Transparent aluminium has been dreamed about as a potential earth-changing material ever since its early mention in Star Trek IV: The Voyage Home. In Star Trek film lore, the material was first used on the Enterprise-D to help it withstand enemy projectiles and other interplanetary obstacles.
Back on Earth, Oxford scientists have now managed to bridge Trek movie history with modern day scientific reality. In an article appearing in Nature Physics magazine and reported by Science Daily, an Oxford team led by Professor Justin Wark of the Department of Physics, used a very powerful laser to fire pulses of soft x-ray light to gain the desired results.
How it works
Soft x-ray light is many times more powerful than the total output produced by a power plant - flashes of the beam are enough to power an entire city. So, as far as traditional laser spectroscopy goes, it is worlds beyond what conventional beams are often capable of.
The team selected the soft light process to better probe the electronic structure of the aluminium. In this case, the team utilised the Hamburg based FLASH laser in Germany - the world's most powerful soft X-ray laser - to assist with the experiment. The record wavelenght of the FLASH beam measures 7 nanometres - a very intense light indeed.
All the power of the FLASH laser was focused on an area no larger than the diameter of less than a twentieth of the width of a human hair. The intense energy focused on the site turned the aluminium briefly transparent, satisfying the long sought -after result of changing one state of matter into another.
But the overall transparency effect was only brief: it lasted just 40 femtoseconds. To put that number in perspective, a nanosecond (ns or nsec) is one billionth (10 -9 ) of a second, while a femtosecond is one millionth of a nanosecond.
It all amounts to an incredibly quick and evolved process for the scientists, whose job it was to show that new exotic materials could be created by shining high ultraviolent light at the aluminium.
Not surprisingly, researchers compared the process with turning lead to gold, a process of alchemy much debated over the centuries and long regarded as chemically impossible.
Just as Star Trek writers imagined a stronger form of material to serve the interplanetary vehicles of those films, modern day scientists have expressed hopes that transparent aluminium offer simiar other-worldly properties.
If we're ever likely to power a mission to Mars, these forms of exotic materials might form the backbone of that research.
Similar technologies and discoveries
While it might be a few years before we see the first industrial uses of transparent aluminium, a similar process is already shaping up to have huge military applications.
Aluminium oxide is better known as alumina and it's been found to be three times stronger than steel. It's also transparent like glass - not far off the fabled Trek material. In a 2005 story appearing on the official US Air Force website, the material, specified as 'ALONtm', was offered as the next big thing in military armour.
A US Airforce Lieutenant described the material as "light years ahead of glass". The material even held up to .30 caliber Russian M-44 sniper rifle fire and a .50 calibre Browning Sniper Rifle with armour piercing bullets. In all tests, the alumina succeeded, while conventional bullet proof glass failed.