Want to Build a Real Life Lightsaber? Ditch Lasers for Plasma

Now a physicist has offered some advice ahead of the launch of the new film in the franchise The Force Awakens for those hoping to create on of their own.

Dr Gianluca Sarri, a lecturer in the school of mathematics and physics at Queen's University Belfast, said the iconic weapons may not be made of light at all - but plasma.

Scroll down for video Writing in the Conversation , Dr Sarri, whose own research focuses on lasers and plasma physics, described the lightsaber as 'probably the coolest weapon ever to make an appearance on the big screen' andoutlines the basic concepts and building blocks needed to build one.

'The obvious way of building a lightsaber would be to use a laser, which can be seen as a particularly bright and directional burst of light,' he said.

'But even though laser technology is continuously striding towards more efficient and practical machines, we are still miles away from a working lightsaber.' In order for the laser beam to be of any use as a blade it would need to be a manageable length, around the 3 feet (91 cm).

However, lasers will continue in a straight line unless the beam is interrupted.

This makes them ideal for long taking distance measurements, such as the distance to from the Earth's surface to the moon [link], but not necessarily for a handheld weapon.

Dr Sarri, said this technical hitch could potentially be overcome by using a small mirror at the top of the blade, although this could create its own problems.

'Can you imagine how embarrassing it would be to show up in the battlefield with a lightsaber surrounded by a whole supporting structure for a tiny mirror at its end?' he added.

In addition to beam length, the power of the laser will be crucial.

The Hollywood franchise has shown us that the Jedi's weapon of choice cut through any material with ease, be it the end of a Storm Trooper's laser blaster or through the arm of your mortal enemy.

'Welding lasers used in industry can do that but they typically require several kilowatts of power,' said Dr Sarri.

'The power supply for these lasers is huge and would certainly not fit in the tiny hilt of a lightsaber.' In addition to these logistical challenges the prospect of using the weapon in a faceoff with an evil adversary could lead to some disappointment.

The fizz and crackle of clashing lightsabers during a fight would not be possible, says Sarri.

'Two laser-based lightsabers would never clash against each other. They would simply pass through one another with no effect.' 'What's more, a laser focuses light in one direction so sharply that you can't see it unless you look directly down its axis. This is the reason why lasers used in clubs need smoke or fog to be seen.' However, Dr Sarri suggests perhaps the best approach would be to abandon lasers altogether and opt for plasma, a super-heated fluid-like state of matter with unique properties.

'Plasma is effectively gas so hot that its atoms are broken into their more fundamental components, namely electrons and nuclei,' explains Dr Sarri.

The researcher added this could even create the different coloured beams associated with the Dark side of the force and the heroes of the Jedi Order.

He said: 'The green lightsabers of Jedi knights could be made of chlorine plasma, which emits predominantly green light, while the red lightsabers of the Sith villains could be made of helium, which mostly emits in the red-to-violet region of the spectrum.' In practice, this could mean a long filament connected to a small power supply in the hilt of the weapon.

This filament would carry the charge as it 'puff some gas around it'. As the filament heats up it would turn the gas to plasma.

'The searing heat of the plasma would instantaneously melt any object it touches, cutting cleanly like a blade.' Issues would still exist around the fitting all of the components into one handheld weapon, and then there's the question of whether it would be able to withstand a blow from someone else wielding a similar weapon.

For now, at least, it seems that the technology will remain far, far away...