Fabrication process may enable creation of invisible materials

According to a statement, the team from Harvard’s School of Engineering and Applied Sciences has cleared an important hurdle in the development of advanced materials that bend light in unconventional ways, known as metamaterials.

The group used extremely short and powerful laser pulses to create three-dimensional patterns of tiny silver dots within a material that are considered essential to making futuristic optical devices that appear to be invisible.

The fabrication process, described in the journal Applied Physics Letters, advances nanoscale metal lithography into three dimensions — and does it at a resolution high enough to be practical for metamaterials.

‘If you want a bulk metamaterial for visible and infrared light, you need to embed particles of silver or gold inside a dielectric and you need to do it in 3D with high resolution,’ said lead author Kevin Vora, a graduate student at the Harvard School of Engineering and Applied Sciences.

‘This work demonstrates that we can create silver dots that are disconnected in X, Y and Z,’ said Vora. ‘There’s no other technique that feasibly allows you to do that. Being able to make patterns of nanostructures in 3D is a very big step towards the goal of making bulk metamaterials.’