Light Falls into a Trap of Chaos express
Anderson localization—the suppression of wave propagation in disordered media due to interference effects—has long been known for various wave types, but for light in three-dimensional systems, its unambiguous observation remained impossible due to experimental artifacts. This work presents the first unequivocal experimental proof of three-dimensional Anderson localization of microwaves in disordered metallic aggregates. Studying samples with different metal volume fractions allowed a clear distinction between diffusive and localized regimes. Localization was confirmed by a scaling analysis of the transmitted beam width, with results in excellent agreement with theoretical and numerical calculations. This demonstration paves the way for fundamental research and practical applications of this extraordinary phenomenon.
Scientists have forced electromagnetic waves to lose themselves forever inside a three-dimensional maze of metallic particles. Until now, this feat was only achieved with sound or electrons. Entropy — a measure of chaos — acted here as a dead end: waves overlapped and mutually canceled each other, losing all sense of direction. It’s like endlessly looping through floors of a building where every hallway looks the same.
By adjusting the metal content, physicists observed a clear transition. When there were few particles, the waves moved freely, scattering around. But once the concentration crossed a critical threshold, the beam froze — its brightness plummeted and the spot stopped expanding. This is direct proof of three-dimensional wave arrest, predicted for electrons back in 1958. For light, it took nearly 70 years to see the effect without distortions.
Remarkably, even the slightest absorption of light by the material would have ruined the trap — the wave would simply disappear. The authors dodged this by finetuning the chaos. The result opens the door to hypersensitive sensors and computing elements built on locked-in radiation.
🎯 Anderson localization was predicted for electrons in 1958, but it took almost 70 years to witness it in three-dimensional light without artifacts.