How do metamaterials bend light and sound in impossible ways?

The answer

Metamaterials are artificially structured materials engineered to have electromagnetic properties impossible in nature, such as negative refractive indices that bend light backward. Duke University demonstrated the first electromagnetic cloaking device in 2006, and by 2024, researchers have created acoustic metamaterials that redirect sound waves around objects, effectively creating zones of silence. Metamaterial-based antennas from Kymeta enable flat, electronically steered satellite dishes for mobile communications. Mechanical metamaterials can exhibit negative Poisson's ratio, expanding when stretched. Recent breakthroughs include metamaterials that absorb 99.9% of specific electromagnetic frequencies for stealth applications and seismic metamaterials that could protect buildings from earthquakes by redirecting seismic waves.