The US army wants uniforms that make soldiers invisible

The US army wants to develop uniforms that will make its troops "invisible" on the battlefield within the next 18 months.

The military wants to test the latest wearable camouflage technologies, and has put out a call for proposals from companies manufacturing "metamaterials". These highly adaptive structures, first demonstrated in 2006, can bend light around the wearer, essentially making them "invisible" from certain angles.

Since then, the technology has been held back by technical restraints, as many of these materials have only worked successfully in a lab under specific conditions and certain spectrums.

But now the military is actively looking to make the technology work -- if not hiding its troops completely, then at least making them "shadowless" in certain wavelengths -- and is turning to lab-created materials for the solution. According to the army's specifications, it's looking to create invisibility uniforms that work in all temperatures and weather conditions and don't require a power supply -- and can still be integrated with the rest of a soldier's equipment.

However, it's unlikely that a truly invisible army will be put into action anytime soon. Speaking to the New Scientist, Martin Wegener from Germany's Karlsruhe Institute of Technology, said: "Complete invisibility of macroscopic objects for all visible colours is fundamentally impossible." His team has created "invisibility cloaks" from photonic crystals -- but they only work on certain wavelengths.