The versatile hybrid perovskite nanocrystals are one of the most promising materials for optoelectronics in virtue of their tunable bandgaps and high photoluminescence quantum yields. However, their inherent crystalline chemical structure limits the chiroptical properties achievable with the material. The production of chiral perovskites has become an active field of research for its promising applications in optics, chemistry or biology. Typically, chiral halide perovskites are obtained by the incorporation of different chiral moieties in the material. Unfortunately, these chemically modified perovskites have demonstrated moderate values of chiral photoluminescence so far. Here we introduce a general and scalable approach to produce chiral photoluminescence from arbitrary nano-emitters assembled into 2D-chiral metasurfaces. The fabrication via nanoimprinting lithography employs elastomeric molds engraved with chiral motifs covering millimeter areas that are used to pattern two types of unmodified colloidal perovskite nanocrystal inks: green-emissive CsPbBr3 and red-emissive CsPbBr1I2. The perovskite 2D-metasurfaces exhibit remarkable photoluminescence dissymmetry factors (glum) of 0.16 that can be further improved up to glum of 0.3 by adding a high refractive index coating on the metasurfaces. This scalable approach to produce chiral photoluminescent thin films paves

Ultrathin metal films (UTMFs) are used in a wide range of applications, from transparent electrodes to infrared mirrors and metasurfaces. Due to their small thickness (<5 nm), the electrical and optical properties of UTMFs can be changed by external stimuli, for example, by applying an electric field through an ion gel. It is also known that oxidized thin films and nanostructures of Au can be reduced by irradiating with short-wavelength light. Here we show that the resistance, reflectance, and resonant optical response of Au UTMFs is changed significantly by ultraviolet light. More specifically, photoreduction and oxidation processes can be sequentially applied for continuous tuning, with observed modulation ranges for sheet resistance (Rs) and reflectance of more than 40% and 30%, respectively. The proposed method has the potential for achieving reconfigurable UTMF structures and trimming their response to specific working points, e.g., a predetermined resonance wavelength and amplitude. This is also important for large scale deployment of such surfaces as one can compensate material nonuniformity, morphological, and structural dimension errors occurring during fabrication.

The characteristic narrow spectral features of surface lattice resonances emerge as great candidates for the rational design of optical nanocavities targeting enhanced light‐matter interaction, ultrasensitive detection, or efficient light‐energy conversion. Traditional fabrication of metal arrays involves thermal evaporation and annealing steps, limiting scalability and adaptability. In contrast, template‐assisted self‐assembly provides a high‐throughput all‐around approach for implementing colloidal plasmonic metasurfaces on a variety of different materials. Here, the use of pre‐synthesized silver nanoparticles is designed and tested for the construction of versatile lasing architectures. Plasmonic arrays are prepared directly on top of the gain media (a photoresist thin film doped with Rhodamine B), creating optical nanocavities with quality factors as high as 85. The proposed architecture circumvents the need for an index‐matching superstrate to promote the generation of collective resonances, leaving the plasmonic surface accessible for post‐assembly modification. Additionally, the angular dispersion of the metasurfaces is used to modify the angle of the lasing emission, achieving both normal and off‐normal lasing upon modification of the lattice parameter of the array. The results demonstrate how state‐of‐the‐art colloidal self‐assembly techniques offer a scalable and versatile alternative for the fabrication of plasmonic and photonic devices targeting advanced and non‐linear optical phenomena.