When a pair of spectacles fog up, it can be nuisance. But when a car windshield or an astronaut’s helmet fogs, the consequences can be fatal. That’s why cars and space suits have their own air-conditioning systems to remove or prevent fogging.

But air-conditioning is expensive, bulky, and environmentally unfriendly. So engineers and materials scientists are keen to find a way to prevent fogging more effectively.

Enter Christopher Walker and colleagues from ETH in Zurich, Switzerland, who have designed a new material with properties unlike anything found in the natural world. Their material—or metasurface, to give it its proper name—captures radiation from the sun and uses it to burn off any condensation or prevent it from forming in the first place. The result is an effective and relatively cheap way of tackling this insidious problem.

A metasurface is a material engineered to have surface properties that are not found in nature. They are often created using a repeating pattern of smaller units, such as nanoparticles.

In this case, the team create their surface by covering a silica sheet with gold nanoparticles and sealing them in place with a layer of titanium dioxide. They then repeated this process to create multiple layers.