Negative refraction achieved propagating light through atomic arrays, without need for artificially manufactured metamaterials

https://www.eurekalert.org/news-releases/1073130

"negative refraction: light in medium bends in opposite direction to what is typically observed in nature,potentially enabling perfect lens capable of focusing/ imaging beyond diffraction limit, or cloaking devices rendering objects invisible... overcomes metamaterial fabrication imperfections/ non-radiative losses... atoms interact collectively enabling negative refraction... trapping atoms in periodic optical lattices providing pristine, clean medium free from fabrication imperfections, without absorption losses"

Related:

Korea develops core radar components for stealth technology
https://techxplore.com/news/2025-08-korea-core-radar-components-stealth.html

Backyard insect inspires large-scale invisibility particles production
https://phys.org/news/2025-12-backyard-insect-large-scale-invisibility.html