An engineer on YouTube has built a real retractable lightsaber akin to Star Wars, Vice reported. The plasma beam weapon requires a backpack to store the gas that fuels it, but it can cut through steel. Most laser-based weapons aren’t as practical.
According to Vice, one of the most sought-after pieces of sci-fi technology just became a little more “science” and a little less “fiction.” “James Hobson—an engineer and a popular YouTuber also known as ‘The Hacksmith’—has created the first functioning lightsaber, using propane gas burning at around 4,000 degrees Fahrenheit to create a retractable plasma beam heat capable of cutting through steel,” the article said.
“The Canadian YouTuber has a following of 10 million subscribers and he works on turning popular science fiction items into reality. He has made various lightsabers previously […] but wanted to make the world’s first, retractable, plasma-based version of it.”
However, it doesn’t seem likely that laser weapons will replace current arms technology any time soon.
Brightness Versus Energy Versus Power
Our ideas of lasers change depending on what we’re referencing, so having a standard definition of what a laser is then helps to solve the puzzle of its application.
“A laser—light amplification by stimulated emission of radiation—is a device that produces very high brightness and spectral purity,” said Dr. Charles L. Adler, Professor of Physics at St. Mary’s College of Maryland. “Brightness means that the beam from the laser is all in the same direction, unlike a light bulb, where the light spreads out in all directions.
“Spectral purity means that the light is all concentrated near a single wavelength—a single color, although lasers can also emit light in the infrared and ultraviolet, where the wavelengths are too long or too short to be seen by the human eye.”
High brightness and spectral purity both make lasers ideal for communication systems and physics applications, Dr. Adler said, but that doesn’t necessarily carry over to weapons design.
“High brightness doesn’t mean high energy or high power,” he said. “You need high energy for laser weapons and there aren’t a whole lot of laser systems around that can provide that sort of power.”
In fact, according to Vice, a lightsaber like Hobson’s would require D batteries more powerful than nuclear power plants to function without the propane-filled backpack.
Apply to Burn
Dr. Adler said he knew of two types of laser weapons that have been developed: a chemical vapor laser, which relies on high-energy chemical reactions to generate a laser beam, and another that “combines many lower-power, solid-state diodes into one huge beam.”
“Applications of laser weapons are of two types: blinding and burning,” he said. “That is, damage the ability of a satellite or missile to see its target, or burn or melt through a part of it to disable it. There are problems.”
The first problem is that the atmosphere usually distorts and disperses laser beams and you can’t fire a laser at a target beyond the horizon. Additionally, it’s easier for someone to harden a target against laser weapons than it is to build up defenses against missile attacks.
Due to this, laser cannons from sci-fi movies aren’t very likely to hit the market soon, even if we have taken another step towards realizing plasma-blade weaponry.
Dr. Charles L. Adler contributed to this article. Dr. Adler is a Professor of Physics at St. Mary’s College of Maryland. He received his PhD, MS, and BS in Physics from Brown University, where he focused on experimental laser physics.