Direct observation of nanoparticle adsorption to the water-oil interface captures early attachment and jamming.

Perovskites have gained widespread attention across various fields such as photovoltaics, displays, and imaging. Despite their promising applications, achieving precise and high‐quality patterning of perovskite films remains a challenge. In this study, femtosecond laser direct writing technology is utilized to achieve rapid and highly precise micro/nanofabrication on perovskites. The study successfully fabricates multiple structured and emission‐tunable perovskite patterns composed of A₂(FA)_n−1Pb_nX_3n+1 (A represents a series of long‐chain amine cations, and X = Cl, Br, I), encompassing 2D, quasi‐2D, and 3D structures. The study delves into the intricate interplay between fabrication technology and the growth of multi‐dimensional perovskites: higher repetition rates, coupled with appropriate laser power, prove more conducive to perovskite growth. By employing precise halogen element design, the simultaneous generation of two distinct color quick‐response (QR) code patterns is achieved through one‐step laser processing. These mirrored QR codes offer a novel approach to anti‐counterfeiting. To further enhance anti‐counterfeiting capabilities, artificial intelligence (AI)‐based methods are introduced for recognizing patterned perovskite anti‐counterfeiting labels. The combination of deep learning algorithms and a non‐deterministic manufacturing process provides a convenient means of identification and creates unclonable features. This integration of materials science, laser fabrication, and AI offers innovative solutions for the future of security features.

Replica symmetry breaking (RSB) has been widely recognized as a statistical analysis approach to understand the disorder and nonlinear interactions in complex systems ranging from atoms to the cosmic scale. However, it is challenging to analyze the nonlinear optical characteristics of random laser (RL) in disordered gain medium via RSB due to the lack of a general RSB‐based statistical analysis framework. In this work, we report the tunable RSB in polymer fiber RL, where the effects of temperature and different structures on RSB are investigated experimentally and theoretically. It experimentally proves that RSB in RL is not robust, and disorder and temperature are responsible for tunable RSB in RL, which contributes to the improvement of the statistical analysis framework for investigating the optical principles of RL using RSB. And the finding of the tunable RSB allows to investigate the dynamical differences for various RL systems, which broadens the directions for the use of spin‐glass theory to explore the physical mechanism of RL.

Modulation of scattering in random lasers (RLs) by magnetic fields has attracted much attention due to its rich physical insights. We fabricate magnetic gain polymer optical fiber to generate RLs. From macroscopic experimental phenomena, with the increase of the magnetic field strength, the magnetic transverse photocurrent exists in disordered multiple scattering of RLs and the emission intensity of RLs decreases, which is the experimental observation of photonic Hall effect (PHE) and photonic magnetoresistance (PMR) in RLs. At the microscopic level, based on the field dependence theory of magnetic disorder in scattered nanoparticles and the replica symmetry breaking theory, the magnetic-induced transverse diffusion of photons reduces the scattering disorder, and then decreases the intensity fluctuation disorder of RLs. Our work establishes a connection between the above two effects and RLs, visualizes the influence of magnetic field on RL scattering at the microscopic level, which is crucial for the design of RLs.

Metal–organic frameworks (MOFs), which have well-defined nanoporous skeletons and whose natural structure can work as optical resonant cavities, are emerging as ideal platforms for constructing micro/nanolasers. However, lasing generated from the light oscillating inside a defined MOFs’ cavity usually suffers the drawback of the lasing performance being difficult to maintain once the cavity is destroyed. In this work, we report a MOF-based self-healing hydrogel fiber random laser (MOF-SHFRL) that can withstand extreme damage. The optical feedback of MOF-SHFRLs does not depend on the light reflection inside the MOF cavity but comes from the multiple scattering effects from the MOF nanoparticles (NPs). The hydrogel fiber's one-dimensional waveguide structure also permits confined directional lasing transmission. Based on such an ingenious design, a robust random lasing is achieved without worrying about the destruction of the MOF NPs. More interestingly, the MOF-SHFRL demonstrates excellent self-healing ability without any external stimulation: it can fully recover its initial morphology and lasing performance even when totally broken (e.g., cut into two parts). The lasing threshold also remains stable, and the optical transmission capability can recover by more than 90% after multiple breaks and self-healing processes. These results indicate that the MOF-SHFRL is a highly stable optical device that can be expected to play a significant role in environmental monitoring, intelligent sensing, and other aspects under extreme conditions.