Cryptographic Strain‐Dependent Light Pattern Generators

Refractive freeform components are becoming increasingly relevant for generating controlled patterns of light, because their capability to spatially-modulate optical signals with high efficiency and low background. However, the use these devices is still limited by difficulties in manufacturing macroscopic elements complex, 3-dimensional (3D) surface reliefs. Here, 3D-printed stretchable magic windows light refraction introduced. The shape and, consequently, texture achieved can be changed through device strain. Cryptographic demonstrated exemplary patterns, including micro-QR-codes, that correctly projected recognized upon strain gating while remaining cryptic as-produced devices. pattern micro-QR-codes also two coupled windows, one them acting as decryption key. Such novel, 3D tailored functionalities applications illumination design, smart labels, anti-counterfeiting systems, cryptographic communication.