Researchers at The University of Alabama created a material that manipulates and reduces the speed of light in a new, more effective way. The resulting "slow light" will lead to the development of optical buffers and delay lines used in next-generation sensors.

"Slow light” refers to the drastic slowdown of light waves from traveling, thus the reduction of the group velocity. An emerging class of materials called metamaterials consists of specially designed metal patterns on the substrate, like silicon, whose size, geometry, and orientation can be selected to allow for exotic optical properties, including the reduction of light speed.

Unlike the best known methods for slowing light that involved cold atoms, metamaterials use no energy and are much less complex to implement. In their lab at UA, the researchers fabricated and measured subwavelength metal patterns they specially designed on top of a silicon substrate. The thin metamaterial behaves “as if it was 1,000 times thicker,” according to the engineering team, enabling integrated photonic sensors on flexible materials.