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Item type:Publication, Access status: with files , Bioinspired curved brick-mortar architectures for enhanced mechanical performance: Insights from cuscuta reflexa stem morphologyWe investigated the epidermal morphology, microstructure, and mechanical properties of the stem of Cuscuta reflexa (dodder) to uncover the mechanisms underlying its high mechanical strength. Natural stems and experimentally fabricated bio-inspired models were examined using microscopy, numerical simulations, and mechanical testing. The results show that the stem’s distinctive curved brick-and-mortar architecture plays a critical role in enhancing mechanical performance, providing superior strength compared to conventional stem structures (e.g., those with straight interfaces). This bio-inspired curved configuration produces tensile stress–strain curves shifted to higher stress levels relative to simple (uncurved) brick-and-mortar designs, enabling the structure to withstand greater tensile loads before failure. Furthermore, flexural tests on the bio-inspired models demonstrated a 20% increase in flexural strength for the modified curved brick-and-mortar structure compared to the basic uncurved configuration. Crack propagation in the modified composite is influenced by elevated shear stress at the interfaces, promoting preferential crack growth perpendicular to the loading direction (horizontal) within the hard mortar phase. This behavior enhances fracture toughness through longer crack propagation paths and increased energy dissipation. Additionally, the larger interfacial area and higher mortar volume fraction in the modified structure contribute to more efficient load transfer and improved crack resistance.Publicationtype: Journal Article6 3 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Universal and scalable fabrication of plasmonic nanocrystals for ultrasensitive SERS(ACS, 2026-05-10); ; ; 17 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Energy-dependent chemical interface damping induced by 1-decanethiol self-assembled monolayer on Au(111)(Soc., 2026-02-11); ; ; ; The chemical interface damping (CID) effect increases the collision frequency of free electrons in metals by changes to the metal surface. We have now experimentally disentangled the two contributions to CID: induced roughness and direct charge transfer. The latter is an important area of research in photoelectrochemistry with potential applications in light-induced chemical reactions. We present a broadband investigation of the CID effect on Au(111) covered by a self-assembled monolayer of decanethiol. Spectroscopic ellipsometry measurements show a photon-energy-dependent increase of the collision frequency. We observe a constant, photon energy-independent contribution, which is attributed to induced roughness, and a contribution that linearly increases with photon energy from about 1 eV upward, which we attribute to direct charge transfer. The onset of the charge transfer mechanism corresponds to the occupied orbitals of thiols bound to the Au surface, as confirmed by density functional theory calculations.Publicationtype: Journal Article32 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Engineered self-assembly of plasmonic gold nanoparticles into two-dimensional and three-dimensional arrays within the pores of porous silicon membranes(Wiley, 2026-02-07); ; ; ; We report a facile centrifugation-based method for assembling polystyrene (PSSH)-functionalized gold nanoparticles (Au NPs) onto porous silicon (pSi) substrates in two distinct configurations: two- and three-dimensional (2D and 3D) assemblies. The 2D assemblies are densely packed monolayer coatings of the exposed Si-surfaces including the inner pore walls, whereas the 3D structures result from Au NPs clustering inside the pores. Remarkably, this shift from 2D to 3D architectures was achieved by minor modification of the PSSH coating thickness. Scanning electron microscopy (SEM) characterization confirmed the homogeneity and high packing density of these assemblies extending over several thousand square micrometers. This approach offers a straightforward and versatile route for the fabrication of well-ordered pSi–Au NP hybrid nanostructures with potential applications in catalysis, surface-enhanced spectroscopy and optical metamaterials.Publicationtype: Journal Article42 65 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Optical push broom effect by a moving refractive index front in a silicon Bragg waveguideHere we report the first experimental demonstration of signal trapping by a refractive index front in a silicon waveguide with a periodic perturbation, the so-called optical push broom effect. The refractive index front generated by a fast pump pulse captures and confines the energy of a CW signal propagating with smaller group velocity near to the band gap of a Bragg grating introduced in the waveguide. The energy of the CW signal is shifted in frequency, accelerated to the front velocity and thus accumulated inside the front. In the experiment a 2 ps free carrier front was generated via two photon absorption of the pump in the silicon waveguide. It collects approximately a 30 ps long packet of the CW signal inside it. The presented effect can be utilized to compress signals in time and space.Publicationtype: Journal Article20 12 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , On-chip temporal telescope via moving index frontsWe propose a scheme for an on-chip signal pulse compression using a temporal telescope formed by a pump-induced moving refractive index front. To the best of our knowledge, this is the first numerical demonstration of such a concept using moving index perturbations. We numerically study the signal dynamics under the influence of a moving refractive index front in optical waveguides, revealing analogies to relativistic event horizon physics. Our simulations show that a free-carrier-induced refractive index front, which lowers the refractive index and induces a blue shift in the waveguide's band diagram, can