Photographs of the QR code treated by three types of light irradiation and the corresponding scanning process (IMAGE)
Caption
On the left, three types of polymers were placed on three clear glass plates and then combined. Note that the function of the three boxes in the QR code was to locate the QR code, which could help the machine interpret and recognize it correctly. In particular, P2 is used to interfere with positioning of the QR code to obtain the information in the QR code under certain conditions. After irradiating the middle area with 460-nm visible light and 365-nm UV light, the QR code under natural light (a, c) or 365-nm UV light (b, d) could not be scanned by a smartphone to obtain information. When the QR code was excited by 254-nm UV light, it also could not obtain information in natural light by smartphone scanning (e). The encrypted information (chemical) could be only read when the interference of QR code localization disappeared (smartphones can identify tiny fluorescence differences) and displayed the correct fluorescent QR code (f). “This optical information encryption/decryption processes under external interference and multi-wavelength light regulation endowed the system with a high level of security. Moreover, on the road to the future optical information encryption exploration, the self-healing properties of materials will hopefully enable us to build deeper information encryption systems that can resist mechanical damage,” Chen says.
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