Mie-Resonant Silicon Nanoparticles for Physically Unclonable Anti-Counterfeiting Labels

Abstract

Security labels produced by nondeterministic processes are a promising platform to shield counterfeiting. Here, we demonstrate the design of a physically unclonable anticounterfeiting label made of clusters of Mie-resonant silicon nanoparticles (NPs) fabricated by the laser-induced forward transfer technique. The number and relative position of clusters form the first security level authenticated by a smartphone with a macro lens. The enhanced optical response from the resonant NPs provides an opportunity to create additional laboratory security levels. These levels are based on spatial and chromatic coordinates as well as NP crystallinity, generating unique cluster fingerprints. The K-means clustering method utilized for the NP dark-field image processing makes it possible to achieve an encoding capacity of 10240000 for a 1000 × 500 pixel image. The widespread material, high-throughput fabrication, and multilevel security make a perfect set for label application in security and tracking of different items from consumer goods to art objects.

Multigram-Scale Production of Hybrid Au-Si Nanomaterial by Laser Ablation in Liquid (LAL) for Temperature-Feedback Optical Nanosensing, Light-to-Heat Conversion, and Anticounterfeit Labeling

“…Even larger values can be easily achieved by increasing the number of pixels analyzed in Raman/PL maps or by functionalizing the hybrid Au-Si product with Raman-active molecules capable of providing additional bands for mapping . Raman and nonlinear PL signals are almost insensitive to the polarization of the pump radiation, facilitating a more reliable readout, in sharp contrast to recently proposed optical PUF labels based on resonant light scattering signals that are extremely sensitive to excitation conditions. − The PUF labels were produced by optimized drop-casting of the as-prepared Au-Si dispersions. The ability to concentrate produced MSs is very advantageous for SERS applications as well as for adequate characterization of the nanomaterial on the stage of synthesis optimization, especially when the droplet contains a small amount of analyzed nanoparticles.…”

Monolayer of Mie-Resonant Silicon Nanospheres for Structural Coloration

“…The crucial issue of this approach is the production of high-quality inks, in which Si NPs with a uniform size and shape are dispersed without agglomeration. Si NP inks satisfying these requirements had been hard to be produced by conventional processes such as plasma synthesis, − chemical vapor deposition, , laser ablation, ,,− and mechanical milling. , In previous work, ,,− we developed a process to produce suspensions of almost perfectly spherical Si NPs [Si nanospheres (Si NSs)] with very narrow size distributions. The suspension exhibited size-dependent vivid structural color due to the Mie resonance. ,, By mixing the suspension with an optically transparent binder such as polyvinylpyrrolidone, we produced the structural color inks and demonstrated coloration of a base material such as a PET film by painting …”

Physically Unclonable Holographic Encryption and Anticounterfeiting Based on the Light Propagation of Complex Medium and Fluorescent Labels

“…In theory, the secret keys of the PUF methods are almost impossible to copy. A challenge receives a response, which is called a challenge–response pair (CRP) of PUF. , CRPs are encoded and recorded in a database for verification and decryption. Searching a huge database for a CRP to verify is time-consuming and laborious.…”