Luminescent security labels are effective platforms for protection of consumer goods from counterfeiting. However, the lifetimes of such security approaches are limited due to narrow-band photoluminescent features of the label elements, which can be used for the protection technology disclosure. In this paper, a novel concept for the application of non-linear white-light luminescence from hybrid metal-semiconductor structures fabricated by direct femtosecond laser writing for the creation of physically unclonable security labels is proposed. A close connection is demonstrated between the internal composition of hybrid structures, which is controlled at the fabrication stage, and their non-linear optical signals. It is shown that the application of decorrelation procedure based on discrete cosine transform and polar codes for label coding can overcome the problem of the white-light photoluminescent spectra correlation. The proposed fabrication approach and coding strategy allows reaching a high degree of device uniqueness (up to 99%), bit uniformity (close to 0.5), and encoding capacity up to 1.25 × 10 437 in a single label element. The results demonstrate that the barriers for the application of white-light luminescent nano-objects for the creation of physically unclonable labels are removed.

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.

Here, we experimentally and theoretically demonstrate a laser-induced change in local color based on the reshaping of gold–silicon asymmetric nanostructures. The evolution of scattering properties enabled by laser reshaping shows the potential of hybrid metal–dielectric nanostructures for color printing applications. The reshaping process can tune the resonance of the nanostructure in the wavelength range between 500 and 800 nm resulting in different colors of illuminated nanostructures. Moreover, the modeling of the scattering diagram of hybrid nanoparticles before and after femtosecond laser reshaping shows that color tuning is simultaneously accompanied by substantial reconfiguration of the distribution pattern for both peaks in the scattering spectrum.

Nanomaterials with tunable optical properties have emerged as active components for advanced nanophotonic devices. Herein, the fabrication of hierarchical nanostructures through the integration of various tunable nanomaterials for diverse applications remains a challenge. Here, a two-step process consisting of the synthesis of silicon nanoparticles (Si NPs) via laser ablation followed by plasma-enhanced chemical vapor deposition of hexagonal-boron-nitride (h-BN) nanowalls has been implemented to form hierarchical Si@h-BN NPs. Experimental and numerical analyses confirm that h-BN decoration modulates the color and brightness of the hierarchical NPs (i.e., shape, intensity, and spectral width of intrinsic optical resonances). Moreover, the color palette of the resulting Si@h-BN NPs can be remotely controlled by infrared laser irradiation. We reveal that this control is related to the modification of the complex morphology of the hierarchical Si@h-BN NPs through the mutual influence of Si NP and h-BN on each other. These results open a way for utilizing hierarchical nanostructures for light manipulation at the nanometer scale for optical data storage and ink-free coloring.

Nowadays the volume of transmitted information exponentially grows and requires the development of new telecommunication systems. Dielectric nanoresonators can be considered as a basic part of such systems to control the emission of the nanoscale source. Here we numerically investigated resonant dielectric nanoresonators for emission enhancements of 2D nanomaterials. We show that the radiative Purcell factor can achieve the value of up to 21 and 12 for the magnetic quadrupole and dipole responses, respectively. Also, we compare the directivity patterns for magnetic dipole and quadrupole resonances. The results obtained in this work can be applied in the development of optical chips and interfaces.