Robust Carbon‐Dot Optical Disks for Orthogonal Amplitude‐Polarization Encryption Storage.

High‐capacity steganography is crucial for the secure exchange of massive information. Exploring orthogonally optical recording can significantly improve encryption levels. However, due to the lack of robust media, the hidden data are easy to be cracked or destructed. Herein, carbon dots have the switchable memory function between optical transmittance and polarization state after receiving excitation power adjustment is discovered. A large‐area carbon‐based disk is further constructed which is measured to resist the high‐temperature damage at 423 K for more than 405 h and is estimated to remain stable at room‐temperature (301 K) beyond 2341 years. With the alternated arrangement of the dual functional carbon dots at one region of the disk, only by using an amplitude‐type holographic diffraction key can the polarized pattern be correctly read out. The ultra‐high secure encryption strategy also puts a bright way to the applications of 3D image hiding, permanent data preservation, and anti‐counterfeiting labels. [ABSTRACT FROM AUTHOR]