overtake and trap a signal pulse, dynamically accelerating it to the front's velocity. As the interaction continues, the signal is eventually released from the front and transitions into a new velocity regime. This process of trapping, acceleration, and release mirrors the behavior of light near gravitational horizons, with the release phase analogous to light escaping a white hole. These results pave the way for new approaches in nonlinear optics and signal processing using compact, chip-scale systems.Publicationtype: Journal Article34 12 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Pulse compression by a refractive index front in periodically modulated silicon waveguide(American Physical Society (APS), 2026-01-12); ; ; ; In this study, we report the experimental demonstration of optical pulse compression with a gradual refractive index front comoving in a periodically modulated silicon waveguide. This spatiotemporal effect, also called optical push broom, captures and confines the input signal pulse inside a faster propagating refractive index front, driven by a pump pulse. The signal is accelerated by the approaching front until its velocity matches the front's velocity, effectively stopping the light relative to the front. In contrast with the previous experiment where we used a cw signal, we now utilized a pulsed signal and thus can vary the initial delay between the signal and the pump. We employ the slowly varying envelope approximation to model the effect and successfully reproduce the experimental frequency shift at the output corresponding to the temporal delay at the input.Publicationtype: Journal Article17 12 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Printing photonic-based thermal barrier coatings onto metal alloy(Nature Publishing Group, 2025-12-01); ; ; ; Reflective coatings based on photonic crystals and photonic glasses are usually produced by traditional colloidal self-assembly techniques characterised by limited control over the deposition surface and lengthy processing times. The emergence of Additive Manufacturing combined with Colloidal Assembly (AMCA) has enabled fast and precise deposition of homogeneous photonic structures, whilst circumventing issues such as the undesired coffee-ring effect. However, the application of this technique was limited to flat substrates. This study investigates the AMCA of ceramic-based colloidal structures onto metallic curved surfaces, relevant to the field of thermal barrier coatings (TBCs). Our results demonstrate the homogeneous ceramic-based photonic glass coatings can be AMCA-printed on different substrates only when a conscious surface charge matching between the colloidal particles and the substrates is made. It also demonstrates the importance of controlling the contact angle of the suspension on the substrates and the printing geometry strategy, differing from traditional direct writing. We further demonstrate the versatility of this method by printing highly porous three-dimensional gadolinium zirconate structures onto curved Inconel substrates. These coatings are engineered for their use as reflective “photonic-based” thermal barrier coatings (rTBCs), capable of suppressing both radiative and conductive heat transport. The resultant AMCA-printed Gd2Zr2O7 rTBCs outperform state-of-the-art TBCs in terms of their reflectance properties and provide a reliable thermal protection to the underlying Inconel alloy, lowering its temperature by about 150 °C in a torch experiment.Publicationtype: Journal Article67 23 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , 2D photonic crystal emitter at 1,400°C for thermophotovoltaic energy harvesting(Elsevier, 2025-10-15); ; ; ; Spectrally selective emitters that endure extreme temperatures (exceeding 1,000°C) are vital for thermophotovoltaic energy harvesting. Here, we report a 2D photonic crystal emitter composed of yttria-stabilized zirconia particles on a tungsten mirror, fabricated through a simple and scalable self-assembly process. The emitter demonstrates spectral stability for 2 h and structural stability for 14 h at 1,400°C under high vacuum, with degradation attributed to zirconium nitridation, which is avoided under Ar or forming gas atmospheres. Long-term durability is demonstrated over 6 months and 200 thermal cycles at 1,050°C, effectively mitigating tungsten oxidation. The emitter achieves 52% spectral efficiency for a 0.72 eV photovoltaic band gap. This work offers perspectives on designing and implementing spectrally selective emitters that remain stable at high temperatures and resilient in harsh environments, representing a significant step forward in developing robust thermophotovoltaic energy-harvesting systems.Publicationtype: Journal Article21 22 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Mitigating the film-substrate decohesion in nanoporous metalsSubstrate-supported films of dealloyed nanoporous metals spontaneously develop a low-connectivity layer at the film-substrate interface, impairing interfacial adhesion strength. Comparable interfacial degradation has been reported for sintered interconnects in microelectronics. The phenomenon arises from a divergence in the diffusive, curvature-driven flux of the material, normal to the interface. This reduces the local solute fraction and eventually leads to disconnection by a Plateau-Rayleigh-type instability. Comparing dealloying and subsequent coarsening in experiments and kinetic Monte Carlo simulation, this work investigates mitigation strategies and, in particular, the effect of distinct porosity-depth profiles on the interfacial connectivity. Two design principles are suggested: First, the profile should be smooth, avoiding jumps and kinks. Second, steep porosity gradients should be placed in low-porosity regions. Exponential profiles are found preferable for avoiding degradation. In the fields of nanoporous thin films as functional materials and of interconnects in microelectronics joining, the findings provide the basis for materials design toward enhanced adhesion and lifetime.Publicationtype: Journal Article20 9