Femtosecond Laser Ablation of Quantum Dot Films toward Physical Unclonable Multilevel Fluorescent Anticounterfeiting Labels

Femtosecond laser ablation (FsLA) technology has been demonstrated to achieve programmable ablation and removal of diverse materials with high precision. Owing to the cross-scale and digital processing characteristics, the FsLA technology has attracted increasing interest. However, the moderate repeatability of FsLA limits its application in the fabrication of advanced micro-/nanostructures due to the nonidentity of each laser pulse and fluctuation of environment. Fortunately, moderate repeatability combined with programmable ablation and high precision perfectly matches with the technical requirements of a physical unclonable fluorescent anticounterfeiting label. Herein, we applied FsLA to quantum dot (QD) films to fabricate a physical unclonable multilevel fluorescent anticounterfeiting label. Visual Jilin University logos, quick response (QR) codes, microlines, and microholes have been achieved for the multilevel anticounterfeiting functions. Of particular significance, the microholes with a macroidentical and microidentifiable geometry guarantee the physical unclonable functions (PUFs). Moreover, the fluorescent anticounterfeiting label is compatible with deep learning algorithms that facilitate authentication to be convenient and accurate. This work shows a fantastic future potential to be a core anticounterfeiting technique for commercial products and drugs.