Micro mirage: Researchers fabricate the world's smallest QR code using infrared information carrier

https://phys.org/news/2024-03-micro-mirage-fabricate-world-smallest.html

"pixel-by-pixel approach to visible camouflage scalable for enhanced infrared surveillance, optical security, and anti-forgery protections... 3D soccer ball-like brochosomes (leafhoppers produce to create cloak) with nanoscale cavities internally absorbing light... each pixel 3D printed with holes or without enabling QR code readable by IR camera alone... <.02' size code only visible under microscope (future: scale up for commercial use, too)... visible camouflage, IR information carrier./ display, data encryption, optical security"