a Samurai movie, this laser-powered weapon would instantly cauterize the wounds.

With this amount of deadly power on tap, it’s recommend that such a weapon have a safety switch in addition to the on/off button. It doesn’t take much imagination to foresee the damage that could result from accidental activation.

This is not to say that the science of Star Wars is practical or even accurately depicted. In fact, I am highly critical of the physics portrayed in most Hollywood Sci-Fi movies. For example, how would a Jedi’s lightsaber be able to block a laser blast traveling at the speed of light? Nobody’s reflexes are that good. The only explanation would be split-second telepathic anticipation of the blaster shooter’s aim and timing (i.e. magic).

The only cinematic lightsaber feature that would be difficult to replicate would be the push button extension of the heated blade from the hilt. It is very difficult to create structured matter from pure energy, but not impossible as Einstein proved with his equation E = mc2. A telescoping mechanism as seen with the toy version would be feasible. If you can do without this feature and instead focus on the glow, sound, and lethal slicing action, then in the near future (in a laboratory not so far away) you just might wield the weapon of your geeky Star Wars dreams.

Featured image: Kylo Ren’s cross-guard lightsaber from starwars.wikia.com/wiki/Lightsaber