The Live Mirror EIC consortium (Horizon EIC #101099220), funded by the Horizon European Innovation Council (EIC), is spearheading the development of an innovative technology for a new lightweight, hybrid meta-material, and selfcorrecting mirror. This cutting-edge mirror relies on three critical elements: (1) precise processes for shaping fire-polished sheet glass; (2) dynamic hybrid metamaterial structure (HM-MS) that incorporates 3D-printed flexible electrodes and electroactive polymer actuators, designed to support the mirror and rectify any deformations resulting from thermal variations, gravitational effects, and wind loads and (3) a metrology & calibration multi-sensing in real-time closed-loop control. These advancements in smart structures are anticipated to produce cost-effective, lightweight, integrated optoelectronic systems and will illustrate novel remote sensing capabilities from both terrestrial and space-based platforms. In this manuscript, we present a thorough update regarding the ongoing research and development initiatives related to the Live Mirror HM-MS technology.

Side-emitting optical fibers allow light to be deliberately outcoupled along the fiber. Introducing a customized side-emission profile requires modulation of the guiding and emitting properties along the fiber length, which is a particular challenge in continuous processing of soft waveguides. In this work, it is demonstrated that multimaterial extrusion printing can generate hydrogel optical fibers with tailored segments for light-side emission. The fibers are based on diacrylated Pluronic F-127 (PluDA). 1 mm diameter fibers are printed with segments of different optical properties by switching between a PluDA waveguiding ink and a PluDA scattering ink containing nanoparticles. The method allows the fabrication of fibers with segment lengths below 500 microns in a continuous process. The length of the segments is tailored by varying the switching time between inks during printing. Fibers with customized side-emission profiles along their length are presented. The functionality of the printed fibers is demonstrated by exciting fluorescence inside a surrounding 3D hydrogel. The presented technology and material combination allow unprecedented flexibility for designing soft optical fibers with customizable optical properties using simple processes and a medical material. This approach can be of interest to improve illumination inside tissues for photodynamic therapy (PDT).

Noble metal colloids in a dielectric matrix material exhibit surface plasmon resonance at visible wavelengths, which is well known to lead to intense coloration effects. The absorption peak at the resonance frequency is linked to a change of the refractive index even at wavelengths only marginally affected by the absorption. We explore the potential of using this refractive index change for creating dielectric waveguides by means of a versatile photocatalytic silver deposition process. The specific planar waveguide structure consists of a thin high refractive index layer comprising the photocatalyst and the silver colloids, topped by a cladding layer, on a low refractive index glass substrate. Using grating coupling, waveguide modes guided predominantly in the cladding could be demonstrated using red light with acceptable losses down to the 10 dB/cm range. However, the change of the effective refractive index that can be achieved with silver colloids at this low attenuation is below 10-4 , only sufficient for very weak lateral guiding. The fundamental mode centered on the high refractive index layer would be more sensitive to the amount of silver colloids, but this applies to both the effective refractive index and the attenuation. A significant reduction of the bandwidth of the surface plasmon resonance peak would be required to improve this trade-off. So far, the greater potential seems to be in the integration of areas containing silver colloids for sensors or nonlinear devices with plasmonic waveguides defined by fully metallized areas.

The application of optical technologies in treating pathologies and monitoring disease states requires the development of soft, minimal invasive and implantable devices to deliver light to tissues inside the body. Here, we present soft and degradable optical waveguides from poly(d,l-lactide) and derived copolymers fabricated by extrusion printing in the desired dimensions and shapes. The obtained optical waveguides propagate VIS to NIR light in air and in tissue at penetration depths of tens of centimeters. Besides, the printed waveguides have elastomeric properties at body temperature and show softness and flexibility in the range relevant for implantable devices in soft organs. Printed waveguides were able to guide light across 8 cm tissue and activate photocleavage chemical reactions in a photoresponsive hydrogel (in vitro). The simplicity and flexibility of the fiber processing method and the optical and mechanical performance of the obtained waveguides exemplify how rational study of medically approved biomaterials can lead to useful inks for printing cost-effective and flexible optical components for potential use in medical contexts.

Two-dimensional photonic structures such as nanostructured pillar gratings are useful for various applications including wave coupling, diffractive optics, and security features. Two-photon lithography facilitates the generation of such nanostructured surfaces with high precision and reproducibility. In this work, we report on nanopillar diffraction gratings fabricated by two-photon lithography with various laser powers close to the polymerization threshold of the photoresist. As a result, defect-free arrays of pillars with diameters down to 184 nm were fabricated. The structure sizes were analyzed by scanning electron microscopy and compared to theoretical predictions obtained from Monte Carlo simulations. The optical reflectivities of the nanopillar gratings were analyzed by optical microscopy and verified by rigorous coupled-wave simulations.

Natural functional surfaces often rely on unique nano- and micropatterns. To mimic such surfaces successfully, patterning techniques are required that enable the fabrication of three-dimensional structures at the nanoscale. It has been reported that two-photon polymerization (TPP) is a suitable method for this. However, polymer structures fabricated by TPP often tend to shrink and to collapse during the fabrication process. In particular, delicate structures suffer from their insufficient mechanical stability against capillary forces which mainly arise in the fabrication process during the evaporation of the developer and rinsing liquids. Here, we report a modified development approach, which enables an additional UV-treatment to post cross-link created structures before they are dried. We tested our approach on nanopillar arrays and microscopic pillar structures mimicking the moth-eye and the gecko adhesives, respectively. Our results indicate a significant improvement of the mechanical stability of the polymer structures, resulting in fewer defects and reduced shrinkage of the structures.

There is great technological interest in elucidating the effect of particle size on the luminescence efficiency of doped rare earth oxides. This study demonstrates unambiguously that there is a size effect and that it is not dependent on the calcination temperature. The Y2O3: Eu and Gd2O3: Eu particles used in this study were synthesized using wet chemistry to produce particles ranging in size between 7 nm and 326 nm and a commercially available phosphor. These particles were characterized using three excitation methods: UV light at 250 nm wavelength, electron beam at 10 kV, and X-rays generated at 100 kV. Regardless of the excitation source, it was found that with increasing particle diameter there is an increase in emitted light. Furthermore, dense particles emit more light than porous particles. These results can be explained by considering the larger surface area to volume ratio of the smallest particles and increased internal surface area of the pores found in the large particles. For the small particles, the additional surface area hosts adsorbates that lead to non-radiative recombination, and in the porous particles, the pore walls can quench fluorescence. This trend is valid across calcination temperatures and is evident when comparing particles from the same calcination temperature.

Es wurden neue Kompositpartikel zur Abtrennung von Schwermetallionen aus wassrigen Abwasserstromen entwickelt. Die Kompositpartikel bestehen aus superparamagnetischen Eisenoxid-Nanopartikeln in einer Borosilikatglasmatrix. Die Oberflache der Kompositpartikel ist mit Organosilanen modifiziert. Eine Siloxanfunktion erlaubt die chemische Anbindung an die Partikel, eine Komplexbildnerfunktionalitat erlaubt die reversible Bindung von Metallionen. Die Kombination der grosen freien Oberflache der superparamagnetischen Kompositpartikel (SPMK) mit einer schnellen Bindungskinetik ermoglicht Abtrennungen insbesondere bei geringen Schwermetallkonzentrationen, die mit herkommlichen Trennverfahren nur unzureichend durchfuhrbar sind. Ein moglicher Einsatz der neuen Technik lohnt sich daher vor allem dann, wenn das abzutrennende Schwermetall hochgiftig ist (z.B. Cd) und deshalb besonders niedrige Grenzwerte zu erfullen sind.

The gravure printing technique is currently under investigation as a possible method for the roll-to-roll production of OLEDs in the 6th framework EU funded project entitled ROLLED - "Roll-to-roll manufacturing technology for flexible OLED devices and arbitrary size and shape displays". The objective in the project is to fabricate an entire OLED structure by using roll-to-roll manufacturing methods and to examine, how the commercial production could be set up and integrated into an existing printing process. In order to attain a roll-to-roll compatibility, all the materials, inks and device structures need to be suitable for printing. Since, such OLED device structures are very sensitive to moisture and oxygen, high barrier materials to be applied as wet chemical coatings on transparent polymer films such as PET by common roll-to-roll coating techniques have been investigated. The barrier films on their respective substrates act as front and back side encapsulation materials, where the front side encapsulation material is to be used as a transparent and flexible substrate for OLED fabrication. The transmission rates to be achieved for both front and back side encapsulation for oxygen and water vapour are 5 mg m-2day-1 (corresponding to 7 cm3m-2day-1 for O2). In this paper, we show how light-emitting devices manufactured by gravure printing operate compared to the ones manufactured by traditional methods. Furthermore, we present recent results on the development of ITO nanoparticle coatings, cathode inks and flexible barrier materials.